JP6624650B2 - antenna - Google Patents

Description

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

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

  The power supply line extends across the opening of the first split ring portion and the second split ring portion, and extends to a region opposed to the first split ring portion on the opposite side. One end of the feed line is connected to at least one conductor via, and the other end is connected to an RF circuit.

  Since the split ring antenna uses the GND current, the antenna itself is very small, and has an advantage that the device can be downsized. On the other hand, since the GND current is used, the characteristics and performance of the antenna are determined to some extent by the GND size and the GND shape, and there is a disadvantage that the characteristics are hardly improved.

  When a two-resonant antenna operating at two frequencies is formed by using the technique described in Patent Document 1, a configuration in which two split ring antennas are arranged and power is supplied by a feed line that branches off from a feed unit may be considered. As described above, the multiband split ring antenna involves an increase in antenna size, and thus miniaturization is one of the issues.

  Patent Literature 2 discloses a technique for downsizing an antenna operating at a plurality of frequencies. In the antenna described in Patent Literature 2, the first additional conductor is arranged in the opening of one split ring resonator so as to be connected to the tip of the split part. Further, 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 arranged to face the first additional conductor. Conductors extending from the first additional conductor and the second additional conductor, respectively, form an additional split portion.

  In the antenna described in Patent Literature 2, the inductance of a coil that is equivalently changed due to a different current path changes, and the capacitance of a capacitor that is equivalently changed by changing the number of split portions that pass through the antenna. Changes. With this configuration, an antenna corresponding to a plurality of frequency bands is realized without increasing the antenna size.

  In recent years, the number of antennas has increased due to advanced MIMO (multiple-input and multiple-output), and antennas are also mounted at high density. For this reason, it is desired to further reduce the size of the split ring antenna and reduce interference between antennas.

  Patent Literature 3 discloses a technique for reducing interference between antennas using a split ring resonator. In Patent Literature 3, a dummy SRR (Sprit Ring Resonator) is disposed between two antennas disposed at an end of a printed circuit board at a position separated by a predetermined distance from the two antennas. Thereby, high-frequency currents emitted from the two antennas and having different directions are absorbed, and interference is reduced.

WO 2013/027824 JP-A-2006-063239 JP-A-2005-046681

  However, in Patent Document 2, the second resonance frequency generated when the current passes through the first split portion and the second split portion is compared with the first resonance frequency generated when the current passes through the first split portion. Becomes higher by the capacity of the second split unit. Therefore, there is a limitation that the second resonance frequency must be set to a frequency higher than the first resonance frequency. Further, since the adjustment range of the second resonance frequency is limited to a range in which the capacitance of the second split unit can be adjusted, there is a problem that the adjustment range of the resonance frequency is narrow.

  Patent Document 2 also has a problem that the radiation efficiency is reduced at the band edge and the band is narrow. Regarding the increase of the bandwidth, there is no effective means in the split ring antenna of Patent Document 1, and this is one of the problems. Further, also in Patent Document 3, the bandwidth for obtaining a predetermined isolation is narrow, and there is a problem of widening the bandwidth.

  An antenna according to one embodiment of the present invention includes a substrate, and a first split ring resonator formed in an opening of the substrate, wherein the first split ring resonator has a first conductor having a first split portion. 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 wider band without expanding the antenna area or lowering the characteristics.

FIG. 3 is a diagram illustrating an example of a configuration of the antenna according to the first embodiment. FIG. 9 is a diagram showing a first configuration example of an antenna according to a second embodiment. FIG. 3 is an enlarged view of the antenna of FIG. 2. FIG. 4 is a sectional view taken along line IV-IV of FIG. 3. FIG. 3 is a diagram illustrating an antenna current flowing through the antenna of FIG. 2. FIG. 3 is a diagram illustrating an antenna current flowing through the antenna of FIG. 2. FIG. 3 is a diagram illustrating return loss characteristics of the antenna of FIG. 2. FIG. 3 is a diagram illustrating radiation efficiency of the antenna of FIG. 2. FIG. 13 is a diagram illustrating a second configuration example of the antenna according to the second embodiment. It is a figure which expands the antenna of FIG. FIG. 10 is a diagram illustrating return loss characteristics of the antenna of FIG. 9. FIG. 13 is a diagram showing a third configuration example of the antenna according to the second embodiment. It is a figure which expands the antenna of FIG. FIG. 13 is a diagram illustrating return loss characteristics of the antenna of FIG. 12. FIG. 13 is a diagram illustrating an example of a configuration of an antenna according to a third embodiment. It is a figure which expands the antenna of FIG. FIG. 16 is a diagram illustrating isolation characteristics of the antenna of FIG. 15. FIG. 9 is a diagram illustrating a configuration of an antenna of Comparative Example 1. It is a figure which expands the antenna of FIG. FIG. 19 is a sectional view taken along line XX-XX of the antenna of FIG. 18. FIG. 19 is a diagram illustrating return loss characteristics of the antenna of FIG. 18. FIG. 19 is a diagram showing the radiation efficiency of the antenna of FIG. 18. FIG. 9 is a diagram illustrating a configuration of an antenna of Comparative Example 2. FIG. 24 is a diagram illustrating return loss characteristics of the antenna of FIG. 23. FIG. 24 is a diagram showing the radiation efficiency of the antenna of FIG. 23. FIG. 9 is a diagram illustrating a configuration of an antenna of Comparative Example 3. FIG. 27 is a diagram showing return loss characteristics of the antenna of FIG. 26. FIG. 27 is a diagram showing the radiation efficiency of the antenna of FIG. 26. FIG. 14 is a diagram illustrating a configuration of an antenna of Comparative Example 4. FIG. 30 is a diagram illustrating return loss characteristics of the antenna of FIG. 29. FIG. 30 is a diagram showing the radiation efficiency of the antenna of FIG. 29. FIG. 30 is a diagram illustrating an antenna current flowing through the antenna of FIG. 29. FIG. 30 is a diagram illustrating an antenna current flowing through the antenna of FIG. 29. FIG. 14 is a diagram illustrating a configuration of an antenna of Comparative Example 5. FIG. 35 is a diagram illustrating isolation characteristics of the antenna of FIG. 34. FIG. 14 is a diagram illustrating a configuration of an antenna of Comparative Example 6. FIG. 37 is an enlarged view of the antenna of FIG. 36. FIG. 37 shows isolation characteristics of the antenna of FIG. 36.

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 achieves a wider 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 embodiments, problems of the split ring antenna according to the comparative example will be described with reference to FIGS. 18 to 22 show Comparative Example 1 in which the split ring antenna is applied to Wi-Fi in the 2.4 GHz band. In Comparative Example 1 shown in FIG. 18, an antenna 30 including a split ring resonator is arranged near the center of the upper end of a 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 GND is removed. A conductor pattern 33 having a split portion 32 is formed in the opening. Power is supplied to the conductor pattern 33 from a power supply unit 34 via a power supply line 35. FIG. 20 shows a sectional view taken along the line XX-XX of FIG. As shown in FIG. 20, at a place where the feed line 35 overlaps with the GND, a part of the GND substrate 31 is deleted, and the feed line 35 is arranged at a predetermined interval 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 power supply line 35 and the GNDs 36 and 37.

  FIG. 21 shows the return loss characteristics of the antenna 30 in FIG. 18, and FIG. 22 shows the radiation efficiency. The return loss characteristic is one of the indexes for measuring the performance of the antenna. The return loss characteristic represents a ratio of a signal input from the power supply unit of the antenna to a signal reflected from the antenna and returned to the power supply unit. In the feeding section of the antenna, the closer the impedance on the antenna side and the impedance on the feeding section side are, the smaller the signal reflection at the feeding section is, and the performance as an antenna is improved.

  In FIG. 21, the horizontal axis indicates frequency (MHz), and the vertical axis indicates reflectivity (dB). Note that the horizontal axis and the vertical axis are the same in the diagrams showing the return loss characteristics in the following description. On the horizontal axis, the frequency increases as going to the right. The vertical axis indicates that the reflection is reduced (emitted more efficiently) at that frequency as going downward. The graph showing the return loss characteristic has a smaller value as the impedance is closer to 50Ω. In the graph showing the return loss characteristics, the portion where the value of the return loss is small is the frequency band in which the antenna resonates and the radio wave is transmitted and received. In order for the antenna to operate satisfactorily, it is generally desirable that the return loss be -5 dB or less at the frequency at which the antenna operates.

  The radiation efficiency (radiation characteristic) is also one of the indices 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 higher the radiation efficiency, the better the performance of the antenna device. In FIG. 22, the horizontal axis indicates frequency (MHz), and the vertical axis indicates emissivity (dB). The horizontal axis and the vertical axis are the same in the figures showing the radiation efficiency in the following description. As shown in FIGS. 21 and 22, the antenna 30 has a single resonance in the 2.4 GHz band.

  23 to 25 show Comparative Example 2 in which the split ring antenna is applied to Wi-Fi in the 5 GHz band. FIG. 23 is an enlarged view of the antenna 30. The GND substrate 31 is formed with an opening of a size of 4 mm × 5 mm from which GND is removed. A conductor pattern 33 having a split portion 32 is formed in the opening. Power is supplied to the conductor pattern 33 from a power supply unit 34 via a power supply line 35. These configurations are the same as the configuration of the 2.4 GHz band antenna described above. FIG. 24 shows the return loss characteristics of the antenna 30 in FIG. 23, and FIG. 25 shows the radiation efficiency. As shown in FIGS. 24 and 25, the single resonance is in the 5 GHz band.

  When a two-resonance antenna is required, a configuration is conceivable in which two split ring antennas are arranged and power is supplied by a feed line branched from a feed unit. 26 to 28 show Comparative Example 3 in which the split ring antenna is multiband. As shown in FIG. 26, the two-resonance antenna 30a is provided on the upper end of the GND substrate 31 so that a conductor pattern 33a having a split portion 32a and a conductor pattern 33b having a split portion 32b are arranged side by side. The conductor patterns 33 a and 33 b are supplied with power by a power supply line 35 branched from a power supply unit 34. FIG. 27 shows the return loss characteristics of the antenna 30 in FIG. 26, and FIG. 28 shows the radiation efficiency.

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

  As described above, Patent Literature 2 discloses an example as a means for solving this problem. 29 to 33 show a comparative example 4 in which the split ring antenna is multibanded using the technique of Patent Document 2. As shown in FIG. 29, a conductor pattern 43b is connected to an open end of a conductor pattern 43a having a split portion 42a in an opening of an antenna 40 using one split ring resonator. Further, 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 arranged to face the conductor pattern 43b. Conductors extending from the conductor patterns 43b and 43c, respectively, form additional split portions 42b. Power is supplied to the conductor pattern 43d from the power supply unit 44 via the power supply line 45.

  FIG. 30 shows the return loss characteristics of the antenna 40 in FIG. 29, and FIG. 31 shows the radiation efficiency. As shown in FIGS. 30 and 31, the configuration of the antenna 40 realizes two resonances of the antenna without increasing the antenna size. FIGS. 31 and 32 show the antenna current flowing through the antenna of FIG. In the configuration of FIG. 29, as shown in FIG. 31, two types of antenna currents are generated around the apparent feed point 46 and the feed point 47 to realize two resonances of the antenna.

  However, in the above-described two-resonating means, compared with the first resonance frequency (2.4 GHz band) generated when passing through the split portion 42a, the frequency is generated when passing through the split portion 42b in addition to the split portion 42a. The second resonance frequency (5 GHz band) is higher by the capacity of the split portion 42b. Therefore, there is a limitation that the second resonance frequency must be set to a frequency higher than the first resonance frequency. Further, since the adjustment range of the second resonance frequency is limited to a range where the capacity of the added split portion 42b can be adjusted, there is a problem that the adjustment range of the resonance frequency is narrow.

  Patent Document 2 also has a problem that the band is narrow. As shown in the radiation efficiency in FIG. 31, particularly in the 5 GHz band where the used band is wide, the radiation efficiency is reduced at the band edge. Regarding the increase of the bandwidth, there is no effective means not only in Patent Literature 2 but also in the split ring antenna of Patent Literature 1 described above, which is one of the problems.

  A technique for reducing interference between antennas using a split ring resonator is disclosed in, for example, Patent Document 3. 34 to 38 are examples illustrating a technique for reducing interference between antennas using a split ring resonator. 34 and 35 show a comparative example 5 of an antenna to which the split ring resonator is not applied. 36 to 38 show Comparative Example 6 of the antenna to which the split ring resonator is applied.

  In Comparative Example 5, a monopole antenna 50a composed of an antenna element 51a connected to a power supply unit 53a and a monopole antenna composed of an antenna element 51b connected to a power supply unit 53b are provided at the upper end of a 100 mm × 100 mm GND substrate 52. 50b are formed. The antenna element 51b is arranged at a position separated from the antenna element 51a by about λ / 4.

  FIG. 35 shows the isolation characteristics of the antenna of FIG. The isolation is a degree indicating interference between a plurality of antennas. The state where the isolation is small is a state where interference between the 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 power supply 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, the interference between antennas is strong, and only about 10 dB of isolation can be obtained.

  36 to 38 show a comparative example 6 illustrating a technique for reducing interference between antennas using a split ring resonator (Patent Document 3). As shown in FIG. 36, a spring ring resonator 54 is arranged 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 effect of about 10 dB is obtained as compared with the case where the spring ring resonator 54 is not provided. However, also in this example, the bandwidth in which the isolation is obtained at 20 dB is as narrow as 93 MHz, and there is a problem of widening the bandwidth.

  In the embodiment, a new structure is added to the split ring antenna having the characteristic of single resonance and narrow band, and the multi-band by multiple resonance is realized without increasing the antenna size, or the band is widened. 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 described below, the same components are denoted by the same reference numerals, and description thereof will be omitted as appropriate. FIG. 1 is a diagram showing a configuration of the antenna 1 according to the first embodiment. The antenna 1 is a spring ring antenna using a split ring resonator 8. Split ring resonator 8 includes conductor patterns 4 a and 4 b having split portion 3, first antenna element 5, and second antenna element 7.

  The antenna 1 includes a split ring resonator 8, a feed unit 6, and a GND substrate 2. An opening from which GND is removed is formed at an end of the GND substrate 2. The split ring resonator 8 is provided in the opening. This opening serves as a region of the split ring resonator 8. The split ring resonator 8 is arranged so as to be in contact with the outer edge of the GND substrate 2.

  The conductor pattern 4 a is provided along the outer edge of the GND substrate 2 from the opening edge on the right side of the opening. One end of the conductor pattern 4a is connected to GND. The other end of the conductor pattern 4 a extends vertically from the outer edge of the GND substrate 2 toward the inside of the GND substrate 2.

  The first antenna element 5 is formed in the area of the split ring resonator 8. That is, the first antenna element 5 is formed in an opening formed in the GND substrate 2. The power supply unit 6 is formed near the opening edge on the left side of the opening of the GND substrate 2. One end of the first antenna element 5 is connected to the power supply 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 position inside the outer edge of the GND substrate 2 by a predetermined distance. One end of the conductor pattern 4b is connected to the other end of the first antenna element 5.

  The conductor pattern 4b is formed along the outer edge of the GND substrate 2. The other end of the conductor pattern 4b extends vertically from the outer edge of the GND substrate 2 toward the inside of the GND substrate 2. The portions of the conductor patterns 4a and 4b that extend vertically from the outer edge of the GND substrate 2 face each other at a predetermined interval to 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 edge of the opening. One end of the second antenna element 7 is directly grounded. The second antenna element 7 is arranged at a predetermined distance G from the first antenna element 5 and the conductor pattern 4b. In the example shown in FIG. 1, the second antenna element 7 is arranged in parallel with the first antenna element 5. Further, the second antenna element 7 is arranged 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 causes resonance when a first current having a frequency that changes within the first frequency band flows. Then, a first resonance frequency is generated. Further, the 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 resonance frequency occurs. That is, the first antenna element 5 is used not only for power feeding but also as an antenna element. As a result, multi-resonance can be achieved without expanding the antenna area or lowering the characteristics.

  Further, in the antenna 1 according to the first embodiment, the second resonance frequency can be adjusted by the length of the second antenna element 7 parallel to the first antenna element 5. Thereby, the frequency adjustment range can be widened. For this reason, 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 multi-resonance and a wide band without increasing an antenna area or reducing characteristics.

Embodiment 2
The antenna according to the second embodiment will be described with reference to FIGS. FIG. 2 is a diagram illustrating 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 sectional view taken along line IV-IV of FIG. The second embodiment is different 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 feed unit 6, a GND substrate 2, and an inductor 9. Split ring resonator 8 includes conductor patterns 4 a and 4 b having split portion 3, first antenna element 5, and second antenna element 7. As described above, the first antenna element 5 serves as both a feed line and an antenna element. The inductor 9 is provided between the second antenna element 7 and an 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 1a is arranged on a GND substrate 2 of 100 mm × 100 mm. As in Comparative Example 1 shown in FIG. 18, the GND substrate 2 has an opening of a size of 14 mm × 5 mm from which the GND is removed. This opening serves as a region 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 interval G was set to 1.5 mm.

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

  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 antenna currents flowing through 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 4a and 4b), 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 feed lines having impedances close to 50Ω. For this reason, the feed point 12 exists at a position apparently close to the second antenna element 7 of the conductor pattern 4b. An antenna current flows around the feeding point 12.

  Further, 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 is present at a position apparently 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 downsized.

  FIG. 7 is a diagram illustrating the return loss characteristics of the antenna of FIG. FIG. 8 is a diagram showing the radiation efficiency of the antenna of FIG. 7 and 8 that it is possible to realize two resonances in the 2.4 GHz band and the 5 GHz band without lowering the radiation efficiency.

  In the antenna 1a according to the second embodiment, the second resonance frequency can be adjusted by the length of the second antenna element 7 parallel to the first antenna element 5 or the inductor. For this reason, the second resonance frequency can be set near the first resonance frequency. Further, the adjustment range of the second resonance frequency can secure 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 widened.

  Another configuration example of the antenna according to the second embodiment will be described with reference to FIGS. FIG. 9 is a diagram illustrating 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 illustrating the return loss characteristics of the antenna of FIG. The second configuration example is an example of a case where the 2.4 GHz band is widened.

  As in the first configuration example, in the second configuration example, the antenna 1b is arranged on the GND substrate 2 of 100 mm × 100 mm. As shown in FIG. 10, the antenna 1b includes a split ring resonator 8, a feed unit 6, a GND substrate 2, and an inductor 9. Split ring resonator 8 includes conductor patterns 4a and 4b having split portion 3, first antenna element 5b, and 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 of the first configuration example. Further, by adjusting the constant of the inductor 9, the second resonance frequency can be adjusted to around 2.7 GHz. From FIG. 11, the range where the return loss in the 2.4 GHz band is −5 dB or less can be widened, and a wide band can be realized.

  FIG. 12 is a diagram illustrating 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 illustrating the return loss characteristics of the antenna of FIG. The third configuration example is an example of a case where the bandwidth of the 5 GHz band is widened.

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

  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 of 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. Further, the constant of the inductor 9 is adjusted. From FIG. 14, it is possible to widen the range where the return loss in the 5 GHz band is −5 dB or less, and to realize a wider band. As described above, in the second embodiment, it is possible to realize multi-resonance and realize a wide band without increasing the antenna area or reducing the characteristics.

Embodiment 3
The antenna according to the third embodiment will be described with reference to FIGS. FIG. 15 is a diagram illustrating an example of a configuration of the antenna according to the third embodiment. FIG. 16 is an enlarged view of the antenna of FIG. FIG. 17 is a diagram showing the isolation characteristics of the antenna of FIG. Embodiment 3 is an example in which the split ring resonator of the present invention is used for reducing interference between antennas.

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

  The split ring resonator 8 is arranged between the monopole antenna 20a and the monopole antenna 20b. That is, the monopole antenna 20a, the split ring resonator 8, and the monopole antenna 20b are formed on the same end of the GND substrate 2 so as to be arranged in this order.

  As shown in FIG. 16, the split ring resonator 8 includes conductor patterns 4a and 4b having a split portion 3, a first antenna element 5d, and a second antenna element 7d. 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 7d 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 characteristics of the antenna 1d of FIG. As shown in FIG. 17, in the third embodiment, the band in which about 20 dB of isolation is obtained is 140 MHz. In the comparative example of FIG. 38, the band in which about 20 dB of isolation 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 increasing the antenna area or lowering the characteristics.

  The present invention is not limited to the above embodiment, and can be appropriately changed without departing from the gist.

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 Feeding section 7 2nd antenna element 7b 2nd antenna element 7c 2nd antenna element 7d 2nd antenna element 8 split ring resonator 9 inductor 1a antenna 10 GND
11 GND
DESCRIPTION OF SYMBOLS 12 Feeding point 13 Feeding point 20a Monopole antenna 20b Monopole antenna 21a Feeding part 21b Feeding part 22a Anantenna element 22b Antenna element 30 Antenna 30a 2 Resonant antenna 31 GND board 32 Split part 32a Split part 32b Split part 33 Conductor pattern 33a Conductor Pattern 33b Conductor pattern 34 Power supply unit 35 Power supply line 36 GND
37 GND
Reference Signs List 40 antenna 41 GND board 42a split part 42b split part 43a conductor pattern 43b conductor pattern 43c conductor pattern 44 feed part 45 feed line 46 feed point 47 feed point 50a monopole antenna 50b monopole antenna 51a antenant element 51b antenna element 52GND 53a power supply unit 53b power supply unit 54 spring ring resonator G interval

Claims (5)

Board and
A first split ring resonator formed in an opening of the substrate,
The first split ring resonator comprises:
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 a,
The first conductor pattern and the second antenna element resonate when a first current having a frequency that changes within 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.
antenna. Board and
A first split ring resonator formed in an opening of the substrate,
The first split ring resonator comprises:
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 a,
A first antenna circuit and a second antenna circuit formed at an 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;
antenna. The second antenna element is arranged in parallel with the first antenna element.
Antenna according to claim 1 or 2. The second antenna element is disposed on the outer peripheral side of the substrate with respect to the first antenna element.
The antenna according to any one of claims 1 to 3 . 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 4 .

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