JP2017220790A - Antenna substrate and antenna device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna substrate and the like that have good isolation characteristics between transmission and reception and is effective in miniaturization.SOLUTION: An antenna substrate 10 or the like includes: a first dielectric layer 1; a second dielectric layer 2 arranged on the first dielectric layer 1; a grounding conductor layer 3 provided on a top surface or inside of the first dielectric layer 1; a pair of planar conductors 4a, 4b arranged spaced apart from each other on a top surface or inside of the second dielectric layer 2 situated on the grounding conductor layer 3; via conductors 5a, 5b connected with the pair of respective planar conductors; and a pair of conductor walls 6a, 6b provided having the pair of planar conductors 4a, 4b in between on the second dielectric layer 2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an antenna substrate and an antenna device including a dielectric substrate provided with a planar conductor.

  For example, a portable electronic device such as a mobile phone has an antenna device for communication with other electronic devices. The antenna device includes an antenna substrate having a radiating conductor layer, and a feeding portion electrically connected to the radiating conductor layer. The antenna substrate includes a dielectric layer made of, for example, a ceramic sintered body. The radiation conductor layer is formed on the surface of the dielectric layer, for example, and is electrically connected to the electronic component.

  Further, in such an antenna substrate, by providing a dielectric layer on the upper surface of the substrate having the ground conductor layer and providing a radiation conductor layer on the upper surface of the dielectric layer, the strength of the radio wave radiated in the plane direction can be reduced. Technology to enhance has been proposed. (For example, refer to Patent Document 1).

International Publication No.2012 / 165336 JP 2005-94440

  In an antenna substrate and an antenna device including the antenna substrate, it is required to increase isolation between a transmission radiation conductor layer and a reception radiation conductor layer. In order to cope with this, for example, a ground conductor may be arranged between the transmission radiation conductor layer and the reception radiation conductor layer (see, for example, Patent Document 2). However, in this case, since a space for arranging the ground conductor is required between the radiating conductor layer for transmission and the radiating conductor layer for reception, the antenna substrate has recently been demanded for further miniaturization. It is difficult to respond.

  An antenna substrate according to one aspect of the present invention includes a first dielectric layer having a first side surface, and third and fourth side surfaces that are parallel to each other, and the third side surface is connected to the first side surface. And a second dielectric layer disposed on the first dielectric layer such that a lower end of the fourth side surface is located within the upper surface of the first dielectric layer, and an upper surface of the first dielectric layer or A pair of ground conductor layers provided inside and a top surface or the inside of the second dielectric layer located on the ground conductor layer and spaced apart from each other along a first direction parallel to the third side surface The planar conductor, the via conductor connected to each of the pair of planar conductors in a direction away from the respective central portions in plan view along the first direction, and the second dielectric layer, Provided with the pair of radiation conductors in between in the first direction And a pair of conductive wall that.

  An antenna device according to one aspect of the present invention includes the antenna substrate having the above-described configuration and a power feeding unit electrically connected to the via conductor.

According to the antenna substrate of one aspect of the present invention, because of the above configuration,
The electric field radiated in the planar direction from one of the pair of planar conductors is attracted in the direction of the adjacent conductor wall and is effectively radiated to the outside from the adjacent third side surface. The conductor wall is in the direction opposite to the other of the pair of planar conductors, and the distance between the pair of planar conductors can be kept small. The third side surface is located in the horizontal direction. Accordingly, it is possible to provide an antenna substrate that is effective for downsizing and that can effectively radiate an electric field in the horizontal direction, and that can easily manufacture an antenna device with improved isolation characteristics. .

  According to the antenna device of one aspect of the present invention, since the antenna substrate having the above-described configuration is included, it is effective for downsizing and effective electric field radiation in the horizontal direction is possible. An antenna device with improved characteristics can be provided.

(A) is a top view which shows the antenna board | substrate and antenna apparatus of embodiment of this invention, (b) is sectional drawing in the AA of (a), (c) is B- of (a). It is sectional drawing in a B line. It is a perspective view which shows the antenna board | substrate and antenna apparatus of embodiment of this invention. (A) And (b) is a perspective view which expands and shows the principal part in the modification of the antenna board | substrate and antenna device which are shown in FIG. 2, respectively. It is a perspective view which expands and shows the principal part in the other modification of the antenna board | substrate shown in FIG. 2, and an antenna apparatus. (A) has shown the isolation characteristic in the antenna apparatus of embodiment, (b) has shown the isolation characteristic in the antenna apparatus of a comparative example. It is a top view which shows the modification of Fig.1 (a).

  An antenna substrate and an antenna device according to embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the distinction between the upper and lower sides in the following description is for the convenience of explanation, and does not limit the upper and lower sides when the antenna substrate and the antenna device are actually used. In addition, even in the attached drawings that are not cross-sectional views, hatching may be applied for easy identification.

  The antenna substrate and the antenna device described below are used by being mounted on a plate-like (thin rectangular parallelepiped) portable electronic device such as a mobile phone (including a smartphone) or a tablet PC (tablet personal computer). An antenna device including an antenna substrate transmits and receives an electric field necessary for transmitting and receiving signals between portable electronic devices or between a portable electronic device and another electronic device.

  FIG. 1A is a plan view showing an antenna substrate 10 and an antenna device 20 according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along the line AA in FIG. (C) is sectional drawing in the BB line of Fig.1 (a). FIG. 2 is a perspective view showing the antenna substrate 10 and the antenna device 20 according to the embodiment of the present invention. In FIG. 1A, the electronic components are omitted for easy understanding, and the positions thereof are indicated by broken lines. In FIG. 2, a part of the portion located inside the dielectric layer is seen through and shown by a broken line.

  The antenna substrate 10 and the antenna device 20 of the embodiment will be described with respect to transmission / reception of an electric field particularly in the lateral direction (one direction orthogonal to the thickness of the portable electronic device) C. The horizontal direction C is an electric field transmission and reception direction, and includes two directions opposite to each other. An arrow pointing away from the antenna substrate 10 indicates a transmission direction, and an arrow toward the antenna substrate 10 indicates a reception direction.

  The antenna substrate 10 of the present embodiment includes a first dielectric layer 1, a second dielectric layer 2 disposed on the first dielectric layer 1, and an upper surface 1u or inside of the first dielectric layer 1 (FIG. 1). In this example, a pair of planar conductors disposed on the upper surface or inside (upper surface in the example of FIG. 1) of the ground conductor layer 3 provided on the upper surface 1u) and the second dielectric layer 2 located on the ground conductor layer 3 4a, 4b, via conductors 5a, 5b connected to each of the pair of planar conductors 4a, 4b, and a pair of conductor walls 6a, 6b provided with the pair of planar conductors 4a, 4b interposed therebetween. doing.

  The first dielectric layer 1 has a flat plate shape as shown in FIGS. 1 and 2, for example, and has a flat first side surface 1a at one end. The second dielectric layer 2 has, for example, a third side surface 2a and a fourth side surface 2b that are parallel to each other in plan view. The third side surface 2a is connected to the first side surface 1a and the lower end of the fourth side surface 2b. Are arranged in the upper surface 1u of the first dielectric layer 1. The first side surface 1a and the third side surface 2a are connected to each other vertically (so-called flush) to form one plane. Of this plane, the portion of the third side surface 2a in particular becomes a passage surface for the electric field transmitted and received in the lateral direction C.

  The first dielectric layer 1 and the second dielectric layer 2 are, for example, a laminated body integrated with each other, and form a single dielectric substrate (no reference numeral as a dielectric substrate). This dielectric substrate functions as a base that holds the pair of planar conductors 4a and 4b in a state of being electrically insulated from each other. The dielectric substrate also functions as a substrate for mounting the electronic component 11 described later, a substrate for holding a conductive path for electrical connection between the planar conductor 4a (4b) and the electronic component 11, and the like.

  The ground conductor layer 3 is a portion for generating an electric field between each of a pair of planar conductors 4a and 4b described later. A signal is transmitted from the electronic component 11 or the outside to each of the pair of planar conductors 4a and 4b, and an electric field is generated between the ground conductor layer 3 and the planar conductor 4a (4b) disposed thereon according to the signal. The electric field is transmitted to the outside or the electric field is received from the outside.

  The pair of planar conductors 4a and 4b are conductors that directly transmit and receive the electric field as described above, and function as a transmission antenna and a reception antenna (no sign as an antenna), respectively. Due to the isolation between transmission and reception, the pair of planar conductors 4a and 4b are separated from each other along a first direction D parallel to the third side surface 2a. The first direction D is, for example, a direction parallel to the long side of the second dielectric layer 2 that is rectangular in plan view as shown in FIG. That is, a pair of planar conductors 4a and 4b each having a rectangular shape are provided so as to be arranged apart from each other in the long side direction.

  In the following description, for convenience, one of the pair of planar conductors 4a and 4b will be described as one planar conductor 4a for transmission and the other planar conductor 4b as a reception one. It may be 4a (or 4b).

  The pair of via conductors 5a and 5b has a function of electrically connecting each of the pair of planar conductors 4a and 4b to a power feeding portion (described later). The pair of via conductors 5a and 5b are directions away from each other along the first direction D from the central portion in plan view (hereinafter also simply referred to as the central portion of the planar conductors 4a and 4b) with respect to each of the planar conductors 4a and 4b. Connected at a position shifted to. The central part of each of the planar conductors 4a and 4b is an intersection of diagonal lines on the rectangular upper surface and its vicinity. In other words, the via conductor 5a (5b) is located at the end portion of the planar conductor 4a (4b).

The pair of conductor walls 6a and 6b are respectively located in the second dielectric layer 2 and sandwich the pair of planar conductors 4a and 4b in the first direction D. In the example shown in FIGS. 1 and 2, the pair of conductor walls 6 a and 6 b is a third side surface 2 a that is a side surface on the long side of the second dielectric layer 2.
And it arrange | positions at a pair of side surface (what is called an end surface) of the short side orthogonal to the 4th side surface 2b. In the present embodiment, each of the pair of conductor walls 6a and 6b is constituted by a conductor layer provided in a layered manner on the entire end face.

  The pair of via conductors 5a and 5b functions as a power feeding portion in each of the pair of planar conductors 4a and 4b. Details of the power feeding unit will be described later. For example, a signal is transmitted to the planar conductor 4a from the end of the via conductor 5a serving as a power feeding portion to the transmitting planar conductor 4a, and an electric field is generated between the planar conductor 4a and the ground conductor layer 3 in response to this signal. Is emitted. On the other hand, with respect to the planar conductor 4b for reception, an electric field is generated between the planar conductor 4b and the ground conductor layer 3 according to a signal received from the outside, and the signal generated by this electric field is used as a power feeding unit. The signal is transmitted from the via conductor 5b to the electronic component 11.

  Note that the pair of planar conductors 4 a and 4 b are disposed on the ground conductor layer 3 in order to enable such a function of transmitting or receiving an electric field. A portion of the second dielectric layer 2 interposed between the pair of planar conductors 4a and 4b and the ground conductor layer 3 is effectively between the pair of planar conductors 4a and 4b and the ground conductor layer 3. It also has a function of generating an electric field.

  According to the antenna substrate 10 of the present embodiment, because of the above configuration, the electric field radiated in the planar direction from one planar conductor 4a of the pair of planar conductors 4a and 4b is drawn toward the adjacent conductor wall 6a. And is effectively radiated to the outside from the third side surface 2a that is close to it. The conductor wall 6a is in the opposite direction to the other planar conductor 4b of the pair of planar conductors 4a and 4b. The same applies to the relationship between the pair of conductor walls 6b and the one planar conductor 4a. The distance between the pair of planar conductors 4a and 4b can be kept small. The third side surface 2a is positioned in the horizontal direction.

  That is, the electric field of the planar conductor 4a or the planar conductor 4b can be kept away from the adjacent planar conductor 4b or the planar conductor 4a without arranging a conductor wall (not shown) between the pair of planar conductors 4a and 4b. . By this effect on the electric field, for example, the electric field radiated from the planar conductor 4a functioning as a transmission antenna toward the planar conductor 4b functioning as a reception antenna can be suppressed.

  Accordingly, it is possible to provide an antenna substrate 10 that is effective for downsizing and that can effectively radiate an electric field in the horizontal direction and that can easily manufacture an antenna device 20 with improved isolation characteristics. Can do.

  The pair of conductor walls 6a and 6b only need to be able to guide an electric field with the pair of planar conductors 4a and 4b interposed therebetween as described above, and may not necessarily be as in the present embodiment. Good. For example, the pair of conductor walls 6a and 6b may be partially or entirely curved, and may not be parallel to each other and not orthogonal to the first direction D.

  However, if the pair of conductor walls 6a and 6b are arranged along the second direction E perpendicular to the first direction D as in this embodiment, the first direction of the second dielectric layer 2 is used. The effect of leading the electric field as described above can be obtained while keeping the dimension at D as small as possible. That is, the antenna substrate 10 and the antenna device 20 that are more advantageous for downsizing can be obtained.

In the antenna substrate 10 and the antenna device 20 of the present embodiment, a space for providing the pair of conductor walls 6a and 6b is necessary, but it is still advantageous for downsizing. For example, the distance between the planar conductor 4a for transmission and the conductor wall 6a, or the distance between the planar conductor 4b for reception and the conductor wall 6b is about 0.7 mm, but the distance between the planar conductors 4a and 4b. Therefore, for example, as in the conventional example, it can be suppressed to be smaller than when a conductor wall is provided between a pair of planar conductors (not shown). Therefore, the antenna substrate 10 and the antenna device 20 that are effective for miniaturization can be obtained.

Specifically, when a conductor wall (not shown) is provided between the planar conductors, the distance between the planar conductors is ½ wavelength or more (for example, 2.5 mm or more at 60 GHz). In the case of the above example in the present embodiment, the distance between the centers of the planar conductors 4a and 4b may be about 2 mm, and the size can be reduced by at least about 0.5 mm.

  In this case, since the fourth side surface 2 b opposite to the third side surface 2 a of the second dielectric layer 2 is located on the ground conductor layer 3, the second dielectric layer 2 is temporarily connected to the first dielectric layer 1. The distance between the pair of planar conductors 4a and 4b and the fourth side surface 2b can be made smaller than when the first side surface 1a extends to the second side surface 1b opposite to the first side surface 1a. Therefore, for example, an electric field transmitted from the planar conductor 4a can be suppressed from being guided in the direction of the fourth side surface 2b, and an external electric field can be effectively radiated from the third side surface 2a. Similarly, the reception planar conductor 4b can also easily receive an external electric field with the planar conductor 4b having a relatively small distance from the third side surface 2a.

  The power feeding portion disposed with respect to the antenna substrate 10 is formed by, for example, the above-described pair of via conductors 5a and 5b and the electronic component 11 that is electrically connected to each of the via conductors 5a and 5b. The electronic component 11 is, for example, a semiconductor integrated circuit element, and is electrically connected to the pair of planar conductors 4a and 4b via the pair of via conductors 5a and 5b.

  In the present embodiment, the electronic component 11 is mounted on the upper surface 1u of the first dielectric layer 1, and is electrically connected to the wiring conductor 7 disposed from the upper surface 1u to each of the pair of planar conductors 4a and 4b. Yes. In FIG. 2, the direction in which the electronic component 11 is mounted is indicated by a hook-shaped arrow, and the region where the electronic component 11 is mounted in the upper surface 1u is indicated by a virtual line (two-dot chain line). The electronic component 11 and each of the pair of planar conductors 4a and 4b are electrically connected to each other by the wiring conductor 7 to form the antenna device 20. In this case, the end portions of the via conductors 5a and 5b that are located in the respective planar conductors 4a and 4b actually function as a power feeding portion (no symbol is given as the power feeding portion).

  For connection of the electronic component 11 to the wiring conductor 7, for example, electrodes (not shown) arranged on the lower surface of the electronic component 11 are opposed to predetermined portions of the wiring conductor 7, and these electrodes are connected via the conductive connecting material 12. And the wiring conductor 7 can be joined. Examples of the conductive connecting material 12 include metal bumps such as solder bumps and bonding wires.

  According to such an antenna device 20, since the antenna substrate 10 having the above-described configuration is included, it is effective for downsizing, and effective electric field radiation in the horizontal direction is possible, and isolation characteristics are effective. An enhanced antenna device 20 can be provided.

  The wiring conductor 7 is electrically insulated from the ground conductor layer 3 by a space (not indicated) having a predetermined width provided between the upper surface 1u of the first dielectric layer 1 and the ground conductor layer 3. . Further, a part of the wiring conductor 7 may be electrically led to the outer surface of the dielectric substrate such as the lower surface of the first dielectric layer 1. In the example shown in FIG. 1, a portion of the wiring conductor 7 disposed on the lower surface of the first dielectric layer 1 is a pad for external connection (the pad has no reference numeral). This pad is electrically connected to an external electric circuit (not shown), and the electronic component 11 and the external electric circuit are electrically connected to each other.

The distance between adjacent planar conductors 4a as a transmitting antenna and planar conductor 4b as a receiving antenna (distance between adjacent outer sides in a plan view) is, for example, 1/2 of the wavelength of an electric field transmitted and received. It only has to be set as follows. At this time, the planar conductors 4a and 4b resonate at the frequency of the electric field, and the electric field can be transmitted and received effectively.

  In addition, for each of the pair of planar conductors 4a and 4b, the adjacent interval with respect to the conductor wall 6a or conductor wall 6b located closest to each other may be set to ¼ or less of the wavelength of the electric field transmitted and received. That's fine. At this time, an electric field is easily generated between the planar conductor 4a (4b) and the conductor wall 6a (6b), and the isolation characteristics between the planar conductors 4a and 4b can be effectively enhanced.

  The first dielectric layer 1 and the second dielectric layer 2 are formed of a ceramic sintered body such as an aluminum oxide sintered body, an aluminum nitride sintered body, a mullite sintered body, or a glass ceramic sintered body. Has been. The first dielectric layer 1 and the second dielectric layer 2 may be formed of an organic resin material such as an epoxy resin, or a composite material containing an organic resin material.

  If both the first dielectric layer 1 and the second dielectric layer 2 are made of, for example, an aluminum oxide sintered body, they can be manufactured as follows. That is, first, raw material powders such as aluminum oxide and silicon oxide are formed into a sheet together with an appropriate organic binder and an organic solvent to produce a plurality of sheet-like ceramic green sheets. Next, these ceramic green sheets are cut in accordance with a predetermined shape and size such as a rectangular shape of the first dielectric layer 1 or the second dielectric layer 2 to produce a plurality of sheets. Thereafter, these sheets are laminated to produce a laminate, and this laminate is fired at a temperature of 1300 to 1600 ° C., whereby the first dielectric layer 1 and the second dielectric layer 2 are integrally manufactured. be able to.

  If the first dielectric layer 1 and the second dielectric layer 2 are made of an organic resin material, a raw material such as an uncured epoxy resin is molded into a predetermined shape with a mold or the like and is heat cured. Thus, the first dielectric layer 1 and the second dielectric layer 2 can be manufactured.

  The first dielectric layer 1 and the second dielectric layer 2 (dielectric substrate) have a multi-cavity configuration in which a large number of substrate regions to be such a dielectric substrate are arranged vertically and horizontally on a mother substrate. It may be produced by.

  At this time, as in the example shown in FIGS. 1 and 2, for example, the first dielectric layer 1 has a rectangular shape in plan view, and the second dielectric layer 2 has a shape higher than that of the first dielectric layer 1 in plan view. If the rectangular shape is small, the first dielectric layer 1 and the second dielectric layer 2 can be easily manufactured, which is advantageous in terms of productivity and economy as the antenna substrate 10 and the antenna device 20.

  Further, when the first dielectric layer 1 has a rectangular shape in plan view and the second dielectric layer 2 has a rectangular shape smaller than the first dielectric layer 1 in plan view, the first dielectric layer 1 As long as the first side face 1a and the third side face 2a of the second dielectric layer 2 have the same length, the first side face 1a and the third side face 2a may be connected to be flush with each other. It is easy, and it is advantageous in terms of productivity in the multi-cavity form.

  Conductor portions (the conductor portions have no reference numerals) such as the ground conductor layer 3, the pair of planar conductors 4a and 4b, the pair of via conductors 5a and 5b, the pair of conductor walls 6a and 6b, and the wiring conductor 7 are, for example, tungsten, molybdenum , Manganese, copper, silver, palladium, gold, platinum, nickel or cobalt. The conductor portion may be formed of an alloy material including these metal materials. Such a metal material or the like is provided inside the dielectric substrate as a metal layer such as a metallized layer.

  When the conductor portion is, for example, a tungsten metallized layer, a metal paste prepared by mixing tungsten powder with an organic solvent and an organic binder is screen-printed at a predetermined position of the ceramic green sheet to be the insulating substrate 1. After printing by a method such as these, they can be formed by a method of co-firing them.

  Of the above-described conductor portions, a portion of the pair of via conductors 5a and 5b and the wiring conductor 7 that extends in the thickness direction in the first dielectric layer 1 is a ceramic green sheet that becomes the first dielectric layer 1 in advance. In addition, holes can be formed by laser processing or the like, and the holes can be filled with a metal paste such as tungsten and then fired.

  Further, in this case, as described above, if the pair of conductor walls 6a and 6b is constituted by a conductor layer provided in a layer form on the entire end face of the second dielectric layer 2, the conductor walls 6a and 6b are formed. Since the metal paste can be so-called solid (no need to be applied in a fine pattern), it is advantageous in terms of productivity as the antenna substrate 10 and the antenna device 20.

  Of the conductor portions, the surfaces exposed to the outside (such as the pair of flat conductors 4a and 4b and the pad portions of the wiring conductor 7) may be covered with a plating layer such as nickel and gold. Thereby, the oxidation of the conductor portion can be effectively suppressed. In addition, it is possible to effectively improve characteristics such as wettability of a brazing material such as solder on the conductor portion.

  FIGS. 3A and 3B are perspective views showing, in an enlarged manner, main portions in modifications of the antenna substrate 10 and the antenna device 20 shown in FIG. In FIG. 3, the same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals. Note that, in the following description of the modification, the description of the same matters as those described in the above embodiment will be omitted.

  In these examples, both of the pair of conductor walls 6a and 6b are not made of a metal paste applied in layers. That is, the conductor walls 6a and 6b only need to form an electromagnetic wall (barrier) having a function of guiding an electric field, and are not necessarily layered or plate-shaped.

  In the example shown in FIG. 3A, the conductor wall 6a and the conductor wall 6b are respectively constituted by a plurality of through conductors 6A penetrating the second dielectric layer 2 in the thickness direction. The plurality of through conductors 6A are arranged along the end surface (side surface on the short side) of the second dielectric layer 2, and a conductor wall 6a (conductor wall 6b) as an electromagnetic barrier is configured by this arrangement. ing.

  In the case where the conductor walls 6a and 6b are constituted by such a plurality of through conductors 6A, it is only necessary that the adjacent interval between the through conductors 6A is set to about 1/4 or less of the wavelength of the electric field transmitted and received.

  As in this example, when the pair of conductor walls 6a, 6b penetrates the second dielectric layer 2 in the thickness direction and includes a plurality of through conductors 6A arranged along the second direction E, Compared to the case where the conductor walls 6a and 6b are formed in a layered manner, the conductor walls 6a and 6b can be easily formed, which is advantageous in terms of design freedom.

  That is, in this case, the position of the arrangement of the plurality of through conductors 6A is not limited to one place such as the end face of the second dielectric layer 2, but for convenience of induction of electric fields from the planar conductors 4a and 4b. Accordingly, the position can be adjusted as appropriate. Further, through conductors 6A as conductor walls 6a and 6b can be formed in the same process as via conductors 5a and 5b.

In the example shown in FIG. 3B, a castellation in which a conductor is filled in a groove (so-called castellation) (not indicated) provided at the end of the second dielectric layer 2 from the lower end to the upper end of this end face. Conductor walls 6a and 6b are constituted by the conductor B. In the example shown in FIG. 3B, the castellation is semicircular when viewed from above, and the castellation conductor 6B is also semicircular when viewed from above. A castellation conductor (not shown) provided in a layer on the wall surface of the castellation may be used.

  These castellation conductors 6B may also be arranged at adjacent intervals similar to the above-described through conductors 6A, for example.

  The plurality of castellation conductors 6B constituting the conductor walls 6a and 6b can also be formed by the same method using the same metal material as the conductor portions such as the via conductors 5a and 5b described above. In this case, a large number of dielectric substrates may be manufactured, and circular through conductors may be provided along the boundaries of the respective substrate regions. When the mother board is cut along this boundary, the circular through conductor is cut in the vertical direction to form a semicircular castellation conductor 6B.

  FIG. 4 is an enlarged perspective view showing a main part in another modification of the antenna substrate 10 and the antenna device 20 shown in FIG. 4, parts similar to those in FIGS. 1 and 2 are denoted by the same reference numerals. Also in the description of this modified example, the description of the same matters as those described in the above embodiment will be omitted.

  In the example shown in FIG. 4, the conductor walls 6 a and 6 b are constituted by the metal layer 6 </ b> C inserted into the second dielectric layer 2. The metal layer 6 </ b> C is, for example, a metal plate, and is inserted into the second dielectric layer 2 so as to be parallel to the end face of the second dielectric layer 2. As a metal material which forms this metal plate, the metal material which forms conductor wall 6a, 6b in embodiment mentioned above, an iron-nickel-cobalt alloy, copper, or a copper alloy etc. are mentioned, for example.

  Such a metal plate or the like as the metal layer 6C is formed by providing a cut parallel to the end face in a part of the second dielectric layer 2, for example, and inserting the cut into the second dielectric layer 2 Can be placed inside. This metal plate may be fixed by a frictional force with the second dielectric layer 2 or may be fixed by a bonding material (not shown) such as an active metal brazing material.

  In the example shown in FIG. 4, a part (side surface part) of the metal layer 6 </ b> C is exposed to the outside from the second dielectric layer 2, but the metal layer is entirely embedded in the second dielectric layer 2. (Not shown).

  As described above, the antenna device 20 according to the embodiment is configured by the antenna substrate 10 having any one of the above-described structures and the power feeding unit electrically connected to the planar conductors 4a and 4b via the via conductors 5a and 5b. Yes.

  For example, as described in the above embodiment, the power feeding unit may be configured by the end portions of the via conductors 5a and 5b. In this case, an electronic component 11 such as a semiconductor element electrically connected to the via conductors 5a and 5b via the wiring conductor 7 may be a power supply body that actually oscillates a signal.

  Further, for the receiving planar conductor 4b, a signal generated according to the electric field received from the outside is transmitted to the electronic component 11 from the power feeding unit. In response to this signal, the electronic component 11 performs various processes such as conversion, storage, and retransmission.

The simulation result regarding the intensity of the radiated radio waves of the antenna device 20 in the present embodiment and the antenna device (not shown) in the comparative example will be described with reference to FIGS.

  The example shown in FIG. 5A is the isolation characteristic in the antenna device 20 of the present embodiment, and the example shown in FIG. 5B is the isolation characteristic in the antenna device of the comparative example. In the antenna device of the comparative example, a conductor wall is provided between a pair of planar conductors, and the configuration other than this is the same as that of the antenna device 20 of the embodiment.

In FIG. 5A, the isolation characteristic at 61.5 GHz of each of the planar conductors 4a and 4b is −19.5 dB. At this time, the distance between the centers of the planar conductors 4a and 4b of the planar conductors 4a and 4b is 2 mm, which is shorter than ½ wavelength (2.5 mm) at 60 GHz.
That is, even when the distance between the planar conductors 4a and 4b is narrow, good isolation characteristics are exhibited.

On the other hand, in the comparative example of FIG. 5B, the isolation characteristic at 61.5 GHz is −8.5 dB. Also in this case, the distance between the centers of the planar conductors is 2 mm. In the comparative example, when the distance between the planar conductors is narrower than ½ wavelength, the isolation characteristics deteriorate.

  As described above, according to the antenna device 20 of the present embodiment, even when the distance between the planar conductors 4a and 4b is narrow, good isolation characteristics can be obtained and a small antenna device can be realized.

  Note that. The present invention is not limited to the above embodiments, and various modifications are possible within the scope of the gist of the present invention. For example, the ground conductor layer 3 may be provided in the first dielectric layer 1 in the same pattern as in the above embodiment. Further, the pair of planar conductors 4a and 4b may be provided in the second dielectric layer 2 in the same pattern as the example of the above embodiment.

  In addition, the first dielectric layer 1 and the second dielectric layer 2 are not limited to a rectangular shape as described in part in the description of the embodiment. Various shapes can be used as long as they do not affect the isolation characteristics. Further, the ground conductor layer 3 and the like can be formed in various patterns within the range of the conditions such as the above characteristics.

  For example, as in the example shown in FIG. 6, the corner portion of the first dielectric layer 1 may be formed in an arc shape (so-called chamfering) so that chipping or the like can be suppressed. A recess may be provided in a part of the housing so that it can be used for alignment with an external electric circuit. Further, a part of the wiring conductor 7 may be disposed outside the ground conductor layer 3 on the upper surface 1 u of the first dielectric layer 1. These wiring conductors 7 can be used as connection pads for so-called passive components (not shown) such as capacitive elements. FIG. 6 is a plan view showing a modification of FIG. 1A. In FIG. 6, the same parts as those in FIG.

  Further, the pair of conductor walls 6a and 6b may have different forms (a combination of a layered structure and a structure including a plurality of through conductors) depending on the design convenience of the antenna substrate 10 and the like.

DESCRIPTION OF SYMBOLS 1 ... 1st dielectric material layer 1a ... 1st side surface 1b ... 2nd side surface 1u ... (upper side of 1st dielectric material layer) 2 ... 2nd dielectric material layer 2a ... 1st 3 side surface 2b ... 4th side surface 3 ... grounding conductor layer 4a, 4b ... plane conductor 5a, 5b ... via conductor 6a, 6b ... conductor wall 6A ... penetrating conductor 6B ... Castoration conductor 6C ... Metal layer 7 ... Wiring conductor
10 Antenna board
11 ... Electronic components
12 ... Conductive connection material
20 ... Antenna device C ... Electric field transmission / reception direction (lateral direction)
D ... 1st direction E ... 2nd direction

Claims (5)

A first dielectric layer having a first side;
The third side surface and the fourth side surface are parallel to each other, the third side surface is connected to the first side surface, and the lower end of the fourth side surface is positioned within the upper surface of the first dielectric layer. A second dielectric layer disposed on the first dielectric layer;
A ground conductor layer provided on or in the upper surface of the first dielectric layer;
A pair of planar conductors disposed on the top surface or inside the second dielectric layer located on the ground conductor layer and spaced apart from each other along a first direction parallel to the third side surface;
Via conductors connected to each of the pair of planar conductors by being shifted in the direction away from the respective central portions in plan view along the first direction;
An antenna substrate comprising: a pair of conductor walls provided on the second dielectric layer with the pair of planar conductors sandwiched therebetween in the first direction. The first dielectric layer is rectangular in plan view;
The antenna substrate according to claim 1, wherein the second dielectric layer has a rectangular shape smaller than the first dielectric layer in plan view. The antenna substrate according to claim 1, wherein the pair of conductor walls are arranged along a second direction orthogonal to the first direction. 4. The antenna substrate according to claim 3, wherein the pair of conductor walls includes a plurality of through conductors arranged along the second direction while penetrating the second dielectric layer in the thickness direction. The antenna substrate according to any one of claims 1 to 4,
An antenna device comprising: a power feeding portion electrically connected to the planar conductor via the via conductor.

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