JP6447119B2 - Antenna device - Google Patents

Description

  The present invention relates to an antenna device including a metal plate functioning as a ground and another metal plate arranged to face the metal plate.

  As disclosed in Patent Document 1, a metal plate that functions as a ground (referred to as a ground plane) and another metal plate that is disposed so as to face the ground plane and that is provided with a feeding point at an arbitrary position ( There is an antenna device that includes a counter conductor plate) and a short-circuit portion (30) that electrically connects the ground plane and the counter conductor plate.

  In this type of antenna device, parallel resonance is generated at a frequency corresponding to the capacitance and the inductance by the capacitance formed between the ground plane and the opposing conductor plate and the inductance provided in the short-circuit portion. And the radio wave of a desired frequency is radiated | emitted and received with the electric field which arises between an opposing conductor plate and a ground plane with parallel resonance.

  Since the capacitance formed between the ground plane and the opposing conductor plate is determined according to the area of the opposing conductor plate, the antenna device is subject to transmission / reception by adjusting the area of the opposing conductor plate. The frequency (referred to as the operating frequency) can be set to a desired frequency.

  Patent Document 1 discloses a configuration in which a ground plane and a counter conductor plate are arranged in an inner layer portion of a printed board including a plurality of layers made of an insulator. More specifically, the antenna device of Patent Document 1 has a configuration in which a ground plate and a counter conductor plate are stacked with a plate-shaped member (insulating plate) made of an insulator interposed therebetween.

JP 2014-107746 A

  In the antenna device disclosed in Patent Document 1, the ground plate and the opposing conductor plate are configured to sandwich an insulating plate. For this reason, the energy of the electric field generated between the opposing conductor plate and the ground plane is lost as thermal energy in the insulating plate (so-called dielectric loss), and the gain of the antenna is reduced.

  The present invention has been made based on this situation, and an object of the present invention is to provide an antenna device capable of suppressing a decrease in gain due to dielectric loss.

In order to achieve the object, the present invention includes a ground plane (10), an opposing conductor plate (20) which is a flat conductor member disposed in parallel with the ground plane at a predetermined interval, an opposing conductor plate and a ground plane. And a support portion (50) made of a dielectric material that supports the opposing conductor plate so that the opposing conductor plate is opposed to the opposing conductor plate with a space therebetween, and a central portion of the opposing conductor plate. A short circuit portion (30) for electrically connecting the opposing conductor plate and the ground plane; and a power feeding portion (40) for supplying power to the opposing conductor plate. The area of the opposing conductor plate is short-circuited at a predetermined frequency. It is an area that forms an electrostatic capacitance that causes parallel resonance with the inductance of the part, and a part of the space between the opposing conductor plate and the ground plane has a lower dielectric constant than the hollow part that is hollow or the support part It is a low dielectric part filled with dielectric, and the support part is A plate-like member, and the shape of the dielectric portion in the cross section perpendicular to the thickness direction is formed to have a lattice or honeycomb structure, the area of the flat portion is greater than the area of the opposing conductor plates It is characterized by that.

  In the above configuration, a hollow portion is formed between the opposing conductor plate and the ground plane. Therefore, compared to the configuration in which a dielectric is filled between the opposing conductor plate and the ground plane as in Patent Document 1, the electric field generated between the opposing conductor plate and the ground plane due to parallel resonance is less than the dielectric. Not easily affected by That is, according to the above configuration, it is possible to suppress a decrease in gain due to dielectric loss.

  In addition, the code | symbol in the parenthesis described in the claim shows the correspondence with the specific means as described in embodiment mentioned later as one aspect, Comprising: The technical scope of this invention is limited is not.

It is a top view of antenna device 100 in a 1st embodiment. It is an enlarged view of the cross section of the antenna apparatus 100 in the 2-2 line shown in FIG. It is a figure which shows schematic structure of the antenna apparatus 100X of a comparison structure. It is a radar chart which shows the directivity of the antenna apparatus 100X of this embodiment, and the antenna apparatus 100X of a comparison structure. It is a figure for demonstrating an example of schematic structure of 100 A of antenna apparatuses in 2nd Embodiment. It is a figure for demonstrating an example of the schematic structure of the antenna apparatus 100B in the modification 1. FIG. It is a figure which shows the relationship between the shape of the support part 50B, and the directivity in a horizontal surface. It is a schematic diagram of a cross section perpendicular | vertical to the thickness direction which shows an example of the schematic structure of 50 C of support parts in the modification 3. FIG. It is a schematic diagram of a cross section perpendicular | vertical to the thickness direction which shows an example of the schematic structure of 50 C of support parts in the modification 4. It is a figure for demonstrating an example of the schematic structure of the printed circuit board 200 containing the antenna apparatus 100E in the modification 5. FIG.

<First Embodiment>
Hereinafter, a first embodiment of the present invention (hereinafter also referred to as a first embodiment) will be described with reference to the drawings. FIG. 1 is a top view illustrating an example of a schematic configuration of an antenna device 100 according to the present embodiment. FIG. 2 is an enlarged view of a cross section of the antenna device 100 taken along line 2-2 shown in FIG. As shown in FIGS. 1 and 2, the antenna device 100 includes a ground plane 10, a counter conductor plate 20, a short-circuit portion 30, a power feeding portion 40, and a support portion 50.

  The antenna device 100 is used, for example, in a vehicle, and is used for transmitting / receiving radio waves of a predetermined frequency (for example, 750 MHz), or for transmitting or receiving. The antenna device 100 is connected to a radio (not shown) via a coaxial cable, for example, and signals received by the antenna device 100 are sequentially output to the radio.

  The wireless device uses a signal received by the antenna device 100 and supplies high-frequency power corresponding to the transmission signal to the antenna device 100. In the present embodiment, description will be made on the assumption that a coaxial cable is employed as a feed line to the antenna device 100, but other known feed lines such as a feeder line may be used.

  The antenna device 100 is preferably installed such that, for example, in the roof portion of the vehicle, the ground plane 10 is substantially horizontal and the direction from the ground plane 10 toward the opposing conductor plate 20 is substantially coincident with the zenith direction. In this case, the antenna device 100 forms the same directivity for all horizontal directions as will be described later. Hereinafter, a specific configuration of the antenna device 100 will be described.

  The ground plane 10 is a square plate (including foil) made of a conductor such as copper. The ground plane 10 is electrically connected to the outer conductor of the coaxial cable to form a ground potential (ground potential) in the antenna device 100. In addition, the ground plane 10 should just be larger than the opposing conductor board 20, and the shape is not restricted to square shape. For example, the base plate 10 may have a rectangular shape, other polygonal shapes, or a circular shape (including an ellipse). Of course, the shape which combined the linear part and the curved part may be sufficient.

  The counter conductor plate 20 is a square plate (including foil) made of a conductor such as copper. The opposing conductor plate 20 is disposed opposite to the ground plane 10 with a predetermined interval h (see FIG. 2) through the support portion 50 so that their surfaces are parallel (including substantially parallel). The interval h may be designed as appropriate, for example, 0.8 mm or 1.0 mm. Here, although the shape of the opposing conductor plate 20 is a square shape, the other configuration may be a rectangular shape or a shape other than a rectangle (for example, a circle or a hexagon). Moreover, a partial notch, a slot, or the like may be provided.

  The opposing conductor plate 20 and the ground plane 10 face each other, and thus can be regarded as a capacitor that forms a capacitance according to the area of the opposing conductor plate 20. The capacitance formed between the ground plane 10 and the opposing conductor plate 20 is determined according to the area of the opposing conductor plate 20.

  The area of the opposing conductor plate 20 is an area that forms an inductance included in the short-circuit unit 30 described later and a capacitance that resonates in parallel at a frequency to be transmitted and received (target frequency). The target frequency may be designed as appropriate, and is 750 MHz exemplified here.

  The short-circuit portion 30 is a portion that is electrically connected to the opposing conductor plate 20 and the ground plane 10, and is provided in the central portion of the opposing conductor plate 20. Here, the center portion refers to the intersection (that is, the center) of the diagonal line of the opposing conductor plate 20 and the vicinity thereof. The short circuit part 30 should just be implement | achieved by the electroconductive pin (it is set as a short pin). The inductance of the short-circuit part 30 can be adjusted by the thickness of the short pin.

  Here, the vicinity of the center of the opposing conductor plate 20 (that is, the central portion) is a directivity bias caused by a deviation between the center of the opposing conductor plate 20 and the position where the short-circuit portion 30 is provided. Refers to a region that falls within a predetermined tolerance.

  The region indicated by the central portion may be appropriately defined depending on the distance from the center, and may be a region within a certain distance from the center of the opposing conductor plate 20, for example. The fixed distance here may be, for example, a length of about one fifth of the length of one side of the counter conductor plate 20.

  The power feeding unit 40 is a part that electrically connects the antenna device 100 and the coaxial cable, and as shown in FIG. 2, a power feeding point 41 where the inner conductor of the coaxial cable and the opposing conductor plate 20 are electrically connected. And a grounding point 42 for electrically connecting the outer conductor of the coaxial cable and the ground plane 10. The power feeding point 41 is, for example, a connection point between one end of a conductive pin (referred to as a power feeding pin) provided so as to penetrate a support portion 50 described later and the opposing conductor plate 20. The other end of the power supply pin is electrically connected to the inner conductor of the coaxial cable. Note that the power feed pin only needs to be provided so as not to be electrically connected to the ground plane 10. For example, the ground plane 10 is provided with a hole for keeping non-contact with the power feed pin, and power is fed through the hole. The other end of the pin and the internal conductor may be connected.

  The position of the feeding point 41 on the opposing conductor plate 20 may be a position where impedance matching between the coaxial cable and the antenna device 100 can be achieved at the target frequency. In this embodiment, it is set as the aspect provided in the vicinity of the short circuit part 30, ie, the center part of the opposing conductor plate 20. FIG. The state where the impedance is matched is not limited to the complete matching state, but includes a state where the loss due to the impedance mismatch is within a predetermined allowable range. Further, the power feeding point 41 may be provided at the end portion of the counter conductor plate 20, as in Patent Document 1.

  The wireless device supplies power energy from the power feeding unit 40 to the antenna device 100 to cause the antenna device 100 to radiate radio waves of the target frequency and to acquire a signal based on the radio waves of the target frequency. The power feeding unit 40 may be configured to connect the coaxial cable and the antenna device 100 via a known matching circuit or filter circuit.

  The support portion 50 is made of an electrically insulating material (that is, a dielectric) such as resin, and holds the opposing conductor plate 20 with a predetermined distance h from the ground plane 10 so that the plane portions thereof face each other. It is a member. In the present embodiment, the support portion 50 is provided so that at least the short-circuit portion 30 and the power feeding portion 40 are not exposed (that is, included).

  More specifically, the support portion 50 is formed in a columnar shape having a radius R with the short-circuit portion 30 as the center. The radius R should just be larger than the distance from the short circuit part 30 to the feeding point 41, and should just be designed suitably. Note that the larger the radius R, the greater the amount of dielectric that exists between the opposing conductor plate 20 and the ground plane 10, and accordingly, there is a concern about an increase in dielectric loss described later. Therefore, it is preferable that the radius R is as small as possible as long as the holding strength of the opposing conductor plate 20 satisfies a condition that is appropriately designed. Here, the radius R is set so that the volume occupied by the support 50 is 15% in the space between the opposing conductor plate 20 and the ground plane 10.

  Hereinafter, of the volume of the portion sandwiched between the opposing conductor plate 20 and the ground plane 10, the proportion of the portion that becomes the hollow portion is referred to as the hollow portion ratio. The hollow portion ratio in the present embodiment is 85%, but this target value may be designed as appropriate.

  This support part 50 should just be formed by inject | pouring a predetermined electrically insulating material between the center part of the opposing conductor board 20, and the ground plane 10, for example. Or after forming the support part 50 on the ground plane 10, you may form the short circuit part 30 and the electric power feeding part 40 by providing a short pin and an electric power feeding pin so that the said support part 50 may be penetrated. That is, the order in the manufacturing process of the antenna device 100 may be any.

  And according to the above structure, as shown in FIG. 2, the part where the distance from the short circuit part 30 becomes more than the radius R among the area | regions pinched | interposed by the opposing conductor plate 20 and the ground plane 10 becomes the hollow part Sp. Here, the centrifugal direction refers to a direction from the short-circuit portion 30 toward the outer edge portion of the opposing conductor plate 20, and the hollow portion Sp refers to a portion where no object exists and a vacuum or a predetermined gas exists.

  In addition, although the shape of the support part 50 is made into a column shape here, it is not restricted to this. As another aspect, the support portion 50 may be a polygonal (for example, quadrangular) pillar. Furthermore, the opposing conductor plate 20 may be supported by a plurality of support portions 50 including a support portion 50 provided at the center portion thereof. For example, a plurality of relatively small columnar support portions may be provided around the columnar support portion 50 provided in the central portion.

  However, the support part 50 preferably has a cross-sectional shape in a plane parallel to the ground plane 10 having a symmetry with respect to the short-circuit part 30. This is because, if the shape of the support portion 50 is asymmetric with respect to the short-circuit portion 30, the influence of the support portion 50 on the electric field from the short-circuit portion 30 toward the outer edge portion of the opposing conductor plate 20 (details will be described later) Moreover, it becomes asymmetric with respect to the short circuit part 30, and there exists a possibility of producing a bias in directivity.

(Operation of the antenna device 100)
Next, the operation of the antenna device 100 will be described. The operation when the antenna device 100 transmits (radiates) radio waves and the operation when the antenna devices 100 receive radio waves are reversible. Therefore, here, as an example, the operation when radiating radio waves will be described, and the description of the operation when receiving radio waves will be omitted.

  As described above, the opposing conductor plate 20 is short-circuited to the ground plane 10 by the short-circuit portion 30 provided at the center thereof, and the area of the opposing conductor plate 20 is parallel resonance at the inductance and the target frequency provided in the short-circuit portion 30. This is the area for forming the capacitance.

  For this reason, parallel resonance occurs due to energy exchange between the inductance and the capacitance, and an electric field perpendicular to the ground plane 10 (and the opposing conductor plate 20) is generated between the ground plane 10 and the opposing conductor plate 20. To do. The vertical electric field propagates from the short-circuit portion 30 toward the outer edge portion of the counter conductor plate 20, and the vertical electric field becomes a vertically polarized electric field and propagates through the space at the outer edge portion of the counter conductor plate 20. That is, the antenna device 100 radiates vertically polarized waves in the centrifugal direction at the outer edge portion of the opposing conductor plate 20.

  More specifically, the current generated in the opposing conductor plate 20 by parallel resonance flows in a direction from the edge of the opposing conductor plate 20 toward the center where the short-circuit portion 30 is provided. That is, the current is concentrated at the central portion of the opposing conductor plate 20, and the amplitude of the current standing wave is maximum at the central portion of the opposing conductor plate 20 and zero at both ends.

  In addition, since the short-circuit portion 30 is provided in the central portion of the counter conductor plate 20, the voltage standing wave has a maximum amplitude at both ends of the counter conductor plate 20, and an amplitude of zero near the center portion. Is the same sign (positive state in the figure) in the vertical direction in any region.

  Since the vertical electric field generated between the opposing conductor plate 20 and the ground plane 10 is proportional to the voltage distribution, the traveling direction thereof is the same in any region as viewed from the short-circuit portion 30 (for example, from the short-circuit portion 30 to the opposing conductor). Direction toward the edge of the plate 20). Further, the strength is 0 near the center portion and is maximum at the outer edge portion of the opposing conductor plate 20. That is, the electric field strength increases from the short-circuit portion 30 toward the outer edge portion of the opposing conductor plate 20, and is emitted as vertically polarized waves at the outer edge portion.

  For this reason, the antenna device 100 has directivity of vertically polarized waves in all directions from the central portion (that is, the short-circuit portion 30) of the counter conductor plate 20 toward the outer edge portion at the target frequency. In particular, when the ground plane 10 is arranged to be horizontal, the antenna device 100 has directivity in the horizontal direction. In addition, since the electric field propagation direction is symmetric about the short-circuit portion 30, it has the same gain with respect to all directions in the horizontal plane.

(About the effect of this embodiment)
Here, the antenna device 100X as a comparative configuration is introduced, and the effect of this embodiment will be described. FIG. 3 is a diagram corresponding to FIG. 1 and showing a schematic configuration of an antenna device 100X as a comparative configuration. However, in order to clarify the difference between the antenna device 100X and the present embodiment, FIG. 3 is a top view through which the counter conductor plate 20 is transmitted. A broken line in the figure indicates an outer edge portion of the counter conductor plate 20. In addition, about the member which has the same function as the member shown in the figure used for description of the structure of this embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  As shown in FIG. 3, the antenna device 100X as a comparative configuration supports the opposing conductor plate 20 by a support portion 50X made of a dielectric material having a hollow portion near the short-circuit portion 30 (that is, the central portion of the opposing conductor plate 20). To do. More specifically, the support portion 50 </ b> X is a member whose inner edge shape is a circular shape centering on the short-circuit portion 30 and whose outer edge shape is parallel to the outer edge of the opposing conductor plate 20.

  However, the dimensions of the support portion 50X are designed so that the hollow portion ratio in the antenna device 100X substantially matches the hollow portion ratio (85%) of the antenna device 100 in the embodiment. Further, the structural difference between the antenna device 100X and the antenna device 100 is only in the shape of the support portion.

  FIG. 4 shows a simulation result of directivity in each horizontal direction when the antenna device 100X and the antenna device 100 described above are arranged so that the ground plane 10 is horizontal. The solid line shown in FIG. 4 represents the gain characteristic of the antenna device 100 in the present embodiment, and the alternate long and short dash line represents the gain characteristic of the antenna device 100X in the comparative configuration.

  As shown in FIG. 4, the antenna device 100 and the antenna device 100X have directivities similar to each other. That is, neither the antenna device 100 nor the antenna device 100X causes a directivity deviation in the horizontal plane, and the directivity in the horizontal plane is substantially circular.

  However, the gain of the antenna device 100 of the present embodiment is greater in any direction than the comparative configuration. More specifically, the average gain of the comparative configuration is −7 dBi, whereas the average gain of the antenna device 100 of the present embodiment is −0.2 dBi.

  This is because the vertical electric field generated between the ground plane 10 and the opposing conductor plate 20 is a dielectric (that is, a support portion) provided between the opposing conductor plate 20 and the ground plane 10 in the present embodiment than in the comparative configuration. It is because it is hard to be influenced by. More specifically, it is as follows.

  As described above, the vertical electric field generated between the ground plane 10 and the opposing conductor plate 20 by the energy exchange between the inductance and the capacitance propagates from the short-circuit portion 30 toward the outer edge portion of the opposing conductor plate 20. . And in the outer edge part of the opposing conductor plate 20, a vertical electric field turns into a vertical polarization electric field, and is radiated | emitted to space. That is, the strength of the vertical electric field increases as the counter conductor plate 20 approaches the outer edge.

  Therefore, the influence of the dielectric on the vertical electric field is relatively small near the center of the counter conductor plate 20, and the influence of the dielectric on the vertical electric field is relatively large near the outer edge of the counter conductor plate. The influence of a dielectric on a vertical electric field is a dielectric loss and means that electromagnetic field energy is lost as thermal energy.

  That is, when the antenna device 100 and the antenna device 100X are compared, even if the hollow portion ratio is approximately the same, the gain characteristics differ depending on the arrangement position of the support portion, and the dielectric as the support portion 50 is near the short-circuit portion 30 ( In other words, a higher gain is achieved when it is formed in the central portion of the opposing conductor plate 20 and is a hollow portion near the outer edge of the opposing conductor plate 20.

  In the configuration of the present embodiment, a dielectric (that is, the support portion 50) for supporting the opposing conductor plate 20 with respect to the ground plane 10 is provided in the vicinity of the short-circuit portion 30 (that is, the central portion of the opposing conductor plate 20). The vicinity of the outer edge portion of the plate 20 is defined as a hollow portion. That is, the dielectric provided between the opposing conductor plate 20 and the ground plane 10 is concentrated between the center portion of the opposing conductor plate 20 and the ground plane 10, and between the area other than the central portion of the opposing conductor plate 20 and the ground plane 10. In the configuration, no dielectric is provided. Thereby, the loss by the said dielectric material can be suppressed.

  In addition, although the above demonstrated the aspect which made parts other than the support part 50 a hollow part among the area | regions between the opposing conductor plate 20 and the ground plane 10, it does not restrict to this. Parts other than the support part 50 may be filled with a dielectric having a dielectric constant smaller than that of the support part 50. Even in such an aspect, the same effects as those of the above-described embodiment can be obtained. A portion filled with a dielectric having a dielectric constant lower than that of the support portion 50 between the opposing conductor plate 20 and the ground plane 10 is referred to as a low dielectric portion.

  As mentioned above, although Embodiment 1 of this invention was demonstrated, this invention is not limited to the above-mentioned embodiment, The following embodiment is also contained in the technical scope of this invention, and also the summary other than the following Various modifications can be made without departing from the scope of the invention.

<Second Embodiment>
Next, a second embodiment of the present invention (hereinafter also referred to as a second embodiment) will be described with reference to the drawings. FIG. 5 is a schematic view corresponding to an exploded perspective view of the antenna device 100A according to the second embodiment. Similarly to the antenna device 100 of the first embodiment, the antenna device 100 </ b> A includes the ground plane 10, the opposing conductor plate 20, the short-circuit portion 30, the power feeding portion 40, and a support portion 50 </ b> A corresponding to the above-described support portion 50.

  In the following description, members having the same functions as those of the configuration of the first embodiment described above are denoted by the same reference numerals and description thereof is omitted. Moreover, in FIG. 5, the short circuit part 30 and the electric power feeding part 40 are only shown in the position on the opposing conductor board 20 and the ground plane 10, and illustration about the part which penetrates 50 A of support parts is abbreviate | omitted.

  The main difference between the second embodiment and the first embodiment described above lies in the manner of providing a hollow portion between the opposing conductor plate 20 and the ground plane 10, that is, the shape of the support portion 50A. Hereinafter, the support portion 50A will be described.

  The support portion 50 </ b> A in the second embodiment is a member on a flat plate made of a dielectric material that has the same area as the counter conductor plate 20 or a larger area than the counter conductor plate 20. More specifically, the support portion 50A has a partition wall made of a dielectric that stands upright with respect to each of the ground plane 10 and the opposing conductor plate 20, and is arranged in a lattice shape so as to form a plurality of rectangular parallelepiped hollow portions. It is configured. That is, the support portion 50A is formed such that a portion where the dielectric exists (partition wall portion) has a lattice shape in a cross section perpendicular to (including substantially vertical to) the thickness direction. The thickness of each partition wall should just be designed suitably. In FIG. 5, for the sake of convenience, the partition wall, the ground plane 10 and the opposing conductor plate 20 are simplified and shown with the thickness omitted. Of course, any member actually has a predetermined thickness.

  In such a configuration, the hollow portion is mainly configured between the opposing conductor plate 20 and the ground plane 10. Therefore, similarly to the first embodiment described above, it is possible to suppress the dielectric loss caused by the support portion 50A for supporting the counter conductor plate 20.

  In addition, although the structure which formed 50 A of support parts so that the outline of a hollow part may become a square in the cross section perpendicular | vertical to a thickness direction was illustrated above, it is not restricted to this. The support portion 50A may be formed so as to have a honeycomb structure whose cross-sectional shape is substantially hexagonal. Further, the support portion 50A only needs to be formed so as to include a plurality of hollow portions, and the cross-sectional shape is not limited to a quadrangle or a hexagon, and may be another shape (for example, an ellipse).

<Modification 1>
In addition, although the support part 50A illustrated the aspect provided with the partition wall along the outer edge part of the opposing conductor plate 20 so that the support part 50A may contact at right angles with the outer edge part of the opposing conductor plate 20, it is not restricted to this. As shown in FIG. 6, the support portion 50 </ b> B of the antenna device 100 </ b> B may not include a partition wall along the outer edge portion of the opposing conductor plate 20. For example, the support portion 50B may be formed so that a cross-sectional shape in a plane parallel to (including substantially parallel to) the ground plane 10 is a cross shape.

<Modification 2>
In the first modification described above, the support portion 50 </ b> B has a shape including a partition wall that equally divides the space sandwiched between the opposing conductor plate 20 and the ground plane 10, but the space sandwiched between the opposing conductor plate 20 and the ground plane 10. The number of divisions by the support part 50B is not limited to this. For example, the space between the opposing conductor plate 20 and the ground plane 10 may be divided into 16 by the support portion 50B, or may be divided into nine.

  FIG. 7 shows the result of a simulation for examining the relationship between the number of divisions by the support portion 50A in the space between the opposing conductor plate 20 and the ground plane 10 and the average gain. More specifically, FIG. 7 is a diagram showing a schematic diagram of the support portion 50B, the directivity in the horizontal plane, and the average gain when the number of divisions is changed to 16, 9, 4, 1. The scale of the radar chart indicating the directivity on the horizontal plane is the same as that of the radar chart shown in FIG.

  Note that the case where the number of divisions is 1 is the minimum necessary for including the support portion 50 in the center portion of the opposing conductor plate 20, the short pin as the short-circuit portion 30, and the power feed pin forming the power feed portion 40. This is the case when the volume is realized. In other words, in the configuration of the first embodiment, the radius R is set to the minimum value in the range in which the power feeding unit 40 is accommodated.

  From FIG. 7, it can be seen that any number of divisions has the same degree of directivity with respect to all the directions on the horizontal plane. In addition, the worst value of the average gain is a case of 16 divisions, but the value is -1.1 dBi.

  In other words, it was confirmed that no practical problem arises regardless of the number of divisions employed. The reason why the average gain slightly decreases as the number of divisions increases is that the larger the number of divisions, the more the dielectric partition walls are arranged closer to the outer edge portion of the opposing conductor plate 20.

<Modification 3>
In the configurations of the second embodiment and the first modification, among the plurality of hollow portions provided in the lattice-shaped support portion, as shown in FIG. 8, a portion that accommodates the short-circuit portion 30 and the power feeding portion 40 inside is a dielectric. It may be filled with. That is, the support portion 50 </ b> C may include an on-column portion (support column) 51 </ b> C in the vicinity of the center of the counter conductor plate 20. The same applies to various configurations mentioned in the second modification. Note that the support portion 50C may be formed by removing the thickness of the plate-shaped member made of a dielectric material so that the support pillar 51C remains and a hollow portion having a desired pattern is formed. good.

<Modification 4>
Moreover, as shown in FIG. 9, you may combine the structure of Embodiment 1, Embodiment 2, and various other modifications. For example, as in the configuration of the second embodiment, the support portion 50D formed so that the shape of the dielectric in the cross section parallel to the ground plane 10 is a lattice shape includes a columnar support column 51D at the center. Also good.

  Also in such an aspect, the density of the support portion 50D filled with the dielectric is smaller in the vicinity of the outer edge portion than in the vicinity of the central portion of the counter conductor plate 20. Therefore, the same effects as those of the first embodiment can be obtained.

<Modification 5>
Further, the antenna device according to the second embodiment and various modifications thereof described above may be realized so as to be included in a printed circuit board 200 including a plurality of layers, as shown in FIG. An example of the configuration of the antenna device 100 </ b> E and the printed circuit board 200 provided in the printed circuit board 200 will be described here.

  FIG. 10 is an exploded perspective view of the printed circuit board 200. The ground plane 10, the opposing conductor plate 20, the short-circuit portion 30, the power feeding portion 40, the first dielectric layer 50E, the second dielectric layer 60, and the metal pattern 70 are illustrated. Prepare.

  Each of the first dielectric layer 50 </ b> E and the second dielectric layer 60 is a plate-like member made of a dielectric having an area larger than at least the opposing conductor plate 20. More specifically, each of the first dielectric layer 50E and the second dielectric layer 60 is formed so that the shape of the portion where the dielectric exists is a lattice shape in a cross section perpendicular to the thickness direction. . In other words, the first dielectric layer 50E and the second dielectric layer 60 are members having a plurality of identically shaped hollow portions surrounded by partition walls arranged in a lattice pattern. The second dielectric layer 60 corresponds to the dielectric plate recited in the claims.

  The ground plane 10 is provided on one side of the first dielectric layer 50E, and the opposing conductor plate 20 is provided on the other side. That is, the first dielectric layer 50E is provided on the ground plane 10, and the opposing conductor plate 20 is laminated on the other surface of the first dielectric layer 50E. The first dielectric layer 50E plays a role of supporting the counter conductor plate 20 so that the distance from the ground plane 10 is a desired distance. Therefore, the first dielectric layer 50E corresponds to the above-described support portion 50B and the like.

  A second dielectric layer 60 is further laminated on the surface of the first dielectric layer 50E where the counter conductor plate 20 is provided. Then, in the second dielectric layer 60, a plate-like or foil-like metal pattern 70 is laminated on the surface that does not face the opposing conductor plate 20 and the first dielectric layer 50E.

  The short-circuit part 30 and the power feeding part 40 may be provided in a state in which, for example, the opposing conductor plate 20 and the ground plane 10 are provided on the first dielectric layer 50E. Note that the short pin as the short-circuit portion 30 and the power supply pin included in the power supply portion 40 may be sealed with the same dielectric as the dielectric constituting the first dielectric layer 50E.

  Of course, as another aspect, the portion where the short-circuit portion 30 and the power feeding portion 40 are provided in the first dielectric layer 50E may be configured to be filled with a dielectric without providing a hollow portion in advance. And it is good also as an aspect which forms the short circuit part 30 and the electric power feeding part 40 by inserting a short pin and an electric power feeding pin in a desired position at a next process.

  With the above configuration, the printed circuit board 200 has a structure in which the ground plane 10, the first dielectric layer 50E, the opposing conductor plate 20, the second dielectric layer 60, and the metal pattern 70 are sequentially laminated.

  Here, both of the first dielectric layer 50E and the second dielectric layer 60 are formed so that the dielectric portion has a lattice shape in a cross section perpendicular to the thickness direction. The first dielectric layer 50E and the second dielectric layer 60 are both larger than the counter conductor plate 20.

  Therefore, according to the above configuration, a hollow portion exists not only between the ground plane 10 and the opposing conductor plate 20 but also in a region outside the outer edge portion of the opposing conductor plate 20. That is, even in the region outside the outer edge portion of the opposing conductor plate 20, the ratio of the presence of the dielectric is suppressed, and the dielectric loss can be suppressed.

  That is, according to the above configuration, even when the antenna device 100E is configured using the inner layer of the printed circuit board 200, loss due to the dielectric can be suppressed.

100 · 100A · 100B · 100E Antenna device, 10 ground plane, 20 opposing conductor plate, 30 short-circuit portion, 40 feeding portion, 50 · 50A to D support portion, 50E first dielectric layer (support portion), 60 second dielectric Layer (dielectric plate), 70 metal pattern, Sp hollow, 200 printed circuit board

Claims (6)

A conductive ground plane (10);
An opposing conductor plate (20) which is a flat conductor member installed in parallel with the ground plate at a predetermined interval;
A support portion made of a dielectric, which is provided between the counter conductor plate and the ground plate, and supports the counter conductor plate so that the counter conductor plate faces the counter conductor plate at the interval. 50),
A short-circuit portion (30) provided at a central portion of the opposing conductor plate and electrically connecting the opposing conductor plate and the ground plane;
A power feeding section (40) that feeds power to the opposing conductor plate,
The area of the opposing conductor plate is an area that forms a capacitance that causes parallel resonance with the inductance included in the short-circuit portion at a predetermined frequency,
A part between the opposing conductor plate and the ground plane is a hollow part that is hollow, or a low dielectric part that is filled with a dielectric having a smaller dielectric constant than the support part ,
The support portion is a flat plate member, and is formed so that the shape of the dielectric portion in a cross section perpendicular to the thickness direction has a lattice shape or a honeycomb structure, and the area of the plane portion is the counter conductor. An antenna device characterized by being larger than an area of a plate . In claim 1,
The feeding portion is provided at a position where the distance from the short-circuit portion is a distance at which the impedance with the feeding line is matched in the central portion of the opposing conductor plate,
The support portion is provided so as to include the power feeding portion and the short-circuit portion in a central portion of the opposing conductor plate, and at least a part between the region other than the central portion in the opposing conductor plate and the ground plate is provided. An antenna device comprising the hollow portion or the low dielectric portion. In claim 2,
The antenna device according to claim 1, wherein the support portion is provided so that a space between the ground plate and a region other than a central portion of the counter conductor plate is the hollow portion. In claim 2,
The antenna device characterized in that the low dielectric portion is provided between a region other than the central portion of the counter conductor plate and the ground plane. In claim 3 or 4,
The antenna device according to claim 1, wherein the support portion has a structure in which a cross-sectional shape in a plane parallel to the ground plane has symmetry with respect to the short-circuit portion. In any one of Claim 1 to 5 ,
The antenna device, wherein a dielectric plate (60) made of a dielectric having the same shape as the support portion is laminated on a surface of the counter conductor plate that is not in contact with the support portion.

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