JP7481026B2 - Antenna Device - Google Patents

Description

The present invention relates to an antenna device.

In recent years, wireless devices are being used in a variety of situations. Efforts are being made to miniaturize wireless devices while at the same time improving their functionality to support multiple wireless communication standards. For this reason, there is a demand for greater freedom in the placement of antennas installed in wireless devices without increasing their size.

Figure 18 shows an example of an antenna device that can be placed anywhere inside the GND plate according to Patent Document 1. Specifically, in this antenna device, an opening 42 is placed so as not to contact any side of the outer periphery of the GND plate 41, and a split section 43 is placed inside the opening 42. Furthermore, in this antenna device, one end of a power supply conductor 44 is connected to one side of the opening 42, and AC power is supplied from a power supply section 45 connected to the other end of the power supply conductor 44 to form a parallel split ring resonator 46.

Furthermore, FIG. 19 is an enlarged view of the parallel split ring resonator shown in FIG. 18. As shown in FIG. 19, the first split section conductor 51 and the second split section conductor 52 are arranged to face each other inside the opening 42 provided in the GND plate 41, and the third split section conductor 53 is arranged to connect the first split section conductor 51 to one side of the opening 42. Similarly, the fourth split section conductor 54 is arranged to connect the second split section conductor 52 to the other side of the opening 42. This allows the split section 43 to be configured. Furthermore, one end of the power supply conductor 44 arranged in parallel with the third split section conductor 53 and the fourth split section conductor 54 is connected to one side of the opening 42, and the other end is connected to the power supply section 45, thereby supplying AC power.

More specifically, Fig. 20 is a schematic diagram showing the current flow when the antenna device shown in Fig. 19 is operated at a predetermined operating frequency, and the current flow is indicated by a dotted line. In this antenna device, a current I1 flows in a loop-shaped path formed by the third split section conductor 53, the first split section conductor 51, the second split section conductor 52, the fourth split section conductor 54, and a part of the outer periphery of the opening 42. A current _I2 flows in a loop-shaped path formed by the power supply conductor 44, the third split section conductor 53, the first split section conductor 51, the second split section conductor 52, the fourth split section conductor 54, and a part of the outer periphery of the opening _42. In the antenna device, the currents _I1 and _I2 serve as wave sources to radiate electromagnetic waves.

Patent No. 6548271

In recent years, wireless devices have become smaller and densely packed on the circuit boards inside the wireless devices, so built-in antennas are required to be small and flexible in placement. At the same time, wireless devices in recent years are required to support multiple wireless communication standards, so antenna devices used in wireless devices are also required to support multiple frequency bands, rather than operating at a single frequency like the related antenna device described in Patent Document 1. The purpose of the present disclosure is to provide an antenna device that solves any of the above-mentioned problems.

The antenna device includes a GND plate, a power supply section that supplies power, an opening disposed on the GND plate, a power supply conductor that is connected to one side of the opening and to the power supply section, a split section that is disposed inside the opening so as to face each other and has two conductors that each connect to the outer periphery of the opening, and at least one of the two conductors disposed so as to face each other is connected to both ends of the conductor and a conductor extension section that extends from the connected position in a direction different from the extension direction of the conductor, and at least a part of the conductor extension section is disposed opposite the outer periphery of the opening.

Provide a compact antenna device that supports multiple frequency bands.

1 is a diagram showing a configuration of an antenna device according to a first embodiment; FIG. 2 is a diagram illustrating an example of an enlarged multi-resonant parallel split ring resonator according to the first embodiment. 4 is a diagram illustrating a schematic diagram of a current flow at a first operating frequency of the antenna device according to the first embodiment. FIG. 1 is a diagram showing an equivalent circuit diagram of the antenna device according to the first embodiment when it operates at a first operating frequency; 5 is a diagram illustrating a schematic diagram of a current flow at a second operating frequency of the antenna device according to the first embodiment. FIG. 1 is a diagram showing an equivalent circuit diagram of the antenna device according to the first embodiment when it operates at a second operating frequency; FIG. 3 is a Smith chart showing impedance characteristics of the antenna device according to the first embodiment; FIG. FIG. 1 is a Smith chart showing impedance characteristics of a related antenna device. 5 is a diagram showing the return loss characteristics of the antenna device according to the first embodiment; FIG. FIG. 13 is a diagram showing the return loss characteristics of a related antenna device. FIG. 11 is a diagram showing a configuration of an antenna device according to a second embodiment. 11 is a diagram illustrating a schematic diagram of a current flow at a first operating frequency of the antenna device according to the second embodiment. FIG. 11 is a diagram illustrating a schematic diagram of a current flow at a second operating frequency of the antenna device according to the second embodiment. FIG. 13 is a diagram illustrating a schematic diagram of a current flow at a third operating frequency of the antenna device according to the second embodiment. FIG. 13 is a diagram showing an equivalent circuit diagram of the antenna device according to the second embodiment when it operates at a third operating frequency. FIG. FIG. 11 is a Smith chart showing impedance characteristics of the antenna device according to the second embodiment. FIG. 11 is a diagram showing the return loss characteristics of the antenna device according to the second embodiment. FIG. 1 is a diagram showing a configuration of a related antenna device. FIG. 1 shows an example of a zoomed-in related multi-resonant parallel split-ring resonator. FIG. 2 is a diagram showing a schematic diagram of current flow when a related antenna device operates at a predetermined operating frequency.

<First embodiment>
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described with reference to the accompanying drawings. Fig. 1 is a diagram showing the configuration of an antenna device 1 according to the present invention.

The antenna device 1 comprises a GND plate 11, an opening 12 arranged so as not to contact any of the sides of the periphery of the GND plate 11, a multi-resonant split section (hereinafter, split section) 13 arranged inside the opening 12 and including two conductors facing each other, a power supply conductor 14 having one end connected to one side of the opening 12, and a power supply section 15 connected to the other end of the power supply conductor 14.

The split section 13 and the power supply conductor 14, which receive AC power from the power supply section 15, form a multi-resonant parallel split ring resonator 16.

Figure 1 shows the view from the perspective facing the plate surface of the GND plate 11, and the same applies to Figures 2 and 3, which will be described later. In the following, unless otherwise specified, the arrangement from the perspective facing the plate surface of the GND plate 11 will be described.

The antenna device 1 in FIG. 1 differs from the related antenna device shown in FIG. 18 in the following ways:

The two opposing conductors arranged in the split section 13 are arranged inside the opening 12 so as not to come into contact with any of the sides of the outer periphery of the GND plate 11, and are shaped like a single conductor with both ends extended. The extended portion of this conductor faces one side of the opening 12.

In the following description, the side of the opening 12 facing the conductor refers to the approximately straight side of the conductor extending in a specified direction that is located at the shortest distance in the perpendicular direction to the extension direction. In the locations where the conductor and the side of the opening 12 face each other, the conductor and the side are described as being sufficiently close to each other without contacting each other.

Furthermore, the state in which the extended conductor faces one side of the opening 12 can be said to be a state in which, from a viewpoint facing the plate surface of the GND plate 11, the extension direction of the conductor at a specified location is approximately parallel to the extension direction of one side of the opening 12.

The multi-resonant parallel split ring resonator 16 is configured to include a split section 13 in which the conductors are arranged in this manner.

Here, FIG. 2 shows an example of an enlarged multi-resonant parallel split ring resonator 16 shown in FIG. 1.

As shown in FIG. 2, in the antenna device 1, a first split section conductor 21 and a second split section conductor 22 are arranged to face each other inside an opening 12 provided in a GND plate 11. In addition, a third split section conductor 23 is arranged to connect the first split section conductor 21 to one side of the outer periphery of the opening 12, and a fourth split section conductor 24 is arranged to connect the second split section conductor 22 to one side of the outer periphery of the opening 12.

Furthermore, the second split section conductor first extension 31 is arranged so as to extend one end of the second split section conductor 22 at a right angle. The second split section conductor second extension 32 is connected to one end of the second split section conductor first extension 31. As a result, the second split section conductor second extension 32 faces one side of the opening 12.

Similarly, the second split section conductor third extension 33 is arranged to extend the other end of the second split section conductor 22 at a right angle. In addition, the second split section conductor fourth extension 34 is connected to one end of the second split section conductor third extension 33. As a result, the second split section conductor fourth extension 34 faces one side of the opening 12.

Here, the conductor that is directly connected to the end of the second split section conductor 22 and arranged so as to extend in a direction different from that of the second split section conductor 22 is defined as the first extension section. Furthermore, the conductor that is connected to the first extension section and arranged so as to extend in a direction further different from the extension direction of the first extension section is defined as the second extension section.

More specifically, at one end of the second split section conductor 22, the second split section conductor first extension 31 and the second split section conductor second extension 32 are combined and considered as one conductor extension. In this case, the second split section conductor first extension 31 is the first extension, and the second split section conductor second extension 32 is the second extension.

Similarly, if the second split section conductor third extension 33 and the second split section conductor fourth extension 34 are combined and considered as one conductor extension, the second split section conductor third extension 33 becomes the first extension, and the second split section conductor fourth extension 34 becomes the second extension.

The power supply conductor 14 is connected to one side of the opening 12, and the other end is connected to the power supply section 15 to supply AC power.

Fig. 3 is a schematic diagram showing a current flow at the first operating frequency in the antenna device 1 shown in Fig. 2. A current (not shown) fed from the power feed section 15 is supplied via the power feed conductor 14, a part of the outer periphery of the opening 12, the third split section conductor 23, and the first split section conductor 21. As a result, a current I11 flows in a loop-shaped path formed by a part of the second split section conductor 22, the first extension section 31 of the second split section conductor, the second extension section 32 of the second split section conductor, a part of the outer periphery of the opening 12, and the fourth split section conductor 24. Also, a current _I12 flows in a loop-shaped path formed by a part of the second split section conductor 22, the third extension section 33 of the second split section conductor, the fourth extension section 34 of the second split section conductor, a part of the outer periphery of the opening ₁₂ , and the fourth split section conductor 24. The antenna device 1 uses these currents _I11 and _I12 as wave sources to radiate electromagnetic waves of the first operating frequency.

Figure 4 is an equivalent circuit diagram of the antenna device 1 when it operates at the first operating frequency. The antenna device 1 has a circuit in which two series resonant circuits are connected in parallel, consisting of coil portion L11, coil portion L12, capacitor portion C11, and capacitor portion C12.

Here, the coil portion L11 is a portion equivalently formed by a path through which the current _I11 flows. The coil portion L12 is a portion equivalently formed by a path through which the current _I12 flows. The capacitor portion C11 is a portion equivalently formed by the second split portion conductor second extension portion 32 and a part of the outer periphery of the opening portion 12. The capacitor portion C12 is a portion equivalently formed by the second split portion conductor fourth extension portion 34 and a part of the outer periphery of the opening portion 12. In the antenna device 1, the first operating frequency is determined by the resonant frequency of this resonant circuit.

High-frequency current is supplied from the power supply section 15 via the power supply conductor 14, a part of the outer periphery of the opening 12, a coil section L10 formed in a pseudo manner by the third split section conductor 23, and a capacitor section C10 formed equivalently by the first split section conductor 21 and a part of the second split section conductor 22.

Furthermore, Fig. 5 is a schematic diagram showing a current flow at the second operating frequency in the antenna device 1 shown in Fig. 2. As shown in Fig. 5, in the antenna device 1, a current I21 flows through a loop-shaped path formed by the third split portion conductor 23, the first split portion conductor 21, a part of the second split portion conductor 22, the first extension portion 31 of the second split portion conductor, the second extension portion 32 of the second split portion conductor, and a part of the outer periphery of the opening portion 12. As a result, a current _I22 flows through a loop-shaped path formed by the third split portion conductor 23, the first split portion conductor 21, a part of the second split portion conductor 22, the third extension portion 33 of the second split portion conductor, the fourth extension portion 34 of the second split portion conductor, the feed conductor 14, and a part of the outer periphery of the opening portion ₁₂ . As a result, the antenna device 1 radiates electromagnetic waves of the second operating frequency with the currents _I21 and _I22 as wave sources.

Figure 6 is an equivalent circuit diagram when the antenna device 1 operates at the second operating frequency. The antenna device 1 is configured by combining coil portion L21, coil portion L22, capacitor portion C21, coil portion L23, coil portion L24, capacitor portion C22, and capacitor portion C23.

Here, the coil portion L21 is a portion equivalently constituted by a part of the outer periphery of the opening 12 and the third split portion conductor 23. The coil portion L22 is a portion equivalently constituted by the power supply conductor 14, a part of the outer periphery of the opening 12, and the third split portion conductor 23. The capacitor portion C21 is a portion equivalently constituted by the first split portion conductor 21 and a part of the second split portion conductor 22. The coil portion L23 is a portion equivalently constituted by a part of the second split portion conductor 22 and the first extension portion 31 of the second split portion conductor. The coil portion L24 is a portion equivalently constituted by a part of the second split portion conductor 22 and the third extension portion 33 of the second split portion conductor. The capacitor portion C22 is a portion equivalently constituted by the second extension portion 32 of the second split portion conductor and a part of the outer periphery of the opening 12. The capacitor section C23 is equivalently configured with the second split section conductor fourth extension section 34 and part of the outer periphery of the opening 12.

The antenna device 1 is configured with two parallel-connected series resonant circuits: one consisting of the combined inductance of the coil parts L21 and L23 and the combined capacitance of the capacitor parts C21 and C22, and the other consisting of the combined inductance of the coil parts L22 and L24 and the combined capacitance of the capacitor parts C21 and C23. In the antenna device 1, the second operating frequency is determined by the resonant frequency of this resonant circuit.

Specifically, in the antenna device 1, the inductance of the equivalently configured coil section can be changed by changing the size of the opening 12 to change the length of the path through which the currents _I11 and _I12 flow, thereby making it possible to adjust the first operating frequency and the second operating frequency in the antenna device 1.

In addition, in the antenna device 1, the capacitance of the equivalently configured capacitor section can be changed by changing the length of the opposing portions of the first split section conductor 21 and the second split section conductor 22 and the distance between them. This makes it possible to adjust the first operating frequency and the second operating frequency in the antenna device 1.

In addition, in the antenna device 1, the length of at least one of the second split section conductor second extension 32 and the second split section conductor fourth extension 34 can be changed. This changes the length of the second split section conductor second extension 32 or the second split section conductor fourth extension 34 facing a part of the outer periphery of the opening 12, and the capacitance of the equivalently configured capacitor section can be changed.

Furthermore, at least one of the distance between the outer periphery of the opening 12 and the second extension 32 of the second split section conductor and the distance between the outer periphery of the opening 12 and the fourth extension 34 of the second split section conductor can be changed. By changing these distances, the capacitance of the equivalently configured capacitor section can be changed.

For example, the capacitance can be changed by moving a part or the whole of the second split section conductor second extension 32 closer to or farther from the outer peripheral edge of the opening 12 to which the second split section conductor second extension 32 faces. Similarly, the capacitance can be changed by moving a part or the whole of the second split section conductor fourth extension 34 closer to or farther from the outer peripheral edge of the opening 12 to which the second split section conductor fourth extension 34 faces. This makes it possible to adjust the first operating frequency and the second operating frequency in the antenna device 1.

Figure 7 shows the impedance characteristics of the antenna device 1 according to the first embodiment, and is a diagram showing the impedance locus versus frequency using a Smith chart. In Figure 7, the points where the impedance locus indicated by the arrow approaches the center of the Smith chart are the first operating frequency and the second operating frequency, respectively.

For comparison, Figure 8 shows the impedance characteristics of a related antenna device that operates at only one operating frequency. As with Figure 7, the operating frequency of the antenna device is the point where the impedance locus is closest to the centre of the Smith chart, or where it intersects with a horizontal line passing through the centre.

Comparing Fig. 7 and Fig. 8, the antenna device 1 according to the first embodiment operates at two operating frequencies, and therefore the impedance locus appears to draw two large circles on the Smith chart shown in Fig. 7. In contrast, the related antenna device operates at one operating frequency, and therefore the impedance locus appears to draw two large circles on the Smith chart shown in Fig. 8.

Figure 9 shows the return loss characteristics of the antenna device 1 according to the first embodiment. Here, the return loss is measured in exactly the same way as the impedance characteristics shown in Figure 7, the chart is simply different, and the closer the impedance is to 50 Ω, the smaller the value becomes. In other words, the closer the impedance locus is to the center in the Smith chart in Figure 7, the smaller the return loss in Figure 9 becomes, and the smaller the return loss value, the better the characteristics of the antenna device.

In addition, the frequency at the valley of the return loss in Figure 9 is called the resonant frequency, and indicates the frequency at which the antenna device operates. For an antenna device to operate well, it is generally desirable for the return loss to be -5 dB or less at the operating frequency.

For example, Figure 10 shows the return loss characteristics of a related antenna device that operates at only one operating frequency. That is, in a related antenna device that operates at one operating frequency, as shown in Figure 10, the return loss is -5 dB or less at one resonant frequency.

On the other hand, when we check Figure 9, we can see that in the antenna device 1 according to the first embodiment, the return loss is -5 dB or less at the first and second operating frequencies indicated by the arrows, and that the antenna device operates as a good antenna device at the two operating frequencies.

In this way, the antenna device 1 can be provided with a GND plate 11, a power supply section 15 that supplies power, an opening 12 arranged on the GND plate 11, a power supply conductor 14 that connects to one side of the opening 12 and the power supply section 15, a split section 13 arranged to face each other inside the opening 12 and having two conductors that each connect to the outer periphery of the opening 12, and a conductor extension section, at least one of the two conductors arranged to face each other is connected to both ends of the conductor and extends from the connected position in a direction different from the extension direction of the conductor. At this time, at least a part of the conductor extension section is arranged to face the outer periphery of the opening 12.

In other words, the conductor arranged in the split section 13 can be extended and arranged so as to face one side of the opening 12. This allows the antenna device 1 to operate satisfactorily as an antenna device at multiple operating frequencies.

In addition, with the antenna device 1 configured in this manner, there is a high degree of freedom in extending the conductor within the split section 13 and changing its position, which prevents the antenna device 1 from becoming too large.

<Embodiment 2>
Fig. 11 is a diagram showing another embodiment in which the configuration of the antenna device is changed. Here, Fig. 11 is an enlarged view of the multi-resonant parallel split ring resonator 16 of the antenna device 2, and corresponds to Fig. 2 according to the first embodiment. In the following, components similar to those described in the antenna device 1 of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

Compared to Figs. 2 and 3, the antenna device 2 shown in Fig. 11 has a second split section conductor fifth extension 35 disposed at one end of the second split section conductor 22 so as to extend at a right angle to the opposite side of the second split section conductor first extension 31. Furthermore, a second split section conductor sixth extension 36 is connected to one end of the second split section conductor fifth extension 35 so as to face one side of the opening 12.

The second split section conductor seventh extension 37 is disposed at the other end of the second split section conductor 22 so as to extend at a right angle to the opposite side of the second split section conductor third extension 33. Furthermore, the second split section conductor eighth extension 38 is connected to one end of the second split section conductor seventh extension 37 so as to face one side of the opening 12.

As a result, the antenna device 2 operates at a third operating frequency in addition to the first and second frequencies.

In this case, if the second split section conductor fifth extension 35 and the second split section conductor sixth extension 36 are considered as one conductor extension, the second split section conductor fifth extension 35 is the first extension, and the second split section conductor sixth extension 36 is the second extension.

Similarly, if the second split section conductor seventh extension 37 and the second split section conductor eighth extension 38 are considered as one conductor extension, the second split section conductor seventh extension 37 is the first extension, and the second split section conductor sixth extension 36 is the second extension.

Fig. 12 is a schematic diagram showing the current flow at the first operating frequency in the antenna device 2 shown in Fig. 11. In the antenna device 2, the currents _I11 and _I12 flow through the same paths as those shown in Figs. 3 and 5 in the first embodiment. This allows the antenna device 2 to radiate electromagnetic waves at the first operating frequency with the currents _I11 and _I12 as wave sources.

Fig. 13 is a schematic diagram showing the current flow at the second operating frequency in the antenna device 2 shown in Fig. 11. In the antenna device 2, the currents _I21 and _I22 flow through the same paths as those shown in Figs. 3 and 5 in the first embodiment. This allows the antenna device 2 to radiate electromagnetic waves at the second operating frequency with the currents _I21 and _I22 as wave sources.

Fig. 14 is a schematic diagram showing a current flow at the third operating frequency in the antenna device 2 shown in Fig. 11. In the antenna device 2, a current I31 flows through a loop-shaped path formed by the second split portion conductor fifth extension 35, the second split portion conductor first extension 31, the second split portion conductor second extension 32, a part of the outer periphery of the opening 12, and the second split portion conductor sixth extension 36. Also, a current _I32 flows through a loop-shaped path formed by the second split portion conductor seventh extension 37, the second split portion conductor third extension 33, the second split portion conductor fourth extension 34, the power supply conductor 14, a part of the outer periphery of the opening 12, and the second split portion conductor eighth extension 38. As a result, the antenna device ₂ radiates electromagnetic waves at the third operating frequency with the currents _I31 and _I32 as wave sources.

Figure 15 is a diagram showing an equivalent circuit diagram of the antenna device 2 according to the second embodiment at the third operating frequency. The antenna device 2 is shown transparently in a configuration combining coil portion L31, coil portion L32, coil portion L33, coil portion L34, capacitor portion C31, capacitor portion C32, capacitor portion C33, and capacitor portion C34.

Here, coil portion L31 is a portion equivalently formed by a part of the outer periphery of opening 12. Coil portion L32 is a portion equivalently formed by power supply conductor 14 and a part of the outer periphery of opening 12. Coil portion L33 is a portion equivalently formed by second split portion conductor first extension 31 and second split portion conductor fifth extension 35. Coil portion L34 is a portion equivalently formed by second split portion conductor third extension 33 and second split portion conductor seventh extension 37. Capacitor portion C31 is a portion equivalently formed by second split portion conductor second extension 32 and a part of the outer periphery of opening 12. Capacitor C32 is a portion equivalently formed by second split portion conductor fourth extension 34 and a part of the outer periphery of opening 12. Capacitor portion C33 is a portion equivalently formed by the sixth extension portion 36 of the second split portion conductor and a portion of the outer periphery of the opening 12. Capacitor portion C34 is a portion equivalently formed by the eighth extension portion 38 of the second split portion conductor and a portion of the outer periphery of the opening 12.

In the antenna device 2, a series resonant circuit consisting of the combined inductance of the coil parts L31 and L33 and the combined capacitance of the capacitor parts C31 and C33, and a series resonant circuit consisting of the combined inductance of the coil parts L32 and L34 and the combined capacitance of the capacitor parts C32 and C34 are connected in parallel to configure the circuit. As a result, in the antenna device 2, the third operating frequency is determined by the resonant frequency of this resonant circuit.

Here, in the antenna device 2, the length of the path through which the currents _I31 and _I32 flow can be changed by changing the size of the opening 12. This changes the inductance of the equivalently configured coil section, and in the antenna device 2, the third operating frequency can be adjusted in the same way as the first operating frequency and the second operating frequency.

In addition, in the antenna device 2, the length of the second split section conductor second extension 32 facing the outer peripheral side of the opening 12 and the distance between the second split section conductor second extension 32 and the outer peripheral side of the opening 12 can be changed. Furthermore, the length of the second split section conductor fourth extension 34 facing the outer peripheral side of the opening 12 and the distance between the second split section conductor fourth extension 34 and the outer peripheral side of the opening 12 can be changed. This changes the capacitance of the equivalently configured capacitor section, and in the antenna device 2, the third operating frequency can be adjusted in the same way as the first operating frequency and the second operating frequency.

In addition, in the antenna device 2, the length of the second split section conductor sixth extension 36 facing the outer peripheral side of the opening 12 and the distance between the second split section conductor sixth extension 36 and the outer peripheral side of the opening 12 can be changed. Furthermore, the length of the second split section conductor eighth extension 38 facing the outer peripheral side of the opening 12 and the distance between the second split section conductor eighth extension 38 and the outer peripheral side of the opening 12 can be changed. This changes the capacitance of the equivalently configured capacitor section, and in the antenna device 2, the third operating frequency can be adjusted.

Figure 16 shows the impedance characteristics of the antenna device 2 according to the second embodiment. In Figure 16, the points where the impedance locus indicated by the arrow approaches the center of the Smith chart are the first operating frequency, the second operating frequency, and the third operating frequency, respectively.

Figure 17 shows the return loss characteristics of the antenna device 2 according to the second embodiment. At the first operating frequency, the second operating frequency, and the third frequency indicated by the arrows in Figure 17, the antenna device 2 has a return loss of -5 dB or less, and can be seen to function as a good antenna.

In this way, by making the extensions of the conductors arranged in the split section face two sides of the opening 12, the antenna device 2 can operate satisfactorily as an antenna that operates at three operating frequencies. In other words, it is possible to configure an antenna that can operate at multiple frequencies without increasing the size of the antenna.

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

REFERENCE SIGNS LIST 1 Antenna device 2 Antenna device 11 GND plate 12 Opening 13 Split section 14 Power supply conductor 15 Power supply section 16 Multi-resonant parallel split ring resonator 21 First split section conductor 22 Second split section conductor 23 Third split section conductor 24 Fourth split section conductor 31 First extension section of second split section conductor 32 Second extension section of second split section conductor 33 Third extension section of second split section conductor 34 Fourth extension section of second split section conductor 35 Fifth extension section of second split section conductor 36 Sixth extension section of second split section conductor 37 Seventh extension section of second split section conductor 38 Eighth extension section of second split section conductor

Claims (7)

A GND plate;
A power supply unit that supplies power;
An opening disposed in the GND plate;
a power supply conductor connected to one side of the opening and to the power supply portion;
split portions disposed inside the opening so as to face each other, each having two conductors connected to an outer periphery of the opening;
At least one of the two conductors arranged to face each other includes a conductor extension portion connected to both ends of the conductor and extending from the connected position in a direction different from the extending direction of the conductor,
At least a portion of the conductor extension portion is disposed opposite to an outer peripheral side of the opening portion.
Antenna device. The two conductors arranged opposite each other inside the opening are variable in length;
performing an operation at an operating frequency that is changed in response to the change in length;
2. The antenna device according to claim 1. The two conductors arranged opposite each other inside the opening are arranged such that the distance between them can be changed,
performing an operation at an operating frequency that is changed in response to the change in the interval;
3. The antenna device according to claim 1 or 2. The conductor extension portion is
a first extension portion connected to an end of the conductor and extending in a direction different from that of the conductor;
a second extension portion connected to an end of the first extension portion and extending in a direction different from that of the first extension portion;
The second extension portion is disposed opposite to an outer peripheral side of the opening portion.
The antenna device according to any one of claims 1 to 3. The length of at least one of the first extension portion and the second extension portion is variable,
performing an operation at an operating frequency that is changed in response to the change in length;
5. The antenna device according to claim 4. At least one of a distance between an outer peripheral side of the opening and the first extension portion or a distance between an outer peripheral side of the opening and the second extension portion is changeable;
performing an operation at an operating frequency that is changed in response to the change in the interval;
6. The antenna device according to claim 4 or 5. The opening is variable in size;
and performing an operation at an operating frequency that is changed in response to the change in the size of the opening.
The antenna device according to any one of claims 1 to 6.

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