JP4926141B2 - Dielectric antenna and communication apparatus using the same - Google Patents

Description

  The present invention relates to a dielectric antenna and a communication device using the same. The communication device can be suitably used for a wireless communication device such as a mobile phone or a wireless LAN.

  In recent years, miniaturization is required for communication equipment. Along with this, miniaturization is also required for dielectric antennas used in communication equipment. Therefore, as described in Patent Document 1, a radiation electrode disposed on the top surface of the dielectric substrate, a ground electrode disposed on the bottom surface of the dielectric substrate, and a radiation electrode positioned in the dielectric substrate There has been proposed a dielectric antenna having a horizontal electrode facing the outer peripheral portion of the antenna and having a capacitance formed between the horizontal electrode and the radiation electrode.

When the dielectric antenna is made smaller, the resonance frequency becomes higher. However, in the cited document 1, since the capacitance is formed between the horizontal electrode and the radiation electrode, the resonance frequency can be made smaller without increasing the radiation electrode. Therefore, the dielectric antenna can be made small.
JP 2004-208203 A

  As described in Patent Document 1, the dielectric antenna can be reduced in size by including a horizontal electrode facing the outer peripheral portion of the radiation electrode. However, by mounting a dielectric antenna on a mounting plate of a communication equipment device, the dielectric antenna is used in the communication equipment device. When this mounting plate is metallic, the mounting space between the mounting plate and the dielectric antenna is used. There is a problem that the resonance frequency is shifted due to the generated gap.

  This shift in resonance frequency can be suppressed by increasing the size of the ground electrode on the back surface of the dielectric antenna to increase the dimensional difference between the radiation electrode and the ground electrode. However, while the shift of the resonance frequency can be suppressed, the dielectric antenna is increased in size. Further, the deviation of the resonance frequency can be suppressed by reducing the size of the radiation electrode and increasing the dimensional difference between the radiation electrode and the ground electrode. However, while the resonance frequency shift can be suppressed, the horizontal electrode facing the radiation electrode must be enlarged in order to adjust the resonance frequency by the size of the radiation electrode. As described above, although the miniaturization effect by the horizontal electrode can be obtained, the gain of the antenna characteristic is lowered.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a high-gain dielectric antenna that is small but suppresses a shift in the resonance frequency.

  The dielectric antenna of the present invention includes a first dielectric having a main surface and a back surface located on the opposite side of the main surface, and a first reference disposed on the back surface of the first dielectric. An electrode; a second dielectric having a main surface disposed on the main surface of the first dielectric; a radiation electrode disposed on the main surface of the second dielectric; A second reference electrode disposed on the outer surface of the radiating electrode and a part of the radiating electrode on the main surface of the first dielectric; A third reference electrode opposed via the second dielectric, a first conductor electrically connecting the first reference electrode and the second reference electrode, and the second reference electrode And a second conductor that electrically connects the third reference electrode.

  According to the dielectric antenna of the present invention, the second reference electrode disposed so as to surround the periphery of the radiation electrode, the main surface of the first dielectric, and a part of the radiation electrode and the second And a third reference electrode facing each other through the dielectric. Therefore, capacitances can be formed between the radiation electrode and the second reference electrode and between the radiation electrode and the third reference electrode, respectively. Since the capacitance is formed between the radiation electrode and the second reference electrode in this way, the third reference electrode can be made smaller. Therefore, the radiation electrode can be made smaller, and the radiation electrode and the first reference electrode can be made smaller. While increasing the dimensional difference from the electrode, it is possible to suppress a decrease in gain of the antenna characteristics. As a result, it is possible to obtain a high-gain dielectric antenna that is small but suppresses the deviation of the resonance frequency.

  Hereinafter, the dielectric antenna of the present invention will be described in detail with reference to the drawings.

  As shown in FIGS. 1 to 3, the dielectric antenna 1 according to the first embodiment of the present invention includes a first dielectric 3 having a main surface and a back surface located on the opposite side of the main surface, A first reference electrode 7 disposed on the back surface of the first dielectric 3, a second dielectric 5 disposed on the main surface of the first dielectric 3, and having a main surface; And a radiation electrode 13 disposed on the main surface of the dielectric 5. Furthermore, the second reference electrode 9 disposed on the main surface of the second dielectric 5 and outside the radiation electrode 13, and the main surface of the first dielectric 3, the radiation electrode A third reference electrode 11 that opposes a part of the first reference electrode 13 with the second dielectric 5 interposed therebetween, and a first conductor 15 that electrically connects the first reference electrode 7 and the second reference electrode 9; And a second conductor 17 that electrically connects the second reference electrode 9 and the third reference electrode 11.

  Thus, the dielectric antenna 1 according to this embodiment includes the second reference electrode 9 disposed on the main surface of the second dielectric 5 and outside the radiation electrode 13, and the first A third reference electrode 11 is provided on the main surface of the dielectric 3 and faces a part of the radiation electrode 13 via the second dielectric 5.

  Therefore, capacitances can be formed between the radiation electrode 13 and the second reference electrode 9 and between the radiation electrode 13 and the third reference electrode 11, respectively. Since the capacitance is formed between the radiation electrode 13 and the second reference electrode 9 as described above, the third reference electrode 11 can be made smaller. While increasing the dimensional difference from the first reference electrode 7, it is possible to suppress a decrease in gain of the antenna characteristics. As a result, it is possible to obtain the high-gain dielectric antenna 1 that is small but suppresses the shift of the resonance frequency.

  In the dielectric antenna described in the cited document 1, since the horizontal electrode is connected to the ground conductor through the vertical conductor formed on the dielectric side surface, the horizontal electrode must be enlarged in order to reduce the radiation electrode. did not become. However, in the dielectric antenna 1 according to this embodiment, the third reference electrode 11 is connected to the first reference electrode 7 via the second reference electrode 9 formed outside the radiation electrode 13. Therefore, the first reference electrode 7 can be made small without increasing the third reference electrode 11.

  Further, in the dielectric antenna 1 of the present embodiment, the capacitance between the radiation electrode 13 and the reference electrode is not only the capacitance between the radiation electrode 13 and the third reference electrode 11 but also the radiation electrode 13 and the first reference electrode 11. It is also formed by the capacitance between the two reference electrodes 9. Therefore, since the capacity between the radiation electrode 13 and the entire reference electrode can be maintained large while reducing the third reference electrode 11, a decrease in gain of the antenna characteristics can be suppressed.

  More specifically, as shown in FIGS. 1 to 3, the dielectric antenna 1 of the present embodiment includes a first rectangular parallelepiped-shaped first dielectric 3 having a top surface as a main surface and a bottom surface as a back surface, and a first And a second dielectric 5 having a rectangular parallelepiped shape and having a top surface as a main surface. In the dielectric antenna 1 of the present embodiment, the first dielectric 3 and the second dielectric 5 have a rectangular parallelepiped shape. However, as shown in FIGS. The second dielectric 5 may be cylindrical. The shapes and dimensions of the first dielectric 3 and the second dielectric 5 are set according to the frequency used and the application.

  As the first dielectric 3 and the second dielectric 5, for example, an inorganic material such as a ceramic material and a resin material can be used. Specifically, as the ceramic material, for example, alumina ceramics, mullite ceramics, and glass ceramics can be used. Examples of the resin material include tetrafluoroethylene-ethylene resin (polytetrafluoroethylene; PTFE), tetrafluoroethylene-ethylene copolymer resin (tetrafluoroethylene-ethylene copolymer resin; ETFE), and tetrafluoride. Fluorine resin such as ethylene-perfluoroalkoxyethylene copolymer resin (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin; PFA), glass epoxy resin, and polyimide can be used.

  The thickness of the second dielectric 5 is preferably smaller than the thickness of the first dielectric 3. As the distance between the radiation electrode 13 and the first reference electrode 7 increases, the gain of the antenna characteristic increases. Further, the smaller the distance between the radiation electrode 13 and the third reference electrode 11, the smaller the radiation electrode 13 can be made. Therefore, when the thickness of the second dielectric 5 is smaller than the thickness of the first dielectric 3, the gain of the antenna characteristics can be increased while the dielectric antenna 1 is reduced.

  A first reference electrode 7 is disposed on the back surface of the first dielectric 3. In the present embodiment, the first reference electrode 7 is disposed on the entire back surface of the first dielectric 3, but may be a part of the back surface of the first dielectric 3.

  As the first reference electrode 7, a metal material can be used. Specifically, Cu, Cr, Mo, Mn, Ni, Ag, Au, Pt, and alloys thereof can be used as the metal material. A separately formed first reference electrode 7 may be disposed on the back surface of the first dielectric 3, and a metal paste containing these metal materials is disposed on the back surface of the first dielectric 3. The first reference electrode 7 may be formed by firing. Further, Ni and Au plating may be formed after disposing these metal materials.

  On the main surface of the second dielectric 5, the radiation electrode 13 and the second reference electrode 9 positioned outside the radiation electrode 13 are disposed. In the present embodiment, the two second reference electrodes 9 are on the main surface of the second dielectric 5 so as to be outside the two opposite sides of the radiation electrode 13 and to be separated from the radiation electrode 13. It is arranged. The second reference electrode 9 is electrically connected to the first reference electrode 7 through the first conductor 15.

  The radiation electrode 13 is disposed on the main surface of the second dielectric 5. In the present embodiment, the radiation electrode 13 is formed in a rectangular shape, but is not particularly limited to this shape. For example, it may be square or oval. As the radiation electrode 13, the same metal material as that of the first reference electrode 7 may be used.

  The second reference electrode 9 is disposed on the main surface of the second dielectric 5 so as to be separated from the radiation electrode 13. At this time, the smaller the distance between the second reference electrode 9 and the radiation electrode 13, the larger the capacity between the second reference electrode 9 and the radiation electrode 13, which is preferable. However, if this distance is too small, an electrical short circuit occurs between the second reference electrode 9 and the radiation electrode 13, and it is necessary to maintain an interval that does not cause this short circuit. From the above, the second reference electrode 9 is particularly preferably disposed along the outer peripheral portion of the radiation electrode 13. The second reference electrode 9 may be made of the same metal material as that of the first reference electrode 7.

  In the present embodiment, the first conductor 15 is disposed on the side surfaces of the first dielectric 3 and the second dielectric 5. In other words, the first conductor 15 is exposed on the side surfaces of the first dielectric 3 and the second dielectric 5. Thus, since the 1st conductor 15 is exposed, evaluation of the characteristic of the dielectric antenna 1 becomes easy, and it is preferable. Specifically, the dimensions of the first conductor 15 can be measured, and the metal terminal can be brought into contact with the first conductor 15, so that the electrical characteristics of the dielectric antenna 1 are measured. Easy to do. In addition, when the first conductor 15 is exposed, the characteristics of the dielectric antenna 1 can be easily adjusted by trimming the first conductor 15. As the first conductor 15, the same metal material as that of the first reference electrode 7 may be used.

  A third reference electrode 11 is disposed on the main surface of the first dielectric 3 so as to face a part of the radiation electrode 13 with the second dielectric 5 interposed therebetween. In other words, in the dielectric antenna 1 of the present embodiment, the third reference electrode 11 is embedded between the first dielectric 3 and the second dielectric 5. As the third reference electrode 11, the same metal material as that of the first reference electrode 7 may be used. The second conductor 17 may be made of the same metal material as that of the first reference electrode 7.

  In particular, the third reference electrode 11 is preferably opposed to at least a part of the outer peripheral portion of the radiation electrode 13 via the second dielectric 5. Since the electric field concentrates on the outer peripheral portion of the radiation electrode 13, the third reference electrode 11 is disposed so as to face at least a part of the outer peripheral portion via the second dielectric 5 layer, This is because the capacitance between the third reference electrode 11 and the radiation electrode 13 can be increased.

  At this time, it is more preferable that the third reference electrode 11 is opposed to the outer peripheral portion of the radiation electrode 13 with the second dielectric 5 interposed therebetween. When the dielectric antenna 1 is used as a linearly polarized antenna, the electric field concentrates in a region facing the outer peripheral portion when the radiation electrode 13 is viewed in plan view. This is because the capacitance between the third reference electrode 11 and the radiation electrode 13 can be further increased by disposing the second dielectric 5 layers so as to face each other.

  Further, as shown in FIG. 6, when the dielectric antenna 1 is viewed from the side perpendicular to the first conductor 15, the first conductor 15 and the second conductor 17 are disposed so as to be displaced. It is preferred that This is because the possibility of a short circuit between the first conductor 15 and the second conductor 17 can be reduced.

  Next, a second embodiment of the present invention will be described.

  As shown in FIG. 7, the dielectric antenna 1 according to the present embodiment has a second reference electrode disposed so as to surround the radiation electrode 13 as compared with the dielectric antenna 1 according to the first embodiment. 9 is provided. Thus, since the second reference electrode 9 is disposed so as to surround the periphery of the radiation electrode 13, the opposing portion of the second reference electrode 9 and the radiation electrode 13 can be enlarged. The capacity between the second reference electrode 9 and the radiation electrode 13 can be increased.

  Further, as shown in FIG. 8, two second reference electrodes 9 that are spaced apart from each other are provided, and the two second reference electrodes 9 are disposed so as to surround the radiation electrode 13. Similarly, since the portion where the second reference electrode 9 and the radiation electrode 13 are opposed to each other can be increased, the capacitance between the second reference electrode 9 and the radiation electrode 13 can be increased.

  Next, a third embodiment of the present invention will be described.

  As shown in FIG. 9, the dielectric antenna 1 of the present embodiment has a third reference electrode 11 that is the same as that of the dielectric antenna 1 of the first embodiment. It is characterized by facing through the dielectric 5.

  As already shown, since the electric field concentrates on the outer peripheral portion of the radiation electrode 13, the third reference electrode 11 is disposed so as to face the entire outer peripheral portion via the second dielectric 5 layer. This is because the capacitance between the third reference electrode 11 and the radiation electrode 13 can be further increased.

  In particular, when the dielectric antenna 1 is used as a circularly polarized antenna, since the portion where the electric field concentrates rotates, the electric field concentrates on the entire outer peripheral portion when the radiation electrode 13 is viewed in plan view. The electrode 11 is disposed so as to face the entire outer peripheral portion with the second dielectric 5 layer interposed therebetween, thereby further increasing the capacitance between the third reference electrode 11 and the radiation electrode 13. Because it can.

  At this time, the third reference electrode 11 may have a rectangular shape facing the entire outer peripheral portion of the radiation electrode 13 with the second dielectric 5 interposed therebetween, and as shown in FIG. An annular shape that opposes the entire outer peripheral portion of the electrode 13 via the second dielectric 5 may be used.

  Next, a fourth embodiment of the present invention will be described.

  As shown in FIG. 11, the dielectric antenna 1 of the present embodiment has a first conductor 15, a first dielectric 3 and a second dielectric, as compared to the dielectric antenna 1 of the first embodiment. It is characterized by being embedded in the body 5.

  When the dielectric antenna 1 is used in an environment where it is exposed to the outside air, the dielectric according to this embodiment is particularly effective. When the first conductor 15 is embedded in the first dielectric 3 and the second dielectric 5 as in the present embodiment, the first conductor 15 is protected by the dielectric, It is because it can suppress that the 1st conductor 15 deteriorates with external air.

  Next, a communication device apparatus according to an embodiment of the present invention will be described.

  As shown in the figure, the communication device 19 of this embodiment includes the dielectric antenna 1 represented by the above embodiment as a transmission / reception means. Specifically, the communication device 19 according to the present embodiment includes the dielectric antenna 1 described above, an IC chip 21 mounted on the dielectric 1 antenna, and a mounting board on which the dielectric antenna 1 is mounted. 23 and a housing 25 in which the mounting plate 23 is disposed. As described above, since the communication device 19 according to the present embodiment includes the dielectric antenna 1 that is small but suppresses the deviation of the resonance frequency, the communication device 19 is small but highly accurate. be able to.

  Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention.

It is a perspective view which shows the dielectric antenna in the 1st Embodiment of this invention. It is a disassembled perspective view of the dielectric antenna shown in FIG. It is sectional drawing of the dielectric antenna shown in FIG. It is a perspective view which shows the modification of the dielectric material antenna in the 1st Embodiment of this invention. FIG. 5 is an exploded perspective view of the dielectric antenna shown in FIG. 4. It is a side view which shows another modification of the dielectric material antenna in the 1st Embodiment of this invention. It is a disassembled perspective view which shows the dielectric antenna in the 2nd Embodiment of this invention. It is a disassembled perspective view which shows the modification of the dielectric material antenna in the 2nd Embodiment of this invention. It is a disassembled perspective view which shows the dielectric antenna in the 3rd Embodiment of this invention. It is a disassembled perspective view which shows the modification of the dielectric material antenna in the 3rd Embodiment of this invention. It is sectional drawing which shows the dielectric antenna in the 4th Embodiment of this invention. It is sectional drawing which shows the communication equipment apparatus concerning one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Dielectric antenna 3 ... 1st dielectric 5 ... 2nd dielectric 7 ... 1st reference electrode 9 ... 2nd reference electrode 11 ... 3rd Reference electrode 13 ... radiation electrode 15 ... first conductor 17 ... second conductor 19 ... communication equipment 21 ... IC chip 23 ... mounting plate 25 ... housing

Claims (8)

A first dielectric having a main surface and a back surface opposite to the main surface;
A first reference electrode disposed on the back surface of the first dielectric;
A second dielectric disposed on a major surface of the first dielectric and having a major surface;
A radiation electrode disposed on a major surface of the second dielectric;
A second reference electrode disposed on the main surface of the second dielectric and outside the radiation electrode;
A third reference electrode on the main surface of the first dielectric and facing a part of the radiation electrode via the second dielectric;
A first conductor that electrically connects the first reference electrode and the second reference electrode;
A dielectric antenna comprising: a second conductor that electrically connects the second reference electrode and the third reference electrode.   2. The dielectric antenna according to claim 1, wherein the third reference electrode is opposed to at least a part of an outer peripheral portion of the radiation electrode via the second dielectric.   3. The dielectric antenna according to claim 2, wherein the third reference electrode is opposed to the outer peripheral portion of the radiation electrode via the second dielectric in the opposing region.   3. The dielectric antenna according to claim 2, wherein the third reference electrode is opposed to the entire outer peripheral portion of the radiation electrode via the second dielectric.   2. The dielectric antenna according to claim 1, wherein the first conductor is exposed to side surfaces of the first dielectric and the second dielectric. 3.   The dielectric antenna according to claim 1, wherein the first conductor is embedded in the first dielectric and the second dielectric.   The dielectric antenna according to claim 1, wherein the thickness of the second dielectric is smaller than the thickness of the first dielectric.   A communication apparatus comprising the dielectric antenna according to claim 1 as a transmission / reception means.

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