JP3930748B2 - Microwave circuit and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a microwave circuit in which a semiconductor element is fixed in a microwave transmission path surrounded by a conductor. Particularly, the invention has a small number of assembly steps, is excellent in withstand voltage, and is used as a diode limiter of a device that handles a large peak power such as a pulse radar. It relates to a suitable microwave circuit.
[0002]
[Prior art]
Conventionally, a waveguide is used in a microwave circuit used in a pulse radar device having a high peak power. This is because the waveguide has an advantage that it can withstand a large electric power and has a small transmission loss. As a microwave circuit in which a semiconductor element is mounted in the waveguide, for example, there is a diode limiter. As a diode limiter using a waveguide, a structure shown in FIG. 5 in which a diode is fixed to a post protruding from the waveguide, a structure using a ridge waveguide, and the like are known.
[0003]
In the diode limiter having the structure shown in FIG. 5, the PIN diodes 60A and 60B used therein are called pill packages, and have a structure in which they are pressed into the waveguide 80 by posts 70A and 70B. However, this structure requires many assembly steps and is not suitable for mass production or cost reduction. In addition, the pill package is difficult to automate the process of packaging the diode chip, requires a large number of assembly steps, and this is also one of the causes that is not suitable for cost reduction.
[0004]
Therefore, a planar circuit such as a microstrip line can be considered as a microwave circuit suitable for mass production. However, the microstrip line has a low withstand voltage on the surface of the dielectric substrate that constitutes the circuit, and when applied to a pulse limiter diode limiter, etc., there is a high possibility that discharge will occur on the circuit surface, and it can be used from the viewpoint of reliability. Absent.
[0005]
As a microwave circuit, a fin line having the structure shown in FIG. 6 in which the waveguide 90 and the planar circuit 100 are combined can be considered. In the case where a resin such as epoxy is used as the dielectric substrate 120 of the circuit 100, the withstand voltage is small and a discharge may occur, and the reliability is low. A material using ceramic as the substrate material of the planar circuit 100 is not problematic in terms of withstand voltage, but when the substrate is fixed to the waveguide 90, damage such as cracking of the substrate is likely to occur, and it is difficult to use.
[0006]
[Problems to be solved by the invention]
As described above, a microwave circuit using a waveguide is not suitable for cost reduction, and a microwave circuit using a planar circuit suitable for mass production has a problem that it has poor withstand voltage and lacks reliability. .
[0007]
SUMMARY OF THE INVENTION An object of the present invention is to provide a microwave circuit that eliminates the above-described problems, requires a relatively small number of assembly steps, and has an excellent withstand voltage, and a method for manufacturing the same.
[0008]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a microwave circuit in which a semiconductor element is fixed in a microwave transmission path surrounded by a conductor. The semiconductor element is fixed to a conductor circuit surface of a dielectric substrate. in parallel to the advance direction of the surface formed with said conductor circuit is a microwave, and in parallel with the high-frequency electric field direction of the microwave, and a high frequency electric field of the microwaves is disposed in the vicinity of maximum, the dielectric substrate prior Symbol The microwave circuit is characterized in that a hole is formed in a portion immediately below the semiconductor element.
[0009]
The invention according to claim 2 is the method of manufacturing a microwave circuit according to claim 1, wherein the dielectric substrate having a cut-out hole is formed, and the microwave substrate extends over the cut-out hole of the dielectric substrate. Soldering the semiconductor element to the conductor circuit surface of the dielectric substrate; and the dielectric substrate to which the semiconductor element is soldered; the conductor circuit surface having a microwave traveling direction; A method of manufacturing a microwave circuit including at least a step of being parallel and parallel to the direction of the high-frequency electric field of the microwave and attaching to a position where the high-frequency electric field of the microwave is maximized.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
[ Reference example ]
1 to 3 is a explanation view of applying the microwave circuit of the reference example to the diode limiter radar device. 10 is a conductive metal plate patterned in a shape in which a hollow hole 11 is formed in the central portion and mounting holes 12 are formed in four corners, and 20A and 20B are surface mount type ceramics or glass having a high withstand voltage. Packaged PIN diodes, 30A and 30B are housings made of a conductive material constituting the waveguide, and 40 is a mounting screw.
[0014]
As shown in FIGS. 1 (a) and 1 (b), the cut-out hole 11 of the metal plate 10 is formed so as to be divided into upper and lower parts, and a pair of opposing protrusions 111 and 112 for mounting the PIN diode 20A. A pair of opposing projections 113 and 114 for mounting 20B, joint portions 115 and 116 to be cut later, cutout portions 117 formed at both ends of one joint portion 115, and formed at both ends of the other joint portion 116. A notch 118 is provided.
[0015]
As shown in FIG. 2, the housings 30 </ b> A and 30 </ b> B are respectively formed with a recess 31 for forming a waveguide space, a recess 32 for positioning the metal plate 10, and a mounting hole 33 for screwing.
[0016]
The assembly process will be described with reference to FIGS. First, the metal plate is cut out to form a patterned metal plate 10 so that a hole 11 having a pattern as shown in FIG. This cut-out can be performed at a low cost and with high pattern accuracy by using an etching method, punching by a press, or the like.
[0017]
Next, the PIN diode 20A is straddled between the protrusions 111 and 112 of the metal plate 10, and the PIN diode 20B is straddled between the protrusions 113 and 114, respectively, as shown in FIG. To do. This soldering can be performed using a conventional solder printer, a mounter for mounting components on a printed circuit board, a reflow furnace for melting and fixing solder, and the like.
[0018]
Next, the metal plate 10 to which the PIN diodes 20A and 20B are soldered is positioned in the recesses 32 of the casings 30A and 30B as shown in FIG. 2, and then sandwiched between the two housings 30A and 30B, as shown in FIG. As shown, the attachment screw 40 is attached to the attachment holes 33 of the housings 30A and 30B and the attachment holes 12 of the metal plate 10 to fix the metal plate 10 to the housings 30A and 30B.
[0019]
Next, when the cut portions 117 and 118 of the metal plate 10 are cut so that the connecting portions 115 and 116 are separated from the metal plate 10, the metal plate 10 is divided into two parts in the vertical direction and assembled in the state shown in FIG. Go up. Note that the notches 117 and 118 of the metal plate 10 are formed when the shape of the metal plate 10 is not collapsed in the process of soldering the PIN diodes 20A and 20B and the process of inserting the metal plate 10 into the housings 30A and 30B. It is set to a dimension that can be easily cut out.
[0020]
As a result, the recesses 31 of the housings 30A and 30B face each other, and a waveguide is formed there, and the PIN diodes 20A and 20B are mounted between the metal plates divided into two vertically in the waveguide, A diode limiter is formed.
[0021]
In this diode limiter, the metal plate 10 in the waveguide is installed at a position (center) where the microwave (TE ₁₀ wave) high-frequency electric field is maximized, and the high-frequency electric field is placed between the metal plates divided into two vertically. Will be applied. Accordingly, the creeping surface between the metal plates divided into the upper and lower parts is only the creeping surface of the package of the PIN diodes 20A and 20B, and it is possible to prevent problems such as discharge by using a ceramic or the like having a high withstand voltage.
[0022]
From the above, the diode limiter of the present reference example has no substrate between the PIN diode electrodes where the high-frequency electric field is concentrated and discharge is likely to occur. Therefore, there is no discharge along the substrate surface and high reliability is obtained. Further, in the assembly, when mounting the PIN diode on the metal plate, it can be surface-mounted by a conventional automatic machine like the assembly of the planar circuit, which is suitable for mass production.
[0023]
[Implementation form]
Figure 4 shows the implementation form of the microwave circuit is applied to the diode limiter of the radar apparatus of the present invention. 50 is a dielectric substrate, 51 and 52 are conductor patterns of the dielectric substrate 50, 53 is a hollow, and 54 is a mounting hole. As shown in FIG. 4A, the cutout hole 53 is provided with a pair of opposing protrusions 531 and 532 and connecting portions 532 and 533 for mounting the PIN diodes 20A and 20B. The other conductor pattern 52 extends in two branches up to the tip of the protrusion 532.
[0024]
In this embodiment, the PIN diodes 20A and 20B are soldered and mounted so as to be connected to the conductor patterns 51 and 52 across the protrusions 531 and 532. The dielectric substrate 50 on which the PIN diodes 20A and 20B are mounted is sandwiched between the casings 30A and 30B and fixed with the mounting screws 40, as in the reference example described with reference to FIGS. The conductor patterns 52 are connected to the lower portions of the housings 30A and 30B, and the diode patterns are formed as shown in FIG. 4B.
[0025]
In the dielectric substrate 50 of the present embodiment, the surfaces of the conductor patterns 51 and 52 are parallel to the traveling direction of the microwaves (TE ₁₀ waves) of the waveguide formed by the recesses 31 of the housings 30A and 30B, and a high-frequency electric field. Parallel to the direction and at a position where the high-frequency electric field is maximum, that is, the high-frequency current is minimum at the mounting portion of the housing and the dielectric substrate. Therefore, even if these attachment portions are in soft contact and there is a slight gap, microwave leakage from this portion can be minimized.
[0026]
In the present embodiment, the dielectric substrate 50 is designed to satisfy predetermined characteristics as it is without being divided into upper and lower parts. Of course, similarly to FIG. 3B, it is possible to provide notches at both ends of the connecting portions 532 and 533 of the dielectric substrate 50, and cut the notches at the final stage of assembly to divide them into two.
[0027]
In the present embodiment, the creeping surface of the dielectric substrate 50 is not between the electrodes of the PIN diodes 20A and 20B, but is the dimension L shown in FIG. 4A (the separation distance outside the conductor patterns 51 and 52). This dimension L is set to the extent that there is no hindrance. If it is divided into two, the creeping surface is only the creeping surface of the package of the PIN diodes 20A and 20B as in the first embodiment, and a diode limiter with higher reliability can be obtained.
[0028]
In the diode limiter, a large high-frequency electric field is applied to the PIN diode portion. In the conventional fin line structure shown in FIG. 6, the dielectric substrate 120 exists in the vicinity of the PIN diodes 110A and 110B. Microwave power loss in a high-frequency electric field also increases. On the other hand, in the diode limiter of FIG. 4 of the present embodiment, the dielectric substrate 50 that causes power loss is limited to the minimum of the electrode mounting portions of the PIN diodes 20A and 20B. Can also reduce the loss of microwaves.
[0029]
[Other Embodiments]
In the above embodiment, the PIN diodes 20A and 20B are mounted by soldering, but mounting using a flip chip bonder is also possible.
[0030]
【The invention's effect】
According to the microwave circuit of the present invention as described above, since it is only necessary minimum dielectric base plate around the semiconductor element such as a PIN diode is present, radar to handle the large microwave peak power As a device diode limiter or the like, a reliable product can be provided at a low cost. Also, the present invention can be applied to an oscillator in which a semiconductor element is an impatt diode. In this case, an impatt oscillator can be produced with a small number of assembly steps.
[Brief description of the drawings]
FIG. 1 is a view showing a metal plate used in a diode limiter of a reference example of the present invention, (a) is a perspective view before attaching a PIN diode, and (b) is a perspective view after attaching the PIN diode. is there.
FIG. 2 is a perspective view showing an assembling process of a diode limiter according to a reference example of the present invention.
FIGS. 3A and 3B are diagrams showing an entire diode limiter according to a reference example of the present invention, in which FIG. 3A is a perspective view in which a metal plate with a PIN diode attached is incorporated in a housing, and FIG. 3B is a part of the metal plate. It is the perspective view which cut off.
[Figure 4] is a diagram showing a diode limiter implementation form of the present invention, (a) is a perspective view of attaching the PIN diodes on the dielectric substrate, the dielectric substrate fitted with (b) is a PIN diode housing It is the perspective view integrated in.
FIG. 5 is a partially cutaway perspective view showing a conventional diode limiter using a post.
FIG. 6 is a partially cutaway perspective view showing a conventional diode limiter having a fin line structure.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10: Metal plate, 11: Hollow hole, 12: Mounting hole, 111-114: Protrusion, 115,116: Connection part, 117,118: Notch part 20A, 20B: PIN diode 30A, 30B: Housing, 31: Recessed part, 32: recess, 33: mounting hole 40: mounting screw 50: dielectric substrate, 51, 52: conductor pattern, 53: hollow hole, 531, 532: protrusion, 54: mounting hole 60A, 60B: PIN diodes 70A, 70B: Post 80: Waveguide 90: Waveguide 100: Planar circuit 110A, 110B: PIN diode 120: Dielectric substrate

Claims (2)

In a microwave circuit in which a semiconductor element is fixed in a microwave transmission path surrounded by a conductor,
The semiconductor element is fixed to a conductor circuit surface of a dielectric substrate, and a surface of the dielectric substrate on which the conductor circuit is formed is parallel to a microwave traveling direction, parallel to a microwave high-frequency electric field direction, and microscopic. installed near the high-frequency electric field of the wave is maximum, the microwave circuit, characterized in that the dielectric substrate is formed is hollowed hole just below the part before Symbol semiconductor device. A method of manufacturing a microwave circuit according to claim 1,
  Creating a dielectric substrate with cutout holes;
  Soldering the semiconductor element to the conductor circuit surface of the dielectric substrate so as to straddle the cutout hole of the dielectric substrate;
  The dielectric substrate to which the semiconductor element is soldered is placed in a conductor housing, and the surface of the conductor circuit is parallel to the microwave traveling direction and parallel to the microwave high-frequency electric field direction. Attaching to the position where the high-frequency electric field of the wave is maximum,
  A method for manufacturing a microwave circuit, comprising:

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