JP2014128004A - Patch antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a patch antenna having a wide specific bandwidth and high gain that are insusceptible to influences of a metal fixture.SOLUTION: A patch antenna 1 includes: a dielectric substrate 11; a first conductor plate 12; a second conductor plate 13; and a passive block 14. In the patch antenna 1, a lower surface of the passive block 14 contacts with the first conductor plate 12 and a side surface of the passive block 14 faces an outer edge of the second conductor plate 13 on an upper surface of the dielectric substrate 11.

Description

  The present invention relates to a patch antenna including two conductive plates facing each other with a dielectric substrate interposed therebetween.

  In recent years, wireless devices such as smartphones are becoming smaller and thinner. As an antenna to be mounted on such a wireless device, a demand for a small planar antenna is increasing.

  A patch antenna is a typical small planar antenna. Since the patch antenna is composed of two conductor plates (one is also referred to as “ground conductor” and the other is also referred to as “radiation conductor”) facing each other through a dielectric substrate, it is easy to reduce the thickness. In addition, it is possible to operate not only in the microwave band (0.3 GHz to 30 GHz) but also in the millimeter wave (30 GHz to 300 GHz).

  However, a patch antenna composed of only two conductor plates (feeding elements) facing each other through a dielectric substrate has a problem that it is difficult to increase the bandwidth. Thus, attempts have been made to expand the operating band of the patch antenna by disposing a parasitic element around the radiation conductor.

  For example, Patent Document 1 discloses a patch antenna in which two parasitic elements are arranged above a radiation conductor (on the side opposite to the ground conductor side). Patent Document 1 discloses a preferable numerical range for expanding the specific bandwidth with respect to the physical dimensions and electrical equivalent dimensions of these parasitic elements.

JP2009-188895 (released on August 20, 2009)

  However, the patch antenna described in Patent Document 1 designed to increase the specific bandwidth has a problem that it is difficult to realize a high gain. Further, the patch antenna described in Patent Document 1 has a problem that characteristics such as a specific bandwidth and a gain are deteriorated when a metal fixture such as a screw is used to fix the patch antenna to a wireless device or the like.

  The present invention has been made in view of the above problems, and an object thereof is a patch antenna having a wide specific bandwidth and a high gain, and the patch antenna is attached to a radio apparatus using a metal fixture. Even in the case of fixing, it is to realize a patch antenna in which these characteristics are not easily influenced by the metal fixture.

  In order to solve the above problems, a patch antenna according to the present invention includes a dielectric substrate, a first conductor plate formed on the lower surface of the dielectric substrate, and a second conductor plate formed on the upper surface of the dielectric substrate. And a parasitic block penetrating the dielectric substrate, a lower surface of the parasitic block is in contact with an upper surface of the first conductive plate, and a side surface of the parasitic block is the dielectric. It is characterized by facing the outer edge of the second conductor plate on the upper surface of the substrate.

  In the above configuration, the parasitic block acts to expand the specific bandwidth, like the parasitic element included in the conventional patch antenna. At the same time, the parasitic block has a lower surface in contact with the first conductor plate (ground conductor) and a side surface facing the second conductor plate (radiation conductor). The gap between the conductor plates functions as a slot in the slot antenna, and the gain is increased by radiation from the gap. Therefore, according to the above configuration, a patch antenna having a wide specific bandwidth and a high gain can be realized.

  Further, when the slot antenna is fixed to a wireless device or the like using a metal fixture such as a screw, a hole for penetrating the metal fixture can be formed in the parasitic block. Then, since the metal fixture is embedded in the parasitic block, the influence of the metal fixture on characteristics such as specific bandwidth and gain can be suppressed.

  In the patch antenna according to the present invention, the second conductor plate includes a square-shaped radiating portion formed at a central portion of the upper surface of the dielectric substrate and a strip-shaped power supply formed at a peripheral portion of the upper surface of the dielectric substrate. A feed path that has one end connected to one side of the radiating portion, and the parasitic block is opposed to three sides of the upper surface of the dielectric substrate except for the one side of the radiating portion. It is preferable to do.

  The above configuration has been confirmed by numerical calculation that the specific bandwidth is wider than when the parasitic block is omitted, and that the gain is higher than when the parasitic block is omitted. Therefore, according to the above configuration, the effects of widening the specific bandwidth and increasing the gain are surely achieved.

  In the patch antenna according to the present invention, it is preferable that b / a is 4 or more and 8 or less, where a is the thickness of the dielectric substrate and b is the height of the parasitic block.

  According to said structure, both a specific bandwidth and a gain can be kept at a high value.

  In the patch antenna according to the present invention, the length of each side of the radiating portion is c, and the width of the gap between the three sides of the radiating portion and the side surface of the parasitic block is d. It is preferable that it is 0.25 or more and 0.85 or less.

  According to said structure, a wide specific bandwidth (for example, 15% or more) is realizable.

  In the patch antenna according to the present invention, the length of each side of the radiating portion is c, and the width of the gap between the three sides of the radiating portion and the side surface of the parasitic block is d. It is preferable that it is 0.75 or more and 0.95 or less.

  According to said structure, a high gain (for example, 4 dBi or more) is realizable.

  The patch antenna according to the present invention is a parasitic element disposed in the same plane as the upper end of the parasitic block, and includes an annular conductor that overlaps an outer edge of the radiating portion, one end connected to the annular conductor, It is preferable to further include a parasitic element having an end and a strip-shaped conductor continuous with the upper end of the parasitic block.

  According to said structure, a gain can be raised further by the radiation | emission from the said annular conductor.

  In the patch antenna according to the present invention, it is preferable that f / e is 0.65 or more, where e is the outer diameter of the annular conductor and f is the inner diameter of the annular conductor.

  According to said structure, a wide specific bandwidth (for example, 15% or more) is realizable.

  In the patch antenna according to the present invention, it is preferable that a hole for penetrating the metal fixture is formed in the parasitic block.

  According to said structure, the said patch antenna can be fixed to a radio | wireless apparatus etc. using the said metal fixture, without causing deterioration of a characteristic (a reduction of a specific bandwidth, a fall of a gain, etc.).

  According to the present invention, it is possible to realize a patch antenna having a wide specific bandwidth and a high gain, and these characteristics are hardly affected by the metal fixture.

It is the top view and sectional drawing which show the structure of the patch antenna which concerns on one Embodiment of this invention. It is the top view and sectional drawing which show the structure of the patch antenna used for a comparison with the patch antenna shown in FIG. 3 is a graph showing the frequency dependence of the reflection coefficient | S11 | for the patch antenna shown in FIG. 1 and the patch antenna shown in FIG. 3 is a graph showing the angle dependence of gain (gains related to Eφ component and Eθ component) in the xz plane for the patch antenna shown in FIG. 1 and the patch antenna shown in FIG. 2. 3 is a graph showing the angle dependence of gain (gain related to Eθ component) in the yz plane for the patch antenna shown in FIG. 1 and the patch antenna shown in FIG. 2. It is a top view of the 2nd conductor board with which the patch antenna shown in FIG. 1 is provided, and a parasitic block. It is the top view and sectional drawing which show the 1st modification of the patch antenna shown in FIG. 9 is a graph showing the frequency dependence of the reflection coefficient | S11 | for the patch antenna (without screw holes) shown in FIG. 1 and the patch antenna (with screw holes) shown in FIG. FIG. 9 is a graph showing the angular dependence of gain (gain regarding Eφ component and Eθ component) in the xz plane for the patch antenna (without screw holes) shown in FIG. 1 and the patch antenna (with screw holes) shown in FIG. 8. 9 is a graph showing the angle dependence of gain (gain related to Eθ component) in the yz plane for the patch antenna (without screw holes) shown in FIG. 1 and the patch antenna (with screw holes) shown in FIG. 8. It is the top view and sectional drawing which show the 2nd modification of the patch antenna shown in FIG. 12 is a graph showing the frequency dependence of the reflection coefficient | S11 | for the patch antenna (without parasitic elements) shown in FIG. 1 and the patch antenna (with parasitic elements) shown in FIG. 12 is a graph showing the angular dependence of the gain (gain regarding Eφ component and Eθ component) in the xz plane for the patch antenna (without parasitic element) shown in FIG. 1 and the patch antenna (with parasitic element) shown in FIG. 12 is a graph showing the angle dependence of gain (gain related to Eθ component) in the yz plane for the patch antenna (without parasitic element) shown in FIG. 1 and the patch antenna (with parasitic element) shown in FIG. It is a top view of the parasitic block and parasitic element with which the patch antenna shown in FIG. 11 is provided. It is a graph which shows the specific height (b / a) dependence of a specific bandwidth (FWB) and a gain. It is a graph which shows the specific bandwidth (d / c) dependence of a specific bandwidth (FWB) and a gain. It is a graph which shows the specific internal diameter (f / e) dependence of a specific bandwidth (FWB) and a gain.

[Configuration of patch antenna]
A configuration of a patch antenna 1 according to an embodiment of the present invention will be described with reference to FIG. FIG. 1A is a top view of the patch antenna 1, and FIG. 1B is a cross-sectional view (AA ′ cross section) of the patch antenna 1. In addition, the numerical value shown in FIG. 1 represents the dimension of each part of the patch antenna 1, and the unit is mm. However, these numerical values merely define one specific example of the patch antenna 1 and can be changed as appropriate.

  As shown in FIG. 1B, the patch antenna 1 includes a dielectric substrate 11, a first conductor plate (sometimes referred to as a “ground conductor”) 12 formed on the lower surface of the dielectric substrate 11, And a second conductor plate (sometimes referred to as a “radiating conductor”) 13 formed on the upper surface of the dielectric substrate 11. An outer conductor of a coaxial cable (not shown) is connected to the first conductor plate 12, and an inner conductor of the coaxial cable is connected to the second conductor plate 13. The first conductor plate 12 and the second conductor plate 13 facing each other with the dielectric substrate 11 function as a patch antenna by the high-frequency current supplied from the coaxial cable.

  In the present embodiment, a square PTFE (polytetrafluoroethylene) substrate having a side of 15 mm is used as the dielectric substrate 11. The dielectric substrate 11 has a relative dielectric constant εr of 2.2, and the dielectric substrate 11 has a thickness a of 0.5 mm. In the present embodiment, a square conductor foil (for example, copper foil) having a side of 15 mm patterned on the lower surface of the dielectric substrate 11 is used as the first conductor plate 12.

  As shown in FIG. 1A, the second conductor plate 13 includes a radiating portion 13a formed at the center of the upper surface of the dielectric substrate 11, and a feed path 13b formed at the peripheral portion of the upper surface of the dielectric substrate 11. And have. One end of the power supply path 13 b is connected to the outer edge of the radiating portion 13 a, and the other end of the power supply path 13 b reaches the outer edge of the upper surface of the dielectric substrate 11. The power supply path 13 b forms a microstrip line together with the first conductor plate 12 that faces the dielectric substrate 11.

  In the present embodiment, a square conductor foil (for example, copper foil) having a side of 3.4 mm patterned on the upper surface of the dielectric substrate 11 is used as the radiating portion 13a. In the present embodiment, a strip-shaped conductor foil (for example, copper foil) having a width of 1.5 mm patterned on the upper surface of the dielectric substrate 11 is used as the power supply path 13b. One end of the feed path 13b is connected to the center of the four sides constituting the outer edge of the radiating portion 13a, and the other end of the feed path 13b constitutes the outer edge of the dielectric substrate 11. Out of the sides, it reaches the center of the side on the y-axis negative direction side.

  The patch antenna 1 includes a parasitic block 14 that penetrates the dielectric substrate 11 in addition to the dielectric substrate 11, the first conductor plate 12, and the second conductor plate 13 described above. As shown in FIG. 1B, the lower surface of the parasitic block 14 is in contact with the upper surface of the first conductor plate 12 formed on the lower surface of the dielectric substrate 11, and the upper surface of the parasitic block 14 is Projecting upward from the upper surface of the dielectric substrate 11. Further, as shown in FIG. 1A, the side surface of the parasitic block 14 (the surface constituting the surface of the parasitic block 14 is a surface orthogonal or substantially orthogonal to the lower surface and the upper surface) of the dielectric substrate 11. On the upper surface, it faces the outer edge of the second conductor plate 13 (more specifically, of the four sides constituting the outer edge of the radiating portion 13a, the three sides excluding the side that continues to the power feed path 13b).

  In the present embodiment, as the parasitic block 14, a conductor block including three conductor walls (for example, copper walls) 14a to 14c combined in a U-shape is used.

  The first conductor wall 14a has a side surface of 5.9 mm × 2 mm parallel to the yz plane and an end surface of 5.9 mm × 2 mm parallel to the xy plane. And as for the 1st conductor wall 14a, a lower end surface (end surface of the z-axis negative direction side) contacts the upper surface of the 1st conductor board 12, and an inner surface (side surface of the x-axis positive direction side) is a radiation | emission part. It is arranged so as to face one side of 13a (side on the x-axis negative direction side).

  The second conductor wall 14b has a side surface of 12.4 mm × 2 mm parallel to the zx plane and an end surface of 12.4 mm × 2 mm parallel to the xy plane. The second conductor wall 14b has a lower end surface (end surface on the z-axis negative direction side) that is in contact with the upper surface of the first conductor plate 12, and an inner side surface (side surface on the y-axis negative direction side) that is the radiating portion. Arranged so as to face one side 13a (side on the positive side of the y-axis).

  The third conductor wall 14c has a side surface of 5.9 mm × 2 mm parallel to the yz plane and an end surface of 5.9 mm × 2 mm parallel to the xy plane. The third conductor wall 14c has a lower end surface (end surface on the z-axis negative direction side) in contact with the upper surface of the first conductor plate 12, and an inner side surface (side surface on the x-axis negative direction side) is a radiating portion. Arranged so as to face one side of 13a (side on the x-axis positive direction side).

  The parasitic block 14 has an effect of enlarging the relative bandwidth of the band where the reflection coefficient | S11 | is equal to or less than a predetermined threshold value (10 dB in the present embodiment), and the upper side (the z-axis positive in FIG. 1). Direction) gain. These effects will be described later with reference to different drawings. In addition, when the parasitic block 14 fixes the patch antenna 1 to a member disposed above (in the positive z-axis direction in FIG. 1), the dielectric substrate 11, the first conductor plate 12, And it also functions as a spacer for separating the second conductor plate 13. This function will be described later with reference to another drawing.

[Effect of non-powered block]
The effect of the parasitic block 14 in the patch antenna 1 will be described with reference to FIGS.

  First, a patch antenna 5 used for comparison with the patch antenna 1 will be described with reference to FIG. FIG. 2A is a top view of the patch antenna 5, and FIG. 2B is a cross-sectional view (BB ′ cross-section) of the patch antenna 5. FIG.

  As shown in FIG. 2, the patch antenna 5 is obtained by omitting the parasitic block 14 from the patch antenna 1. The dielectric substrate 51, the first conductor plate 52, and the second conductor plate 53 included in the patch antenna 5 are the dielectric substrate 11, the first conductor plate 12, and the second conductor included in the patch antenna 1, respectively. It corresponds to the plate 13.

  FIG. 3 is a graph showing the frequency dependence of the reflection coefficient | S11 | of the patch antenna 1 (with a parasitic block) and the patch antenna 5 (without a parasitic block). From the graph shown in FIG. 3, it can be seen that the addition of the parasitic block 14 increases the specific bandwidth FWB of the band where the reflection coefficient | S11 | is 10 dB or more from 16% to 18%.

  Here, the specific bandwidth FWB is defined by FWB = (f2−f1) / {(f2 + f1) / 2} where f1 and f2 are a lower limit frequency and an upper limit frequency of a band where the reflection coefficient | S11 | is 10 dB or more. The numerical value to be expressed as a percentage.

  FIG. 4 is a graph illustrating radiation patterns (gain dependence on Eθ and Eφ components) on the zx plane of the patch antenna 1 (with a parasitic block) and the patch antenna 5 (without a parasitic block). From the graph shown in FIG. 4, it can be seen that the addition of the parasitic block 14 increases the gain in the zenith direction for both the Eθ component and the Eφ component.

  FIG. 5 is a graph showing radiation patterns (gain dependence on the Eθ component) on the yz plane of the patch antenna 1 (with a parasitic block) and the patch antenna 5 (without a parasitic block). From the graph shown in FIG. 5, it can be seen that the addition of the parasitic block 14 increases the gain in the zenith direction at least with respect to the Eθ component.

  Such an increase in the gain in the zenith direction occurs because the second conductor plate 13 and the parasitic block 14 facing each other through a gap function as a slot antenna on the upper surface of the dielectric substrate 11. It is thought that. The second conductor plate 13 facing each other through a gap is added to the gain generated by the function of the first conductor plate 12 and the second conductor plate 13 facing each other via the dielectric substrate 11 as a patch antenna. Thus, the gain generated by the parasitic block 14 functioning as a slot antenna is added.

  For example, as shown in FIG. 6, a length c = 3.4 mm and a width d = 2.5 mm are provided between the side 13a1 of the radiating portion 13a and the portion 14p1 of the parasitic block 14 facing the side 13a1. A gap is formed. Since the length of the gap is approximately equal to 2 / λ (2.5 mm when the resonance frequency is 60 GHz), the radiating portion 13a and the parasitic block 14 that are opposed to each other through the gap are provided as slots. Functions as an antenna. In fact, it is confirmed by numerical simulation that an electric field distribution as shown by an arrow in FIG. 6 is formed in this gap, that is, radiation is generated from this gap.

  Further, as shown in FIG. 6, a length c = 3.4 mm and a width d = 2.5 mm are also present between the side 13a2 of the radiating portion 13a and the portion 14p2 of the parasitic block 14 facing the side 13a2. A gap is formed. Since the length of the gap is approximately equal to 2 / λ, the radiating portion 13a and the parasitic block 14 facing each other through the gap function as a slot antenna. In fact, it is confirmed by numerical simulation that an electric field distribution as shown by an arrow in FIG. 6 is formed in this gap, that is, radiation is generated from this gap.

  As described above, the parasitic block 14 contributes to the increase in the gain in the zenith direction, as described above, the portion 14p1 facing the side 13a1 of the radiating portion 13a and the portion facing the side 13a2 of the radiating portion 13a. 14p2. Therefore, even if the remaining part is removed from the parasitic block 14, the effect of increasing the gain in the zenith direction is still obtained.

[Modification 1]
Next, a first modification of the patch antenna 1 will be described with reference to FIGS.

  The configuration of the patch antenna 1 according to this modification is shown in FIG. FIG. 7A is a top view of the patch antenna 1 according to this modification, and FIG. 7B is a cross-sectional view (AA ′ section) of the patch antenna 1 according to this modification. The patch antenna 1 according to this modification is different from the patch antenna 1 shown in FIG. 1 in that four screw holes 14 d 1 to 14 d 4 are formed in the parasitic block 14.

  As shown in FIG. 7B, each of the screw holes 14d1 to 14d4 is formed from the upper end surface of the parasitic block 14 toward the lower end surface, and the patch antenna 1 is a member disposed above the screw hole 14d1 to 14d4. Used to penetrate a screw (metal fixture) for fixing. At this time, the parasitic block 14 functions as a spacer for separating the second conductor plate 13 from the conductor member.

  FIG. 8 is a graph showing the frequency dependence of the reflection coefficient | S11 | of the patch antenna 1 (with screw holes) according to the present modification and the patch antenna 1 (without screw holes) shown in FIG. From the graph shown in FIG. 8, it can be seen that the reflection coefficient | S11 | at each frequency does not depend on the presence or absence of the screw holes 14d1 to 14d4. Note that the reflection coefficient | S11 | of the patch antenna 1 (with a screw hole) according to this modification is a characteristic in a state where M3 size screws are inserted into the screw holes 14d1 to 14d4.

  FIG. 9 shows the radiation pattern (gain dependence on the Eθ and Eφ components) on the zx plane of the patch antenna 1 (with screw holes) and the patch antenna 1 (without screw holes) shown in FIG. It is a graph to show. From the graph shown in FIG. 9, it can be seen that the gain in each direction in the zx plane does not depend on the presence or absence of the screw holes 14d1 to 14d4 for both the Eθ component and the Eφ component. The gain of the patch antenna 1 (with a screw hole) according to this modification is a characteristic in a state where M3 size screws are inserted into the screw holes 14d1 to 14d4.

  FIG. 10 is a graph showing radiation patterns (gain dependence on Eθ component) on the yz plane of the patch antenna 1 (with screw holes) and the patch antenna 1 (without screw holes) shown in FIG. is there. From the graph shown in FIG. 10, it can be seen that the gain in each direction in the yz plane does not depend on the presence or absence of the screw holes 14d1 to 14d4 at least with respect to the Eθ component. The gain of the patch antenna 1 (with a screw hole) according to this modification is a characteristic in a state where M3 size screws are inserted into the screw holes 14d1 to 14d4.

[Modification 2]
Next, a second modification of the patch antenna 1 will be described with reference to FIGS.

  The configuration of the patch antenna 1 according to this modification is shown in FIG. FIG. 11A is a top view of the patch antenna 1 according to the present modification, and FIG. 11B is a cross-sectional view (AA ′ section) of the patch antenna 1 according to the present modification. The patch antenna 1 according to this modification is different from the patch antenna 1 shown in FIG. 1 in that a parasitic element 15 is added.

  The parasitic element 15 is composed of a plate-like conductor, and is disposed in the same plane as the upper end surface of the parasitic block 14. Here, the fact that the parasitic element 15 is arranged in the same plane as the upper end surface of the parasitic block 14 means that any of the following three conditions is satisfied. (1) The upper surface of the parasitic element 15 is included in the same plane as the upper end surface of the parasitic block 14. (2) The lower surface of the parasitic element 15 is included in the same plane as the upper end surface of the parasitic block 14. (3) A plane sandwiched between the upper surface and the lower surface of the parasitic element 15 is included in the same plane as the upper end surface of the parasitic block 14. As shown in FIG. 11B, the patch antenna 1 according to this modification satisfies the condition (1).

  As shown in FIG. 11A, the parasitic element 15 includes an annular conductor 15 a whose outer edge overlaps with the outer edge of the radiating portion 13 a, one end connected to the outer edge of the annular conductor 15 a, and the other end of the upper end surface of the parasitic block 14. It is comprised by the strip | belt-shaped conductor 15b which continues to the outer edge.

  In this modification, the outer edge and the inner edge of the annular conductor 15a are square. The outer diameter e of the annular conductor 15a, that is, the length of each side constituting the outer edge of the annular conductor 15a is 3.4 mm, and the inner diameter f of the annular conductor 15a, that is, each of the inner edges of the annular conductor. The length of the side is 3.0 mm. The width of the strip conductor 15b is 1.5 mm, and the length of the strip conductor 15b is 2.5 mm.

  FIG. 12 is a graph showing the frequency dependence of the reflection coefficient | S11 | of the patch antenna 1 (with a parasitic element) and the patch antenna 1 (without a parasitic element) shown in FIG. From the graph shown in FIG. 12, by adding the parasitic element 15, (1) the reflection coefficient | S11 | decreases near the resonance frequency (58 GHz and 65 GHz), and (2) the reflection coefficient | S11 | It can be seen that the specific bandwidth FWB of the band in which is 10 dB or more is increased from 18% to 19%.

  FIG. 13 shows the radiation pattern on the zx plane of the patch antenna 1 (with a parasitic element) and the patch antenna 1 (without a parasitic element) shown in FIG. 1 (gain dependence on Eθ and Eφ components). ). From the graph shown in FIG. 13, it can be seen that the addition of the parasitic element 15 increases the gain in the zenith direction with respect to the Eφ component.

  FIG. 14 shows radiation patterns (gain dependence on the Eθ component) on the yz plane of the patch antenna 1 (with a parasitic element) and the patch antenna 1 (without a parasitic element) shown in FIG. It is a graph. From the graph shown in FIG. 14, it can be seen that the addition of the parasitic element 15 increases the gain in the zenith direction at least with respect to the Eθ component.

  Such an increase in the gain in the zenith direction is considered to be due to radiation from the parasitic element 15. Actually, it is confirmed by numerical simulation that a current distribution as shown by an arrow in FIG. 15 is formed in the parasitic element 15, that is, that radiation can be generated from the parasitic element 15.

[Preferred shape]
Next, a preferable height b (see FIG. 1B) of the parasitic block 14 will be described with reference to FIG. Hereinafter, the quotient b / a obtained by dividing the height b of the parasitic block 14 by the thickness a of the dielectric substrate 11 (see FIG. 1B) is referred to as “standardized height b / a”.

  FIG. 16 is a graph showing the normalized height b / a dependence of the specific bandwidth (FWB) and gain (gain in the zenith direction) related to the patch antenna 1 (FIG. 11) according to the second modification. From the graph shown in FIG. 16, it can be seen that when the normalized height b / a is 4 or more and 8 or less, the specific bandwidth and the gain are maintained at high values. Therefore, it can be said that the normalized height b / a is preferably 4 or more and 8 or less.

  Next, a preferred gap width d between the parasitic block 14 and the radiating portion 13a (see FIG. 1A) will be described with reference to FIG. Hereinafter, the quotient d / c obtained by dividing the gap width d between the parasitic block 14 and the radiating portion 13a by the length c of one side of the radiating portion 13a (see FIG. 1A) is referred to as a “normalized gap”. Width d / c ".

  FIG. 17 is a graph showing the normalized gap width d / c dependence of the specific bandwidth (FWB) and gain (gain in the zenith direction) related to the patch antenna 1 (FIG. 11) according to the second modification. From the graph shown in FIG. 17, (1) when the normalized gap width d / c is 0.25 or more and 0.85 or less, the specific bandwidth is 15% or more, and (2) the normalized band. It can be seen that the gain is 4 dBi or more when the width d / c is 0.75 or more and 0.95 or less. Therefore, the normalized gap width d / c is preferably (1) from 0.25 to 0.85 from the viewpoint of the specific bandwidth, and (2) gain from 0.75 to 0.95. From the viewpoints of (3), it can be said that (3) from 0.75 to 0.85 is preferable from the viewpoint of both the specific bandwidth and the gain.

  Finally, a preferable inner diameter f (see FIG. 11A) of the annular conductor 15a will be described with reference to FIG. Hereinafter, a quotient f / e obtained by dividing the inner diameter f of the annular conductor 15a by the outer diameter e (see FIG. 11A) of the annular conductor 15a is referred to as a “standardized inner diameter f / e”.

  FIG. 17 is a graph showing the dependence of the specific bandwidth (FWB) and gain (gain in the zenith direction) on the normalized inner diameter f / e for the patch antenna 1 (FIG. 11) according to the second modification. From the graph shown in FIG. 17, it can be seen that the specific bandwidth is 15% or more when the normalized inner diameter f / e is 0.65 or more. Therefore, it can be said that the normalized inner diameter f / e is preferably 0.65 or more.

[Additional Notes]
The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims. That is, embodiments obtained by combining technical means appropriately modified within the scope of the claims are also included in the technical scope of the present invention.

  The present invention can be suitably used for a patch antenna mounted on a wireless device or the like.

DESCRIPTION OF SYMBOLS 1 Patch antenna 11 Dielectric board 12 1st conductor board 13 2nd conductor board 13a Radiation part 13b Feeding path 14 Parasitic block 15 Parasitic element 15a Annular conductor 15b Strip-shaped conductor

Claims (8)

A dielectric substrate;
A first conductor plate formed on the lower surface of the dielectric substrate;
A second conductor plate formed on the upper surface of the dielectric substrate;
A parasitic block penetrating the dielectric substrate,
A lower surface of the parasitic block is in contact with an upper surface of the first conductive plate, and a side surface of the parasitic block is opposed to an outer edge of the second conductive plate on the upper surface of the dielectric substrate;
This is a patch antenna. The second conductor plate is a square-shaped radiating portion formed at the center of the top surface of the dielectric substrate, and a belt-shaped power supply path formed at the periphery of the top surface of the dielectric substrate, one end of which is the above-mentioned A power supply line connected to one side of the radiation part,
The parasitic block has a side surface facing three sides excluding the one side of the radiating portion on the upper surface of the dielectric substrate.
The patch antenna according to claim 1. The thickness of the dielectric substrate is a, the height of the parasitic block is b, and b / a is 4 or more and 8 or less,
The patch antenna according to claim 2. When the length of each side of the radiating portion is c and the width of the gap between the three sides of the radiating portion and the side surface of the parasitic block is d, d / c is 0.25 or more and 0.85 or less. is there,
The patch antenna according to claim 2 or 3, wherein When the length of each side of the radiating portion is c and the width of the gap between the three sides of the radiating portion and the side surface of the parasitic block is d, d / c is 0.75 or more and 0.95 or less. is there,
The patch antenna according to any one of claims 2 to 4, wherein the patch antenna is provided. A parasitic element disposed in the same plane as the upper end of the parasitic block, the annular conductor overlapping at least a part of the second conductor plate, one end connected to the annular conductor, and the other end It further includes a parasitic element having a strip-shaped conductor connected to the upper end of the parasitic block.
The patch antenna according to any one of claims 1 to 5, wherein: The outer diameter of the annular conductor is e, the inner diameter of the annular conductor is f, and f / e is 0.65 or more.
The patch antenna according to claim 6. A hole for penetrating the metal fixture is formed in the non-feeding block.
The patch antenna according to any one of claims 1 to 7, characterized in that: