JP2017123586A - Antenna device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a patch antenna technique capable of easily performing assembly work and holding down manufacturing costs, and achieving wide directivity at the same time.SOLUTION: An antenna device comprises: an upper dielectric substrate including a first and a second surface; a patch electrode including a third and a fourth surface; an intermediate dielectric substrate including a fifth and a sixth surface; a ground electrode including a seventh and an eighth surface; and a lower dielectric substrate including a ninth and a tenth surface. The upper dielectric substrate and the patch electrode are arranged so that the second surface comes into contact with the third surface. The patch electrode and the intermediate dielectric substrate are arranged so that the fourth surface comes into contact with the fifth surface. The intermediate dielectric substrate and the ground electrode are arranged so that the sixth surface faces the seventh surface via a gap. The ground electrode and the lower dielectric substrate are arranged so that the eight surface faces the ninth surface.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an antenna device.

  An antenna device (hereinafter also referred to as “antenna”) is an important component that determines communication performance of a wireless communication system. There are various types of antennas, but there is a patch antenna as an antenna that realizes one-side directivity. For example, Patent Document 1 discloses a structure example of a patch antenna.

International Publication No. 2004/09539

  Patent Document 1 describes a patch antenna having a structure in which a ground conductor portion and a patch conductor portion face each other. This type of patch antenna has a dielectric constant and dielectric loss tangent (degree of electrical energy loss in the capacitor) of a dielectric material such as a printed circuit board that supports conductor parts such as a ground conductor part and patch conductor part. Determine efficiency. For example, when the dielectric constant is large, the wavelength of the current flowing through the patch conductor portion is shortened, the current density is increased, and the conductor loss is increased. In addition, when the dielectric loss tangent is large, the dielectric loss of the electromagnetic wave passing through the dielectric increases.

  However, the patch antenna described in Patent Document 1 has a problem of high assembly cost. In addition, in order to use a patch antenna for a wireless communication system (particularly a mobile communication system), a patch antenna having a wide directivity is required.

  Therefore, the present invention provides a patch antenna technology that can be easily assembled, can reduce the manufacturing cost, and has a wide directivity.

In order to solve the above problems, the present invention employs, for example, the configurations described in the claims. The present specification includes a plurality of means for solving the above problems.
“An upper dielectric substrate having a first surface and a second surface;
A patch electrode having a third surface and a fourth surface;
An intermediate dielectric substrate having a fifth surface and a sixth surface;
A ground electrode having a seventh surface and an eighth surface;
A lower dielectric substrate having a ninth surface and a tenth surface;
The upper dielectric substrate and the patch electrode are disposed such that the second surface and the third surface are in contact with each other,
The patch electrode and the intermediate dielectric substrate are disposed so that the fourth surface and the fifth surface are in contact with each other,
The intermediate dielectric substrate and the ground electrode are arranged so that the sixth surface and the seventh surface face each other with a gap therebetween,
The antenna device, wherein the ground electrode and the lower dielectric substrate are disposed so that the eighth surface and the ninth surface are opposed to each other. ".

  According to the present invention, it is possible to realize a patch antenna that can be easily assembled and reduced in manufacturing cost, and at the same time has a wide directivity. Problems, configurations, and effects other than those described above will become apparent from the following description of embodiments.

1 is a diagram illustrating a schematic structure of an antenna device according to Embodiment 1. FIG. 3 is a diagram illustrating a schematic cross-sectional structure of the antenna device according to the first embodiment. The figure which decomposes | disassembles and shows the antenna apparatus which concerns on Example 1 to a component. FIG. 3 is a diagram illustrating a structural unit of the antenna device according to the first embodiment. The figure which shows an example of the upper surface pattern of an upper printed circuit board. The figure which shows an example of the lower surface pattern of an upper printed circuit board. The figure which shows an example of the upper surface pattern of an intermediate | middle dielectric substrate. The figure which shows an example of the lower surface pattern of an intermediate dielectric substrate. The figure which shows an example of the upper surface pattern of a lower printed circuit board. The figure which shows an example of the lower surface pattern of a lower printed circuit board. FIG. 3 is a diagram illustrating a substrate support structure of the antenna device according to the first embodiment. The figure which expands and shows the structure of the electric power feeding part of the antenna apparatus which concerns on Example 1 partially. The figure explaining mounting of the electronic circuit on the lower surface of a lower printed circuit board. The figure which shows an example of the internal structure of an electronic circuit. FIG. 6 is a diagram illustrating a schematic structure of an antenna device according to a second embodiment. FIG. 6 is a diagram illustrating a connection structure of a power feeding unit of an antenna device according to a second embodiment. FIG. 6 is a diagram illustrating a schematic structure of an antenna device according to a third embodiment. FIG. 10 is a diagram illustrating a schematic structure of an antenna device according to a fourth embodiment. The figure which shows the example of a design of the antenna apparatus which concerns on an Example. The figure which shows the positional relationship of three design examples (FIG. 19) within the design range of tu, ti, and dg in the antenna apparatus which concerns on an Example. The figure which shows the simulation result of the radiation pattern of the antenna apparatus corresponding to the design example A. The figure which shows the simulation result of the radiation pattern of the antenna apparatus corresponding to the design example B. The figure which shows the simulation result of the radiation pattern of the antenna apparatus corresponding to the design example C.

  In the following description, the description of the same or similar parts will not be repeated in principle unless particularly necessary. Further, in the following description, when it is necessary for the sake of convenience, the description will be divided into a plurality of sections or examples, but they are not irrelevant to each other unless otherwise specified. Some or all of the modifications, details, supplementary explanations, and the like exist.

  Also, in the following description, when referring to the number of elements (including the number, numerical value, quantity, range, etc.), unless otherwise specified, or in principle limited to a specific number in principle, It is not limited to the specific number, and may be a specific number or more.

  In the following description, it is needless to say that the constituent elements (including element steps and the like) are not necessarily indispensable, unless otherwise specified and clearly considered essential in principle. .

  In addition, in the following explanation, when it is stated that “consisting of A”, “consisting of A”, “having A”, and “including A”, it is specifically stated that only the element is included. Except for the above, it does not exclude other elements. Similarly, in the following description, when referring to the shape and positional relationship of components, etc., the shape or the like of the component is substantially changed unless otherwise specified or otherwise apparent in principle. Approximate or similar. The same applies to the above numerical values and ranges.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In all the drawings used for the description of the embodiments, members having the same function are denoted by the same reference numerals, and repeated description thereof is omitted.

(1) Example 1
FIG. 1 shows a schematic structure of an antenna device 1 according to this embodiment. The antenna device 1 includes an upper dielectric substrate 2, a patch electrode 3, an intermediate dielectric substrate 4, a gap 5, a ground electrode 6, and a lower dielectric substrate 7. As shown in FIG. 2, the lower surface of the upper dielectric substrate 2 and the upper surface of the intermediate dielectric substrate 4 are in contact with each other, and the patch electrode 3 is sandwiched between the upper dielectric substrate 2 and the intermediate dielectric substrate 4. The dimensions of the patch electrode 3 are designed based on the resonance frequency to be obtained in the same manner as a normal patch antenna. In the case of FIG.1 and FIG.2, the patch electrode 3 is square. However, the shape of the patch electrode 3 may be a rectangle, a circle, an ellipse or the like as long as desired characteristics are obtained. The patch electrode 3 is formed as a plate or thin film made of copper, aluminum, gold or the like. The ground electrode 6 is disposed so as to cover the upper surface of the lower dielectric substrate 7. The ground electrode 6 faces the lower surface of the intermediate dielectric substrate 4 with the gap 5 interposed therebetween. The ground electrode 6 is formed as a plate or thin film made of copper, aluminum, gold or the like. In the present embodiment, the ground electrode 6 is in contact with the upper surface of the lower dielectric substrate 7 as long as it is opposed.

  The material of the upper dielectric substrate 2, the intermediate dielectric substrate 4, and the lower dielectric substrate 7 is FR4, acrylic, Teflon (registered trademark), or the like. The dimension L of each substrate is the same as the dimension of the ground electrode 6 and needs to be sufficiently large at the operating frequency of the antenna device 1. In other words, the dimension L of each substrate is sufficiently wider than the dimension of the patch electrode 3. The dimension L of each substrate is preferably about 100 to 300 mm when the operating frequency is about 1 GHz, for example.

  The antenna device 1 can design an operation gain and a bandwidth by using the thickness tu of the upper dielectric substrate 2, the thickness ti of the intermediate dielectric substrate 4, and the gap distance dg as design parameters (FIG. 2). tu, ti, and dg are designed within the following range.

  Here, λ is the wavelength in the free space of the electromagnetic wave with respect to the use frequency of the antenna device 1, and is about 300 mm at 1 GHz, for example. The upper equation is a condition for operating the antenna device 1 as a micro antenna, and the lower equation is a condition for satisfying a design requirement. For example, a value corresponding to the applied wireless communication system is used.

  Below, each component of the antenna apparatus 1 is demonstrated using FIG. Here, description will be made assuming that the antenna device 1 is a patch antenna. An electronic component that transmits a high-frequency signal to a signal line connected to the antenna device 1 is mounted on the lower surface 7 b of the lower dielectric substrate 7 of the antenna device 1.

  The upper dielectric substrate 2 has a first surface (upper surface) 2a and a second surface (lower surface) 2b. The patch electrode 3 has a third surface (upper surface) 3a and a fourth surface (lower surface) 3b. The intermediate dielectric substrate 4 has a fifth surface (upper surface) 4a and a sixth surface (lower surface) 4b. The ground electrode 6 has a seventh surface (upper surface) 6a and an eighth surface (lower surface) 6b. The lower dielectric substrate 7 has a ninth surface (upper surface) 7a and a tenth surface (lower surface) 7b.

  Hereinafter, the antenna device 1 will be described in more detail with reference to FIGS. FIG. 4 is an exploded view of the antenna device 1 as structural units. As shown in FIG. 4, the antenna device 1 is composed of three substrates: an upper dielectric substrate 2, an intermediate dielectric substrate 4, and a lower dielectric substrate 7. These substrates are manufactured by a PCB (Printed Circuit Board) generally used as an electronic circuit board, and more specifically, are manufactured by a double-sided copper-clad printed circuit board (double-layer board). In this embodiment, a structure composed of the upper dielectric substrate 2 and the patch electrode 3 is referred to as an upper printed circuit board 11, and a structure composed of the ground electrode 6 and the lower dielectric substrate 7 is referred to as a lower printed circuit board 12. .

  As shown in FIG. 5, a first signal land portion 9 that is a first land portion is formed on the upper surface 2 a of the upper printed circuit board 11. The upper printed board 11 has a through hole (conductor) 11c. As shown in FIG. 6, the patch electrode 3 that is the first conductor portion is formed on the lower surface 2 b of the upper printed board 11.

  As shown in FIGS. 7 and 8, the electrode (copper foil) is completely removed from the upper surface 4a and the lower surface 4b of the intermediate dielectric substrate 4, and a through hole 4c through which the signal line passes is opened. As shown in FIGS. 9 and 10, the ground electrode 6 as the second conductor portion is formed on the substantially entire surface of the upper surface 6 a of the lower printed circuit board 12, and the second electrode is formed on the lower surface 7 b of the lower printed circuit board 12. A land portion 10 for ground which is a land portion is formed. Note that a through hole 12c and a via hole wiring 12d are formed in the lower printed circuit board 12. The via hole wiring 12d is formed so as to surround the through hole 12c.

  Returning to the description of FIG. As shown in FIG. 4, the intermediate dielectric substrate 4 and the ground electrode 6 are arranged to face each other with a gap 5 therebetween. That is, the air gap 5 is formed between the intermediate dielectric substrate 4 and the lower printed circuit board 12, and the antenna device 1 having a hollow structure is realized. The patch electrode 3 is formed on the lower surface 2 b of the upper printed circuit board 11, and the ground electrode 6 is formed on the upper surface 6 a of the lower printed circuit board 12. For this reason, the patch electrode 3 and the ground electrode 6 are opposed to the intermediate dielectric substrate 4 via the gap 5. The first signal land portion 9 and the patch electrode 3 are electrically connected through the through hole 11c, and the ground electrode 6 and the ground land portion 10 are electrically connected through the through holes 12c and 12d.

  As shown in FIG. 9, the ground electrode 6 formed on the upper surface 6a of the lower printed circuit board 12 is formed over substantially the entire upper surface 6a. Accordingly, the size of the ground electrode 6 in plan view is larger than the size of the patch electrode 3 on the lower surface 2b of the upper printed board 11 shown in FIG.

  In the antenna device 1, a feeding point 8 (FIG. 1) is provided at a position on the upper surface 2 a of the upper dielectric substrate 2 above the patch electrode 3, and a high frequency signal is input / output through the feeding point 8. The feeding point 8 corresponds to the first signal land portion 9 described above. In the case of this embodiment, the impedance of the feeding point 8 is 50Ω. The feeding point 8 is selected at a position where the high-frequency signal enters most efficiently. In this embodiment, the feeding point 8 is selected at a position slightly deviated from the center of the patch electrode 3.

  For the upper printed board 11, the intermediate dielectric board 4, and the lower printed board 12, printed boards made of glass epoxy resin are preferably used, but they are formed by polymerizing acrylic board, ABS (acrylonitrile, butadiene, styrene). Resin) or a dielectric such as a glass plate.

  Next, the dimensions of the antenna device 1 will be described. The size of the patch electrode 3 in the antenna device 1 is determined by the carrier frequency of the wireless system. In general, the length of one side of the patch electrode 3 is often set based on the length of ½ wavelength of the carrier frequency. Based on the wavelength in free space, the length of one side of the patch electrode 3 is, for example, about 140 mm in the case of the 920 MHz band and about 78 mm in the case of the 1.6 GHz band. However, since the antenna device 1 is subjected to wavelength shortening due to the dielectric constant of the upper dielectric layer 2, the intermediate dielectric substrate 4, and the lower dielectric substrate 7 that support each electrode, the actual size of the patch electrode 3 is The dimension is smaller by several% to several tens of% than the dimension based on the wavelength in the free space.

  The substrate dimension L (FIG. 1) of the antenna device 1 corresponds to the dimension of the ground electrode 6 on the upper surface 6a of the lower printed circuit board 12 shown in FIG. Although it is desirable to make it small, when importance is attached to miniaturization of the antenna device 1, it may be further reduced.

  The upper printed board 11 and the lower printed board 12 may have different sizes. In this case, the size of the lower printed circuit board 12 on which the ground electrode 6 is disposed is set as a guide to the size of the patch electrode 3 according to the above example, and the upper printed circuit board 11 has a dimension that allows the patch electrode 3 to be disposed. It may be smaller.

  FIG. 11 shows an example of a support structure for each substrate. In the case of FIG. 11, the upper dielectric substrate 2 and the lower dielectric substrate 7 are supported and fixed by poles (columns) 13 and screws 14 arranged at four corners. The pole 13 and the screw 14 are preferably made of resin, but may be made of metal when strength is required. However, the arrangement positions of the pole 13 and the screw 14 may be any positions as long as they do not adversely affect the electromagnetic waves radiated from the patch electrode 3, and may be disposed at arbitrary positions on the edge portion of each substrate, for example. As shown in FIG. 11, by disposing poles 13 and screws 14 at the four corners of each substrate, it is possible to avoid adverse effects on electromagnetic waves radiated from the patch electrode 3, and to suppress the deterioration of antenna characteristics. Can be supported.

  However, even if the pole 13 and the screw 14 are positions where they interfere with the patch electrode 3, they can be disposed as long as they do not seriously affect the antenna characteristics. For example, the input impedance is 0 at the center of the patch electrode 3 in the plane direction, and it is theoretically considered that the influence on the antenna characteristics is small even if a conductor or a dielectric is touched. Is possible. Thus, by providing the pole (column part) 13 in the center part of the patch electrode 3, the bending of the board | substrate by a hollow structure can be reduced and high antenna performance can be maintained. In particular, in severe use conditions such as industrial applications, it is assumed that many mechanical impacts are applied, and such a structure that increases the strength may be required. Further, although four poles 13 are provided in FIG. 11, the number of poles may be increased or decreased depending on conditions such as required strength and cost.

  3 to 10, a layout example of a conductor pattern for connecting the signal line on the lower printed circuit board 12 side and the upper printed circuit board 11 through the lower printed circuit board 12 and the intermediate dielectric substrate 4. explain. As shown in FIG. 10, on the lower surface 7b of the lower printed circuit board 12, through holes 12c for passing a signal line 15 shown in FIG. (Conductor) 12d is formed.

  Further, as shown in FIG. 9, on the upper surface 6a of the lower printed circuit board 12, through holes 12c for passing the signal lines 15 and a plurality of via hole wirings 12d arranged around the through holes 12c are formed. Yes. The upper surface 6a of the lower printed circuit board 12 is substantially the ground electrode 6, and the ground electrode 6 on the upper surface 6a and the ground land portion 10 on the lower surface 7b are electrically connected via a plurality of via-hole wirings 12d. Connected. Further, as shown in FIG. 6, a through hole 11 c for passing the signal line 15 is formed in the lower surface 2 b of the upper printed board 11. The through hole 11c also penetrates the patch electrode 3.

  Further, as shown in FIG. 5, the upper surface 2a of the upper printed circuit board 11 is formed with a first signal land portion 9 and a through hole 11c through which the signal line 15 is passed. As shown, a through-hole wiring (conductor) is formed on the inner wall of the through-hole 11 c so as to electrically connect the patch electrode 3 and the first signal land portion 9. That is, in the upper printed circuit board 11, the first signal land portion 9 formed on the upper surface 2a and the patch electrode 3 formed on the lower surface 2b are electrically connected by through-hole wiring.

  FIG. 12 shows a partially enlarged structure of the antenna device 1 in an assembled state. As shown in FIG. 12, the feeding point 8 on the upper printed circuit board 11 side and the conductor pattern on the lower printed circuit board 12 side are electrically connected through the intermediate dielectric substrate 4 and the lower printed circuit board 12. As described above, the first signal land portion 9 formed on the upper surface 2a of the upper printed circuit board 11 and the patch electrode 3 formed on the lower surface 2b are electrically connected by the through-hole wiring.

  On the other hand, in the lower printed circuit board 12, the ground electrode 6 formed on the upper surface 6a and the ground land portion 10 formed on the lower surface 7b are electrically connected through a plurality of via-hole wirings. A second signal land 16 is formed on the lower surface 7b of the lower printed circuit board 12 inside the ground land 10 with a gap 10c therebetween. That is, the ground land portion 10 and the second signal land portion 16 are separated by the gap portion 10c. For this reason, the ground land portion 10 and the second signal land portion 16 are not electrically connected. In other words, the ground land portion 10 and the second signal land portion 16 are insulated.

  Here, the signal line 15 extends over three through holes (that is, a through hole 11c formed in the upper printed board 11, a through hole 4c in the intermediate dielectric board 4, and a through hole 12c in the lower printed board 12). Be placed. Note that one end (upper end) of the signal line 15 and the first signal land portion 9 are electrically connected by solder 17, and the other end (lower end) of the signal line 15 and the second signal land portion 16 are soldered 17. Are electrically connected to each other. The first signal land 9 and the patch electrode 3 are electrically connected through a through-hole wiring. For this reason, the second signal land 16 on the lower surface 7 b of the lower printed circuit board 12 and the patch electrode 3 on the lower surface 2 b of the upper printed circuit board 11 are electrically connected through the signal line 15.

  In the case of the present embodiment, a clearance 6c is provided on the upper surface 6a of the lower printed circuit board 12 so as to surround the through hole 12c, and the ground land 10 is disposed further outside the clearance 6c. Therefore, the signal line 15 and the ground land portion 10 can be reliably insulated as compared with the case where the gap 6c is not provided. As a result, an electrical short circuit between the signal line 15 and the ground land portion 10 can be prevented.

  As described above, the second signal land portion 16 formed on the lower surface 7 b of the lower printed circuit board 12 and the patch electrode 3 formed on the lower surface 2 b of the upper printed circuit board 11 are electrically connected via the signal line 15 and the solder 17. Connected. The first signal land portion 9 on the upper surface 2a of the upper printed circuit board 11 and the patch electrode 3 on the lower surface 2b are electrically connected at the feeding point 8, and are insulated from the ground. On the other hand, the ground land portion 10 on the lower surface 7b of the lower printed circuit board 12 is insulated from the feeding point 8 (signal line 15), and is electrically connected (electrically connected) to the ground electrode 6 on the upper surface 6a. )

  That is, the signal line 15 and the first signal land portion 9 are soldered to the upper surface 2a of the upper printed circuit board 11, and the signal line 15 and the second signal land portion 16 are grounded on the lower surface 7b of the lower printed circuit board 12. Soldered in a state of being insulated from the land portion 10. Therefore, when the antenna device 1 is assembled, the signal line 15 can be soldered to the upper surface 2a side (outer side) of the upper printed circuit board 11 and the lower surface 7b side (outer side) of the lower printed circuit board 12. Easy to do. In FIG. 12, the ground land portion 10 is connected to the ground terminal 18 f of the electronic circuit (circuit element) 18, and the second signal land portion 16 is connected to the antenna terminal of the electronic circuit (circuit element) 18 via the microstrip line 19. (Input terminal) 18a is connected.

  FIG. 13 shows a connection relationship between the microstrip line 19 provided on the lower surface 7 b of the lower printed circuit board 12 and the electronic circuit 18. As shown in FIGS. 12 and 13, the lower surface 7 b of the lower printed circuit board 12 extends from the second signal land portion 16 joined to the signal line 15 through the solder 17 and the second signal land portion 16. A microstrip line 19 is formed, and the microstrip line 19 is electrically connected to an electronic circuit (circuit element) 18. The electronic circuit 18 includes a low noise amplifier circuit.

  FIG. 14 shows the internal configuration of the electronic circuit 18. FIG. 14 is a configuration example of the electronic circuit 18 in the case of configuring an active antenna using a low noise amplifier. The electronic circuit 18 includes an antenna terminal 18a, a low noise amplifier (LNA) 18c, a band-pass filter (BPF) 18d, a bias connected to the antenna 20 (a part excluding the electronic circuit 18 in FIG. 12) in order from the input side. It has a tee (Bias Tee) 18e and an output terminal 18b. The output terminal 18b is connected to a demodulation IC 21 (demodulator), which is an external receiving circuit.

  As described above, the signal line 15 is connected to the microstrip line 19 via the second signal land 16 on the lower surface 7 b side of the lower printed circuit board 12. That is, since the second signal land portion 16 is also a part of the microstrip line 19, the second signal land portion 16 and the microstrip line 19 are provided with a predetermined distance from the ground land portion 10. Yes. Specifically, the second signal land 16 and the microstrip line 19 are provided via the ground land 10 and a gap 10c having a predetermined width. Thereby, the microstrip line 19 can transmit a high frequency signal. The gap 10c is designed so that the characteristic impedance of the microstrip line 19 becomes a desired value (usually 50Ω).

  Here, since the upper surface 6a of the lower printed circuit board 12 is a surface (ground surface) on which the ground electrode 6 is formed, the lower surface 7b is electromagnetically separated from the antenna portion. Therefore, the electronic circuit 18 can be mounted by mounting circuit components or the like on the lower surface 7b.

  As described above, the antenna device 1 of this embodiment includes the intermediate dielectric substrate 4 between the patch electrode 3 of the upper printed circuit board 11 and the ground electrode 6 of the lower printed circuit board 12 disposed to face the patch electrode 3. The patch antenna structure is formed by disposing the gap 5. Thereby, the antenna device 1 can implement | achieve a patch antenna using an inexpensive printed circuit board (dielectric substrate).

  As a result, the material cost for manufacturing the patch antenna can be reduced. That is, the antenna device 1 according to the present embodiment forms a hollow patch antenna by three printed boards (upper printed board 11, intermediate dielectric board 4, and lower printed board 12). Due to this mass production effect, the cost of the patch antenna can be reduced.

  In the manufacturing process of the antenna device 1, the signal line 15 is connected to the upper printed circuit board 11 and the lower printed circuit board by soldering on the upper surface 2 a side (outer side) of the upper printed circuit board 11 and the lower surface 7 b side (outer side) of the lower printed circuit board 12. It can be fixed to the substrate 12. That is, the soldering operation can be performed on the outer surfaces of the two printed boards, and the soldering operation can be easily performed. This facilitates the assembly work of the antenna device 1 and contributes to a reduction in manufacturing cost.

  Further, in the antenna device 1 according to the present embodiment, the position of the central portion in plan view of the patch electrode 3 of the upper printed board 11 and the position of the central portion in plan view of the ground electrode 6 of the lower printed board 12 Are substantially opposed to each other. As a result, an electric field is easily collected at the center of the patch electrode 3, and the degree of increase in radiation efficiency in the antenna device 1 can be further increased.

  Further, in the antenna device 1 according to this embodiment, the intermediate dielectric substrate 4 is disposed on the lower surface of the patch electrode 3. For this reason, the antenna device 1 is expected to have a wavelength shortening effect due to the influence of the dielectric constant, compared to an antenna device having a structure without the intermediate dielectric substrate 4 (hereinafter referred to as “comparator”). Due to the wavelength shortening effect, the size of one side of the patch electrode 3 can be made smaller than that of the comparison device, and accordingly, the antenna device 1 can be made smaller than the comparison device that handles the same radio wave. Further, since one side of the patch electrode 3 is reduced, the area of the patch electrode 3 can be smaller than the area of the patch electrode of the comparison device. This acts in the direction of weakening the beam forming effect of the electromagnetic field radiated by the current flowing through the patch electrode 3, and the directivity can be expanded as compared with the comparison device.

  Due to the spread of directivity, the antenna device 1 is suitable for use in a wireless communication system, for example. In particular, in a mobile communication system, the positional relationship (direction) between a transmitter and a receiver cannot be specified in many cases. Therefore, the wide directivity antenna device 1 is suitable for use in a mobile communication system.

(2) Example 2
FIG. 15 shows a schematic structure of the antenna device 1A according to the present embodiment. Also in the case of FIG. 15, the pole 13 and the screw 14 are omitted. In the antenna device 1A according to the present embodiment, a coaxial connector 25 is mounted on the lower surface 7b of the lower dielectric substrate 7, as shown in FIGS. The antenna device 1A is shipped as a patch antenna alone, for example.

  The coaxial connector 25 has a signal terminal 25a and a ground terminal 25b. The signal line 15 is provided in the through hole 11 c provided in the upper printed board 11, the through hole 4 c provided in the intermediate dielectric board 4, and the lower printed board 12 as in the antenna device 1 of the first embodiment. The through hole 12c formed is penetrated. One end (upper end portion) of the signal line 15 is electrically connected to the patch electrode 3 by a first signal land portion 9 formed on the upper surface 2 a of the upper printed board 11, through-hole wiring, and solder 17. On the other hand, the other end (lower end) of the signal line 15 is exposed as a signal terminal 25 a of the coaxial connector 25 mounted on the lower surface 7 b of the lower dielectric substrate 7.

  The feeding point 8 does not need to be at the center position of the patch electrode 3 as in the first embodiment, and is slightly displaced from the center of the patch electrode 3 with respect to the X direction in FIG. 15 (impedance becomes 50Ω). Position). Also in this embodiment, as shown in FIG. 16, a gap 6c is formed on the upper surface 6a of the lower printed circuit board 12 so as to surround the through hole 12c, and the signal line 15 and the ground electrode 6 are connected by the gap 6c. Insulated. Further, a clearance 6c may be formed between the lower printed circuit board 12 and the ground land 10 so as to surround the through hole 12c. The gap 6c is formed with a width of 0.2 mm, for example, from the edge of the opening of the through hole 12c. Thereby, an electrical short circuit (short circuit) among the signal line 15, the ground electrode 6, and the ground land portion 10 can be prevented.

  In the case of FIG. 16, the ground terminal 25 b of the coaxial connector 25 is electrically connected to the ground land portion 10 and the via hole wiring (conductor) via the solder 17 on the lower surface 7 b of the lower printed circuit board 12. The ground electrode 6 on the upper surface 6a of the lower printed board 12 and the ground land portion 10 on the lower surface 7b are electrically connected via a plurality of via-hole wirings.

  With the above connection relationship, the signal terminal 25a (that is, the signal line 15) of the coaxial connector 25 mounted on the lower surface 7b of the lower printed circuit board 12 is connected to the patch electrode 3 formed on the lower surface 2b of the upper printed circuit board 11 and the solder 17 And electrically connected through the through-hole wiring. Thus, also in the case of the antenna device 1 of the present embodiment, the signal line 15 and the first signal land portion 9 are joined by the solder 17 on the upper surface 2a of the upper printed circuit board 11, while the lower printed circuit board 12 On the lower surface 7 b, the ground terminal 25 b of the coaxial connector 25, the ground land portion 10, and the via hole wiring are joined by the solder 17.

  That is, also in the case of the present embodiment, the first signal land portion 9 on the upper surface 2a of the upper printed circuit board 11 and the patch electrode 3 on the lower surface 2b are electrically connected at the feeding point 8, and are insulated from the ground. Has been. On the other hand, the ground land portion 10 on the lower surface 7b of the lower printed circuit board 12 is insulated from the feeding point 8 (signal terminal 25a) and is electrically connected (electrically connected) to the ground electrode 6 on the upper surface 6a. )

  Therefore, when the antenna device 1A is assembled, the signal terminal 25a (that is, the signal line 15) of the coaxial connector 25 can be soldered on the upper surface 2a side (outside) of the upper printed board 11, and the coaxial connector 25 The ground terminal 25b can be soldered on the lower surface 7b side (outside) of the lower printed circuit board 12. That is, the soldering operation can be performed on the outer surfaces of the two substrates, and the above operation can be easily performed. In particular, the coaxial connector 25 can be soldered from the outside of the vertically stacked structure of the antenna device 1A, and the antenna device 1A can be easily assembled. As a result, as in the case of the first embodiment, the assembly operation can be facilitated and the manufacturing cost can be reduced in the antenna device 1A.

(3) Example 3
FIG. 17 shows a schematic structure of the antenna device 1B according to the present embodiment. The antenna device 1B shown in FIG. 17 has two feeding points 8a and 8b on the upper surface 2a of the upper printed board 11. These two feed points 8a and 8b are feed points that can receive orthogonal polarization components, respectively, and can be used as antennas for polarization diversity. Furthermore, an antenna capable of receiving circularly polarized waves can be configured by combining signals received at the feeding point 8a and the feeding point 8b with a phase difference of 90 degrees. Although this embodiment has been described assuming a receiving antenna, the same discussion can be applied to a transmitting antenna as it is.

(4) Example 4
FIG. 18 shows a configuration example of the antenna device 1 </ b> C configured such that the feeding point 8 </ b> A penetrates the intermediate dielectric substrate 4 but does not penetrate the upper dielectric substrate 2. In the case of this embodiment, the feeding point 8A is directly connected to the patch electrode 3 by a conductive material. Here, as the conductive material, a material such as a silver paste or a conductive adhesive, a conductive double-sided tape such as a copper tape, an aluminum tape, or the like can be used. Of course, solder may be used.

(5) Design Example Hereinafter, a specific design example of the antenna device 1, 1A, 1B (hereinafter simply referred to as “1”) will be described. Here, the case of using the antenna device for GPS (center frequency 1575.42 MHz) will be described. FIG. 19 shows three design examples, Design A (Design A), Design B (Design B), and Design C (Design C). Although not shown in FIG. 19, the dimensions of the patch electrode 3 are designed so that the antenna devices of Design A, Design B, and Design C all have a resonance frequency of 1575.42 MHz.

  FIG. 20 shows the positional relationship between the designs A, B, and C within the design range of the antenna device 1 according to the embodiment. FIG. 21 shows a simulation result of the radiation pattern obtained by the antenna device of design A. The operating gain of the antenna device of design A is shown in unit dBi. Both the polarization component in the θ direction and the polarization component in the φ direction have an operating gain of approximately 5 dBi, and the −3 dB half-value width is approximately ± 40 ° for the polarization component in the θ direction and approximately ± 45 ° for the polarization component in the φ direction. It is.

  FIG. 22 shows a simulation result of the radiation pattern obtained by the antenna device of design B. The operating gain of the antenna device of design B is shown in unit dBi. Both the polarization component in the θ direction and the polarization component in the φ direction have an operating gain of approximately 2 dBi, and the −3 dB half-value width is approximately ± 50 ° for the polarization component in the θ direction and approximately ± 40 ° for the polarization component in the φ direction. It is.

  FIG. 23 shows a simulation result of the radiation pattern obtained by the antenna device of design C. The operational gain of the antenna device of design C is indicated in dBi. Both the polarization component in the θ direction and the polarization component in the φ direction have an operating gain of about 3 dBi, and the −3 dB half bandwidth is about ± 55 ° for the polarization component in the θ direction and about ± 40 ° for the polarization component in the φ direction. It is.

  As described above, the antenna apparatus according to the present invention appropriately selects tu, ti, and dg within the range of Equation 1, so that the radiation pattern characteristics such as gain, beam width, etc., and the frequency bandwidth can be set to the specifications of the radio system. It is possible to design appropriately.

(6) Other Embodiments The present invention is not limited to the above-described embodiments, and includes various modifications. For example, in the description of the above-described embodiment, the case where the upper printed circuit board 11 and the lower printed circuit board 12 of the antenna device 1 are supported by the pole 13 and the screw 14 at each of the four corners has been described. However, if the signal line 15 formed of a highly rigid conductor member is bonded to each substrate with a solder 17 with a high bonding force, the antenna device 1 does not necessarily provide the poles 13 and the screws 14 at the four corners. It's okay.

  In addition, although the present invention has been specifically described in the above-described embodiments, it is needless to say that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. In addition, this invention is not limited to above-described embodiment, Various modifications are included. For example, the above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to one having all the configurations described.

  Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. . In addition, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment. In addition, each member and relative size which were described in drawing are simplified and idealized in order to demonstrate this invention clearly, and it becomes a more complicated shape on mounting.

DESCRIPTION OF SYMBOLS 1, 1A, 1B, 1C ... Antenna apparatus 2 ... Upper dielectric substrate 3 ... Patch electrode 4 ... Intermediate dielectric substrate 4c ... Through-hole 5 ... Air gap 6 ... Ground electrode 6c ... Gap part 7 ... Lower dielectric substrate 8, 8A ... Feeding points 9, 16 ... Signal land 10 ... Ground land 10c ... Gap 11 ... Upper printed circuit board 11c, 11d ... Through hole 12 ... Lower printed circuit board 12c ... Through hole 12d ... Via hole wiring 13 ... Pole 14 ... Screw 15 ... Signal line 17 ... Solder 18 ... Electronic circuit 19 ... Microstrip line 25 ... Coaxial connector

Claims (9)

An upper dielectric substrate having a first surface and a second surface;
A patch electrode having a third surface and a fourth surface;
An intermediate dielectric substrate having a fifth surface and a sixth surface;
A ground electrode having a seventh surface and an eighth surface;
A lower dielectric substrate having a ninth surface and a tenth surface;
The upper dielectric substrate and the patch electrode are disposed such that the second surface and the third surface are in contact with each other,
The patch electrode and the intermediate dielectric substrate are disposed so that the fourth surface and the fifth surface are in contact with each other,
The intermediate dielectric substrate and the ground electrode are arranged so that the sixth surface and the seventh surface face each other with a gap therebetween,
The ground electrode and the lower dielectric substrate are disposed such that the eighth surface and the ninth surface are opposed to each other.
Antenna device. The antenna device according to claim 1,
Let λ be the wavelength in free space at the center frequency,
The thickness of the upper dielectric substrate is tu,
The thickness of the intermediate dielectric substrate is ti,
When the thickness of the gap is dg,
An antenna device characterized by satisfying the following relationship:

The antenna device according to claim 1,
A first land portion formed on the first surface;
A second land portion formed on the tenth surface;
A third land portion formed on the tenth surface and electrically insulated from the second land portion;
The upper dielectric substrate; the intermediate dielectric substrate; and a conductor member penetrating the lower dielectric substrate.
The first land portion and the patch electrode are electrically connected;
The second land portion and the ground electrode are electrically connected;
The antenna device, wherein the third land portion and the first land portion are electrically connected via the conductor member. The antenna device according to claim 3, wherein
There is a plurality of the conductor members. An antenna device, wherein: The antenna device according to claim 1,
The antenna device further comprising an electronic circuit mounted on the tenth surface. The antenna device according to claim 5, wherein
The electronic circuit includes a low-noise amplifier circuit, and a signal line is electrically connected to an input terminal of the electronic circuit. The antenna device according to claim 1,
A first land portion formed on the first surface;
A second land portion formed on the tenth surface;
A connector that has a ground terminal and a signal terminal electrically insulated from each other, and is attached to the tenth surface;
The upper dielectric substrate; the intermediate dielectric substrate; and a conductor member penetrating the lower dielectric substrate.
The first land portion and the patch electrode are electrically connected;
The second land portion and the ground electrode are electrically connected;
The second land portion and the ground terminal are electrically connected;
One end of the first land portion is electrically connected to the other end of the conductor member that forms the signal terminal. The antenna device according to claim 1,
A first land portion formed on the tenth surface;
A connector that has a ground terminal and a signal terminal electrically insulated from each other, and is attached to the tenth surface;
The intermediate dielectric substrate; and a conductor member penetrating the lower dielectric substrate;
The first land portion and the ground electrode are electrically connected;
The first land portion and the ground terminal are electrically connected;
One end of the patch electrode is directly directly connected to the other end of the conductor member forming the signal terminal. The antenna device according to claim 1,
An antenna apparatus, further comprising: a plurality of poles for connecting and supporting the upper dielectric substrate, the patch electrode, the substrate member composed of the intermediate dielectric substrate, and the lower dielectric substrate.

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