JP3966855B2 - Multi-frequency antenna - Google Patents

Description

TECHNICAL FIELD The present invention relates to a technical field of a multi-frequency antenna capable of sharing a plurality of frequency bands , and in particular, a laminated structure in which two or more planar conductor patches are arranged opposite to each other at a predetermined interval on a ground plate. The present invention relates to a mold-like inverted F type multi-frequency shared antenna .

  In recent years, mobile terminals such as mobile phones have become widespread, but for wireless communication of these mobile terminals, various systems coexist and a plurality of different frequency bands are used. Therefore, there is a demand for a multi-frequency antenna that can share a large number of frequency bands with one antenna. In general, an inverted-F antenna is widely used as an antenna that can be built in a portable terminal. As one of the methods of increasing the frequency of the inverted F antenna, a method of multilayering a planar patch is known.

  In the first method, as shown in FIG. 13, two patches 101 and 102 are arranged on a ground plate 103 so as to face each other in parallel at a predetermined interval, and a multi-layer in which a feeding conductor 104 and a grounding conductor 105 are provided. This is a flat antenna. In the configuration of FIG. 13, the power supply conductor 104 connected to the output end of the power supply element of the ground plate 103 and the ground conductor 105 connected to the ground plate 103 are connected to one end of the lower patch 102 in proximity to each other. In addition, a short-circuit conductor 105 provided on the same side is connected between one ends of the upper and lower two patches 101 and 102 to connect the two.

In the second method, as shown in FIG. 14, the arrangement of the two patches 201 and 202, the ground plate 203, the feeding conductor 204, and the grounding conductor 205 is the same as in FIG. The arrangement of the conductor 206 is different from that shown in FIG. 13 (see, for example, Non-Patent Document 1). Specifically, in the configuration of FIG. 14, the shorting conductor 206 is connected between one end of the upper and lower two patches 201 and 202 on the side facing the power supply conductor 204 and the grounding conductor 205 to connect the two. is doing.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION.VOL.47.NO.4.APRIL 1999 Lakhdar Zaid, Georges Kossiavas, Jean-Yves Dauvignac, Josiane Cazajous, and Alber Papiernik ”Dual-Frequency and Broad-Band Antennas with Stacked Quarter Wavelength Elements”

  However, when the first conventional method is employed, the current path including the upper and lower patches 101 and 102 cannot be secured for a long time when viewed from the feeding point, so that the two resonance frequencies approach each other. Therefore, it is mainly used for the purpose of widening the inverted F antenna, and is not suitable for operation in two separate frequency bands.

  On the other hand, when the second conventional method is employed, the current path including the two upper and lower patches 201 and 202 when viewed from the feeding point can be secured long by the arrangement of the short-circuiting conductor 206, so that two resonances The frequency can be set in a relatively separated relationship. However, in the configuration of FIG. 14, the electric field applied between the radiating conductor and the ground plate is dominated by the effect of the lower patch 202 on the lower side compared to the upper patch 201 on the upper side, and the current path is sufficient. However, the two resonance frequencies cannot be sufficiently separated.

  For example, a dual system of 900 MHz / 1800 MHz is assumed as a system applied to a mobile phone, or a dual system of 2.5 GHz / 5 GHz is assumed as a system applied to a wireless LAN. Thus, while it is desirable to separate the resonance frequency by about twice, there is a problem that it is difficult to cope with both of the above two conventional methods.

Therefore, the present invention has been made to solve these problems, and in the case where an antenna capable of sharing a large number of frequency bands by laminating a plurality of patches by a laminated planar inverted F antenna is used. An object of the present invention is to provide a multi-frequency antenna that can be set separately for a plurality of resonance frequencies without increasing the size, and can be applied to various systems.

In order to solve the above-mentioned problems, the multi-frequency antenna of the present invention is a laminated planar inverted-F multi-frequency antenna in which two or more planar conductor patches are arranged opposite to each other at a predetermined interval on the ground plate. The patch has substantially the same size and shape, and the uppermost patch in the patch and the output end of the feeding element are connected by a feeding conductor, and the uppermost patch and the ground plate Are connected by a grounding conductor, the patches are sequentially connected by a shorting conductor, and the shorting conductor that connects the uppermost patch and the patch immediately below the shorting conductor is grounded. The multi-frequency shared antenna is arranged at a position on the patch opposite to the position on the patch where the conductor is provided.

According to the present invention, in the multi-layer planar inverted-F type multi-frequency antenna, two or more planar conductors having substantially the same size and shape are used as the patch, and the output end of the feed element is located in the patch. And connecting the grounding plate to the uppermost patch, connecting the patches in sequence by a shorting conductor, and connecting the uppermost patch of the shorting conductor and directly below it. Since the short-circuiting conductor that connects to the patch located on the patch is arranged at a position on the patch opposite to the position on the patch where the grounding conductor is provided , resonance occurs in a plurality of frequency bands according to the combination of patches to be connected. The multi-frequency shared antenna can be realized with a small and simple configuration. The two or more ( multiple ) patches that are integrally connected have a long current path through the short-circuiting conductor, and the power supply conductor and the grounding conductor are connected to the uppermost patch. Therefore, electric field coupling balanced between the patches from the uppermost patch toward the lower layer is possible. Therefore, it is possible to realize a multi-frequency shared antenna that can be used in a wide frequency range by setting a large number of resonance frequencies separately without increasing the antenna size. Note that the intervals between the plurality of patches arranged in a stacked manner need not be the same.

Preferably, the two or more patches are connected in order from the uppermost patch toward the lowermost patch.

Therefore, the electric field generated between each patch and the ground plate can be made more uniform, and a large number of resonance frequencies can be sufficiently separated according to the patch size.

Preferably, of the two or more patches, an arbitrary patch having the upper and lower patches opposed to each other is connected to one short-circuit conductor connected to the upper patch and the lower patch. The other short-circuiting conductors are arranged at positions facing each other on the patch plane.

Thereby, a current path passing through two or more patches can be made sufficiently long, and even a small antenna size can cope with a large number of resonance frequencies.

In one aspect, the grounding conductor and the plurality of shorting conductors are each formed of a plate-like conductor having a common width with the patch.

Therefore, it is possible to incorporate a multi-frequency shared antenna that can be built in a portable terminal or the like that supports multi-frequency and has excellent manufacturability.

In one aspect, the number of the two or more patches is two. In this case, the multi-frequency shared antenna is used as a dual-frequency antenna.

According to this configuration , in the stacked planar inverted-F antenna, it is possible to realize operation in two frequency bands sufficiently separated without increasing the antenna size. For example, it is possible to realize a dual frequency shared antenna in which the two frequencies used have a frequency ratio of approximately 1: 2.

  According to the present invention, a plurality of patches are sequentially laminated, and a short-circuiting conductor for connecting the patches, a feeding conductor and a grounding conductor connected to the uppermost patch, and at least one short-circuiting conductor is provided. Since it arrange | positions so that it may oppose on the patch plane with respect to the conductor for grounding, when sharing many frequency bands, it can respond to many frequency bands fully separated. In this case, a long current path can be secured and the electric field between each layer and the ground plate can be made uniform, so that a large number of resonance frequencies can be sufficiently separated over a wide frequency range without increasing the antenna size. A multi-frequency shared antenna applicable to various systems can be provided.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Here, a case where the present invention is applied to a dual-frequency antenna that can share two frequency bands will be described as an example of the multi-frequency antenna according to the present invention.

  First, the configuration of the dual frequency antenna according to the present embodiment will be described with reference to FIGS. FIG. 1 is a perspective view showing the structure of a dual-frequency antenna 1 according to this embodiment. Moreover, regarding the dual frequency antenna 1 of FIG. 1, a top view is shown in FIG. 2, and a side view is shown in FIG.

  As shown in FIGS. 1 to 3, the dual-frequency antenna 1 according to the present embodiment has a structure in which three layers of an upper patch 11, a lower patch 12, and a ground plate 13 are sequentially stacked. . The upper patch 11 is laminated on the upper part of the lower patch 12 and is arranged in parallel with the lower patch 12 at a predetermined interval. The lower patch 12 is laminated on the upper part of the ground plate 13 and is fixed to the ground plate 12. They are in a positional relationship where they are opposed to each other in parallel with an interval. Further, as can be seen from FIG. 2, the upper patch 11 and the lower patch 12 are each formed of a rectangular conductor having substantially the same size. It is assumed that the ground plate 13 is formed to have a ground pattern that is sufficiently wider than the upper patch 11 and the lower patch 12.

  At the end of the upper patch 11 disposed above, a power supply terminal 11a and a ground terminal 11b are provided. A power feeding conductor 15 is connected to the power feeding terminal 11a as a power feeding point, and a grounding conductor 16 is connected to the grounding terminal 11b. The power supply conductor 15 extends downward and is electrically connected to the output end of the power supply element 14. The grounding end of the power feeding element 14 is electrically connected to the ground plate 13. The grounding conductor 16 extends downward in parallel with the power feeding conductor 15 and is electrically connected to the grounding pattern of the grounding plate 13.

  It is desirable that the distance between the power feeding conductor 15 and the grounding conductor 16 is appropriately set within a range in which a desired impedance of the dual-frequency shared antenna 1 can be adjusted.

  On the other hand, in the upper patch 11, a short-circuit conductor 17 is connected to a connection portion 11 c provided at an end portion of the upper patch 11 that is opposed to the position of the grounding terminal 11 b on the plane of the patch 11. The short-circuiting conductor 17 extends downward and is electrically connected to a connection portion 12 a provided at the end of the lower patch 12. As described above, the short-circuiting conductor 17 has a role of integrally connecting the upper patch 11 and the lower patch 12 that are opposed to each other vertically.

  Only the short-circuit conductor 17 is connected to the lower patch 12, and other conductors are not connected. That is, when viewed from the ground plate 13 side, the upper patch 11 located above via the power supply conductor 15 and the ground conductor 16 is connected to the base end side, and from the upper patch 11 via the short-circuit conductor 17. One antenna pattern in which the lower patch 12 located below is connected to the distal end side is formed.

  1 to 3, the power supply conductor 15 and the grounding conductor 16 are arranged close to each other, but may be arranged at a certain distance. However, it is a condition that the feeding conductor 15 and the grounding conductor 16 are arranged so as to maintain the positional relationship facing the short-circuiting conductor 17 on the patch plane. For example, the upper patch 11 may be provided with a feeding point at a predetermined position near the center, not limited to the end thereof, and may be connected to the feeding conductor 15 therefrom.

  1 to 3, the grounding conductor 16 and the short-circuiting conductor 17 are both formed by linear conductors. However, these may be formed by plate-like conductors. . For example, each of these conductors may be a plate-like conductor having a length of one side of a rectangle constituting the upper patch 11.

  Here, FIG. 4 is a perspective view showing a structure corresponding to FIG. 1 regarding a modification of the dual-frequency antenna 1 according to the present embodiment. In this modification, the structures of the upper patch 11, the lower patch 12, and the ground plate 13 are substantially the same as those in FIG. 1, but the structure and arrangement of the feeding conductor 21, the grounding conductor 22, and the shorting conductor 23 are the same. Is different.

  As shown in FIG. 4, a power supply terminal 11 a is provided at a position near the center of the upper patch 11, and a power supply conductor 21 is connected thereto. The power feeding conductor 21 extends downward and is electrically connected to the output end of the power feeding element 14 provided on the ground plate 13 through the through hole 12 b provided in the lower patch 12.

  On the other hand, as shown in FIG. 4, unlike the case of FIG. 1, the grounding conductor 22 and the short-circuiting conductor 23 are each made of a plate-like conductor formed in the same width as one side of the upper patch 11. The grounding conductor 22 electrically connects one side of the upper patch 11 and a predetermined position of the grounding plate 13. Further, the short-circuiting conductor 23 electrically connects one side of each of the upper patch 11 and the lower patch 12 facing each other vertically.

  When the grounding conductor 22 is formed so as to extend vertically downward from one side of the upper patch 11, it is necessary to avoid direct contact between the grounding conductor 22 and the lower patch 12. For that purpose, the lower patch 12 may be formed in a size slightly smaller than the size of the upper patch 11.

  Hereinafter, the operation of the dual frequency antenna 1 configured as described above will be described. In the present embodiment, the dual frequency antenna 1 is operated so that the resonance frequency on the low frequency side and the resonance frequency on the high frequency side can be shared. For the resonance frequency on the low frequency side, the upper patch 11 and the lower patch 12 operate integrally as a radiating element, whereas for the resonance frequency on the high frequency side, the upper patch 11 is mainly used as the radiating element. Operate.

  When the dual-frequency antenna 1 is used as an antenna for a mobile phone, it is desirable that the antenna can be applied to two frequency bands as far apart as possible in order to adapt to various systems. In the configuration of the present embodiment as shown in FIG. 1, the feeding conductor 15 and the grounding conductor 16 are arranged on the upper patch 11 away from the short-circuiting conductor 17. As a result, compared to the current path corresponding to the resonance frequency on the high frequency side, a longer distance is secured from the upper patch 11 to the lower patch 12 via the shorting conductor 17 for the current path corresponding to the resonance frequency on the lower frequency side. It will be possible. For this reason, the difference in wavelength between the two frequency bands becomes large due to the difference in the current path, which is advantageous in the case of separating the two frequency bands.

  Further, in the configuration of the present embodiment, the connection order is defined such that the ground plate 13 is connected to the upper patch 11 via the power supply conductor 15 and the ground conductor 16 and then connected to the lower patch 12. ing. Accordingly, the upper patch 11 becomes a radiating element close to the base end side of the entire antenna pattern, and the lower patch 12 becomes a radiating element far from the base end side of the entire antenna pattern and close to the front end side. Therefore, the electric field between these two radiation conductors and the ground plate 13 is applied relatively evenly. Therefore, it is possible to avoid the electric fields from the upper and lower patches from becoming uneven as in the conventional case, and it is possible to further separate the two frequency bands.

  As described above, the upper patch 11 and the lower patch 12 are not limited to being substantially the same size, and both can be configured in different sizes. The relationship between the two resonance frequencies may be appropriately adjusted by freely changing the size of. Further, the shape of the upper patch 11 and the lower patch 12 is not limited to a rectangular shape, but may be any shape as long as it can operate as a radiation conductor.

  Next, the examination result of the antenna characteristic by simulation regarding the dual frequency resonant antenna 1 according to the present embodiment will be described. In the simulation of the dual-frequency shared antenna 1, it is assumed that the dual-frequency shared antenna 1 has a basic structure as shown in FIG. 4 and is assumed to be used in two frequency bands around 1 GHz and 2 GHz. FIG. 5 is a diagram showing a specific structure of the dual-frequency shared antenna 1 that is a simulation target. FIG. 5A is a top view and FIG. 5B is a side view, respectively.

Table 1 shows design conditions for the dual-frequency antenna 1 shown in FIG. When determining such design conditions, adjustments are made so that impedance matching and radiation characteristics can be secured within an appropriate range for the two frequency bands, and the distance between the upper patch 11 and the lower patch 12 and between the lower patch 12 and the ground plate 13 are adjusted. The intervals were adjusted so that the radiation characteristics were appropriate. A feeding point corresponding to the above-described feeding terminal 11a was set near the center away from the short-circuiting conductor 23.

一方、図５に示す２周波共用アンテナ１とのアンテナ特性の比較のため、本実施形態の構成を採用しない従来の２周波共用アンテナについて比較のシミュレーションを行った。ここでは、図６、図７にそれぞれ構成を示すような２種のタイプの２周波共用アンテナを想定した。図６に示す第１のタイプにおいては、接地用導体２２が下部パッチ１２と接地板１３とを接続し、この接地用導体２２と同じ側に設けた短絡用導体２３が上部パッチ１１と下部パッチ１２を接続する位置関係にある。また、図７に示す第２のタイプにおいては、接地用導体２２が下部パッチ１２と接地板１３とを接続し、この接地用導体２２と対向する側に設けた短絡用導体２３が上部パッチ１１と下部パッチ１２を接続する位置関係にある。また、第１のタイプと第２のタイプのいずれも、下部パッチ１２の所定位置に給電点１２ａが設けられ、給電用導体２１を介して給電素子１４に接続されている。

On the other hand, for comparison of antenna characteristics with the dual-frequency antenna 1 shown in FIG. 5, a comparative simulation was performed for a conventional dual-frequency antenna that does not employ the configuration of this embodiment. Here, two types of dual-frequency antennas whose configurations are shown in FIGS. 6 and 7 are assumed. In the first type shown in FIG. 6, the grounding conductor 22 connects the lower patch 12 and the ground plate 13, and the short-circuiting conductor 23 provided on the same side as the grounding conductor 22 includes the upper patch 11 and the lower patch. 12 are connected to each other. In the second type shown in FIG. 7, the ground conductor 22 connects the lower patch 12 and the ground plate 13, and the short-circuit conductor 23 provided on the side facing the ground conductor 22 is the upper patch 11. And the lower patch 12 are connected. Further, in each of the first type and the second type, a feeding point 12 a is provided at a predetermined position of the lower patch 12 and is connected to the feeding element 14 through a feeding conductor 21.

Table 2 shows design conditions for the first type dual-frequency shared antenna 1 shown in FIG. Table 3 shows design conditions for the second type dual-frequency antenna 1 shown in FIG. When determining each design condition, adjustments were made so that the antenna characteristics could be optimized as in the design conditions shown in Table 1.

図８は、表１の設計条件に適合する２周波共用アンテナ１のアンテナ特性のうち、周波数とＶＳＷＲの関係を示す図であり、周波数０．５〜２．５ＧＨｚの範囲におけるＶＳＷＲの変化をグラフ化している。このグラフによれば、周波数１ＧＨｚの近くにＶＳＷＲの第１のピークが現れるとともに、周波数２ＧＨｚの近くにＶＳＷＲの第２のピークが現れている。このように、低周波側及び高周波側の２つの共振周波数は、本実施形態に係る２周波共用アンテナ１の作用に基づき、２倍程度に分離した特性となっている。

FIG. 8 is a diagram showing the relationship between the frequency and the VSWR among the antenna characteristics of the dual-frequency shared antenna 1 that meets the design conditions shown in Table 1. The graph shows the change in VSWR in the frequency range of 0.5 to 2.5 GHz. It has become. According to this graph, the first peak of VSWR appears near the frequency of 1 GHz, and the second peak of VSWR appears near the frequency of 2 GHz. As described above, the two resonance frequencies on the low frequency side and the high frequency side have characteristics separated about twice based on the action of the dual frequency antenna 1 according to the present embodiment.

  On the other hand, FIG. 9 is a diagram showing the relationship between the frequency and the VSWR for the configuration of FIG. 6 that meets the design conditions of Table 2, and FIG. 10 shows the configuration of FIG. It shows the relationship between the frequency of VSWR and VSWR. In both cases, similar to the case of FIG. 8, the change in VSWR in the frequency range of 0.5 to 2.5 GHz is graphed.

  According to the graph of FIG. 9, two peaks of VSWR are close to each other and have frequency characteristics that are not separated over a frequency range of 1.25 to 1.5 GHz. On the other hand, according to the graph of FIG. 10, the first peak of VSWR appears near the frequency of 1.25 GHz, the second peak appears near the frequency of 1.65 GHz, and the two resonance frequencies are separated. However, compared with the case of FIG. 8, the two resonance frequencies are not sufficiently separated.

  Thus, it has been confirmed that by using the dual-frequency antenna 1 according to the present embodiment, it is possible to realize a characteristic that sufficiently separates two resonance frequencies as compared with the conventional configuration. That is, in the conventional configuration of FIG. 6, the grounding conductor 22 and the short-circuiting conductor 23 are arranged on the same side with respect to the upper patch 11 and the lower patch 12, and a long current path cannot be secured. Further, in both the conventional configurations of FIGS. 6 and 7, the lower patch 12 is provided with a feeding point, so the lower patch 12 closer to the base end side of the antenna pattern is more grounded than the upper patch 11. The electric field between the two becomes strong and a uniform electric field distribution cannot be obtained. Since the dual-frequency antenna 1 according to the present embodiment employs a configuration that can avoid these factors, the two resonance frequencies can be separated widely compared to either configuration of FIGS. It becomes possible.

  Next, a case where the present invention is applied to a multi-frequency antenna that can share three or more frequency bands will be described. The dual-frequency antenna 1 has a three-layer structure in which two patches and a ground plate 13 are stacked. When the present invention is applied to an N-frequency shared antenna, N patches and a ground plate are used. N + 1 layer structure in which is stacked.

  FIG. 11 is a perspective view showing a structure of a three-frequency shared antenna 2 that can share three frequency bands as an application example of the multi-frequency shared antenna. FIG. 12 is a side view of the three-frequency shared antenna of FIG. 11 and 12 has a structure in which four layers of an upper patch 51, a center patch 52, a lower patch 53, and a ground plate 54 are sequentially laminated. These four layers are arranged opposite to each other in parallel at a predetermined interval, and the size and shape of each layer are substantially the same as in the case of FIG.

  In FIG. 11, as in the case of FIG. 1, the power supply conductor 56 electrically connects the power supply terminal 51a of the upper patch 51 and the output end of the power supply element 55 (the ground end of the power supply element 55 is connected). The grounding conductor 57 electrically connects the grounding terminal 51b of the upper patch 51 and the grounding plate 54). Further, the first short-circuiting conductor 58 electrically connects the connecting portion 51c of the upper patch 51 and the connecting portion 52a of the central patch 52 in the same arrangement as in FIG.

  In addition to this, in the configuration of FIG. 11, the second short-circuit conductor 59 is connected to the connecting portion 52b provided at the end of the central patch 52 opposite to the position of the connecting portion 52a, and is extended downward. Are connected to a connecting portion 53 a provided at an end of the lower patch 53. The second short-circuiting conductor 59 has a role of integrally connecting the center patch 52 and the lower patch 53 that are disposed to face each other vertically.

  With this configuration, when viewed from the ground plate 13 side, the uppermost upper patch 51 is connected to the base end side via the power feeding conductor 56 and the grounding conductor 57, and the first patch is connected to the first patch 51. Are connected to the central patch 52 via a short-circuit conductor 58. Furthermore, one antenna pattern in which the lower patch 53 is connected to the distal end side from the central patch 52 via the second shorting conductor 59 is formed.

  In the case of the three-frequency shared antenna 2 shown in FIG. 11, similarly to the configuration of FIG. 4, a feeding point can be provided at a predetermined position near the center of the upper patch 51. 8 shows an example in which the grounding conductor 57, the first short-circuiting conductor 58, and the second short-circuiting conductor 59 are formed of linear conductors. However, as in the configuration of FIG. You may form with a plate-shaped conductor.

  The multi-frequency shared antenna 1 configured as described above operates so that three resonance frequencies can be shared. For the resonance frequency on the low frequency side, the upper patch 51, the center patch 52, and the lower patch 53 operate integrally as a radiating element, and for the middle resonance frequency, mainly the upper patch 51 and the center patch 52. Integrally operate as a radiating element, and the upper patch 51 mainly operates as a radiating element for the resonance frequency on the high frequency side.

  The configuration shown in FIG. 11 is adopted, and the power supply conductor 56 and the grounding conductor 57 are arranged away from the first shorting conductor 58, and the second shorting conductor 59 is the first shorting conductor. Since the arrangement is far from 58, a sufficiently long current path can be secured when the frequency is low. In addition, since the upper patch 51, the central patch 52, and the lower patch 53 are sequentially connected from the upper part to the lower part through the power feeding conductor 56 and the grounding conductor 57 from the ground plate 53, The electric field between each radiation conductor and the ground plate 54 is applied relatively evenly by the same operation as that of the dual-frequency antenna 1. Due to these factors, the multi-frequency shared antenna 2 shown in FIG. 11 can sufficiently separate the three resonance frequencies.

  In the embodiment described above, the configuration in which the connection order of each patch is connected in order from the upper side to the lower side has been described. However, if the power supply conductor and the grounding conductor are connected to the uppermost patch, the patch is in the middle. The patch connection order may be partially changed. In addition, the effect of the present invention can be obtained if the short-circuiting conductor is disposed at a position facing the feeding conductor and the grounding conductor on the patch plane in at least one of the plurality of patches.

It is a perspective view which shows the structure of the dual frequency shared antenna which concerns on this embodiment. FIG. 2 is a top view of the dual frequency antenna shown in FIG. 1. FIG. 2 is a side view of the dual frequency antenna shown in FIG. 1. It is a perspective view which shows the structure corresponding to FIG. 1 regarding the modification of the dual frequency antenna which concerns on this embodiment. It is a figure which shows the specific structure of the dual frequency shared antenna made into the object of simulation, Fig.5 (a) is a top view, FIG.5 (b) is a side view. It is a figure which shows the specific structure of the 1st type among the dual frequency shared antennas of the conventional structure used as the object of the comparison simulation, Fig.5 (a) is a top view, FIG.5 (b) is a side view. It is. It is a figure which shows the specific structure of the 2nd type among the dual frequency antennas of the conventional structure used as the object of the comparison simulation, Fig.5 (a) is a top view, FIG.5 (b) is a side view. It is. It is a figure which shows the relationship between the frequency and VSWR about the dual frequency common antenna which adapts to the design conditions of Table 1. FIG. It is a figure which shows the relationship between the frequency and VSWR about the structure of FIG. 6 which adapts the design conditions of Table 2. FIG. It is a figure which shows the relationship between the frequency and VSWR about the structure of FIG. 7 which adapts to the design conditions of Table 3. FIG. It is a perspective view which shows the structure of the 3 frequency shared antenna as an application example of the multi frequency shared antenna which concerns on this embodiment. It is a side view of the 3 frequency shared antenna of FIG. It is a figure which shows the structure in the 1st method of multilayering the conventional inverted F antenna. It is a figure which shows the structure in the 2nd method of multilayering the conventional inverted F antenna.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... 2 frequency shared antenna 2 ... 3 frequency shared antenna 11 ... Upper patch 12 ... Lower patch 13 ... Grounding plate 14 ... Feeding element 15 ... Feeding conductor 16 ... Grounding conductor 17 ... Shorting conductor 11 ... Upper patch 12 ... Lower part Patch 13 ... Grounding plate 14 ... Feeding elements 15, 21 ... Feeding conductors 16, 22 ... Grounding conductors 17, 23 ... Short-circuiting conductor 51 ... Upper patch 52 ... Center patch 53 ... Lower patch 54 ... Grounding plate 55 ... Feeding element 56 ... Feeding conductor 57 ... Grounding conductor 58 ... First shorting conductor 59 ... Second shorting conductor

Claims (6)

In the laminated planar inverted F type multi-frequency shared antenna in which two or more planar conductor patches are arranged opposite to each other at a predetermined interval on the ground plate,
The patches have substantially the same size and shape;
In the patch, the uppermost patch at the uppermost part and the output end of the feeding element are connected by a feeding conductor,
Connecting the top patch and the ground plate with a grounding conductor;
The patches are sequentially connected with a short-circuiting conductor,
The shorting conductor connecting the uppermost patch and the patch immediately below the shorting conductor is disposed at a position on the patch opposite to the position on the patch where the grounding conductor is provided. Multi-frequency shared antenna. More said shorting member, said two or more patches, multi-frequency antenna according to claim 1, characterized in that connected to the order from the top of the patch at the bottom of the patch. Among the patches, any patch whose upper and lower patches are opposed to each other has one short-circuit conductor connected to the upper patch and the other short-circuit conductor connected to the lower patch. The multi-frequency shared antenna according to claim 1 , wherein the multi-frequency shared antenna is disposed at a position facing each other on the patch plane. The multi-frequency shared antenna according to claim 1, wherein the grounding conductor and the plurality of short-circuiting conductors are each formed of a plate-like conductor having a width common to the patch. The multi-frequency shared antenna according to claim 1, wherein the number of the two or more patches is two, and is used as a dual-frequency shared antenna. 6. The multi-frequency shared antenna according to claim 5, wherein the two frequencies used by the dual-frequency shared antenna have a frequency ratio of approximately 1: 2.

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