antenna

Abstract

To widen the frequency bandwidth while reducing the reflection loss of the antenna. [Solution] The antenna 100 comprises a dielectric substrate 1 having a through hole 11, a radiating electrode 21 provided around the through hole 11 on the surface 12 of the dielectric substrate 1, and a ground conductor 4 arranged on the opposite side of the surface 12 of the dielectric substrate 1, through which the radiating electrode 21 is electrically connected via the side surface of the through hole 11. Furthermore, the antenna 100 comprises a radiating plate 31 arranged above the surface 12 of the dielectric substrate 1 so as to overlap with the radiating electrode 21, and a support conductor 32 that supports the radiating plate 31 and is inserted through the through hole 11 and fixed to the ground conductor 4.

Description

Technical Field

[0001] The present invention relates to an antenna.

Background Art

[0002] Non-Patent Document 1 discloses a ring patch antenna provided with a conductor that short-circuits between the central portion of an antenna electrode disposed spaced above a ground conductor and the ground conductor.

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above-described antenna, similar to a general configuration that does not short-circuit between the antenna electrode and the ground conductor, when a feeding point is set at a position where the values of the input impedance of the antenna and the characteristic impedance of the feeding line match, the reflection loss is reduced, and electromagnetic waves are efficiently radiated in a direction perpendicular to the surface of the antenna electrode. However, there is a problem that the frequency band with reduced reflection loss is very narrow, about 2% to 3% in terms of the specific bandwidth.

[0005] The present invention has been made in view of the above problems, and an object thereof is to widen the frequency band while reducing the reflection loss of the antenna.

Means for Solving the Problems

[0006] In the present invention FirstAccording to one embodiment, the antenna comprises a dielectric substrate having through holes; radiating electrodes provided on the surface of the dielectric substrate around the through holes; a ground conductor disposed on the surface of the dielectric substrate opposite to the surface, through which the radiating electrodes are electrically connected via the side surface of the through holes; a radiating plate disposed above the surface of the dielectric substrate so as to overlap with the radiating electrodes; and a support conductor that supports the radiating plate and is inserted through the through holes and fixed to the ground conductor. The radiating electrode and the radiating plate are substantially the same size. According to a second aspect of the present invention, the antenna comprises a dielectric substrate having through holes, a radiating electrode provided on the surface of the dielectric substrate around the through holes, a ground conductor disposed on the surface of the dielectric substrate opposite to the surface and through which the radiating electrode is electrically connected via the side surface of the through holes, a radiating plate disposed above the surface of the dielectric substrate so as to overlap with the radiating electrode, and a support conductor that supports the radiating plate and is inserted through the through holes and fixed to the ground conductor. The radiating electrode is smaller than the radiating plate. According to a third aspect of the present invention, the antenna comprises a dielectric substrate having a through hole, a radiating electrode provided on the surface of the dielectric substrate around the through hole, a ground conductor disposed on the surface of the dielectric substrate opposite to the surface and through which the radiating electrode is electrically connected via the side surface of the through hole, a radiating plate disposed above the surface of the dielectric substrate so as to overlap with the radiating electrode, and a support conductor that supports the radiating plate and is inserted through the through hole and fixed to the ground conductor. The radiating plate and the support conductor are integrally formed and fastened to the ground conductor by fixing screws. According to a fourth aspect of the present invention, the antenna comprises a dielectric substrate having through holes, radiating electrodes provided on the surface of the dielectric substrate around the through holes, a ground conductor disposed on the surface of the dielectric substrate opposite to the surface and through which the radiating electrodes are electrically connected via the side surface of the through holes, a radiating plate disposed above the surface of the dielectric substrate so as to overlap with the radiating electrodes, and a support conductor that supports the radiating plate and is inserted through the through holes and fixed to the ground conductor. The antenna transmits electromagnetic waves in a direction perpendicular to the radiating plate. [Effects of the Invention]

[0007] According to this embodiment, the antenna has a first radiation structure in which electrical conductivity is established between the radiating electrode and the ground conductor through the side of a through-hole, as well as a second radiation structure in which electrical conductivity is established between the radiating plate, which is positioned above the radiating electrode, and the ground conductor through a support conductor inserted through a through-hole.

[0008] By employing such a dual radiation structure, it is possible to combine two resonant frequencies that are appropriately offset in the frequency characteristics of the reflection loss, thereby reducing the reflection loss of the antenna while broadening its frequency characteristics. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 shows the structure of an antenna according to the first embodiment of the present invention. [Figure 2] Figure 2 illustrates the simulation results of the frequency characteristics of reflection loss for an antenna. [Figure 3] Figure 3 illustrates the simulation results of the frequency characteristics of the gain of an antenna. [Figure 4] Figure 4 illustrates the simulation results of the radiation pattern related to the antenna. [Figure 5] Figure 5 is a perspective view showing the structure of an array antenna according to the second embodiment. [Figure 6] FIG. 6 is a diagram showing the structure of two first radiation parts provided in the array antenna shown in FIG. 5. [Figure 7] FIG. 7 is a diagram showing the structure of the second radiation part provided in the array antenna shown in FIG. 5. [Figure 8] FIG. 8 is a diagram illustrating a simulation result of the frequency characteristics of reflection loss related to the array antenna. [Figure 9] FIG. 9 is a diagram illustrating a measured result of the frequency characteristics of reflection loss related to the array antenna. [Figure 10] FIG. 10 is a diagram illustrating a simulation result of the frequency characteristics of gain related to the array antenna. [Figure 11] FIG. 11 is a diagram illustrating a simulation result of the radiation pattern related to the array antenna.

BEST MODE FOR CARRYING OUT THE INVENTION

[0010] Hereinafter, each embodiment of the present invention will be described with reference to the drawings. In this specification, the same or equivalent elements are denoted by the same reference numerals throughout.

[0011] (First Embodiment) FIG. 1 is a diagram showing the structure of an antenna according to the first embodiment of the present invention. FIG. 1(a) shows a top view of the antenna according to this embodiment, and FIG. 1(b) shows a cross-sectional view when the antenna is cut along the B-B line shown in FIG. 1(a).

[0012] The antenna 100 according to the first embodiment is a microstrip antenna that transmits and receives electromagnetic waves in the gigahertz order, so-called a patch antenna.

[0013] Antenna 100 is applied to, for example, communication antennas in the gigahertz band. As a specific example, Antenna 100 can be applied to communication antennas in the range of several [GHz] used in mobile terminals, and communication antennas in the range of several [GHz] to several tens [GHz] used in satellite communications such as C-band, X-band, and Ku-band. Antenna 100 of this embodiment is used as a communication antenna in the 2 [GHz] band as an example.

[0014] As shown in FIGS. 1(a) and (b), Antenna 100 includes a dielectric substrate 1, a first radiation portion 2, a second radiation portion 3, a ground conductor 4, and a feeding portion 5.

[0015] The dielectric substrate 1 is a printed substrate having dielectric properties. In this embodiment, a Teflon (registered trademark) substrate having copper foil as a conductor layer on both sides is used as the dielectric substrate 1. The thickness of the dielectric substrate 1 is, for example, about several [mm], and in this embodiment, the dielectric substrate 1 with a thickness of 1.6 [mm] is used.

[0016] The first radiation portion 2 is formed on the dielectric substrate 1. The first radiation portion 2 is composed of a radiation electrode 21 for transmitting and receiving electromagnetic waves and an annular short-circuit layer 22 for short-circuiting the radiation electrode 21 and the ground conductor 4 at the central portion of the radiation electrode 21.

[0017] In this embodiment, the dielectric substrate 1 is rectangular, and for example, it is formed into a square with a side length of about 100 [mm]. Further, the dielectric substrate 1 has a circular through-hole 11 at its central portion. For example, the diameter of the circular through-hole 11 is designed to be around 15 [mm] to 20 [mm].

[0018] Also, a circular radiation electrode 21 is formed as a first radiation element on the surface 12 which is the first surface of the dielectric substrate 1. For example, the diameter of the circular radiation electrode 21 is designed to be around 50 [mm]. The radiation electrode 21 is formed, for example, by an etching process.

[0019] Furthermore, an annular short-circuit layer 22 is formed on the entire circumference, i.e., the inner surface, of the side of the through-hole 11 formed in the dielectric substrate 1. The short-circuit layer 22 is a conductor and, in this embodiment, is realized by a conductive plating layer, the thickness of which is, for example, several tens of micrometers. Therefore, the diameter of the annular short-circuit layer 22 is approximately the same as the diameter of the through-hole 11.

[0020] Furthermore, a ground conductor electrode 41 is formed on the back surface 13, which is the second surface of the dielectric substrate 1 and opposite to the front surface 12. For example, the ground conductor electrode 41 is formed over the entire back surface 13 of the dielectric substrate 1. The ground conductor electrode 41 and the radiating electrode 21 are conductive layers formed on the back surface 13 and front surface 12 of the dielectric substrate 1, respectively, and in this embodiment, they are formed of copper foil.

[0021] Thus, the first radiating section 2 of this embodiment constitutes an annular patch antenna comprising an annular radiating electrode 21 and an annular short-circuit layer 22 connected to the ground conductor 4.

[0022] The second radiating section 3 is positioned above the radiating electrode 21 and consists of a radiating plate 31 for transmitting and receiving electromagnetic waves, and a support conductor 32 for short-circuiting the radiating plate 31 and the ground conductor 4 at the center of the radiating plate 31.

[0023] The radiating plate 31 is a second radiating element and is positioned above the surface 12 of the dielectric substrate 1 so that, in a top view, the radiating plate 31 overlaps with the radiating electrode 21. The support conductor 32 supports the radiating plate 31 and is inserted through a through hole 11 in the dielectric substrate 1 and fixed to the ground conductor 4.

[0024] In this embodiment, the radiating plate 31 and the supporting conductor 32 are formed integrally. For example, the thickness of the radiating plate 31 is designed to be a few millimeters, and the shape of the radiating plate 31 is circular, the same as the shape of the radiating electrode 21. The surface area of ​​the radiating plate 31 is approximately the same as the area of ​​the radiating electrode 21, and slightly larger than the radiating electrode 21.

[0025] The support conductor 32 is formed into a cylindrical shape by machining and supports the central part of the radiation plate 31. For example, the diameter of the support conductor 32 is designed to be about 15 mm, and the height of the support conductor 32 is designed to be about 10 mm.

[0026] By adjusting the height of the support conductor 32, it becomes possible to appropriately control the resonant frequency and coupling amount of the radiating electrode 21 and the radiating plate 31 so as to broaden the usable frequency band of the antenna 100.

[0027] The radiating plate 31 and the supporting conductor 32 are both conductors, and are formed from, for example, aluminum, brass, or copper. The radiation characteristics of the antenna 100 are maintained even if the shape of the supporting conductor 32 is such that it short-circuits the radiating plate 31 and the ground conductor 4 in an annular shape. Therefore, the shape of the supporting conductor 32 may be formed as a hollow cylinder with a central portion that forms an annular shape instead of a columnar shape. Also, the radiating plate 31 and the supporting conductor 32 may be formed from different materials.

[0028] In this embodiment, the radiating plate 31 and the support conductor 32 constituting the second radiating section 3 are fastened to the ground conductor 4 by fixing screws 33. Specifically, screw holes 34 are formed in the center of the radiating plate 31 and the support conductor 32, and they are screwed to the ground conductor 4 by fixing screws 33.

[0029] The fixing screw 33 may be a conductor or an insulator. In this embodiment, the fixing screw 33 is made of stainless steel. The diameter of the screw hole 34 formed in the radiating plate 31 and the support conductor 32 is designed to be, for example, about 6 mm.

[0030] Thus, the second radiating section 3 of this embodiment constitutes an annular patch antenna comprising an annular radiating plate 31 and an annular support conductor 32 connected to the ground conductor 4.

[0031] As shown in Figure 1(b), the ground conductor 4 is composed of a ground conductor electrode 41 formed on the back surface 13 of the dielectric substrate 1 and a ground conductor plate 42 electrically connected to the ground conductor electrode 41. The ground conductor plate 42 is a conductor for fixing the second radiating portion 3 and is made of, for example, aluminum, brass, or copper. The thickness of the ground conductor plate 42 is designed to be, for example, around 10 [mm].

[0032] The power supply unit 5 is a component for supplying power to the radiating electrode 21 formed on the surface 12 of the dielectric substrate 1. The power supply unit 5 has a power supply line connected to a part of the radiating electrode 21, and in this embodiment, a microstrip line is formed on the surface 12 of the dielectric substrate 1 as the power supply unit 5. One end of the power supply unit 5 is connected to a power supply circuit (not shown).

[0033] The power supply unit 5 may be configured such that a pin inserted from the ground conductor 4 in a direction perpendicular to the dielectric substrate 1 is connected to a specific power supply point within the radiating electrode 21. In this case, power is supplied from the power supply circuit to the radiating electrode 21 via the pin.

[0034] Thus, the antenna 100 has a stacked structure in which the lower first radiating section 2 and the upper second radiating section 3 are stacked, and by adopting this stacked structure, it is possible to improve the radiation performance of the antenna 100.

[0035] Next, the results of the simulation of the radiation performance of antenna 100 will be explained with reference to Figures 2 to 4.

[0036] The preconditions for simulating the radiation performance of antenna 100 are as follows: the square dielectric substrate 1 has a side length of 120 mm and a thickness of 1.6 mm; the diameter of the radiation electrode 21 is 52 mm; and the width of the feed point 5 is 4.3 mm.

[0037] The circular radiation plate 31 has a diameter of 52 mm and a thickness of 2.5 mm, while the cylindrical support conductor 32 has a diameter of 14.3 mm and a height of 10.5 mm.

[0038] Figure 2 illustrates the simulation results of the frequency characteristics of the reflection loss for antenna 100. In Figure 2, the vertical axis represents the reflection loss [dB] and the horizontal axis represents the transmission frequency [MHz].

[0039] As shown in Figure 2, the frequency bandwidth BW1 at which the reflection loss of electromagnetic waves is -10 dB or less is approximately 330 MHz, and the relative bandwidth is approximately 13.5%.

[0040] In contrast, the conventional antenna described in the prior art document, which has the second radiating section 3 removed, has a relative bandwidth of about 3%, so it can be said that the frequency bandwidth BW1 of the antenna 100 in this embodiment has been significantly widened.

[0041] In the frequency characteristics of the reflection loss shown in Figure 2, the resonant frequency of the first radiator 2 is approximately 2.39 GHz, and the resonant frequency of the second radiator 3 is approximately 2.5 GHz. It is presumed that the frequency bandwidth was broadened by the combination of these resonant frequencies.

[0042] As described above, the resonant frequencies and coupling amounts of the first radiating section 2 and the second radiating section 3 can be controlled mainly by adjusting the height of the support conductor 32. By appropriately controlling these, the frequency bandwidth can be broadened.

[0043] Figure 3 illustrates the simulation results of the frequency characteristics of the gain for antenna 100. In Figure 3, the vertical axis represents the antenna gain [dBi] and the horizontal axis represents the transmission frequency [MHz].

[0044] As shown in Figure 3, an antenna gain of approximately 9 [dBi] is secured in the frequency bandwidth BW1 shown in Figure 2, which is about the same as the gain of the conventional narrowband antenna described above. In contrast, a standard patch antenna that does not short-circuit the radiating electrode 21 and the ground conductor 4 has a gain of approximately 7 [dBi], so it can be said that the antenna 100 of this embodiment maintains a high antenna gain.

[0045] As shown in Figures 2 and 3, the antenna 100 of this embodiment can widen the usable frequency bandwidth while reducing the reflection loss of electromagnetic waves compared to conventional antennas.

[0046] Figure 4 illustrates the simulation results of the radiation pattern for antenna 100. Here, the radiation pattern for a transmission frequency of 2450 [MHz] is shown, with the vertical axis representing relative radiation intensity [dB] and the horizontal axis representing the radiation angle [°].

[0047] In Figure 4, the radiation pattern of the E-plane, which is the electric field plane along the extension direction of the power supply unit 5 toward the center of the radiating plate 31, is shown by a solid line, and the radiation pattern of the H-plane, which is the magnetic field plane perpendicular to the E-plane and passing through the center of the radiating plate 31, is shown by a dashed line.

[0048] As shown in Figure 4, the radiation pattern on the H-plane is a standard dome shape, and the radiation pattern on the E-plane is also generally dome-shaped, although the pattern is slightly distorted due to the influence of the feed point 5. Therefore, it can be said that antenna 100 has a standard radiation pattern while achieving low loss and wide bandwidth.

[0049] Figures 2 to 4 show the radiation performance of antenna 100, but the reception performance of antenna 100 is also approximately the same as its radiation performance.

[0050] Next, the effects and benefits of the first embodiment will be described.

[0051] In the first embodiment, the antenna 100 comprises a dielectric substrate 1 having a through hole 11, a radiating electrode 21 provided around the through hole 11 on the surface 12 of the dielectric substrate 1, and a ground conductor 4 arranged on the back surface 13 of the dielectric substrate 1, which is the opposite surface 12, and through which the radiating electrode 21 is electrically connected via the side surface of the through hole 11. Furthermore, the antenna 100 comprises a radiating plate 31 arranged above the surface 12 of the dielectric substrate 1 so as to overlap with the radiating electrode 21, and a support conductor 32 that supports the radiating plate 31 and is inserted through the through hole 11 and fixed to the ground conductor 4.

[0052] According to this configuration, the antenna 100 has a first radiation structure in which the radiating electrode 21 and the ground conductor 4 are electrically connected through the side of the through-hole 11, and a second radiation structure in which the radiating plate 31, which is positioned above the radiating electrode 21, and the ground conductor 4 are electrically connected through a support conductor 32 inserted through the through-hole 11.

[0053] By employing such a dual radiation structure, two resonant frequencies are combined in the frequency characteristics of the reflection loss of antenna 100, thereby reducing the reflection loss of antenna 100 while expanding the usable frequency characteristics.

[0054] Furthermore, both the radiating electrode 21 and the radiating plate 31 in this embodiment are circular in shape.

[0055] With this configuration, compared to shapes such as rectangles, polygons, or ellipses, it becomes easier to adjust the positional relationship between the radiating electrode 21 and the radiating plate 31 so that they overlap sufficiently when viewed from above.

[0056] Furthermore, the radiating electrode 21 and the radiating plate 31 in this embodiment have substantially the same size.

[0057] With this configuration, by forming the two radiating electrodes 21 and radiating plate 31, which function as antenna elements, to be approximately the same size, it becomes easy to adjust the radiation performance of the antenna 100, which is formed by stacking the two antenna elements.

[0058] In this embodiment, it is preferable that the radiating electrode 21 is smaller than the radiating plate 31. This configuration makes it easier to transfer energy from the radiating electrode 21 to the radiating plate 31, thereby suppressing a decrease in the radiation efficiency of the antenna 100.

[0059] Furthermore, in this embodiment, the radiating plate 31 and the support conductor 32 are integrally formed and fastened to the ground conductor 4 by fixing screws 33.

[0060] With this configuration, the radiating plate 31 and the support conductor 32 can be formed integrally by simply cutting the portion corresponding to the support conductor 32 from a columnar base material for forming the radiating plate 31 and the support conductor 32.

[0061] In addition, by fastening the integrally formed radiating plate 31 and support conductor 32 to the ground conductor 4 with fixing screws 33, the radiating plate 31 and support conductor 32 can be easily fixed in an electrically connected state to the ground conductor 4 without affecting the radiation characteristics of the antenna 100.

[0062] This cutting and screwing process allows the radiating plate 31 and support conductor 32 to be easily formed and fixed to the ground conductor 4 while suppressing manufacturing costs, making it possible to mass-produce the antenna 100 at a low cost.

[0063] (Second embodiment) In the first embodiment, the antenna 100 has one stack structure, but two or more stack structures may be arranged. Therefore, an configuration in which two stack structures are arranged will be described below with reference to Figures 5 to 7.

[0064] Figure 5 is a perspective view showing the structure of the array antenna 101 according to the second embodiment. Figure 6 is a diagram showing the structure of the first radiating section 2 that constitutes the array antenna 101. Figure 6(a) shows a top view showing the surface 12A of the dielectric substrate 1A on which the two first radiating sections 2 are formed, and Figure 6(b) shows a side view showing the side of the dielectric substrate 1A and the ground conductor 4A.

[0065] Figure 7 shows the structure of the two second radiating sections 3 that make up the array antenna 101 shown in Figure 6. Figure 7(a) shows the top surface of the second radiating section 3, Figure 7(b) shows the side surface of the second radiating section 3, and Figure 7(c) shows the bottom surface of the second radiating section 3.

[0066] As shown in Figures 5 to 7, the array antenna 101 includes a dielectric substrate 1A, two first radiating sections 2, a second radiating section 3, a ground conductor 4A, and a feed section 5A.

[0067] The dielectric substrate 1A has the same configuration as the dielectric substrate 1 shown in Figures 1 and 2, and in the second embodiment, it has two through holes 11A and 11B of the same shape. The through holes 11A and 11B correspond to the first through hole and the second through hole, respectively.

[0068] The two first radiating units 2 have the same or equivalent configuration as the first radiating units 2 shown in Figures 1 and 2, respectively. In the second embodiment, the two first radiating units 2 are arranged side by side on the surface 12A of the dielectric substrate 1A. One of the radiating electrodes 21 constituting the first radiating unit 2 corresponds to the first radiating electrode, and the other radiating electrode 21 constituting the first radiating unit 2 corresponds to the second radiating electrode.

[0069] The two second radiating sections 3 have the same or equivalent configuration as the second radiating sections 3 shown in Figures 1 and 2, respectively, and in the second embodiment, the two second radiating sections 3 are inserted through the through holes 11A and 11B, respectively.

[0070] Specifically, the radiating plate 31 and support conductor 32 of the second radiating section 3 inserted through the through hole 11A correspond to the first radiating plate and the first support conductor, respectively, and the radiating plate 31 and support conductor 32 of the second radiating section 3 inserted through the through hole 11B correspond to the second radiating plate and the second support conductor, respectively.

[0071] The support conductor 32, which corresponds to the first support conductor, supports the radiating plate 31, which corresponds to the first radiating plate, and is inserted through the through hole 11A and fixed to the ground conductor 4A. The support conductor 32, which corresponds to the second support conductor, supports the radiating plate 31, which corresponds to the second radiating plate, and is inserted through the through hole 11B and fixed to the ground conductor 4A.

[0072] The ground conductor 4A has the same configuration as the ground conductor 4A shown in Figures 1 and 2. In the second embodiment, it is composed of a ground conductor electrode 41A formed on the entire back surface 13A of the dielectric substrate 1A, and a ground conductor plate 42A electrically connected to the ground conductor electrode 41A.

[0073] The power supply section 5A is positioned on the surface 12A of the dielectric substrate 1A and is a power supply line that supplies power to the radiating electrodes 21 of the two first radiating sections 2. Similar to the power supply section 5 shown in Figures 1 and 2, it forms a microstrip line.

[0074] The power supply unit 5A of this embodiment includes a power supply line 51A extending from the center point 50A of the surface 12A of the dielectric substrate 1A to a branching point 50B, and power supply lines 52A and 52B extending from the branching point 50B to the connection points 50C and 50D of the two radiating electrodes 21. The branching point 50B is located at a position where the lengths of the two power supply lines 52A and 52B are equal.

[0075] Thus, since the array antenna 101 has two array elements arranged in a stack structure in which a first radiating section 2 and a second radiating section 3 are stacked, the antenna gain can be increased compared to the antenna 100 of the first embodiment.

[0076] Next, the results of the simulation of the radiation performance of the array antenna 101 will be explained with reference to Figures 8 to 11.

[0077] The prerequisites for simulating the radiation performance of the array antenna 101 are that the rectangular dielectric substrate 1 has a short side of 119 mm and a long side of 159 mm. Also, the diameter of the radiation electrode 21 is 54 mm.

[0078] The circular radiating plate 31 has a diameter of 54 mm and a thickness of 2.5 mm, while the cylindrical support conductor 32 has a diameter of 14.3 mm and a height of 9.5 mm.

[0079] Figure 8 illustrates the simulation results of the frequency characteristics of the reflection loss for the array antenna 101. Figure 9 illustrates the measured results of the frequency characteristics of the reflection loss for the array antenna 101. In Figures 8 and 9, the vertical axis represents the reflection loss [dB] and the horizontal axis represents the transmission frequency [MHz].

[0080] In the simulation results shown in Figure 8, the frequency bandwidth BW2s at which the reflection loss of electromagnetic waves is -10 dB or less is approximately 380 MHz, and the relative bandwidth is approximately 15.5%. In the measured results shown in Figure 9, the frequency bandwidth BW2a at which the reflection loss of electromagnetic waves is -10 dB or less is approximately 375 MHz, and the relative bandwidth is approximately 15.4%.

[0081] Thus, it was confirmed that the simulation results and actual measurement results for the array antenna 101 were generally the same. Based on these results, it can be said that the usable frequency bandwidth of the array antenna 101 is significantly wider than that of conventional antennas.

[0082] Figure 10 illustrates the simulation results of the frequency characteristics of the gain for the array antenna 101. In Figure 10, the vertical axis represents the antenna gain [dBi] and the horizontal axis represents the transmission frequency [MHz].

[0083] As shown in Figure 10, the antenna gain is approximately 10.5 [dBi] in the frequency bandwidth BW2s shown in Figure 8. Therefore, the gain of the array antenna 101, which has two array elements, is increased by approximately 1.5 [dB] compared to the antenna 100, which has one array element, in the first embodiment.

[0084] As shown in Figures 8 to 10, the array antenna 101 of this embodiment can increase the antenna gain while widening the usable frequency bandwidth compared to the antenna 100 of the first embodiment.

[0085] Figure 11 illustrates the simulation results of the radiation pattern for the array antenna 101. Here, the radiation pattern for a transmission frequency of 2450 [MHz] is shown, with the vertical axis representing relative radiation intensity [dB] and the horizontal axis representing radiation angle [°].

[0086] Figure 11 shows the radiation pattern of the E-plane, which is the electric field plane aligned with the direction passing through the centers of the two radiating plates 31, as a solid line, and the radiation pattern of the H-plane, which is the magnetic field plane perpendicular to the E-plane and passing through the middle of the two radiating plates 31, as a dashed line.

[0087] As shown in Figure 11, similar to the antenna 100 of the first embodiment, the radiation pattern on the H-plane is a standard dome shape, and the radiation pattern on the E-plane is also generally dome-shaped, although the pattern is slightly distorted due to the influence of the feed point 5.

[0088] Furthermore, in this embodiment, since two array elements are arranged along the E-plane direction, it was confirmed that the radiation pattern on the E-plane is sharper than the radiation pattern on the H-plane.

[0089] Thus, the array antenna 101 can be said to have a standard radiation pattern while achieving high gain and wide bandwidth.

[0090] Figures 8 to 11 show the radiation performance of the array antenna 101, but the reception performance of the array antenna 101 is equivalent to its radiation performance.

[0091] Next, the effects and benefits of the second embodiment will be described.

[0092] In the array antenna 101 of the second embodiment, the dielectric substrate 1A has through holes 11A and 11B corresponding to the first and second through holes, the two radiating electrodes 21 function as the first and second radiating electrodes, and the two radiating plates 31 function as the first and second radiating plates. The two support conductors 32 include a first support conductor that supports the radiating plate 31 corresponding to the first radiating plate and is inserted through the through hole 11A and fixed to the ground conductor 4A, and a second support conductor that supports the radiating plate 31 corresponding to the second radiating plate and is inserted through the through hole 11B and fixed to the ground conductor 4A. A feed line that supplies power to the two radiating electrodes 21 is arranged on the surface 12A of the dielectric substrate 1A as a feed section 5A.

[0093] In this configuration, the array antenna 101 includes a first array element that provides electrical conductivity between the radiating electrode 21 and the ground conductor 4 through the side surface of the through-hole 11A, and provides electrical conductivity between the radiating plate 31 positioned above the radiating electrode 21 and the ground conductor 4 through a support conductor 32 inserted through the through-hole 11A. In addition, the array antenna 101 includes a second array element that provides electrical conductivity between the radiating electrode 21 and the ground conductor 4 through the side surface of the through-hole 11B, and provides electrical conductivity between the radiating plate 31 positioned above the radiating electrode 21 and the ground conductor 4 through a support conductor 32 inserted through the through-hole 11B.

[0094] In this way, by arranging the two array elements on the dielectric substrate 1A, the radiation characteristics of the two array elements are combined, which allows for an increase in antenna gain while expanding the usable frequency bandwidth of the array antenna 101.

[0095] Although embodiments of the present invention have been described above, these embodiments only represent a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.

[0096] In the above embodiment, the ground conductors 4 and 4A are electrically connected to the ground conductor plates 42 and 42A by forming ground conductor electrodes 41 and 41A over the entire back surface 13 and 13A of the dielectric substrates 1 and 1A, but the embodiment is not limited to this. For example, ground conductor electrodes 41 and 41A may be formed only near the through holes 11, 11A and 11B on the back surface 13 and 13A of the dielectric substrates 1 and 1A. [Explanation of Symbols]

[0097] 100 antennas 101 Array antenna (antenna) 1. 1A Dielectric Substrate 11, 11A, 11B through hole 2 First radiation part 21 Radiation electrode (first radiation electrode, second radiation electrode) 3. Second Radiation Section 31 Radiation plate (first radiation plate, second radiation plate) 32 Support conductors (first support conductor, second support conductor) 4, 4A Ground conductor 41, 41A Ground conductor electrode (ground conductor) 42, 42A Ground conductor plate (ground conductor) 5. 5A power supply section

Claims

1. A dielectric substrate having through holes, A radiating electrode provided around the through-hole on the surface of the dielectric substrate, A ground conductor is disposed on the surface opposite to the surface of the dielectric substrate, and the radiating electrode is electrically connected to it through the side of the through hole, A radiating plate is positioned above the surface of the dielectric substrate so as to overlap with the radiating electrode, The system comprises a support conductor that supports the radiating plate and is inserted through the through hole and fixed to the ground conductor, The radiating electrode and the radiating plate have substantially the same size. antenna.

2. A dielectric substrate having through holes, A radiating electrode provided around the through-hole on the surface of the dielectric substrate, A ground conductor is disposed on the surface opposite to the surface of the dielectric substrate, and the radiating electrode is electrically connected to it through the side of the through hole, A radiating plate is positioned above the surface of the dielectric substrate so as to overlap with the radiating electrode, The system comprises a support conductor that supports the radiating plate and is inserted through the through hole and fixed to the ground conductor, The aforementioned radiating electrode is smaller than the aforementioned radiating plate. antenna.

3. A dielectric substrate having through holes, A radiating electrode provided around the through-hole on the surface of the dielectric substrate, A ground conductor is disposed on the surface opposite to the surface of the dielectric substrate, and the radiating electrode is electrically connected to it through the side of the through hole, A radiating plate is positioned above the surface of the dielectric substrate so as to overlap with the radiating electrode, The system comprises a support conductor that supports the radiating plate and is inserted through the through hole and fixed to the ground conductor, The radiating plate and the supporting conductor are integrally formed and fastened to the ground conductor by fixing screws. antenna.

4. An antenna according to any one of claims 1 to 3, The aforementioned radiation electrode and radiation plate are both circular in shape. antenna.

5. An antenna according to any one of claims 1 to 3, The dielectric substrate has a first through hole and a second through hole as the through holes, The aforementioned radiation electrode includes a first radiation electrode and a second radiation electrode. The aforementioned radiating plate includes a first radiating plate and a second radiating plate, The aforementioned support conductor is A first support conductor that supports the first radiating plate and is inserted through the first through-hole and fixed to the ground conductor, Includes a second support conductor that supports the second radiating plate and is inserted through the second through-hole and fixed to the ground conductor, A power supply line for supplying power to the first radiation electrode and the second radiation electrode is arranged on the surface of the dielectric substrate. antenna.

6. A dielectric substrate having through holes, A radiating electrode provided around the through-hole on the surface of the dielectric substrate, A ground conductor is disposed on the surface opposite to the surface of the dielectric substrate, and the radiating electrode is electrically connected to it through the side of the through hole, A radiating plate is positioned above the surface of the dielectric substrate so as to overlap with the radiating electrode, The system comprises a support conductor that supports the radiating plate and is inserted through the through hole and fixed to the ground conductor, Electromagnetic waves are transmitted perpendicular to the aforementioned radiating plate. antenna.

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