WO2005078860A1

WO2005078860A1 - Antenna

Info

Publication number: WO2005078860A1
Application number: PCT/JP2005/001600
Authority: WO
Inventors: Kazuhiko Okawara; Kenichi Moue; Masahiro Ekawa
Original assignee: Fdk Corporation
Priority date: 2004-02-18
Filing date: 2005-02-03
Publication date: 2005-08-25
Also published as: JP2005236534A

Abstract

An antenna that provide an easy impedance matching, an easy frequency adjustment, and a high flexibility of positioning, and that is less affected by peripheral objects and hence exhibits an excellent stability. There are included a feeder electrode (6) connected to a feeder line (22) of a circuit board (20); a main radiating electrode (2) connected to the feeder electrode (6); and a plurality of grounded electrodes (3) connected to a grounded member (21) of the circuit board (20). The main radiating electrode (2) is spaced by a given distance from and sandwiched by the grounded electrodes (3), and at least a portion of a part, which is opposed by a part where the main radiating electrode (2) is formed, is a non-grounded conductive area. The antenna (1) is mounted such that at least a portion of a part of the circuit board (20) opposed by the main radiating electrode (2) is a non-grounded conductive area (20a).

Description

Specification

Antenna

Technical field

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

Background art

Conventionally, the above-mentioned antenna has a basic principle of resonating a main radiation electrode having an effective electric length of about 1Z2 wavelength or about 1Z4 wavelength.

It is also known that antennas can be miniaturized by loading them with capacitive or inductive reactance or dielectric or magnetic materials.In addition, inductor and capacitor components can be connected in series or parallel to the antenna feed line. In addition, a technique for lowering the resonance frequency of the antenna is widely used.

[0003] The form in which the most compact shape can be expected as a chip antenna combining these technologies is:

It has a main radiating electrode with an effective electrical length of about 1Z4 wavelength, and is a method that generates an image current outside the antenna (ground conductor of the circuit board on which the chip antenna is mounted). . As a prior art of such a chip antenna, for example, Patent Document 1 is disclosed.

[0004] FIGS. 14A and 14B show a conventional example of a 1Z4 wavelength chip antenna 1 having a ground electrode 3 on the entire back surface opposite to the main radiation electrode 2 on the upper surface, and a mounting example on a circuit board. . Reference numeral 5 denotes a short-circuit electrode connecting the ground conductor 21 of the circuit board 20 and the main radiation electrode 2, and reference numeral 6 denotes a power supply electrode connected to the power supply line 22 of the circuit board 20.

When a resonance current flows through the main radiation electrode 2, an image current is induced on the opposite ground electrode 3.

Generally, in the chip antenna 1 having such a structure, since the ground electrode 3 on the back surface and the main radiation electrode 2 on the top surface are strongly electromagnetically coupled, a force for obtaining stable antenna characteristics is reduced. It is known that, particularly when the chip antenna 1 is made thinner and the coupling strength becomes too strong, the bandwidth is reduced and the radiation efficiency is likely to be reduced. [0005] For example, when the antenna 1 having the above-mentioned electrode structure is formed on a thin rectangular parallelepiped dielectric substrate of about 15 X 5 X 5 mm, a 1575.42 MHz antenna for GPS has a voltage standing wave ratio VSWR of 2 The fractional bandwidth is less than 0.5-1% and the radiation efficiency is as low as about 50%. Furthermore, when the antenna shape is reduced in size, the relative bandwidth and the radiation efficiency are remarkably deteriorated, and the antenna becomes impractical.

[0006] To solve the above problem, as in the conventional example shown in FIGS. 15A and 15B, the ground electrode 3 on the back surface is removed and the ground conductor 21 of the circuit board 20 has the role of effectively removing it. There is known a technique for increasing the volume of an antenna. In this case, an image current is generated in the ground conductor 21.

In the chip antenna 1 having such a structure, a wide bandwidth and a high radiation efficiency can be obtained in a small and low posture, but the area of the ground conductor 21, peripheral mounting parts (not shown), a shield case, a human body, and other nearby objects are obtained. There is a disadvantage that the antenna characteristics are easily deteriorated due to the influence of physical strength, and in addition, as shown in FIG. 15B, a relatively large area for mounting the chip antenna 1 on the circuit board 20 is required. There is also a disadvantage that it is not suitable for high-density mounting because it is necessary to secure a conductor area.

[0007] For example, when the chip antenna 1 is configured on a small and thin dielectric substrate 4 of about 10 X 3 X 2 mm and mounted on the non-ground conductor area 20a (about 20 X 15 mm) on the circuit board 20, The fractional bandwidth where VSW R is less than 2 is as wide as 5-6% and the radiation efficiency is as good as 90% or more, but the actual area on the circuit board 20 occupied by the antenna 1 is very large In addition, since other components cannot be mounted on the non-ground conductor region 20a, it is not suitable for high-density mounting.

[0008] As another example, in the conventional example shown in Figs. 16A and 16B, the resonance frequency is reduced by capacitively coupling the loading electrode 7 to the tip of the main radiating electrode 2, thereby enabling high-density mounting. This is the chip antenna 1 obtained.

This chip antenna 1 is formed on a dielectric base material 4 having the same size as that of FIGS. 15A and 15B and having a size of about 10 × 3 × 2 mm, and as shown in FIG. When mounted in an area, there is a drawback that the radiation efficiency at which a VSWR of less than 2 can be obtained with a fractional bandwidth of about 12% or less is significantly reduced to 30-50%.

Depending on the mounting position of the antenna (for example, the mounting example shown in FIG. 8), New electromagnetic coupling occurs between the ground conductor 21 and the main radiating electrode 2 of the chip antenna 1, and the resonance frequency and impedance greatly change, making matching difficult.Therefore, it may be necessary to redesign the antenna. Occurs.

[0009] Further, Patent Document 1 discloses a chip antenna that stabilizes antenna characteristics with respect to an external structure. Since one of the main radiation electrodes is largely open, an electromagnetic shield is provided. The structure is inadequate and it is difficult to prevent the influence from the same direction.

Patent Document 1: JP-A-2002-158521

Disclosure of the invention

[0010] The present invention has been made in view of the above-mentioned drawbacks of the conventional antenna, and can easily perform impedance matching and resonance frequency adjustment, and can reduce the influence of a nearby object having a high degree of freedom in mounting. The objective is to provide an antenna with excellent stability that is difficult to receive and a wireless communication device using the antenna.

[0011] According to the present invention, in a small antenna using an image current (mapping) effect of an external ground conductor, in order to improve electromagnetic stability against external elements and obtain stable antenna characteristics, the antenna is mainly used. It was noted that the coupling between the radiation electrode and the ground conductor of the mounting substrate should be stabilized.

[0012] That is, according to the first aspect of the present invention, there is provided an antenna mounted on a portion of a circuit board having a feeder line and a ground conductor, at least a part of which faces the main radiation electrode, 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, wherein the main radiation electrode includes: At least a part of a portion corresponding to the main radiation electrode is not grounded, and is arranged so as to be sandwiched at a predetermined distance by the ground electrode. It is characterized by being formed as a conductor region.

In the above configuration, the main radiation electrode is shielded by the ground electrode formed on the same antenna at a predetermined distance, so that the main radiation electrode and the ground electrode are coupled in an electromagnetically stable state. Therefore, it is less likely to be affected by external elements such as a ground conductor on a circuit board located farther than the ground electrode, a nearby object, or a human body. This makes it possible to turn Stable antenna characteristics are obtained without being affected by the antenna mounting position of the road board.

[0014] Further, in the second aspect of the present invention, 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 capacitively coupled to the power supply electrode, one or more short-circuit electrodes connecting the main radiation electrode and the ground conductor, A ground electrode connected to the ground conductor, and a high-potential portion of the main radiating electrode is connected to the ground electrode and the main radiating electrode connected to the ground electrode and the short-circuit electrode. The low-potential portion is disposed so as to be sandwiched at a predetermined distance, and the surface opposite to the surface on which the main radiation electrode is formed is at least a part of a portion corresponding to the main radiation electrode. Is defined as an ungrounded conductor area. It is the butterflies.

In this configuration, in addition to the same operation and effect as the first embodiment, the impedance matching of the antenna can be easily performed by adjusting the coupling capacitance between the main radiation electrode and the feed electrode and the arrangement of the short-circuit electrode. I can do it. It is also possible to use the low potential portion of the main radiation electrode as a part of the shield ground electrode.

[0016] In the third embodiment of the present invention, the first embodiment or the second embodiment described above.

And an adjustment electrode that is capacitively coupled to the power supply electrode, the main radiation electrode, or the short-circuit electrode, or one or more of these electrodes, and that is connected to the ground conductor. Characteristic.

In this configuration, by providing the adjustment electrode, an effect of connecting the reactance component to the main radiation electrode in parallel is obtained, thereby lowering the resonance frequency and, correspondingly, further increasing the antenna shape. Can be reduced in size. In other words, the capacitance component and the induction component of the adjusting electrode can be easily changed, so that the impedance matching range of the antenna is expanded.

In a fourth embodiment of the present invention, in the antenna according to the first embodiment or the second embodiment, a branch path is provided in the main radiation electrode to configure a plurality of resonance circuits. It is characterized by.

[0019] In this configuration, the end of the branch path may be an open end or may be capacitively coupled to a ground electrode. You can. This makes it possible to provide a multi-frequency or wide-band antenna having a plurality of resonance modes.

Further, a fifth embodiment of the present invention is characterized in that the fifth embodiment is a wireless communication device equipped with the antenna according to the first embodiment or the second embodiment.

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 antenna occupying area on the circuit board are extremely small. To provide an antenna suitable for high-density mounting that can maintain high radiation efficiency and is less susceptible to external factors, so that the degree of freedom on the device side when mounting the antenna can be increased. Can be.

Further, by using this antenna, a wireless communication device having excellent antenna characteristics can be realized.

Brief Description of Drawings

FIG. 1 is an explanatory view showing an antenna according to a first embodiment of the present invention.

FIG. 2 is an explanatory view showing an antenna according to a second embodiment of the present invention.

FIG. 3 is an explanatory view showing an antenna according to a third embodiment of the present invention.

FIG. 4 is an explanatory view showing an antenna according to a fourth embodiment of the present invention.

FIG. 5A is a diagram showing a plurality of resonance circuits configured on an antenna.

FIG. 5B is a diagram showing a plurality of resonance circuits configured on the antenna.

FIG. 5C is a diagram showing a plurality of resonance circuits configured on the antenna.

FIG. 6 is an explanatory view in which the chip antenna of the present invention is mounted on a circuit board.

FIG. 7 is a development view of the chip antenna of FIG. 6.

FIG. 8 is a view showing a mounting example different from FIG. 6;

FIG. 9 is a diagram in which a metal case is arranged near a chip antenna of the present invention.

FIG. 10 is a configuration diagram of a wireless communication device according to the present invention.

FIG. 11 is a diagram showing a resonance frequency versus voltage standing wave ratio characteristic.

FIG. 12 is a diagram showing a characteristic of a distance to a metal case versus a resonance frequency or a bandwidth.

FIG. 13 is a view showing a distance-gain characteristic with respect to a metal case.

FIG. 14A is a diagram showing a conventional antenna. FIG. 14B illustrates an example of mounting on a circuit board.

FIG. 15A is a diagram showing another conventional antenna different from FIG. 14;

[15B] Diagram showing an example of mounting on a circuit board.

FIG. 16A is a diagram showing another conventional antenna different from FIG. 15;

FIG. 16B shows an example of mounting on a circuit board.

Explanation of symbols

2 Main radiation electrode

2a High potential section

2b Low potential section

3 Ground electrode

5 Short-circuit electrode

6 Power supply electrode

9 Adjustment electrode

11 fork

14-1 16 Resonant circuit

20 Circuit board

20a Non-ground conductor area

21 Earth conductor

2

30 Wireless communication equipment

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. For the sake of simplicity, the same reference numerals are used in the following description for members common to the conventional art.

FIG. 1 shows a first embodiment of the antenna according to the present invention.

In FIG. 1, reference numeral 1 denotes an antenna, reference numeral 20 denotes a main part of a circuit board on which the antenna 1 is mounted, and almost the entire front and back surfaces of the circuit board 20 are covered with a ground conductor 21.

. Each electrode structure of the antenna 1 is shown as a planar configuration. As shown in FIG. 1, the antenna 1 has one end of the main radiation electrode 2 connected to the feed line 22 of the circuit board 20 via the feed electrode 6, and the other end open. Ground electrodes 3, 3 are arranged along the longitudinal direction so as to sandwich the main radiation electrode 2 at a predetermined distance. In addition, on the back surface facing the main radiating electrode 2, no ground conductor (a conductor portion that is electrically connected to the ground conductor 21 of the circuit board 20) is formed, or at least a part of a portion corresponding to the main radiating electrode 2 is formed. This ground conductor has been removed. The area without the ground conductor is called the non-ground conductor area. The main radiation electrode 2 has a substantial electric length of about 1Z4 wavelength.

On the other hand, a portion where the ground conductor 21 is removed in a U-shape is provided at the end of the circuit board 20, and the antenna 1 is mounted on the non-ground conductor region 20 a, and the ground electrode 3 has a plurality of ground electrodes 3. Are connected to the ground conductor 21 at a plurality of locations via the electrode 5.

For this reason, the main radiating electrode 2 is surrounded by a ground conductor including the ground electrode 3 so as to be open at one end and is electromagnetically shielded, and the gap between the main radiating electrode 2 and the ground electrode 3 Is always set at a fixed distance determined by the electrode structure, so the magnetic stability is extremely high!

In the above configuration, the main radiation electrode 2 and the ground electrode 3 are coupled in an electromagnetically stable state, and the ground conductor 21 of the circuit board 20 located farther than the ground electrode 3 and the vicinity (not shown) Electromagnetic effects can be minimized as much as possible, and the antenna is mounted on the circuit board 20 in a small size, but it is always stable without being affected by the area and mounting position of the non-ground conductor area 20a. The obtained antenna characteristics are obtained.

Next, FIG. 2 shows a second embodiment of the antenna 1 according to the present invention.

In this antenna 1, as shown in FIG. 2, one end of a main radiation electrode 2 is capacitively coupled to a feed electrode 6 via a gap 8, and the other end formed in a U-shape is connected via a short-circuit 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 a ground conductor 21 is provided along the high potential portion 2a of the main radiation electrode 2. Also in this case, as in the first embodiment, the back surface facing the main radiation electrode 2 has a force in which the entire surface is an ungrounded conductor region, or has a small portion corresponding to the main radiation electrode 2. At least part of the region is an ungrounded conductor region. 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 radiating electrode 2 is regarded as a ground conductor, and the ground electrode 3 and the low potential portion 2b of the main radiating electrode 2 constitute the high potential portion 2a of the main radiating electrode 2. Is sandwiched between them. By sandwiching between the low potential portions 2b, the electrode structure can be simplified.

Therefore, as described above, the main radiation electrode 2 is in a state of being electromagnetically shielded by being surrounded by the ground conductor including the ground electrode 3, and this shielding effect causes the ground conductor 21 and the ground conductor 21 of the circuit board 20. The magnetic effect of the nearby object force can be minimized as much as possible, and a stable antenna characteristic can be always obtained without being affected by the mounting state of the antenna on the circuit board 20 despite its small size.

In FIG. 2, a new ground electrode 3 is provided along the outside of the low-potential portion 2b using the low-potential portion 2b of the main radiating electrode 2 as a ground conductor, and the main radiating electrode 2 is sandwiched between the ground electrodes 3, 3. Of course, the structure may be used.

In addition, in this configuration, in addition to the above-described functions and effects, the coupling capacitance between the high-potential portion 2a of the main radiation electrode 2 and the power supply electrode 6 (that is, the gap distance and facing width of the gap 8) and the low-potential portion 2b side By adjusting the arrangement of the short-circuit electrode 5 of this embodiment, there is also a merit 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 via the 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, an effect of connecting a reactance component to the main radiation electrode 2 in parallel can be obtained, so that the resonance frequency of the antenna can be reduced, and the antenna shape can be further reduced in size. Further, by adjusting the length of the adjustment electrode 9 and the gap distance of the gap 10, the capacitance component and the induction 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 or more of the feeding electrode 6, the main radiation electrode 2, and the short-circuit electrode 5. Figure 2 also shows the structure The present invention is not limited to this and can be applied to the antenna shown in FIG.

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

The antenna 1 shown in FIG. 4 is different from the antenna 1 of FIG. 3 in 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 connected to the ground electrode 3 via a gap 13. Therefore, the main radiation electrode 2 or the main radiation electrode 2 and the branch path 11 form a plurality (three) of resonance circuits having current paths indicated by broken lines in FIGS. 5A to 5C. Can be configured. Further, the end of the branch path 11 may be an open end.

As a result, a multi-frequency antenna having a plurality of resonance modes by a plurality of resonance circuits 14-16 can be provided, and a broadband antenna 1 can be provided if the resonance frequencies of the resonance circuits 14-16 are extremely close. Can be.

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. 1 and 2.

As described above, according to the first to fourth embodiments of the present invention, the 1Z4 wavelength antenna using the image current (mapping) effect of the ground conductor 21 of the circuit board 20 is used, and the main radiation electrode 2 By providing the ground electrode 3 for stabilizing the coupling between the antenna and the ground conductor 21 of the circuit board 20 and nearby structures, the antenna shape can be reduced while maintaining stable antenna characteristics, and in particular, the GPS An antenna 1 having appropriate band characteristics and high radiation efficiency suitable for use in a portable electronic device or the like having a receiving function can be provided.

[0040] Further, the antenna 1 having the above configuration can further reduce the size by loading a dielectric, an inductance, and a capacitance on the electrode to lower the resonance frequency. One embodiment will be described with reference to FIG.

Example

FIG. 6 shows a state where the chip antenna 1 for surface mounting is mounted on the circuit board 20, and FIG. 7 shows a state where the chip antenna 1 is expanded. , Left side, upper main side, right side.

[0042] The circuit board 20 was formed of a glass epoxy board and had a size of 60 x 35.0 x 0.5mm. Almost the entire surface of both sides of the circuit board 20 is covered with a Cu conductor serving as the ground conductor 21, and the feeder line 23 that supplies high-frequency power to the antenna 1 has a characteristic impedance of approximately 50 Ω. It consists of a microstrip line.

In addition, 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 substrate 4 having a specific dielectric constant (ε r) of 20. . Each of the conductors described below is obtained by attaching an Ag paste to the surface of the dielectric substrate 4 in a predetermined shape and firing the paste.

As shown in FIG. 7, the power supply electrode 6 connected to the power supply line 23 of the circuit board 20 is disposed from the left side surface of the dielectric base material 4 to the upper main surface. Connected to one end of 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 meandering shape, and is connected to the ground conductor 21 of the circuit board 20 via a plurality of short-circuit electrodes 5 on the right side surface. This electrode structure is similar to that of FIG.

[0045] The portion where the main radiation electrode 2 is connected to the short-circuit electrode 5 is a low potential region (ie, low potential portion 2b) due to the large current flowing through the antenna, and the portion near the feed electrode 6 has a high potential. It is a region (that is, the high potential portion 2a).

Further, on the left side surface, a plurality of ground electrodes 3 are arranged in addition to the power supply electrode 6, and each of them is connected to the ground conductor 21 of the circuit board 20. As a result, the main radiating electrode (high potential portion 2a) on the upper main surface is sandwiched between the plurality of ground electrodes 3 arranged on the left side and the main radiating electrode (low potential portion 2b) arranged on the right side. And is in an electromagnetically shielded state. Thus, the shielding effect can be obtained even if the ground electrode 3 is intermittently arranged near the main radiation electrode 2. In addition, only the soldering terminals 12 for surface mounting corresponding to the respective electrodes are arranged on the lower main surface side.

Further, in the present embodiment, the path leading to the short-circuit electrode 5 of the main radiation electrode 2 is formed on the right side, and is branched into a T-shape to provide a branch path 11, and the open end thereof is formed with a gap 13 on the left side. To form a plurality of resonance circuits, extend the ground electrode 3 on the left side, and capacitively couple to the feed electrode 6 via the gap 10 to form the adjustment electrode 9 Electrode structure.

The chip antenna 1 of the above embodiment has a small shape and a dedicated mounting area on the circuit board 20. At a resonance frequency of 1575.42 MHz, the input impedance is matched to approximately 50 Ω without requiring an external matching element.

In addition, the fractional bandwidth with a voltage standing wave ratio VSWR of less than 2 is 1.0-1.5% (see the characteristic of resonant frequency vs. voltage standing wave ratio in Fig. 11), and the radiation efficiency is 70-80%. Have been obtained. Even when the chip antenna 1 is mounted as shown in FIG. 8, the same antenna characteristics as described above are obtained, and it is a component that the degree of freedom when mounting the chip antenna 1 on a circuit board is high.

Further, as shown in FIG. 9, even when a metal case 24 having a height of about 2 mm is arranged close to the chip antenna 1 on the circuit board 20, the change in antenna characteristics is small. When the distance approaches the extreme vicinity (the distance from the metal case 24 B <4 mm), the resonance frequency shifts slightly higher, but the other characteristics (bandwidth characteristics and gain characteristics) are extremely stable (Fig. 12). (Refer to the distance to the metal case vs. resonance frequency or bandwidth characteristics, and the distance to the metal case vs. gain characteristics in Figure 13).

The point where the resonance frequency shifts high in the vicinity of the metal case 24 can be dealt with by previously calculating the frequency change due to the surrounding structure and determining the electrode dimensions of the chip antenna 1. In the present invention, since the length of the adjustment electrode 9 and the gap between the feed electrode 6 and the main radiation electrode 2 may be adjusted, the adjustment can be performed very easily.

FIG. 10 shows a wireless communication device of the present invention. The wireless communication device 30 includes the above-described antenna 1 of the present invention, the high-frequency circuit 31, and the signal processing unit 32, which are collectively mounted on the circuit board 20.

By mounting the antenna 1 of the present invention, a small-sized wireless communication device having 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 into a low-frequency band. Further, the electric signal supplied from the signal processing section 32 is frequency-mixed, band-filtered, amplified, and transmitted from the antenna 1 as a radio wave. The signal processing unit 32 demodulates the electric 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.

Industrial applicability

According to the present invention, an electrode structure in which a ground electrode is arranged so as to sandwich a main radiation electrode is provided. Therefore, high radiation efficiency can be maintained while the antenna shape and the antenna occupied area on the circuit board are extremely small, and the antenna is not easily affected by external elements. The degree of freedom on the side can be increased, and an antenna suitable for high-density mounting can be provided. Also, by using this antenna, a wireless communication device having excellent antenna characteristics can be realized.

Claims

The scope of the claims

[1] An antenna mounted on a portion of a circuit board having a feeder line and a ground conductor, at least a portion of the portion facing the main radiation electrode being 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;

Comprising a plurality of ground electrodes connected to the ground conductor,

The main radiation electrode is arranged so as to be sandwiched at a predetermined distance by the ground electrode,

Further, the antenna is characterized in that at least a part of a portion corresponding to the main radiation electrode on a surface facing the surface on which the main radiation electrode is formed is a non-grounded conductor region.

[2] An antenna mounted on a portion of the circuit board having a feeder line and a ground conductor, at least a portion of the portion facing the main radiation electrode being 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,

Comprising one or more ground electrodes connected to the ground conductor,

The high-potential portion of the main radiating electrode is sandwiched at a predetermined distance by the plurality of ground electrodes, or by the low-potential portion of the main radiating electrode connected to the ground electrode and the short-circuit electrode. Are located in

Further, an antenna is characterized in that at least a part of a portion corresponding to the main radiating electrode on a surface facing the surface on which the main radiating electrode is formed is a non-grounded conductor region.

[3] The power supply electrode, the main radiation electrode, the short-circuit electrode, or one of these electrodes is capacitively coupled to one or more of the electrodes, and includes an adjustment electrode connected to the ground conductor. The antenna according to claim 1 or claim 2, wherein

4. The antenna according to claim 1, wherein a branch path having an open end is provided in the main radiation electrode to form a plurality of resonance circuits.

[5] A wireless communication device equipped with the antenna according to claim 1 or 2.