JP2019047183A - antenna - Google Patents

Abstract

To provide an antenna area capable of achieving wide bandwidth without increasing antenna region or reducing characteristics.SOLUTION: An antenna 1 in an embodiment comprises a split-ring resonator 8 formed in an opening of a GND substrate 2. The split-ring resonator 8 includes; conductor patterns 4a, 4b having a split portion 3; a first antenna element 5 connected to one end of the conductor pattern 4b; and a second antenna element 7 disposed while being interposed a predetermined distance G from the first antenna element 5 and the first conductor pattern 4b.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an antenna of a wireless device, and more particularly to an antenna using a split ring resonator.

  Patent Document 1 discloses a split ring antenna using a split ring resonator. In the antenna described in Patent Document 1, a first split ring portion and a second split ring portion in which a first conductor layer and a second conductor layer opposed to each other with a dielectric layer interposed therebetween are continuous in a substantially C shape, respectively. Have. The split ring resonator itself is used as an antenna radiator by connecting the first split ring portion and the second split ring portion with a conductor via.

  The feed line straddles the openings of the first split ring portion and the second split ring portion, and extends in a region facing the opposite first split ring portion. One end of the feed line is connected to at least one conductor via, and the other end is connected to the RF circuit.

  Since the split ring antenna utilizes GND current, the antenna itself is very compact, and there is an advantage that the device can be miniaturized. On the other hand, there is also a disadvantage that the characteristics and performance of the antenna are determined to some extent by the GND size and the GND shape because the GND current is used, and it is difficult to improve the characteristics.

  In the case of forming a two-resonance antenna operating at two frequencies by using the technique described in Patent Document 1, a configuration in which two split ring antennas are arranged and fed by two feed lines branched from a feed unit can be considered. Thus, since the multi-banding of the split ring antenna is accompanied by the expansion of the antenna size, miniaturization is one of the problems.

  Patent Document 2 discloses a technique for miniaturizing an antenna operating at a plurality of frequencies. In the antenna described in Patent Document 2, the first additional conductor is disposed in the opening of one split ring resonator so as to be connected to the tip of the split portion. In addition, a second additional conductor is provided, one end of which is connected to the opening edge of the opening and the other end of which is opposed to the first additional conductor. Conductors respectively extending from the first additional conductor and the second additional conductor form an additional split portion.

  In the antenna described in Patent Document 2, the inductance of a coil equivalently changed due to different current paths, and the capacitance of a capacitor equivalently changed due to a change in the number of split parts passing through. Changes. With this configuration, an antenna corresponding to a plurality of frequency bands is realized without expanding the antenna size.

  In recent years, the number of antennas has been increased by advanced multiple-input and multiple-output (MIMO), and the antennas are also mounted with high density. Therefore, further miniaturization of the split ring antenna and reduction of inter-antenna interference are desired.

  Patent Document 3 discloses a technique for reducing interference between antennas by a split ring resonator. In Patent Document 3, a dummy SRR (Sprit Ring Resonator) is disposed at a predetermined distance from the two antennas between two antennas disposed at the end of the printed circuit board. This absorbs high frequency currents of different directions emitted from the two antennas and reduces interference.

WO 2013/027824 JP, 2016-063239, A JP, 2015-046681, A

  However, in Patent Document 2, the second resonance frequency generated when passing the first split portion and the second split portion, as compared with the first resonance frequency generated when the current passes the first split portion Is a frequency that is higher by the capacity of the second split part. Therefore, there is a limitation that the second resonant frequency has to be set to a high frequency with respect to the first resonant frequency. Further, the adjustment range of the second resonance frequency is limited to a range in which the capacity of the second split portion can be adjusted, so that the adjustment range of the resonance frequency is narrow.

  Moreover, in patent document 2, the fall of radiation efficiency is seen at a band edge, and it also has the subject that a zone is narrow. With regard to the broadening of the bandwidth, there is no effective means even in the split ring antenna of Patent Document 1, which is one of the problems. Furthermore, also in Patent Document 3, the bandwidth in which predetermined isolation can be obtained is narrow, and broadening is a problem.

  An antenna according to an aspect of the present invention includes a substrate and a first split ring resonator formed in an opening of the substrate, the first split ring resonator including a first conductor having a first split portion. It has a pattern, a first antenna element connected to one end of the first conductor pattern, and a second antenna element arranged at a predetermined distance from the first antenna element and the first conductor pattern.

  According to the embodiment, it is possible to realize a wide band without expanding the antenna area and degrading the characteristics.

FIG. 2 is a diagram showing an example of a configuration of an antenna according to Embodiment 1; FIG. 7 is a diagram showing a first configuration example of the antenna according to the second embodiment. It is a figure which expands the antenna of FIG. It is IV-IV sectional drawing of FIG. It is a figure which shows the antenna current which flows into the antenna of FIG. It is a figure which shows the antenna current which flows into the antenna of FIG. It is a figure which shows the return loss characteristic of the antenna of FIG. It is a figure which shows the radiation efficiency of the antenna of FIG. FIG. 16 is a diagram illustrating a second configuration example of the antenna according to Embodiment 2. It is a figure which expands the antenna of FIG. It is a figure which shows the return loss characteristic of the antenna of FIG. FIG. 16 is a diagram illustrating a third configuration example of the antenna according to Embodiment 2. It is a figure which expands the antenna of FIG. It is a figure which shows the return loss characteristic of the antenna of FIG. FIG. 16 is a diagram showing an example of the configuration of an antenna according to Embodiment 3. It is a figure which expands the antenna of FIG. It is a figure which shows the isolation characteristic of the antenna of FIG. It is a figure which shows the structure of the antenna of the comparative example 1. FIG. It is a figure which expands the antenna of FIG. It is XX-XX sectional drawing of the antenna of FIG. It is a figure which shows the return loss characteristic of the antenna of FIG. It is a figure which shows the radiation efficiency of the antenna of FIG. It is a figure which shows the structure of the antenna of the comparative example 2. FIG. It is a figure which shows the return loss characteristic of the antenna of FIG. It is a figure which shows the radiation efficiency of the antenna of FIG. It is a figure which shows the structure of the antenna of the comparative example 3. FIG. It is a figure which shows the return loss characteristic of the antenna of FIG. It is a figure which shows the radiation efficiency of the antenna of FIG. It is a figure which shows the structure of the antenna of the comparative example 4. FIG. It is a figure which shows the return loss characteristic of the antenna of FIG. It is a figure which shows the radiation efficiency of the antenna of FIG. It is a figure which shows the antenna current which flows into the antenna of FIG. It is a figure which shows the antenna current which flows into the antenna of FIG. It is a figure which shows the structure of the antenna of the comparative example 5. FIG. It is a figure which shows the isolation characteristic of the antenna of FIG. It is a figure which shows the structure of the antenna of the comparative example 6. FIG. It is a figure which expands the antenna of FIG. It is a figure which shows the isolation characteristic of the antenna of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The present invention relates to an antenna of a wireless device, and more particularly to an antenna using a split ring resonator. The present invention is to realize a wide band without increasing the antenna size by adding a new structure to an antenna using a split ring resonator having characteristics of single resonance and narrow band.

  Before describing the embodiment, the problems of the split ring antenna according to the comparative example will be described with reference to FIGS. FIGS. 18-22 has shown the comparative example 1 which applied the split ring antenna to Wi-Fi of 2.4 GHz band. In Comparative Example 1 shown in FIG. 18, an antenna 30 formed of a split ring resonator is disposed in the vicinity of the center of the upper end portion of the 100 mm × 100 mm GND substrate 31.

  FIG. 19 is an enlarged view of the antenna 30 of FIG. The GND substrate 31 has an opening with a size of 14 mm × 5 mm from which the GND is removed. A conductor pattern 33 having a split portion 32 is formed in the opening. The conductor pattern 33 is fed from the feed unit 34 via the feed line 35. In FIG. 20, XX-XX sectional drawing of FIG. 19 is shown. As shown in FIG. 20, where the feed line 35 overlaps the GND, a part of the GND substrate 31 is removed, and the feed line 35 is disposed at a predetermined distance from the GND 36 of the same layer and the GND 37 of the lower layer. That is, a strip line is formed between the feed line 35 and the GND 36 and the GND 37.

  The return loss characteristic of the antenna 30 of FIG. 18 is shown in FIG. 21, and the radiation efficiency is shown in FIG. The return loss characteristic is one of the indices for measuring the performance of the antenna. The return loss characteristic represents the ratio of the signal input from the feed portion of the antenna to the signal reflected by the antenna and returned to the feed portion. In the feeding part of the antenna, as the impedance on the antenna side and the impedance on the feeding part side are closer, the signal reflection at the feeding part is less and the performance as the antenna is improved.

  In FIG. 21, the horizontal axis represents frequency (MHz), and the vertical axis represents reflectance (dB). Note that the horizontal axis and the vertical axis are the same also in the figures showing return loss characteristics in the following description. In the horizontal axis, the frequency increases toward the right. The vertical axis represents that the lower the direction is, the less the reflection (the more efficiently the radiation) at that frequency. The graph showing the return loss characteristic has a smaller value as the impedance approaches 50 Ω. In the graph showing the return loss characteristic, the portion where the value of return loss is small is the frequency band in which the antenna resonates and radio waves are transmitted and received. In order for the antenna to operate well, it is generally desirable that the return loss be less than -5 dB at the frequency at which the antenna operates.

  The radiation efficiency (radiation characteristics) is also one of the indicators for measuring the performance of the antenna. The radiation efficiency is determined by the ratio of the power output as radio waves from the antenna to the power input to the antenna. The radiation efficiency indicates that the higher the value, the better the performance of the antenna device. In FIG. 22, the horizontal axis indicates frequency (MHz) and the vertical axis indicates emissivity (dB). In addition, also in the figure which shows the radiation efficiency of the following description, a horizontal axis and a vertical axis | shaft are the same. As shown in FIGS. 21 and 22, the antenna 30 has a single resonance in the 2.4 GHz band.

  FIGS. 23-25 has shown the comparative example 2 which applied the split ring antenna to Wi-Fi of 5 GHz band. FIG. 23 is an enlarged view of the antenna 30. FIG. The GND substrate 31 has an opening with a size of 4 mm × 5 mm from which the GND is removed. A conductor pattern 33 having a split portion 32 is formed in the opening. The conductor pattern 33 is fed from the feed unit 34 via the feed line 35. These configurations are similar to the configuration of the 2.4 GHz band antenna described above. The return loss characteristic of the antenna 30 of FIG. 23 is shown in FIG. 24, and the radiation efficiency is shown in FIG. As shown in FIGS. 24 and 25, it is single resonance of 5 GHz band.

  When a two-resonance antenna is required, a configuration may be considered in which two split ring antennas are arranged and power is supplied by a feed line branched from a feed unit into two. 26 to 28 show Comparative Example 3 in which the split ring antenna is multibanded. As shown in FIG. 26, the two-resonance antenna 30a is provided at the upper end portion of the GND substrate 31 so that the conductor pattern 33a having the split portion 32a and the conductor pattern 33b having the split portion 32b are aligned. The conductor patterns 33a and 33b are fed by the feed line 35 branched from the feed unit 34 into two. The return loss characteristic of the antenna 30 of FIG. 26 is shown in FIG. 27, and the radiation efficiency is shown in FIG.

  As shown in FIGS. 27 and 28, there are two resonances of 2.4 GHz band and 5 GHz band. However, in the antenna 30a shown in FIG. 26, since the split ring resonators are arranged side by side at the end portion of the GND substrate 31, there is a problem that the antenna size is enlarged.

  As mentioned above, an example is shown by patent document 2 as a means to solve this problem. 29 to 33 show Comparative Example 4 in which the split ring antenna is multibanded using the technique of Patent Document 2. FIG. As shown in FIG. 29, a conductor pattern 43b is connected to the open end of a conductor pattern 43a having a split portion 42a in the opening of an antenna 40 using one split ring resonator. Also, a conductor pattern 43c is provided, one end of which is connected to the opening edge of the opening and the other end of which is opposed to the conductor pattern 43b. Conductors respectively extended from the conductor patterns 43b and 43c form additional split portions 42b. Power is supplied to the conductor pattern 43 d from the feed unit 44 via the feed line 45.

  The return loss characteristic of the antenna 40 of FIG. 29 is shown in FIG. 30, and the radiation efficiency is shown in FIG. As shown in FIGS. 30 and 31, by the configuration of the antenna 40, two resonances of the antenna are realized without enlarging the antenna size. 31 and 32 show the antenna current flowing in the antenna of FIG. In the configuration of FIG. 29, as shown in FIG. 31, two types of antenna currents are generated with an apparent feeding point 46 and feeding point 47 as a center, and two resonances of the antenna are realized.

  However, the above-mentioned two-resonance generating means occurs when passing through the split part 42b in addition to the split part 42a as compared with the first resonance frequency (2.4 GHz band) generated when passing through the split part 42a The second resonance frequency (5 GHz band) is characterized by being a frequency higher by the capacity of the split unit 42b. Therefore, there is a limitation that the second resonant frequency has to be set to a frequency higher than the first resonant frequency. Further, since the adjustment range of the second resonance frequency is limited to a range in which the capacity of the added split portion 42b can be adjusted, the adjustment range of the resonance frequency is narrow.

  Moreover, in patent document 2, it also has the subject that a zone is narrow. As shown in the radiation efficiency of FIG. 31, a decrease in the radiation efficiency is observed at the band edge, particularly in the 5 GHz band where the used band is wide. With regard to broadening the bandwidth, there is no effective means not only in Patent Document 2 but also in the split ring antenna of Patent Document 1 shown above, which is one of the problems.

  An inter-antenna interference reduction technique by a split ring resonator is shown, for example, in Patent Document 3. 34 to 38 illustrate an example of the interference reduction technology between antennas by a split ring resonator. 34 and 35 show Comparative Example 5 of the antenna to which the split ring resonator is not applied. Moreover, FIGS. 36-38 have shown the comparative example 6 of the antenna which applied the split ring resonator.

  In Comparative Example 5, a monopole antenna 50a consisting of the antenna element 51a connected to the feeding part 53a and a monopole antenna consisting of the antenna element 51b connected to the feeding part 53b at the upper end of the GND substrate 52 of 100 mm × 100 mm. 50b is formed. The antenna element 51b is disposed at a distance of about λ / 4 from the antenna element 51a.

  FIG. 35 shows the isolation characteristic of the antenna of FIG. Isolation is a degree that indicates interference between a plurality of antennas. The state in which the isolation is small is a state in which the interference between a plurality of antennas is large and adversely affects the antenna characteristics of each other. The isolation characteristic indicates the ratio of the output power to the input power of the signal output from the feed line. In FIG. 35, the horizontal axis represents frequency (MHz), and the vertical axis represents isolation (dB). Note that the horizontal axis and the vertical axis are the same in the drawings showing the isolation characteristics in the following description. As shown in FIG. 35, in this case, interference between the antennas is strong, and isolation is only about 10 dB.

  36 to 38 show a comparative example 6 for explaining the inter-antenna interference reduction technique (Patent Document 3) by the split ring resonator. As shown in FIG. 36, a spring ring resonator 54 is disposed between the monopole antenna 50a and the monopole antenna 50b. FIG. 37 is an enlarged view of the antenna of FIG. As shown in FIG. 38, the isolation at this time is about 20 dB, and an improvement of about 10 dB is observed as compared with the case where the spring ring resonator 54 is not disposed. However, also in this example, the bandwidth for obtaining 20 dB of isolation is as narrow as 93 MHz, and broadening is a problem.

  In the embodiment, a new structure is added to a split ring antenna having single resonance and narrow band characteristics, and multiband realization by multiple resonance is realized or without increasing the antenna size. Is realized. Hereinafter, embodiments will be described.

Embodiment 1
The antenna according to the first embodiment will be described with reference to the drawings. In the drawings to be described below, the same components are denoted by the same reference numerals, and the description thereof will be omitted as appropriate. FIG. 1 is a diagram showing the configuration of the antenna 1 according to the first embodiment. The antenna 1 is a spring ring antenna using a split ring resonator 8. The split ring resonator 8 includes conductor patterns 4 a and 4 b having a split portion 3, a first antenna element 5, and a second antenna element 7.

  The antenna 1 includes a split ring resonator 8, a feeding unit 6, and a GND substrate 2. The GND substrate 2 is formed with an opening at its end where the GND is removed. The split ring resonator 8 is provided in the opening. This opening is the area of the split ring resonator 8. Split ring resonator 8 is arranged in contact with the outer edge of GND substrate 2.

  A conductor pattern 4 a is provided along the outer edge of the GND substrate 2 from the right opening edge of the opening. One end of the conductor pattern 4a is connected to GND. The other end of the conductor pattern 4 a extends perpendicularly from the outer edge of the GND substrate 2 in a direction toward the inside of the GND substrate 2.

  A first antenna element 5 is formed in the region of the split ring resonator 8. That is, the first antenna element 5 is formed in the opening formed in the GND substrate 2. The feeding portion 6 is formed in the vicinity of the left opening edge of the GND substrate 2 opening. One end of the first antenna element 5 is connected to the feeding unit 6, and AC power is supplied. That is, the first antenna element 5 is used as a feed line. The first antenna element 5 extends parallel to the outer edge of the GND substrate 2 at a predetermined distance from the outer edge of the GND substrate 2. One end of the conductor pattern 4 b is connected to the other end of the first antenna element 5.

  The conductor pattern 4 b is formed along the outer edge of the GND substrate 2. The other end of the conductor pattern 4 b extends vertically from the outer edge of the GND substrate 2 in a direction toward the inside of the GND substrate 2. The portions of the conductor pattern 4a and the conductor pattern 4b extending perpendicularly from the outer edge of the GND substrate 2 face each other at a predetermined distance, and form a split portion 3. The conductor pattern 4a and the conductor pattern 4b correspond to the first conductor pattern described in the claims.

  The second antenna element 7 is provided along the outer edge of the GND substrate 2 from the left opening edge of the opening. One end of the second antenna element 7 is directly grounded. The second antenna element 7 is disposed at a predetermined distance G from the first antenna element 5 and the conductor pattern 4 b. In the example shown in FIG. 1, the second antenna element 7 is disposed in parallel with the first antenna element 5. Further, the second antenna element 7 is disposed on the outer peripheral side of the GND substrate 2 with respect to the first antenna element 5.

  In the first embodiment, the loop formed by the first conductor pattern (conductor patterns 4a and 4b) and the second antenna element 7 resonates when the first current having a frequency that changes in the first frequency band flows. And a first resonant frequency is generated. In addition, a loop formed by the first antenna element 5 and the second antenna element 7 resonates when a second current having a frequency that changes in a second frequency band different from the first frequency band flows, A second resonant frequency is generated. That is, the first antenna element 5 is used not only for feeding but also as an antenna element. As a result, multiple resonances can be achieved without expanding the antenna area or degrading the characteristics.

  Furthermore, in the antenna 1 according to the first embodiment, the second resonant frequency can be adjusted by the length of the second antenna element 7 parallel to the first antenna element 5. Thereby, the adjustment range of the frequency can be broadened. Therefore, it is also possible to set the second resonance frequency near the first resonance frequency. As described above, in the antenna 1 according to the first embodiment, it is possible to realize a wide band as well as multi-resonance without expanding the antenna area and degrading the characteristics.

Embodiment 2
The antenna according to the second embodiment will be described with reference to FIGS. FIG. 2 is a diagram showing a first configuration example of the antenna according to the second embodiment. FIG. 3 is an enlarged view of the antenna of FIG. 2, and FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. The second embodiment differs from the first embodiment in that an inductor 9 is added.

  As shown in FIG. 3, the antenna 1 includes a split ring resonator 8, a feeding unit 6, a GND substrate 2, and an inductor 9. The split ring resonator 8 includes conductor patterns 4 a and 4 b having a split portion 3, a first antenna element 5, and a second antenna element 7. As described above, the first antenna element 5 doubles as a feed line and an antenna element. The inductor 9 is provided between the second antenna element 7 and the opening edge of the GND substrate 2. One end of the second antenna element 7 is grounded via the inductor 9. The inductor 9 is arranged to facilitate miniaturization and frequency adjustment.

  In the first configuration example, the antenna 1 a is disposed on the GND substrate 2 of 100 mm × 100 mm. As in the comparative example 1 shown in FIG. 18, the GND substrate 2 is formed with an opening with a size of 14 mm × 5 mm from which the GND is removed. This opening is the area of the split ring resonator 8. When the distance G between the first antenna element 5 and the second antenna element 7 is about 1 mm to 2 mm, the effect of the present invention is most easily obtained. In the first configuration example, the distance G is 1.5 mm.

  As shown in FIG. 4, in a portion where the first antenna element 5 overlaps with the GND, a part of the GND substrate 2 is removed, and the first antenna element 5 is separated from the GND 10 in the same layer and the GND 11 in the lower layer at a predetermined distance. Be placed. That is, a strip line is formed between the first antenna element 5 and GND10 and GND11. However, the configuration of the first antenna element 5 is not limited to this, and other configurations may be used as long as feeding can be performed.

  Next, the operation of the antenna 1a according to the first configuration example will be described with reference to FIGS. 5 and 6 are diagrams showing an antenna current flowing to the antenna of FIG. As shown in FIG. 5, in the first configuration example, a first resonance frequency is generated by a loop formed by the first conductor pattern (conductor patterns 4 a and 4 b), the second antenna element 7, and the inductor 9. In this case, the first antenna element 5 and the second antenna element 7 operate as a feed line whose impedance is close to 50Ω. Thus, apparently, the feeding point 12 is present at a position close to the second antenna element 7 of the conductor pattern 4b. An antenna current flows around this feed point 12.

  In addition, a second resonance frequency is generated by a loop formed by the first antenna element 5, the second antenna element 7, and the inductor 9. In this case, the feeding point 13 apparently exists at a position close to the opening end of the GND substrate 2 of the first antenna element 5. An antenna current flows around the feeding point 13. As described above, in the first configuration example, multi-resonance can be realized in one antenna region, and the antenna can be miniaturized.

  FIG. 7 is a diagram showing return loss characteristics of the antenna of FIG. FIG. 8 is a diagram showing the radiation efficiency of the antenna of FIG. It can be seen from FIGS. 7 and 8 that it is possible to realize two resonances of the 2.4 GHz band and the 5 GHz band without reducing the radiation efficiency.

  Further, in the antenna 1 a according to the second embodiment, the second resonant frequency can be adjusted by the length of the second antenna element 7 parallel to the first antenna element 5 or the inductor. Therefore, the second resonance frequency can be set near the first resonance frequency. Further, the adjustment range of the second resonance frequency can be ensured as a continuous band from the first resonance frequency to the second resonance circumference. Thus, in the second embodiment, the adjustment range of the second resonance frequency can be broadened.

  Another configuration example of the antenna according to the second embodiment will be described with reference to FIGS. FIG. 9 is a diagram showing a second configuration example of the antenna according to the second embodiment. FIG. 10 is an enlarged view of the antenna of FIG. FIG. 11 is a diagram showing return loss characteristics of the antenna of FIG. The second configuration example is an example when the 2.4 GHz band is broadened.

  As in the first configuration example, in the second configuration example, the antenna 1 b is disposed on the GND substrate 2 of 100 mm × 100 mm. As shown in FIG. 10, the antenna 1 b includes a split ring resonator 8, a feeding unit 6, a GND substrate 2, and an inductor 9. The split ring resonator 8 includes conductor patterns 4a and 4b having a split portion 3, a first antenna element 5b, and a second antenna element 7b.

  In the second configuration example, the lengths of the first antenna element 5b and the second antenna element 7b are longer than the first antenna element 5 and the second antenna element 7 in the first configuration example. Furthermore, it is possible to adjust the second resonance frequency to around 2.7 GHz by adjusting the constant of the inductor 9. From FIG. 11, it is possible to widen the range in which the return loss in the 2.4 GHz band is −5 dB or less, and it is possible to realize a wide band.

  FIG. 12 is a diagram showing a third configuration example of the antenna according to the second embodiment. FIG. 13 is an enlarged view of the antenna of FIG. FIG. 14 is a diagram showing return loss characteristics of the antenna of FIG. The third configuration example is an example when the 5 GHz band is broadened.

  As in the first configuration example, in the third configuration example, the antenna 1 c is disposed on the GND substrate 2. As shown in FIG. 13, the antenna 1 c includes a split ring resonator 8, a feeding unit 6, a GND substrate 2, and an inductor 9. The split ring resonator 8 includes conductor patterns 4 a and 4 b having a split portion 3, a first antenna element 5 c and a second antenna element 7 c.

  In the second configuration example, the lengths of the first antenna element 5c and the second antenna element 7c are shorter than those of the first antenna element 5 and the second antenna element 7 in the first configuration example. Therefore, the size of the opening formed in the GND substrate 2 is smaller than the size of the opening in the first configuration example. Furthermore, the constant of the inductor 9 is adjusted. From FIG. 14, it is possible to widen the range in which the return loss in the 5 GHz band is −5 dB or less, and it is possible to realize a wide band. As described above, in the second embodiment, it is possible to realize multi-resonance and to achieve a wide band without expanding the antenna area and degrading the characteristics.

Third Embodiment
The antenna according to the third embodiment will be described with reference to FIGS. FIG. 15 is a diagram showing an example of the configuration of the antenna according to the third embodiment. FIG. 16 is an enlarged view of the antenna of FIG. FIG. 17 is a view showing the isolation characteristic of the antenna of FIG. The third embodiment is an example in which the split ring resonator of the present invention is used to reduce interference between antennas.

  As shown in FIGS. 15 and 16, the antenna 1 d includes monopole antennas 20 a and 20 b, a split ring resonator 8, a GND substrate 2, and an inductor 9. The monopole antenna 20a has an anantenna element 22a connected to the feeding part 21a, and the monopole antenna 20b has an antenna element 22b connected to the feeding part 21b. The monopole antennas 20 a and 20 b are arranged at a predetermined distance at the upper end portion of the GND substrate 2.

  A split ring resonator 8 is disposed between the monopole antenna 20a and the monopole antenna 20b. That is, the monopole antenna 20 a, the split ring resonator 8, and the monopole antenna 20 b are formed on the same side of the GND substrate 2 in this order.

  As shown in FIG. 16, the split ring resonator 8 includes conductor patterns 4 a and 4 b having a split portion 3, a first antenna element 5 d, and a second antenna element 7 d. The inductor 9 is provided between the second antenna element 7 d and the opening edge of the GND substrate 2. One end of the second antenna element 7 d is grounded via the inductor 9. One end of the first antenna element 5d is grounded, and the other end is connected to the conductor pattern 4b.

  FIG. 17 shows the isolation characteristic of the antenna 1d of FIG. As shown in FIG. 17, in the third embodiment, the band for which isolation can be obtained by about 20 dB is 140 MHz. In the comparative example of FIG. 38, the band in which isolation is about 20 dB is obtained is 93 MHz, and in the third embodiment, it is possible to realize about 1.5 times wider band. As described above, in the third embodiment, it is possible to improve the isolation characteristics and realize a wider band without expanding the antenna region and degrading the characteristics.

  The present invention is not limited to the above embodiment, and can be appropriately modified without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 antenna 1a antenna 1b antenna 1c antenna 1d antenna 2 GND board 3 split part 4a conductor pattern 4b conductor pattern 5 1st antenna element 5b 1st antenna element 5c 1st antenna element 5d 1st antenna element 6 feed part 7 2nd antenna element 7b Second antenna element 7c Second antenna element 7d Second antenna element 8 Split ring resonator 9 Inductor 1a Antenna 10 GND
11 GND
12 feeding point 13 feeding point 20a monopole antenna 20b monopole antenna 21a feeding section 21a feeding section 22a anantenna element 22b antenna element 30 antenna 30a 2 resonance antenna 31 GND substrate 32 split section 32a split section 32b split section 33 conductor pattern 33a conductor Pattern 33b Conductor pattern 34 Feeding part 35 Feeding line 36 GND
37 GND
40 Antenna 41 GND Substrate 42a Split Part 42b Split Part 43a Conductor Pattern 43b Conductor Pattern 44 c Conductor Pattern 44 Feed Part 45 Feeding Line 46 Feeding Point 47 Feeding Point 50a Monopole Antenna 50b Monopole Antenna 51a Anantenna Element 51b Antenna Element 52 GND Substrate 53a feeding portion 53b feeding portion 54 spring ring resonator G distance

Claims (6)

A substrate,
And a first split ring resonator formed in the opening of the substrate,
The first split ring resonator is
A first conductor pattern having a first split portion;
A first antenna element connected to one end of the first conductor pattern;
A second antenna element disposed at a predetermined distance from the first antenna element and the first conductor pattern;
Have
antenna. The second antenna element is disposed in parallel with the first antenna element.
The antenna according to claim 1. The second antenna element is disposed on the outer peripheral side of the substrate than the first antenna element.
The antenna according to claim 1 or 2. One end of the second antenna element is grounded via an inductor or grounded without an inductor,
The antenna according to any one of claims 1 to 3. The first conductor pattern and the second antenna element resonate when a first current having a frequency that changes in a first frequency band flows,
The second antenna element and the first antenna element resonate when a second current having a frequency that changes in a second frequency band different from the first frequency band flows.
The antenna according to any one of claims 1 to 4. It further comprises a first antenna circuit and a second antenna circuit formed at the end of the substrate,
The first split ring resonator is disposed at the end between the first antenna circuit and the second antenna circuit.
The first antenna element is grounded.
The antenna according to any one of claims 1 to 4.

Images