WO2021210080A1 - Heat dissipation structure, high frequency circuit, and antenna device - Google Patents

Abstract

The present invention comprises: a signal conductor (3a); a signal conductor (3b); a signal conductor (4a) which has an end connected to a connection point between the signal conductor (3a) and the signal conductor (3b) and which has a length of one fourth the wavelength of an operation frequency; and a signal conductor (4b) which is provided to an inner layer of a dielectric substrate (5) and which has a length of one fourth the wavelength of the operation frequency, wherein the signal conductor(4a) is connected to the connection point between the signal conductor (3a) and the signal conductor (3b), and the signal conductor (4b) is provided so as to at least partially overlap the signal conductor (4a) in a plan view and be parallel to a plane including the signal conductor (4a).

Description

Heat dissipation structure, high frequency circuit and antenna device

This disclosure relates to a heat dissipation structure, a high frequency circuit and an antenna device.

In a radar device that handles signals in the high frequency band or microwave band, a large amount of transmission power is required to propagate the transmission signal over a long distance, and a power amplifier that increases the output power is used. Generally, in a power amplifier, the power consumption inside the power amplifier increases as the output power increases, so that the amount of heat generated from the power amplifier increases. The heat generated in the power amplifier is dissipated through the board on which the power amplifier is mounted or the heat dissipation fins attached to the power amplifier. However, a part of the heat that cannot be dissipated is transferred to the high frequency circuit through the high frequency transmission line connected to the power amplifier. If the amount of heat transferred to the high-frequency circuit is large, it may not only induce malfunction of the high-frequency circuit but also shorten the life of the circuit.

For example, Patent Document 1 includes a transmission line having a length of about 1/4 of the wavelength of the operating frequency and whose tip is short-circuited with a metal having good heat dissipation, that is, a so-called tip short-circuit 1/4 wavelength stub. A heat dissipation structure is described in which the heat generated in the power amplifier is dissipated through a short-circuited 1/4 wavelength stub at the tip. Since the tip short circuit 1/4 wavelength stub can be regarded as open at the center frequency, it does not adversely affect the operation of the high frequency circuit. In order to reduce the amount of heat transferred to the high-frequency circuit, it is necessary that the thermal resistance of the 1/4 wavelength stub at the tip short circuit from the transmission line is small. In general, the thermal resistance of an object is proportional to the length of the object and inversely proportional to its cross-sectional area. Since the length of the tip short-circuit 1/4 wavelength stub is determined by the operating frequency, it is important how to increase the cross-sectional area in order to improve the heat dissipation.

Japanese Unexamined Patent Publication No. 2011-109201

When the cross-sectional area of the tip short-circuit 1/4 wavelength stub is increased, the characteristic impedance of the transmission line constituting the tip short-circuit 1/4 wavelength stub becomes low, and the frequency band that can be regarded as open in the high frequency band becomes a narrow band. This means that the frequency bandwidth that can be operated in the high frequency circuit is reduced. As described above, in the conventional heat dissipation structure, when a tip short-circuited 1/4 wavelength stub is used, there is a trade-off relationship between heat dissipation and operating bandwidth, and if one is improved, the other is deteriorated. there were.

The present disclosure solves the above problems, and an object of the present invention is to obtain a heat dissipation structure, a high frequency circuit, and an antenna device capable of improving heat dissipation without narrowing the operating bandwidth.

The heat dissipation structure according to the present disclosure has a first surface, a second surface opposite to the first surface, and a dielectric substrate provided with a ground conductor on the second surface, and a dielectric substrate. A first signal conductor provided on the first surface of the high frequency signal, one end of which is connected to the input terminal of the high frequency signal, and one provided on the first surface of the dielectric substrate and one end to the output terminal of the high frequency signal. A second signal conductor whose ends are connected and whose other end is connected to the end opposite to the input terminal in the first signal conductor, and a second signal conductor provided on the first surface of the dielectric substrate for operation. A third signal conductor having a length of one-fourth of the frequency wavelength and a fourth signal provided in the inner layer of the dielectric substrate and having a length of one-fourth of the operating frequency wavelength. A first connecting conductor that connects one end of the conductor and the fourth signal conductor to the connection point between the first signal conductor and the second signal conductor, and the other end of the fourth signal conductor. The third signal conductor is provided with a third signal conductor and a second connecting conductor that connects to the ground conductor, and the third signal conductor is connected to the connection point between the first signal conductor and the second signal conductor, and the fourth signal conductor is connected to the second signal conductor. The signal conductor is arranged parallel to the plane including the third signal conductor so that at least a part of the third signal conductor overlaps with the third signal conductor when viewed in a plane.

According to the present disclosure, a first signal conductor having one end connected to an input terminal of a high frequency signal and an input terminal of the first signal conductor having one end connected to an output terminal of a high frequency signal. A second signal conductor having the other end connected to the end opposite to the one, and a first signal conductor and a second signal conductor having a length of a quarter of the wavelength of the operating frequency. A third signal conductor whose end is connected to the connection point with, a fourth signal conductor provided in the inner layer of the dielectric substrate and having a length of one-fourth of the operating frequency wavelength, and a third signal conductor. A first connecting conductor that connects one end of the signal conductor 4 to the connection point between the first signal conductor and the second signal conductor, and a third connecting conductor that connects the other end of the fourth signal conductor. The third signal conductor is connected to the connection point between the first signal conductor and the second signal conductor, and the fourth signal conductor is When viewed in a plane, they are arranged parallel to the plane including the third signal conductor so that at least a part of the third signal conductor overlaps. The third signal conductor and the fourth signal conductor are connected in parallel, and are arranged parallel to the plane including the third signal conductor so that the third signal conductor and the fourth signal conductor overlap each other when viewed in a plane. ing. As a result, the heat dissipation structure according to the present disclosure allows the third signal conductor and the fourth signal conductor to be connected from the connection point between the first signal conductor and the second signal conductor without narrowing the operating bandwidth. The apparent thermal resistance can be reduced and the heat dissipation can be improved.

FIG. 1A is a perspective view showing a heat radiating structure according to the first embodiment, and FIG. 1B is a cross-sectional view showing a cross section of the heat radiating structure according to the first embodiment cut along the line AA'of FIG. 1A. FIG. 1C is a cross-sectional view showing a cross section of the heat radiating structure according to the first embodiment cut along the line BB'of FIG. 1A. It is a circuit diagram which shows the equivalent circuit of the heat dissipation structure which concerns on Embodiment 1. FIG. 3A is a perspective view showing a conventional heat dissipation structure, FIG. 3B is a cross-sectional view showing a cross section of the conventional heat dissipation structure cut along the line AA'of FIG. 3A, and FIG. 3C is a conventional cross section. FIG. 5 is a cross-sectional view showing a cross section of the heat radiating structure cut along the line BB'of FIG. 3A. It is a circuit diagram which shows the equivalent circuit of the conventional heat dissipation structure. It is a graph which shows the example of the calculation result of the reflection amplitude in the equivalent circuit of the conventional heat dissipation structure. It is a graph which shows the example of the calculation result of the reflection amplitude in the equivalent circuit of the heat dissipation structure which concerns on Embodiment 1. FIG. It is a graph which shows the electromagnetic field analysis result of the reflection amplitude in the heat dissipation structure and the conventional heat dissipation structure which concerns on Embodiment 1. FIG. FIG. 8A is a cross-sectional view showing a cross section and dimensions of the heat radiating structure according to the first embodiment cut along the line AA'of FIG. 1A, and FIG. 8B shows a conventional heat radiating structure taken along the line AA of FIG. 3A. It is sectional drawing which shows the cross section and the dimension cut along the A'line. FIG. 9A is a perspective view showing a modified example of the heat radiating structure according to the first embodiment, and FIG. 9B is a modified example of the heat radiating structure according to the first embodiment cut along the line AA'of FIG. 9A. 9C is a cross-sectional view showing a cross section, and FIG. 9C is a cross-sectional view showing a modified example of the heat dissipation structure according to the first embodiment cut along the line BB'of FIG. 9A. 10A is a perspective view showing the heat dissipation structure according to the second embodiment, and FIG. 10B is a cross-sectional view showing a cross section of the heat dissipation structure according to the second embodiment cut along the line AA'of FIG. 10A. 10C is a cross-sectional view showing a cross section of the heat radiating structure according to the second embodiment cut along the line BB'of FIG. 10A. 11A is a perspective view showing the heat dissipation structure according to the third embodiment, and FIG. 11B is a cross-sectional view showing a cross section of the heat dissipation structure according to the third embodiment cut along the line AA'of FIG. 11A. 11C is a cross-sectional view showing a cross section of the heat radiating structure according to the third embodiment cut along the line BB'of FIG. 11A. It is a circuit diagram which shows the equivalent circuit of the heat dissipation structure which concerns on Embodiment 3. It is a graph which shows the electromagnetic field analysis result of the reflection amplitude in the heat radiation structure which concerns on Embodiment 1 and the heat radiation structure which concerns on Embodiment 3. It is a block diagram which shows an example of the high frequency circuit which includes at least one heat dissipation structure which concerns on Embodiments 1 to 3. It is a block diagram which shows an example of the antenna device which includes at least one heat dissipation structure which concerns on Embodiments 1 to 3.

Embodiment 1.
FIG. 1A is a perspective view showing a heat dissipation structure 1 according to the first embodiment. FIG. 1B is a cross-sectional view showing a cross section of the heat dissipation structure 1 cut along the line AA'of FIG. 1A. FIG. 1C is a cross-sectional view showing a cross section of the heat dissipation structure 1 cut along the line BB'of FIG. 1A. In FIGS. 1A, 1B and 1C, the heat dissipation structure 1 is, for example, a high frequency circuit into which a high frequency signal is input / output, an input terminal 2a into which the high frequency signal is input, an output terminal 2b in which the high frequency signal is output, and a signal. It includes a conductor 3a, a signal conductor 3b, a signal conductor 4a, a signal conductor 4b, a dielectric substrate 5, a ground conductor 6, a connecting conductor 7a, and a connecting conductor 7b.

The signal conductor 3a is provided on the first surface (plane in the + z direction) of the dielectric substrate 5, one end is connected to the input terminal 2a, and the other end is connected to the end of the signal conductor 3b. It is the first signal conductor. The signal conductor 3b is provided on the first surface of the dielectric substrate 5, one end is connected to the output terminal 2b, and the other end is at the end of the signal conductor 3a opposite to the input terminal 2a. It is a connected second signal conductor. The signal conductor 4a is provided on the first surface of the dielectric substrate 5, has a length of one-fourth of the wavelength of the operating frequency, and one end is a connection point between the signal conductor 3a and the signal conductor 3b. It is a third signal conductor connected to.

As shown in FIGS. 1B and 1C, the signal conductor 4b is provided in the inner layer of the dielectric substrate 5, has a length of one-fourth of the wavelength of the operating frequency, and is at least equal to the signal conductor 4a in terms of plan. It is a fourth signal conductor arranged parallel to the plane including the signal conductor 4a so as to partially overlap. A ground conductor 6, which is a solid pattern of a conductor, is formed on a second surface (a surface in the −z direction) opposite to the first surface of the dielectric substrate 5.

The connecting conductor 7a and the connecting conductor 7b are provided in the inner layer of the dielectric substrate 5. The connecting conductor 7a is a first connecting conductor that connects one end of the signal conductor 4b to the connection point between the signal conductor 3a and the signal conductor 3b. The connecting conductor 7b is a second connecting conductor that connects the other end of the signal conductor 4b to the signal conductor 4a and the ground conductor 6.

The coupling conductor 8 is an electrically coupled signal conductor 4a and a signal conductor 4b having a length of one-fourth of the wavelength of the operating frequency. The distance between the signal conductor 4a and the signal conductor 4b in the thickness direction (z direction) is, for example, one tenth or less of the thickness of the dielectric substrate 5. The signal conductor 3a, the signal conductor 3b, the signal conductor 4a, and the signal conductor 4b function together with the ground conductor 6 as a transmission line for transmitting a high frequency signal.

When the physical size of the connecting conductor 7a and the connecting conductor 7b is sufficiently smaller than the wavelength of the operating frequency, the influence of the connecting conductor 7a and the connecting conductor 7b can be ignored in the high frequency band. The length of the connecting conductor 7a and the connecting conductor 7b is preferably one tenth or less of the wavelength of the operating frequency.

FIG. 2 is a circuit diagram showing an equivalent circuit of the heat dissipation structure 1, and is an equivalent circuit showing the electrical operation of the heat dissipation structure 1. The equivalent circuit shown in FIG. 2 is composed of an input terminal 2a into which a high-frequency signal is input, an output terminal 2b in which a high-frequency signal is output, a power supply line 9a, a power supply line 9b, a transmission line 10a, and a transmission line 10b. The transmission line 10a and the transmission line 10b have a length of one-fourth of the wavelength of the operating frequency.

One end of the power supply line 9a is connected to the input terminal 2a, and the other end is connected to the end of the power supply line 9b. One end of the power supply line 9b is connected to the output terminal 2b, and the other end is connected to the end of the power supply line 9a opposite to the input terminal 2a. The coupling line 11 is configured by electrically coupling the transmission line 10a and the transmission line 10b.

Of the ends of the transmission line 10a and the transmission line 10b, the ends on the same side are connected to each other. One of the end portions of the transmission line 10a and the transmission line 10b connected to each other is connected to the connection point between the power supply line 9a and the power supply line 9b, and the other is grounded.

The signal conductor 3a and the signal conductor 3b shown in FIG. 1 together with the ground conductor 6 function as a transmission line for transmitting a high frequency signal. In FIG. 2, the feeding line 9a corresponds to the signal conductor 3a, and the feeding line 9b corresponds to the signal conductor 3b. The transmission line 10a corresponds to the signal conductor 4a shown in FIG. 1, and the transmission line 10b corresponds to the signal conductor 4b.

Before explaining the effect of the heat dissipation structure 1, the conventional heat dissipation structure will be described.
FIG. 3A is a perspective view showing a conventional heat dissipation structure 100. FIG. 3B is a cross-sectional view showing a cross section of the heat radiating structure 100 cut along the line AA'of FIG. 3A. FIG. 3C is a cross-sectional view showing a cross section of the heat radiating structure 100 cut along the line BB'of FIG. 3A.

As shown in FIGS. 3A, 3B and 3C, the heat dissipation structure 100 includes an input terminal 101a for inputting a high-frequency signal, an output terminal 101b for outputting a high-frequency signal, a signal conductor 102a, a signal conductor 102b, and a signal conductor 103a. It includes a dielectric substrate 104, a ground conductor 105, and a connecting conductor 106.

The signal conductor 102a is provided on the first surface (plane in the + z direction) of the dielectric substrate 104, one end thereof is connected to the input terminal 101a, and the other end is connected to the end of the signal conductor 102b. NS. The signal conductor 102b is provided on the first surface of the dielectric substrate 104, one end is connected to the output terminal 101b, and the other end is the end of the signal conductor 102a opposite to the input terminal 101a. Connected to. The signal conductor 103a is provided on the first surface of the dielectric substrate 104, has a length of one-fourth of the wavelength of the operating frequency, and is connected to the connection point between the signal conductor 102a and the signal conductor 102b. ..

As shown in FIGS. 3B and 3C, the heat radiating structure 100 does not include the members corresponding to the signal conductor 4b and the connecting conductor 7a in the heat radiating structure 1. In the heat dissipation structure 100, the signal conductor 102a, the signal conductor 102b, and the signal conductor 103a, together with the ground conductor 105, function as a transmission line for transmitting a high frequency signal. One end of the signal conductor 103a is connected to the ground conductor 105 by a connecting conductor 106.

FIG. 4 is a circuit diagram showing an equivalent circuit of the conventional heat dissipation structure 100. When the size of the connecting conductor 106 shown in FIG. 3B is sufficiently small compared to the wavelength of the operating frequency, the influence of the connecting conductor 106 is small and can be ignored. Therefore, the heat dissipation structure 100 is represented by the equivalent circuit shown in FIG. The equivalent circuit shown in FIG. 4 is a circuit in which the transmission line 10b is removed from the equivalent circuit shown in FIG.

In the equivalent circuit of the heat dissipation structure 100 shown in FIG. 4, the input impedance _{Z in} seen a transmission line 108a from the connection point between the feeder line 107a and the feeder line 107b, using the characteristic impedance Zs and the electrical length θ of the transmission line 108a, It is expressed as the following equation (1).

The electrical length θ is expressed by the following equation (2). In the following equation (2), l is the physical length of the transmission line 108a and β is the phase constant.

The phase constant β is expressed by the following equation (3) using the _{effective wavelength λ eff.}

By using the above equation (1), the above equation (2), and the above equation (3), the input impedance Z _in is expressed as the following equation (4).

In the above equation (4), when l = λ _eff / 4, Z _in = ∞ and can be regarded as open. Thus, the internal impedance of the input terminal 101a side, the load impedance of the output terminal 101b side, and, if the characteristic impedance of the feeder line 107a and 107 b, were all the same impedance _{Z 0,} the frequency at which l = λ _eff / 4 Is that the high frequency signal input from the input terminal 101a is output to the output terminal 101b without being reflected. However, at frequencies other than the frequency where _{l = λ eff / 4, Z in} ≠ ∞, so that a part of the high frequency signal input from the input terminal 101a is reflected and output to the input terminal 101a.

FIG. 5 is a graph showing an example of the calculation result of the reflection amplitude in the equivalent circuit of the heat dissipation structure 100. In FIG. 5, the horizontal axis represents the frequency standardized by the frequency at which θ = π / 2 (rad), and the vertical axis represents the reflection amplitude. The calculation result of the reflection amplitude in FIG. 5 was Z ₀ = 50Ω, and the characteristic impedance Z _S of the transmission line 108a was changed to 25Ω (one-point broken line), 50Ω (solid line), and 100Ω (broken line) to calculate the reflection amplitude. The result. In the following calculation of the reflection amplitude, Z ₀ = 50Ω.

As is clear from FIG. 5, as the characteristic impedance Z _S increases, the bandwidth that becomes below a certain reflection amplitude becomes wider. If the target is a reflection amplitude of -20 dB or less, the specific bandwidth is 12% _{when Z S = 25 Ω, the specific bandwidth is 48% when Z S} = 100 Ω, and as described above, the larger the _{characteristic impedance Z S, the more.} It is wideband. This is clear from the fact that in the above equation (1), if the input impedance Z _in is to be increased regardless of the electrical length θ, the characteristic impedance Z _{S needs to be increased.} Therefore, in order to obtain a wider bandwidth, it is necessary to design the _{characteristic impedance Z S to be high.}

For example, in the heat dissipation structure 100, a ground conductor 105 is formed on the second surface of the dielectric substrate 104, and a transmission called a microstrip line formed of copper foil is used as a signal conductor on the first surface of the dielectric substrate 104. Use a railroad. In this case, as shown in Reference 1, by using the thickness h of the dielectric substrate 104, the relative permittivity ε _{r of the} dielectric substrate 104, and the width W of the signal conductor, the characteristic impedance Z _S is expressed by the following equation ( It can be calculated according to 5).

(Reference 1) J. S. Hong and M. J. Lancaster, "Microtrip Filters for RF / Microwave Applications", Second Edition, John Wiley & Sons Inc, 2011.

_{In the calculation of the characteristic impedance Z S} using the above equation (5), it is assumed that the value of the thickness of the copper foil forming the microstrip line is much smaller than the value of the thickness h of the dielectric substrate 104. ing. The above equation (5) is an example of an approximate equation, and many approximate equations have been reported for microstrip lines, and even if the characteristic impedance Z _S is calculated using an approximate equation other than the above equation (5). good.

As is clear from the above equation (5), in the microstrip line, when the thickness h of the dielectric substrate 104 and the relative permittivity ε _r of the dielectric substrate are unchanged, the characteristic impedance Zs is the line width of the signal conductor. It can be increased by narrowing W.

Next, heat dissipation from the device mounted on the substrate will be described.
Strictly speaking, as a heat dissipation path from the device mounted on the substrate, heat transfer by a copper foil or heat dissipation via a dielectric substrate or air can be considered. However, under natural convection, air has a large thermal resistance, and especially for small package parts, the heat dissipation area is small and it is difficult to dissipate heat.

Furthermore, when an inexpensive resin-based substrate is used as the dielectric substrate, the thermal resistance of the resin-based substrate is about 100 to 1000 times that of a metal such as copper, and the thermal resistance is very large. Therefore, it is considered that the heat dissipation of the heat dissipation structure 1 is mainly due to heat dissipation of the copper foil forming the signal conductor, and the thermal resistance of the signal conductor 4a will be described.

As a premise, the ground conductor 6 to which the signal conductor 4a is connected has a very small thermal resistance. _{The thermal resistance RS} of the signal conductor 4a is expressed using the following equation (6). In the following formula (6), ρ is the thermal resistance, t is the thickness of the signal conductor 4a, W is the width of the signal conductor 4a, and l is the length of the signal conductor 4a. ..

In order to reduce the thermal resistance _RS of the signal conductor 4a, it is necessary to shorten the length l of the signal conductor 4a or increase the thickness t and the width W according to the above equation (6). However, as described above, the length l of the signal conductor 4a _{needs to be l = λ eff} / 4 at the wavelength of the operating frequency, and is determined by the operating frequency.

On the other hand, when the signal conductor 4a is formed on the dielectric substrate 5 by using the copper foil, the thickness of the copper foil is basically the same as the thickness t of the signal conductor 4a. Although it is possible to increase the thickness t of the signal conductor 4a by plating or the like, the plating thickness that can be manufactured in a normal substrate manufacturing process is limited, and the substrate manufacturing cost is high. Therefore, in order to reduce the thermal resistance Rs, it is necessary to widen the width W of the signal conductor 4a.

In order to widen the operating bandwidth, it is necessary to narrow the width W of the signal conductor 4a, but in order to improve the heat dissipation, it is necessary to widen the width W of the signal conductor 4a. Therefore, in the heat dissipation structure 100, there is a trade-off relationship between the operating bandwidth and the heat dissipation, and if one is tried to be improved, the other is deteriorated.

The operation of the heat dissipation structure 1 according to the first embodiment will be described with reference to FIG.
First, the heat dissipation by the heat dissipation structure 1 is basically the same as that of the conventional heat dissipation structure 100. In the heat dissipation structure 1, since the signal conductor 4a and the signal conductor 4b are connected in parallel, the combined thermal resistance R _Se of the signal conductor 4a and the signal conductor 4b is represented by the following equation (7). R _sA is the thermal resistance of the signal conductor 4a, and R _sB is the thermal resistance of the signal conductor 4b.

Using the thickness t, width W, and length l of the signal conductor 4a and the signal conductor 4b, the thermal resistance _RS is expressed by the above equation (6). When 2R _sA = 2R _sB = _{RS , the combined thermal resistance R Se} of the signal conductor 4a and the signal conductor 4b and the thermal resistance R _S of the signal conductor 4a become equal (R _Se = R) according to the above equation (7). _S ).

The electrical operation of the heat dissipation structure 1 will be described with reference to the equivalent circuit shown in FIG. Generally, when _{two transmission lines having a characteristic impedance Z S} are electrically coupled to form a coupled line, the coupled line has two propagation modes called even mode and odd mode. At this time, the characteristic impedance and the propagation constant exist in each mode.

The characteristic impedance of even mode and Z _0e and an electrical length theta _e, the characteristic impedance Z _0o and electrical length in the odd mode and theta _o. As shown in Reference 2, in an ideal equivalent circuit, the characteristic impedance Z _0e in the even mode and the characteristic impedance Z _{0o in the} odd mode are described below using the coupling degree c representing the strength of these electrical couplings. It is expressed as the formula (8a) and the following formula (8b). The degree of coupling c is 0 <c <1.

(Reference 2) R. E. Collin, "Foundations for Microwave Engineering", Second Edition, McGRAW-HILL, Inc, 1992.

_{Focusing on the characteristic impedance Z 0e} of the even mode in the above equations (8a) and (8b), the characteristic of the even mode is that the denominator in the radical symbol approaches 0 as the coupling degree c approaches 1. Impedance Z _0e diverges. For example, in the above equation (8a), if the degree of coupling c is c ≧ _3/5 , then Z 0e ≧ 2Z _S , which is the characteristic impedance Z of the even mode that is more than twice as large as _{the characteristic impedance Z S} of the original transmission line. _0e is realized. _{The input impedance Zine} when the coupling line 11 is viewed from the node of the feeding line 9a and the feeding line 9b in the equivalent circuit shown in FIG. 2 _{sets the characteristic impedance Z 0e} of the even mode and the electrical length θ _e of the even mode in the coupling line 11. It is expressed by the following equation (9).

The electrical length θ _e in the even mode _{is expressed by the following equation (10) by using the phase constant β e in} the even mode and the physical length l of the transmission line 10a and the transmission line 10b.

The phase constant β _e in the even mode is expressed by the following equation (11) using the _{effective wavelength λ effe in the even mode.}

Similar to the conventional heat dissipation structure 100, the heat dissipation structure 1 has _Zine = ∞ by determining the physical length l so that _{θ e = π / 2 at the operating frequency.} That is, at the operating frequency, the high frequency signal input to the input terminal 2a is output from the output terminal 2b without reflection. Comparing the above equation (9) with the above equation (1) in which the electrical length θ is θ _e , the difference between the two equations is the characteristic impedance Z _S and Z 0 _e / 2.

By increasing the degree of electrical coupling c between the even-mode characteristic impedance and the odd-mode characteristic impedance in the coupling conductor 8, the even-mode characteristic impedance Z _0e is more than twice the characteristic impedance Z _{S (Z 0e).} ≧ 2Z _S ). Therefore, the heat dissipation structure 1 in which the width W between the signal conductor 4a and the signal conductor 4b and the distance between the signal conductor 4a and the signal conductor 4b in the thickness direction are designed so that 2Z _S = Z _{0e is a heat dissipation structure.} It has the same reflection characteristics as 100. At this time, by comparing _{the thermal resistance R s2} of the coupling line 11 with the thermal resistance _RS of the heat radiating structure 100 _{and designing so that R Se} < _RS , the heat radiating structure 1 has a reflection characteristic and a heat radiating structure. It is possible to improve the heat dissipation while making it the same as 100.

In the heat dissipation structure 1, it is desirable that _{the characteristic impedance Z 0e} and the characteristic impedance Z _{S in} the even mode have _{a relationship of 2Z S} = Z _0e while increasing the line width W in order to improve the heat dissipation. Therefore, in the heat dissipation structure 1, it is required to reduce the distance between the signal conductor 4a and the signal conductor 4b in the thickness direction and increase the degree of coupling c as much as possible in manufacturing.

FIG. 6 is a graph showing an example of the calculation result of the reflection amplitude in the equivalent circuit of the heat dissipation structure 1. In FIG. 6, the horizontal axis represents the frequency standardized by the frequency at which θ = π / 2 (rad), and the vertical axis represents the reflection amplitude. The calculation result of the reflection amplitude shown in FIG. 6 is Z _{0 = 50Ω, and the characteristic impedance Z Oe} of the even mode of the coupling line 11 is changed to 50Ω (dashed line), 100Ω (solid line), and 200Ω (dashed line) for reflection. This is the result of calculating the amplitude.

As is clear from FIG. 6, as the characteristic impedance Z _Oe increases, the bandwidth that becomes below a certain reflection amplitude becomes wider. If the target is a reflection amplitude of -20 dB or less, the specific bandwidth is 12% _{when Z Oe} = 50 Ω, and the specific bandwidth is 48% _{when Z Oe = 200 Ω. The larger the characteristic impedance Z Oe, the} wider the band. It has become. _{This is equivalent to the calculation result when the characteristic impedance Z S} is changed to 25Ω, 50Ω, and 100Ω in the equivalent circuit of the heat dissipation structure 100 as shown in FIG. As is clear from the calculation result of the equivalent circuit, _{by designing the characteristic impedance Z 0e} of the even mode in the heat dissipation structure 1, the electric characteristics equivalent to those of the heat dissipation structure 100 can be obtained.

FIG. 7 is a graph showing the electromagnetic field analysis results of the reflection amplitudes of the heat dissipation structure 1 and the conventional heat dissipation structure 100 according to the first embodiment, where the horizontal axis shows the frequency and the vertical axis shows the reflection amplitude. The electromagnetic field analysis result of the reflection amplitude shown in FIG. 7 is obtained with the dielectric constant of the dielectric substrate 5 or 104 being 3.7 and the lengths of the signal conductor 4a, the signal conductor 4b, and the signal conductor 103a being 18.75 mm. It was done. The relationship of the broken line with the reference numeral C is the electromagnetic field analysis result of the heat dissipation structure 1, and the relationship of the broken line with the reference numeral D is the electromagnetic field analysis result of the heat dissipation structure 100.

FIG. 8A is a cross-sectional view showing a cross section and dimensions of the heat radiating structure 1 cut along the line AA'of FIG. 1A. FIG. 8B is a cross-sectional view showing a cross section and dimensions of the heat radiating structure 100 cut along the line AA'of FIG. 3A. _{In FIGS. 8A and 8B, the thickness t c} of the signal conductor 4a, the signal conductor 4b and the signal conductor 103a is 0.036 mm, and the thickness h of the dielectric substrate 5 and the dielectric substrate 104 is 1.5 mm. be. The distance d between the signal conductor 4a and the signal conductor 4b in the thickness direction is 0.15 mm. The width W of the signal conductor 4a and the signal conductor 4b is 1.1 mm, and the width W of the signal conductor 103a is 1.5 mm.

In the heat radiating structure 1, _{in order to realize a higher even mode characteristic impedance Z 0e} while widening the width W of the signal conductor, the distance d in the thickness direction between the signal conductor 4a and the signal conductor 4b is the dielectric substrate 5. It is set to be about 1/10 of the thickness h. As shown in FIG. 7, the reflection amplitude of the heat dissipation structure 1 and the reflection amplitude of the heat dissipation structure 100 are substantially the same, and the same operating bandwidth is obtained. _{When the ratio R Se} / _RS of the thermal resistance between the heat radiation structure 1 and the heat radiation structure 100 is calculated based on the dimensions shown in FIGS. 8B and 8C, R _Se / _RS = 0.68, and the heat radiation structure 100 In comparison, the thermal resistance is reduced by about 30%.

FIG. 9A is a perspective view showing a heat radiating structure 1A which is a modification of the heat radiating structure 1 according to the first embodiment. FIG. 9B is a cross-sectional view showing a modified example of the heat dissipation structure 1A cut along the line AA'of FIG. 9A. FIG. 9C is a cross-sectional view showing a modified example of the heat dissipation structure 1A cut along the line BB'of FIG. 9A. The heat radiating structure 1A includes a heat transfer member 12 and a metal body 13 in addition to the structure of the heat radiating structure 1. A metal body 13 is connected to the ground conductor 6 in the heat radiating structure 1A via a heat transfer member 12. By having these members, the heat radiating structure 1A improves the heat radiating property from the ground conductor 6. A heat conductive grease, a heat conductive sheet, or a conductive adhesive is used for the heat transfer member 12. The metal body 13 may be provided with heat radiating fins in order to further improve the heat radiating property.

In the explanation so far, the case where the signal conductor 4a and the signal conductor 4b have the same line width has been shown, but the line widths of both may be different. Further, the case where the signal conductor 4b is arranged so as to overlap the signal conductor 4a when viewed in a plane is shown. For example, the signal conductor 4a and the signal conductor 4b are perpendicular to the length direction and the plane of the dielectric substrate 5. It may be arranged offset in the direction. In order to further improve the heat dissipation of the heat dissipation structure 1, it is necessary to increase the coupling degree c, and the offset amount is assumed to be the line width W or less, and the signal conductor 4a and the signal conductor 4b are viewed in a plane. It is desirable that at least a part of them overlap each other.

Further, in the description so far, the heat dissipation structure 1 or 1A which is a so-called microstrip line structure in which the ground conductor 6 is arranged on the second surface of the dielectric substrate 5 and the signal conductor is formed on the first surface is provided. Indicated. However, the heat dissipation structure 1 or 1A may be a strip line structure in which ground conductors are provided on both sides of the dielectric substrate 5 and signal conductors are provided in the inner layer of the dielectric substrate 5.

As described above, in the heat dissipation structure 1 according to the first embodiment, one end is connected to the signal conductor 3a to which one end is connected to the input terminal 2a of the high frequency signal, and one end is connected to the output terminal 2b of the high frequency signal. , A signal conductor 3b in which the other end is connected to an end opposite to the input terminal 2a in the signal conductor 3a, and a signal conductor 3a and a signal having a length of one-fourth of the wavelength of the operating frequency. A signal conductor 4a whose end is connected to a connection point of the conductor 3b, a signal conductor 4b provided in the inner layer of the dielectric substrate 5 and having a length of a quarter of the operating frequency wavelength, and a signal conductor 4b. It includes a connecting conductor 7a that connects one end to a connection point between the signal conductor 3a and the signal conductor 3b, and a connecting conductor 7b that connects the other end of the signal conductor 4a to the signal conductor 4b and the ground conductor 6. .. The signal conductor 4a is connected to the connection point between the signal conductor 3a and the signal conductor 3b, and the signal conductor 4b is parallel to the plane including the signal conductor 4a so that at least a part of the signal conductor 4a overlaps the signal conductor 4a when viewed in a plane. Is located in. The signal conductor 4a and the signal conductor 4b are connected in parallel, and are arranged in parallel with the plane including the signal conductor 4a so that the signal conductor 4a and the signal conductor 4b overlap each other when viewed in a plane. As a result, the heat dissipation structure 1 reduces the thermal resistance of the signal conductor 4a and the signal conductor 4b from the connection point between the signal conductor 3a and the signal conductor 3b without narrowing the operating bandwidth equivalent to that of the heat dissipation structure 100. It can improve heat dissipation.

Embodiment 2.
10A is a perspective view showing the heat dissipation structure 1B according to the second embodiment. FIG. 10B is a cross-sectional view showing a cross section of the heat radiating structure 1B cut along the line AA'of FIG. 10A. FIG. 10C is a cross-sectional view showing a cross section of the heat radiating structure 1B cut along the line BB'of FIG. 10A. In FIGS. 10A, 10B and 10C, the heat dissipation structure 1B is, for example, a high frequency circuit into which a high frequency signal is input / output, and is an input terminal 2a, an output terminal 2b, a signal conductor 3a, a signal conductor 3b, a signal conductor 4a, and a signal. It includes a conductor 4b, a dielectric substrate 5, a ground conductor 6, a connecting conductor 7b, a connecting conductor 7c, and an electrode 14.

The electrode 14 is an electrode provided on the second surface (plane in the −z direction) of the dielectric substrate 5 and formed by removing a part of the ground conductor 6. The signal conductor 3a is provided on the first surface (plane in the + z direction) of the dielectric substrate 5, one end is connected to the input terminal 2a, and the other end is connected to the end of the signal conductor 3b. It is the first signal conductor. The signal conductor 3b is provided on the first surface of the dielectric substrate 5, one end is connected to the output terminal 2b, and the other end is at the end of the signal conductor 3a opposite to the input terminal 2a. It is a connected second signal conductor.

The signal conductor 4a is provided on the first surface of the dielectric substrate 5, has a length of one-fourth of the wavelength of the operating frequency, and one end is a connection point between the signal conductor 3a and the signal conductor 3b. It is a third signal conductor connected to. As shown in FIGS. 10B and 10C, the signal conductor 4b is provided in the inner layer of the dielectric substrate 5, has a length of one-fourth of the wavelength of the operating frequency, and is at least equal to the signal conductor 4a in terms of plan. It is a fourth signal conductor arranged parallel to the plane including the signal conductor 4a so as to partially overlap. A ground conductor 6, which is a solid pattern of a conductor, is formed on a second surface of the dielectric substrate 5 opposite to the first surface.

The connecting conductor 7b is a second connecting conductor provided in the inner layer of the dielectric substrate 5 and connecting the other end of the signal conductor 4b to the signal conductor 4a and the ground conductor 6. The connecting conductor 7c is provided in the inner layer of the dielectric substrate 5, and the connecting conductor 7c connects one end of the signal conductor 4a to the connection point between the signal conductor 3a and the signal conductor 3b, the signal conductor 4b and the electrode 14. It is the first connecting conductor to be used. The coupling conductor 8 is an electrically coupled signal conductor 4a and a signal conductor 4b having a length of one-fourth of the wavelength of the operating frequency.

Similar to the heat dissipation structure 1 according to the first embodiment, the heat dissipation structure 1B dissipates heat generated in the power amplifier connected to the input terminal 2a to the ground conductor 6 via the coupling conductor 8. Further, as shown in FIG. 1B, the heat dissipation structure 1 includes a connecting conductor 7a connecting the inner layer provided with the signal conductor 4b from the first surface of the dielectric substrate 5 provided with the signal conductor 4a, and a dielectric material. It has two types of connecting conductors with a connecting conductor 7b arranged so as to penetrate the substrate 5.

Since the heat radiating structure 1 has not only a connecting conductor penetrating the dielectric substrate 5 but also a connecting conductor that stops at the inner layer of the dielectric substrate 5, it is necessary to separately perform viahole processing in order to provide these connecting conductors. Yes, the man-hours will increase. On the other hand, as the connecting conductors 7b and 7c included in the heat radiating structure 1B, only the connecting conductors penetrating the dielectric substrate 5 are used, and these connecting conductors can be obtained by one via hole processing. As a result, the heat dissipation structure 1B can reduce the manufacturing man-hours.

As described above, the heat radiating structure 1B according to the second embodiment includes an electrode 14 provided on the second surface of the dielectric substrate 5 and formed by removing a part of the ground conductor 6. The connecting conductor 7c connects one end of the signal conductor 4b to the connection point between the signal conductor 3a and the signal conductor 3b and the electrode 14. The size of the connecting conductor 7c and the electrode 14 is sufficiently small compared to the wavelength of the operating frequency, and the influence from the connecting conductor 7c and the electrode 14 can be ignored. Therefore, the heat dissipation structure 1B can be manufactured by a simple manufacturing method while having the same operating bandwidth and heat dissipation performance as the heat dissipation structure 1. As a result, the manufacturing cost is also reduced.

Embodiment 3.
FIG. 11A is a perspective view showing the heat dissipation structure 1C according to the third embodiment. FIG. 11B is a cross-sectional view showing a cross section of the heat radiating structure 1C cut along the line AA'of FIG. 11A. FIG. 11C is a cross-sectional view showing a cross section of the heat radiating structure 1C cut along the line BB'of FIG. 11A. In FIGS. 11A, 11B and 11C, the heat dissipation structure 1C is, for example, a high frequency circuit into which a high frequency signal is input / output, and is an input terminal 2a, an output terminal 2b, a signal conductor 3a, a signal conductor 3b, a signal conductor 4c, and a signal. A conductor 4d, a dielectric substrate 5, a ground conductor 6, a connecting conductor 7a, a connecting conductor 7b, a connecting conductor 7d, an electrode 14a, an electrode 14b, and a chip capacitor 15 are provided.

The signal conductor 3a is provided on the first surface (plane in the + z direction) of the dielectric substrate 5, one end is connected to the input terminal 2a, and the other end is connected to the end of the signal conductor 3b. It is the first signal conductor. The signal conductor 3b is provided on the first surface of the dielectric substrate 5, one end is connected to the output terminal 2b, and the other end is at the end of the signal conductor 3a opposite to the input terminal 2a. It is a connected second signal conductor.

The signal conductor 4c is provided on the first surface of the dielectric substrate 5, has a length of one-fourth of the wavelength of the operating frequency, and one end is a connection point between the signal conductor 3a and the signal conductor 3b. It is a third signal conductor connected to. As shown in FIGS. 11B and 11C, the signal conductor 4d is provided in the inner layer of the dielectric substrate 5, has a length of one-fourth of the wavelength of the operating frequency, and is at least equal to the signal conductor 4c in terms of plan. It is a fourth signal conductor arranged parallel to the plane including the signal conductor 4c so that a part of the signal conductor overlaps. A ground conductor 6, which is a solid pattern of a conductor, is formed on a second surface (a surface in the −z direction) opposite to the first surface of the dielectric substrate 5.

The electrode 14a is a first electrode provided on the first surface of the dielectric substrate 5 and connected to a connection point between the signal conductor 3a and the signal conductor 3b. The electrode 14b is a second electrode provided on the first surface of the dielectric substrate 5 and connected to the ground conductor 6 by the connecting conductor 7d. The chip capacitor 15 is a capacitor that connects the electrode 14a and the electrode 14b.

The connecting conductor 7a is a first connecting conductor that connects one end of the signal conductor 4c to the connection point between the signal conductor 3a and the signal conductor 3b and the signal conductor 4d. The connecting conductor 7b is a second connecting conductor that connects the other end of the signal conductor 4c to the signal conductor 4c and the ground conductor 6. The connecting conductor 7d is a third connecting conductor provided in the inner layer of the dielectric substrate 5 and connecting the electrode 14b to the ground conductor 6.

The coupling conductor 16 is an electrically coupled signal conductor 4c and a signal conductor 4d having a length of one-fourth of the wavelength of the operating frequency. The distance d in the thickness direction (z direction) between the signal conductor 4c and the signal conductor 4d is, for example, one tenth or less of the thickness of the dielectric substrate 5. The signal conductor 3a, the signal conductor 3b, the signal conductor 4c, and the signal conductor 4d function together with the ground conductor 6 as a transmission line for transmitting a high frequency signal.

In the heat dissipation structure 1, the physical length l was determined so that the _{input impedance Z in} = ∞ at the operating frequency so as not to affect the high frequency characteristics. Therefore, the lengths of the signal conductor 4a and the signal conductor 4b are limited by the operating frequency. As shown in the above equation (6), the thermal resistance of the signal conductor 4a and the signal conductor 4b is proportional to the length l of the signal conductor. The thermal resistance of the signal conductor can be reduced by shortening the length l of the signal conductor.

However, in order to reduce the thermal resistance, it is necessary to design parameters other than the lengths of the signal conductor 4a and the signal conductor 4b in the heat dissipation structure 1. On the other hand, in the heat dissipation structure 1C, the chip capacitor 15 is connected in parallel with the coupling conductor 16, and the length of the coupling conductor 16 can be set to 1/4 or less of the wavelength of the operating frequency by the chip capacitor 15. , It is possible to reduce the thermal resistance.

FIG. 12 is a circuit diagram showing an equivalent circuit of the heat dissipation structure 1C according to the third embodiment, and is an equivalent circuit showing the electrical operation of the heat dissipation structure 1C. The equivalent circuit shown in FIG. 12 is composed of an input terminal 2a into which a high-frequency signal is input, an output terminal 2b in which a high-frequency signal is output, a power supply line 9a, a power supply line 9b, a transmission line 10c, and a transmission line 10d. The transmission line 10c and the transmission line 10d have a length of one-fourth of the wavelength of the operating frequency.

One end of the power supply line 9a is connected to the input terminal 2a, and the other end is connected to the end of the power supply line 9b. One end of the power supply line 9b is connected to the output terminal 2b, and the other end is connected to the end of the power supply line 9a opposite to the input terminal 2a. The capacitor of the chip capacitor 15 shown in FIG. 11 is the capacitor shown in FIG. Hereinafter, it will be referred to as a capacitor 15. One end of the capacitor 15 is connected to the connection point between the feeding line 9a and the feeding line 9b, and the other end is grounded.

The coupling conductor 16 is configured by electrically coupling a transmission line 10c having a length of one-fourth of the wavelength of the operating frequency and a transmission line 10d, and functions as a tip short-circuit 1/4 wavelength stub. Of the ends of the transmission line 10c and the transmission line 10d, the ends on the same side are connected to each other. One of the end portions of the transmission line 10c and the transmission line 10d connected to each other is connected to the connection point between the power supply line 9a and the power supply line 9b, and the other is grounded.

The signal conductor 3a and the signal conductor 3b shown in FIG. 11 together with the ground conductor 6 function as a transmission line for transmitting a high frequency signal. In FIG. 12, the feeding line 9a corresponds to the signal conductor 3a, and the feeding line 9b corresponds to the signal conductor 3b. The transmission line 10c corresponds to the signal conductor 4c shown in FIG. 11, and the transmission line 10d corresponds to the signal conductor 4d.

As shown in FIG. 12, the capacitor 15 is loaded in parallel with the tip short-circuited 1/4 wavelength stub which is the coupling conductor 16. The tip short circuit 1/4 wavelength stub operates as an LC parallel resonant circuit near the operating frequency. By loading the capacitor 15 in parallel with the tip short-circuit 1/4 wavelength stub, the resonance frequency is shifted to the low frequency side. As a result, the heat dissipation structure 1C can make the lengths of the signal conductors 4a and the signal conductors 4b shorter than the length of one-fourth of the wavelength of the operating frequency even when they are operated at the same frequency. Further reduction of thermal resistance becomes possible.

FIG. 13 is a graph showing the electromagnetic field analysis results of the reflection amplitude in the heat dissipation structure 1 according to the first embodiment and the heat dissipation structure 1C according to the third embodiment, and is a reflection of the equivalent circuit of the heat dissipation structure 1 shown in FIG. The amplitude calculation result E and the reflection amplitude calculation result F of the equivalent circuit of the heat dissipation structure 1C shown in FIG. 12 are shown. In FIG. 13, the horizontal axis represents the frequency standardized by the frequency at which θ = π / 2 (rad), and the vertical axis represents the reflection amplitude. In the calculation results of the reflection amplitudes shown in FIG. 13, both of the heat dissipating structure 1 and the heat radiating structure 1C, the characteristic impedance _{Z Oe} even mode and 100 [Omega, capacitor 15 has a C = 3.2 pF.

As is clear from FIG. 13, the calculation result F of the equivalent circuit of the heat dissipation structure 1C shown in FIG. 12 and the calculation result E of the reflection amplitude of the equivalent circuit of the heat dissipation structure 100 shown in FIG. 4 are both standards. The conversion frequency is around 1.0, and the reflection amplitude is minimized. At this time, in the equivalent circuit of the heat dissipation structure 1 shown in FIG. 2, when the normalized frequency is 1.0, θ _e = π / 2 rad. On the other hand, in the equivalent circuit shown in FIG. 12, θ _e = π / 4rad. Is. The electrical length θe and the length l of the signal conductor are in a proportional relationship as shown in the above equation (10), and if θ _e is halved, the length l is also halved. Therefore, in the heat dissipation structure 1C, the combined thermal resistance of the signal conductor 4c and the signal conductor 4d is half of the combined thermal resistance in the heat dissipation structure 1 shown in FIG. 1, and the heat dissipation property is further improved. The heat dissipation structure 1C according to the third embodiment shows actual numerical values such as capacitance and electrical length as an example when describing the operation as a high frequency circuit, but this is an example.

As described above, the heat dissipation structure 1C according to the third embodiment is provided on the first surface of the dielectric substrate 5, and has an electrode 14a connected to a connection point between the signal conductor 3a and the signal conductor 3b, and a dielectric material. An electrode 14b provided on the first surface of the substrate 5, a chip capacitor 15 provided on the first surface of the dielectric substrate 5 and connecting between the electrode 14a and the electrode 14b, and an inner layer of the dielectric substrate 5. A connecting conductor 7d for connecting the 14b electrode to the ground conductor 6 is provided. In the heat radiating structure 1C, the combined thermal resistance of the signal conductor 4c and the signal conductor 4d is half the combined thermal resistance of the heat radiating structure 1 shown in FIG. 1, so that the heat radiating property is further improved.

The heat dissipation structures 1, 1A to 1C shown in the first to third embodiments can be used in a high frequency circuit.
FIG. 14 is a block diagram showing an example of a high frequency circuit 19 including at least one of the heat dissipation structures 1, 1A to 1C according to the first to third embodiments. The high-frequency circuit 19 includes an input terminal 17a for inputting at least one or more high-frequency signals, an output terminal 17b for outputting a high-frequency signal, at least one of heat dissipation structures 1, 1A to 1C, and first. And a second high frequency device 18a, 18b. The first high frequency device 18a includes at least one or more power amplifiers.

The output terminals of the first high-frequency device 18a are connected to the input terminals 2a of the heat-dissipating structures 1, 1A to 1C, and the input terminals of the second high-frequency device 18b are connected to the output terminals 2b of the heat-dissipating structures 1, 1A to 1C. Is connected. The input terminal of the first high frequency device 18a and the output terminal of the second high frequency device 18b are the input terminal 17a and the output terminal 17b in the high frequency circuit 19, respectively. The high frequency circuit 19 has a function of converting a high frequency signal input to the input terminal 17a and outputting it from the output terminal 17b. The "conversion" is a function of amplifying or attenuating the amplitude of a high-frequency signal, adjusting the phase, or converting the frequency.

The first high-frequency device 18a generates heat with the conversion of the high-frequency signal, and this heat is transferred from the output terminal of the first high-frequency device 18a to the heat dissipation structures 1, 1A to 1C via the input terminal 2a and is dissipated. .. In this heat dissipation, if the operating bandwidths of the first and second high- frequency devices 18a and 18b are narrower than the operating bandwidths of the heat-dissipating structures 1, 1A to 1C, the operating bandwidth of the high-frequency circuit 19 is increased. The heat from the first high frequency device 18a can be efficiently dissipated without narrowing the band. As a result, it is possible to suppress the heat generated by the first high-frequency device 18a from being transferred to the second high-frequency device 18b. Therefore, fluctuations in electrical characteristics and circuit malfunctions due to temperature changes in the second high-frequency device 18b are prevented.

Further, the heat dissipation structures 1, 1A to 1C shown in the first to third embodiments can be used for the antenna device. FIG. 15 is a block diagram showing an example of the antenna device 20 including at least one of the heat dissipation structures 1, 1, 1A to 1C according to the first to third embodiments. The antenna device 20 includes an input terminal 17a for inputting a high frequency signal, at least one of heat dissipation structures 1, 1A to 1C, and a first high frequency device 18a. The first high frequency device 18a includes at least one or more power amplifiers.

The output terminal of the first high frequency device 18a is connected to the input terminals 2a of the heat dissipation structures 1, 1A to 1C, and the antenna 21 is connected to the output terminals 2b of the heat dissipation structures 1, 1A to 1C. The input terminal of the first high frequency device 18a is the input terminal 17a of the antenna device 20. The antenna device 20 has a function of converting a high frequency signal input to the input terminal 17a and radiating it from the antenna 21. The "conversion" is a function of amplifying or attenuating the amplitude of a high-frequency signal, adjusting the phase, or converting the frequency.

The first high-frequency device 18a generates heat with the conversion of the high-frequency signal, and this heat is transferred from the output terminal of the first high-frequency device 18a to the heat dissipation structures 1, 1A to 1C via the input terminal 2a and is dissipated. .. In this heat dissipation, if the operating bandwidths of the first high-frequency device 18a and the antenna 21 are narrower than the operating bandwidths of the heat dissipation structures 1, 1A to 1C, the operating bandwidth of the antenna device 20 is narrowed. The heat from the first high-frequency device 18a can be efficiently dissipated without being converted. As a result, it is possible to suppress the heat generated by the first high-frequency device 18a from being transferred to the antenna 21. Therefore, distortion due to the temperature change of the antenna 21 or fluctuation of the electrical characteristics due to the distortion of the antenna 21 is prevented.

It should be noted that the combination of each embodiment, the modification of each arbitrary component of the embodiment, or the omission of any component in each of the embodiments is possible.

The heat dissipation structure according to the present disclosure can be used, for example, in a high frequency circuit included in a radar device.

1,1A to 1C heat dissipation structure, 2a input terminal, 2b output terminal, 3a, 3b, 4a to 4d signal conductor, 5 dielectric substrate, 6 ground conductor, 7a to 7d connection conductor, 8 coupling conductor, 9a, 9b power supply line 10a-10d transmission line, 11 coupling line, 12 heat transfer member, 13 metal body, 14, 14a, 14b electrode, 15 chip capacitor, 16 coupling conductor, 100 heat dissipation structure, 101a input terminal, 101b output terminal, 102a, 102b , 103a signal conductor, 104 dielectric substrate, 105 ground conductor, 106 connection conductor, 107a, 107b power supply line, 108a transmission line, 17a input terminal, 17b output terminal, 18a first high frequency device, 18b second high frequency device, 19 high frequency circuit, 20 antenna device, 21 antenna.

Claims (8)

1. A dielectric substrate having a first surface and a second surface opposite to the first surface and provided with a ground conductor on the second surface.
   A first signal conductor provided on the first surface of the dielectric substrate and having one end connected to an input terminal for a high frequency signal.
   One end is connected to the output terminal of a high frequency signal provided on the first surface of the dielectric substrate, and the other end is connected to the end of the first signal conductor opposite to the input terminal. With the second signal conductor to which
   A third signal conductor provided on the first surface of the dielectric substrate and having a length of one-fourth of the wavelength of the operating frequency,
   A fourth signal conductor provided on the inner layer of the dielectric substrate and having a length of one-fourth of the wavelength of the operating frequency,
   A first connecting conductor that connects one end of the fourth signal conductor to a connecting point between the first signal conductor and the second signal conductor.
   The other end of the fourth signal conductor includes the third signal conductor and a second connecting conductor that connects to the ground conductor.
   The third signal conductor is connected to a connection point between the first signal conductor and the second signal conductor.
   The fourth signal conductor is arranged in parallel with the plane including the third signal conductor so that at least a part of the third signal conductor overlaps the third signal conductor when viewed in a plane. structure.
2. With a metal body
   A heat transfer member that connects the ground conductor to the metal body,
   The heat radiating structure according to claim 1, wherein the heat radiating structure is provided.
3. An electrode provided on the second surface of the dielectric substrate and formed by removing a part of the ground conductor is provided.
   The first connecting conductor is characterized in that one end of the fourth signal conductor is connected to a connection point between the first signal conductor and the second signal conductor and the electrode. Item 1. The heat dissipation structure according to item 1.
4. A first electrode provided on the first surface of the dielectric substrate and connected to a connection point between the first signal conductor and the second signal conductor.
   A second electrode provided on the first surface of the dielectric substrate and
   A capacitor provided on the first surface of the dielectric substrate and connecting between the first electrode and the second electrode.
   A third connecting conductor provided in the inner layer of the dielectric substrate and connecting the second electrode to the ground conductor,
   The heat radiating structure according to claim 1, wherein the heat radiating structure is provided.
5. The heat dissipation structure according to claim 1, wherein the distance between the third signal conductor and the fourth signal conductor is 1/10 or less of the thickness of the dielectric substrate.
6. The heat dissipation structure according to claim 1, wherein the third signal conductor and the fourth signal conductor have the same line width.
7. The heat dissipation structure according to any one of claims 1 to 6,
   With one or more power amplifiers connected to the input terminals,
   A high-frequency circuit characterized by being equipped with.
8. The heat dissipation structure according to any one of claims 1 to 6,
   A high frequency circuit containing one or more power amplifiers connected to the input terminal, and
   With the antenna connected to the output terminal,
   An antenna device characterized by being equipped with.

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