JP2005236534A - Antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna to be hardly affected from a nearby object in which impedance matching and frequency regulation are facilitated while exhibiting high degree of freedom in mounting and excellent stability . <P>SOLUTION: The antenna comprises a feeding electrode 6 being connected with the power supply line 22 of a circuit board 20, a main radiation electrode 2 being connected with the feeding electrode 6, and a plurality of ground electrodes 3 being connected with the ground conductor 21 of the circuit board 20. The main radiation electrode 2 is arranged to be clamped by the ground electrodes 3 while spaced apart with a predetermined distance wherein a part corresponding to the main radiation electrode 2 becomes a non-ground conductor region at least partially on the surface opposing the surface where the main radiation electrode 2 is formed. The antenna 1 is mounted at such a part of the circuit board 20 facing the main radiation electrode 2 as becoming the non-ground conductor region 20a at least partially. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a small antenna having stable antenna characteristics, and a radio communication device using the antenna.

Conventionally known antennas have a basic principle of resonating a main radiation electrode having an effective electrical length of about ½ wavelength or ¼ wavelength.
It is also known that the antenna can be miniaturized by loading capacitive and inductive reactances, dielectrics and magnetic materials, and adding an inductor component or capacitor component in series or in parallel to the antenna feed line. Therefore, a technique for reducing the resonance frequency of the antenna is also widely used.

The most compact form of a chip antenna that combines these technologies is provided with a main radiation electrode having an effective electrical length of about ¼ wavelength, and an external ground conductor (chip antenna is mounted). In this method, an image current is generated in the ground conductor of the circuit board. As a prior art of such a chip antenna, for example, Patent Document 1 is disclosed.
JP 2002-158521 A

FIG. 14 shows a conventional example of a quarter-wavelength chip antenna 1 having a ground electrode 3 on the entire back surface facing the main radiation electrode 2 on the upper surface and an example of mounting on a circuit board. Reference numeral 5 denotes a short-circuit electrode that connects the ground conductor 21 of the circuit board 20 and the main radiation electrode 2, and reference numeral 6 denotes a feed electrode that is connected to the feed line 22 of the circuit board 20.
When a resonance current flows through the main radiation electrode 2, an image current is induced in the opposing ground electrode 3.
In general, the chip antenna 1 having such a structure can obtain stable antenna characteristics because the ground electrode 3 on the back surface and the main radiation electrode 2 on the top surface are strongly electromagnetically coupled, but the antenna volume can be reduced. In particular, it is known that if the chip antenna 1 is made thinner and this coupling strength becomes too strong, the bandwidth and the radiation efficiency are likely to decrease.

  For example, when the antenna 1 having the above electrode structure is formed on a thin rectangular parallelepiped dielectric base of about 15 × 5 × 5 mm, the GPS standing wave ratio VSWR is a ratio of less than 2 for a 1575.42 MHz antenna for GPS. The bandwidth is as narrow as 0.5 to 1%, and the radiation efficiency is as low as about 50%. Further, when the antenna shape is reduced in size, the specific bandwidth and the radiation efficiency are remarkably deteriorated and become impractical.

In order to solve the above problem, as in the conventional example shown in FIG. 15, the ground electrode 3 on the back surface is removed and the role of the ground conductor 21 of the circuit board 20 is given to increase the effective antenna volume. Techniques are known. In this case, an image current is generated in the ground conductor 21.
The chip antenna 1 having such a structure can obtain a wide bandwidth and high radiation efficiency while being small and low in posture, but from the area of the ground conductor 21 and nearby objects such as peripheral mounting parts (not shown), shield cases, and human bodies. In addition, there is a drawback that the antenna characteristics are easily deteriorated due to the influence of the above, and in addition, as shown in FIG. 15B, a relatively large area non-ground for mounting the chip antenna 1 on the circuit board 20 is present. Since it is necessary to secure a conductor region, there is a disadvantage that it is not suitable for high-density mounting.

  For example, when the chip antenna 1 is configured on a small and short dielectric base material 4 of about 10 × 3 × 2 mm and mounted on the non-ground conductor region 20a (about 20 × 15 mm) on the circuit board 20, the VSWR is 2 The specific bandwidth below is as wide as 5 to 6% and the radiation efficiency is as good as 90% or more. However, the substantial area of the circuit board 20 occupied by the antenna 1 is very large. Since other components cannot be mounted on the ground conductor region 20a, it is not suitable for high-density mounting.

As another example, the conventional example shown in FIG. 16 is a chip antenna 1 in which the loading frequency 7 is capacitively coupled to the tip of the main radiation electrode 2 to reduce the resonance frequency and enable high-density mounting. .
This chip antenna 1 is formed on a dielectric base material 4 having the same size as that of FIG. 15 and having a size of about 10 × 3 × 2 mm, and as shown in FIG. 16B, a narrow non-conductor region of about 12 × 5 mm on the circuit board 20. In the case where it is mounted, the specific bandwidth having a VSWR of less than 2 is about 1 to 2%, but the radiation efficiency is remarkably lowered to 30 to 50%.
In addition, a new electromagnetic coupling occurs between the ground conductor 21 of the circuit board 20 and the main radiation electrode 2 of the chip antenna 1 depending on the mounting position of the antenna (for example, the mounting example shown in FIG. 8), and the resonance frequency and impedance increase. Since it becomes difficult to match due to the change, it may be necessary to redesign the antenna.

  In addition, Patent Document 1 discloses a chip antenna that stabilizes antenna characteristics with respect to an external structure. However, since one of the main radiation electrodes is largely open, an electromagnetic shield structure is not possible. It is enough to prevent the influence from the same direction.

  The present invention has been made in view of the drawbacks of the conventional antenna described above, and can easily perform impedance matching and resonance frequency adjustment, has a high degree of freedom in mounting, and is hardly affected by nearby objects. An object of the present invention is to provide an excellent antenna and a wireless communication device using the antenna.

  In the present invention, in a small antenna using the image current (mapping) effect in the external ground conductor, in order to improve the electromagnetic stability with respect to the external element and obtain stable antenna characteristics, the main radiation electrode of the antenna and the mounting substrate We focused on stabilizing the bond with the earth conductor.

  That is, the present invention according to claim 1 is an antenna mounted on a portion where at least a part of a portion facing a main radiation electrode of a circuit board having a feeder line and a ground conductor is a non-ground conductor region. A power supply electrode connected to the power supply line; a main radiation electrode having one end connected to the power supply electrode; and a plurality of ground electrodes connected to the ground conductor; The opposing surface of the surface on which the main radiation electrode is formed is arranged so as to be sandwiched with a predetermined distance, and at least a part of the portion corresponding to the main radiation electrode forms an ungrounded conductor region. It is characterized by being.

  In this configuration, the main radiating electrode and the ground electrode are coupled in an electromagnetically stable state by shielding the main radiating electrode with a ground electrode formed on the same antenna at a certain distance, and grounding. It is difficult to be influenced by external elements such as a ground conductor, a nearby object, or a human body of a circuit board located farther from the electrode. Thereby, it is possible to obtain a stable antenna characteristic which is small but is not affected by the antenna mounting position of the circuit board.

  According to a second aspect of the present invention, there is provided an antenna mounted on a portion where at least a part of a portion facing a main radiation electrode of a circuit board including a feeder line and a ground conductor is a non-ground conductor region. A power supply electrode connected to the power supply line, a main radiation electrode having one end capacitively coupled to the power supply electrode, one or more short-circuit electrodes connecting the main radiation electrode and the ground conductor, and the ground conductor One or more ground electrodes connected to each other, and the high potential portion of the main radiation electrode includes the plurality of ground electrodes or the low potential portion of the main radiation electrode connected to the ground electrode and the short-circuit electrode; Therefore, at least a part of the portion corresponding to the main radiation electrode is a non-grounded conductor region. It is characterized by being made That.

  In this configuration, in addition to the same effects as in the first aspect, the impedance matching of the antenna can be easily performed by adjusting the coupling capacitance between the main radiation electrode and the feeding electrode and the arrangement of the short-circuit electrode. It is also possible to use the low potential portion of the main radiation electrode as a part of the ground electrode for shielding.

  According to a third aspect of the present invention, in the antenna according to the first or second aspect, the feeding electrode, the main radiation electrode, the short-circuit electrode, or one of these electrodes It is characterized in that an adjustment electrode connected to the ground conductor is provided while being capacitively coupled to the above electrodes.

  In this configuration, by providing the adjustment electrode, the effect of connecting the reactance component to the main radiation electrode in parallel can be obtained, thereby reducing the resonance frequency and further reducing the antenna shape. It becomes possible. In addition, since the capacitive component and the inductive component of the adjustment electrode can be easily varied, the impedance matching range of the antenna is expanded.

  According to a fourth aspect of the present invention, there is provided the antenna according to any one of the first to third aspects, wherein a branch path is provided in the main radiation electrode to form a plurality of resonance circuits. Yes.

  In this configuration, the end of the branch path can be an open end, or can be capacitively coupled to the ground electrode. As a result, a multi-frequency or broadband antenna having a plurality of resonance modes can be provided.

  Moreover, the present invention described in claim 5 is a wireless communication device equipped with the antenna according to any one of claims 1 to 4.

As described above, according to the present invention, since the ground electrode is disposed so as to sandwich the main radiation electrode, the antenna shape and the area occupied by the antenna on the circuit board are extremely small, and high radiation efficiency is achieved. Since it can be maintained and hardly affected by external elements, the degree of freedom on the device side when mounting the antenna can be increased, and an antenna suitable for high-density mounting can be provided.
Further, by using this antenna, a wireless communication device having excellent antenna characteristics can be realized.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. In addition, in order to simplify description, the same code | symbol was used about the member common in the past in the following description.

FIG. 1 shows a first embodiment of an antenna according to the present invention.
In FIG. 1, reference numeral 1 denotes an antenna, and reference numeral 20 denotes a main part of a circuit board on which the antenna 1 is mounted. The circuit board 20 is covered with a ground conductor 21 on almost the entire surface. Each electrode structure of the antenna 1 is shown as a planar configuration.

  In the antenna 1, as shown in FIG. 1, one end of the main radiation electrode 2 is connected to the power supply line 22 of the circuit board 20 through the power supply electrode 6, and the other end is an open end. Ground electrodes 3 and 3 are arranged along the longitudinal direction so as to sandwich the main radiation electrode 2 with a predetermined distance. Note that a ground conductor (a conductor portion conducting to the ground conductor 21 of the circuit board 20) is not formed on the back surface facing the main radiation electrode 2, or at least a part of the portion corresponding to the main radiation electrode 2 This ground conductor is removed. The portion without the ground conductor is referred to as a non-ground conductor region. The main radiation electrode 2 has a substantial electrical length of about ¼ wavelength.

On the other hand, the end portion of the circuit board 20 is provided with a portion where the ground conductor 21 is removed in a U-shape, the antenna 1 is mounted on the non-ground conductor region 20a, and the ground electrode 3 is a plurality of short-circuit electrodes. 5 to the ground conductor 21 at a plurality of locations.
Therefore, the main radiation electrode 2 is surrounded by a ground conductor including the ground electrode 3 in an open state and electromagnetically shielded, and the gap between the main radiation electrode 2 and the ground electrode 3 Is always set to a certain distance determined by the electrode structure, and therefore the magnetic stability is extremely high.

  In the above configuration, the main radiating electrode 2 and the ground electrode 3 are coupled in an electromagnetically stable state, and the circuit board 20 located farther than the ground electrode 3 is not connected to the ground conductor 21 or a nearby object (not shown). Electromagnetic effects can be minimized, and the antenna mounting state on the circuit board 20, that is, the area of the non-ground conductor region 20 a and the mounting position are not affected by the mounting state of the antenna on the circuit board 20. can get.

Next, FIG. 2 shows a second embodiment of the antenna 1 according to the present invention.
In the antenna 1, as shown in FIG. 2, one end of the main radiating electrode 2 is capacitively coupled to the feeding electrode 6 through a gap 8, and the other end formed in a U shape is connected to the shorting electrode 5. It is connected to the ground conductor 21 of the circuit board 20. The other end of the power supply electrode 6 is connected to the power supply line 22 of the circuit board 20.

  A ground electrode 3 connected to the ground conductor 21 is disposed along the high potential portion 2 a of the main radiation electrode 2. Also in this case, as in the first embodiment, the entire back surface facing the main radiation electrode 2 is a non-ground conductor region, or at least a part of the portion corresponding to the main radiation electrode 2 is a non-ground conductor region. It is said that. The antenna 1 is also mounted on the U-shaped non-ground conductor region 20a at the end of the circuit board 20.

  In this configuration, the low potential portion 2b of the main radiation electrode 2 is regarded as a ground conductor, and the high potential portion 2a of the main radiation electrode 2 is sandwiched between the ground electrode 3 and the low potential portion 2b of the main radiation electrode 2 It is said. By sandwiching between the low potential portions 2b, the electrode structure can be simplified.

Therefore, as described above, the main radiation electrode 2 is surrounded and electromagnetically shielded by the ground conductor including the ground electrode 3, and this shielding effect causes the ground conductor 21 of the circuit board 20 and nearby objects to be shielded. Therefore, stable antenna characteristics can always be obtained without being influenced by the antenna mounting state on the circuit board 20 while being small in size.
In FIG. 2, the low potential portion 2b of the main radiation electrode 2 is used as a ground conductor. However, a new ground electrode 3 is provided along the outside of the low potential portion 2b, and the main radiation electrode 2 is replaced by the ground electrodes 3 and 3. Of course, it does not matter as a sandwiching structure.

  Further, in this configuration, in addition to the above-described effects, the coupling capacitance between the high potential portion 2a of the main radiation electrode 2 and the feeding electrode 6 (that is, the gap distance and the opposing width of the gap 8) and the short-circuit electrode on the low potential portion 2b side. By adjusting the arrangement of 5, there is also an advantage that the impedance matching of the antenna can be easily performed.

  Next, FIG. 3 shows a third embodiment of the antenna 1 according to the present invention.

The antenna 1 shown in FIG. 3 has an electrode structure in which an adjustment electrode 9 is provided on the antenna of FIG. The adjustment electrode 9 is capacitively coupled to the main radiation electrode 2 and the power supply electrode 6 through a gap 10, and a part of the adjustment electrode 9 is connected to the ground conductor 9 of the circuit board 20.
By providing the adjustment electrode 9, the effect of connecting the reactance component in parallel with the main radiation electrode 2 can be obtained, so that the resonance frequency of the antenna can be lowered, and the antenna shape can be further miniaturized accordingly. Further, by adjusting the length of the adjustment electrode 9 and the gap distance of the gap 10, the capacitance component and the inductive component can be easily changed, so that the impedance matching range can be expanded.

  The adjustment electrode 9 may be capacitively coupled to at least one of the power supply electrode 6, the main radiation electrode 2, and the short-circuit electrode 5, and the electrode structure of the antenna 1 is also shown in FIG. Of course, the present invention can also be applied to the antenna of FIG. 1, and the same effect as described above can be obtained.

  Next, FIG. 4 shows a fourth embodiment of the antenna 1 according to the present invention.

The antenna 1 shown in FIG. 4 is the same as the antenna 1 shown in FIG. 3 except that a branch path 11 is provided in the middle of the main radiation electrode 2, and the end of the branch path 11 is capacitively coupled to the ground electrode 3 via a gap 13. As a result, the main radiation electrode 2 or the main radiation electrode 2 and the branch path 11 allow a plurality (three) of resonance circuits 14 to 16 having current paths indicated by broken lines in FIGS. Can be configured. Further, the end of the branch path 11 may be an open end.
Accordingly, it is possible to provide a multi-frequency antenna having a plurality of resonance modes by a plurality of resonance circuits 14 to 16 and a broadband antenna 1 if the resonance frequencies of the resonance circuits 14 to 16 are very close to each other. it can.
Note that this configuration is not limited to the antenna 1 shown in FIG. 3, but can be applied to each antenna 1 shown in FIGS.

  As described above, according to the first to fourth embodiments of the present invention, the main radiating electrode 2 and the circuit are arranged in the quarter wavelength antenna using the image current (mapping) effect by the ground conductor 21 of the circuit board 20. By providing the ground electrode 3 that stabilizes the coupling state of the substrate 20 to the ground conductor 21 and nearby structures, the antenna shape can be reduced while maintaining stable antenna characteristics, and in particular, the GPS receiving function. It is possible to provide an antenna 1 having appropriate band characteristics and high radiation efficiency suitable for use in portable electronic devices having

  Further, the antenna 1 having the above-described configuration can be further reduced in size by loading a dielectric, an inductance, and a capacitance on an electrode to lower the resonance frequency, and is based on FIGS. 6 and 7 below. One embodiment will be described.

  FIG. 6 shows a state in which the chip antenna 1 for surface mounting is mounted on the circuit board 20, and FIG. 7 shows a state in which the chip antenna 1 is unfolded. The upper main surface and the right side surface are shown.

The circuit board 20 was composed of a glass epoxy board, and the size was 60 × 35.0 × 0.5 mm. Almost the entire surface of both sides of the circuit board 20 is covered with a Cu conductor serving as a ground conductor 21, and the feeder line 23 that supplies high-frequency power to the antenna 1 is configured by a microstrip line having a characteristic impedance of approximately 50Ω. .
The ground conductor 21 where the chip antenna 1 is mounted is removed in a U shape on both the front and back surfaces. The area of the non-ground conductor region 20a was about 10 × 5 mm.

  On the other hand, the chip antenna 1 has a rectangular parallelepiped shape having a size of 8.0 × 3.0 × 1.5 mm, and is configured using a dielectric base material 4 having a relative dielectric constant (εr) of 20. Each conductor to be described later is obtained by attaching an Ag paste to the surface of the dielectric substrate 4 in a predetermined shape and firing it.

As shown in FIG. 7, the power supply electrode 6 connected to the power supply line 23 of the circuit board 20 is arranged from the left side surface of the dielectric substrate 4 to the upper main surface and is connected to one end of the main radiation electrode 2 through the gap 8. Connected. The gap 8 may be formed on either the side surface or the upper main surface.
The main radiation electrode 2 on the upper main surface is formed in a meander shape, and is connected to the ground conductor 21 of the circuit board 20 through the plurality of short-circuit electrodes 5 on the right side surface. This electrode structure is similar to that of FIG.

The portion where the main radiation electrode 2 is connected to the short-circuit electrode 5 becomes a low potential region (that is, the low potential portion 2b) because the current flowing through the antenna is large, and the portion close to the feeding electrode 6 is a region where the potential is high (that is, High potential portion 2a).
In addition to the feeding electrode 6, a plurality of ground electrodes 3 are arranged on the left side, and each is connected to the ground conductor 21 of the circuit board 20. Thereby, the main radiation electrode (high potential portion 2a) on the upper main surface is sandwiched between the plurality of ground electrodes 3 disposed on the left side and the main radiation electrode (low potential portion 2b) disposed on the right side. It is in an electromagnetically shielded state. Thus, even if the ground electrode 3 is intermittently disposed in the vicinity of the main radiation electrode 2, a shielding effect can be obtained.
Note that only the solder terminals 12 for surface mounting corresponding to the respective electrodes are disposed on the lower main surface side.

  Further, in this embodiment, the path leading to the short-circuit electrode 5 of the main radiation electrode 2 is branched in a T shape on the right side surface to provide a branch path 11, and the open end thereof is connected to the ground electrode 3 via the gap 13 on the left side surface. In this structure, a plurality of resonance circuits are formed, and the ground electrode 3 on the left side surface is extended, and the electrode 9 for adjustment is formed by capacitive coupling with the feeding electrode 6 through the gap 10. .

The chip antenna 1 of the above embodiment has a small shape and a small exclusive mounting area on the circuit board 20, and the input impedance is matched to approximately 50Ω at a resonance frequency of 1575.42 MHz without providing a matching element outside. .
Further, the specific bandwidth with a voltage standing wave ratio VSWR of less than 2 is 1.0 to 1.5% (refer to the resonance frequency to voltage standing wave ratio characteristics in FIG. 11), and the radiation efficiency is 70 to 80%. It has been. Even when the chip antenna 1 is mounted as shown in FIG. 8, it is understood that the same antenna characteristics as those described above are obtained, and thus the degree of freedom in mounting on the circuit board is high.

  In addition, as shown in FIG. 9, even when a metal case 24 having a height of about 2 mm is disposed on the circuit board 20 in the vicinity of the chip antenna 1, the change in antenna characteristics is small, and the metal case 24 is in the vicinity of the pole. When approaching (distance B <4 mm from the metal case 24), the resonance frequency shifts slightly higher, but other characteristics (bandwidth characteristics and gain characteristics) are extremely stable (with the metal case in FIG. 12). See distance vs. resonant frequency or bandwidth characteristics, distance vs. gain characteristics with metal case in FIG. 13).

  Incidentally, the point that the resonance frequency shifts high in the vicinity of the metal case 24 can be dealt with by determining the electrode dimensions of the chip antenna 1 in advance by calculating the frequency change due to the surrounding structure. Since the length of the adjustment electrode 9 and the gap between the feeding electrode 6 and the main radiation electrode 2 may be adjusted, this can be done very easily.

FIG. 10 shows a wireless communication device of the present invention. The wireless communication device 30 includes the antenna 1, the high-frequency circuit 31, and the signal processing unit 32 of the present invention described above, and these are collectively mounted on the circuit board 20.
By mounting the antenna 1 of the present invention, a wireless communication device having a small size and excellent antenna characteristics can be realized.

  Here, the high frequency circuit 31 frequency-mixes, amplifies, and band-filters the radio wave received by the antenna 1 and converts the frequency to a low frequency band. Further, the electric signal supplied from the signal processing unit 32 is frequency mixed, band-filtered, amplified, and transmitted from the antenna 1 as a radio wave. The signal processing unit 32 demodulates the electrical signal sent from the high frequency circuit 31 to obtain a signal before modulation. Further, the transmission signal is modulated and supplied to the high frequency circuit 31.

Explanatory drawing which shows the antenna which concerns on 1st Embodiment of this invention. Explanatory drawing which shows the antenna which concerns on 2nd Embodiment of this invention. Explanatory drawing which shows the antenna which concerns on 3rd Embodiment of this invention. Explanatory drawing which shows the antenna which concerns on 4th Embodiment of this invention. The figure which shows the some resonance circuit comprised on the antenna. BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which mounted the chip antenna of this invention on the circuit board. FIG. 7 is a development view of the chip antenna of FIG. 6. The figure which shows the example of mounting different from FIG. The figure which has arrange | positioned the metal case in the vicinity of the chip antenna of this invention. The block diagram of the radio | wireless communication apparatus which concerns on this invention. The figure which shows the resonant frequency versus voltage standing wave ratio characteristic. The figure which shows the distance with respect to a metal case versus the resonant frequency or a bandwidth characteristic. The figure which shows the distance vs. gain characteristic with a metal case. (A) is a figure which shows the conventional antenna, (b) is a figure which shows the example of mounting to a circuit board. (A) is a figure which shows the conventional antenna different from FIG. 14, (b) is a figure which shows the example of mounting to a circuit board. (A) is a figure which shows the conventional antenna different from FIG. 15, (b) is a figure which shows the example of mounting to a circuit board.

Explanation of symbols

1 Antenna (chip antenna)
2 Main Radiation Electrode 2a High Potential Portion 2b Low Potential Portion 3 Ground Electrode 5 Shorting Electrode 6 Feeding Electrode 9 Adjustment Electrode 11 Branch Path 14-16 Resonant Circuit 20 Circuit Board 20a Non-Ground Conductor Region 21 Ground Conductor 22 Feeding Line 30 Wireless Communication machine

Claims (5)

An antenna mounted on a portion where at least a part of a circuit board provided with a feeder line and a ground conductor faces a main radiation electrode is a non-ground conductor region,
A feeding electrode connected to the feeding line;
A main radiation electrode having one end connected to the feeding electrode;
A plurality of ground electrodes connected to the ground conductor;
The main radiation electrode is arranged so as to be sandwiched by a predetermined distance by the ground electrode,
The antenna is characterized in that at least a part of a portion corresponding to the main radiating electrode is formed as a non-grounded conductor region on the surface opposite to the surface on which the main radiating electrode is formed. An antenna mounted on a portion where at least a part of a circuit board provided with a feeder line and a ground conductor faces a main radiation electrode is a non-ground conductor region,
A feeding electrode connected to the feeding line;
A main radiation electrode having one end capacitively coupled to the feeding electrode;
One or more short-circuit electrodes connecting the main radiation electrode and the ground conductor;
Comprising one or more ground electrodes connected to the ground conductor;
The high potential portion of the main radiation electrode is sandwiched by a plurality of ground electrodes or a predetermined distance between the ground electrode and the low potential portion of the main radiation electrode connected to the short-circuit electrode. Has been placed,
The antenna is characterized in that at least a part of a portion corresponding to the main radiating electrode is formed as a non-grounded conductor region on the surface opposite to the surface on which the main radiating electrode is formed. The power supply electrode, the main radiation electrode, the short-circuit electrode, or one or more of these electrodes are capacitively coupled, and an adjustment electrode connected to the ground conductor is provided. The antenna according to any one of claims 1 and 2. The antenna according to any one of claims 1 to 3, wherein a branch path with an open end is provided on the main radiation electrode to constitute a plurality of resonance circuits. A wireless communication device comprising the antenna according to any one of claims 1 to 4.

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