JPH077321A - Antenna system - Google Patents

Abstract

PURPOSE:To miniaturize and lighten the antenna system. CONSTITUTION:The antenna system is formed by making radiation conductor elements 51 and 52 orthogonal each other while using the surface conductor foil of a both-face printed circuit board 1. A ground layer 3 is formed by using the rear face conductor foil of the bath-face printed circuit board 1. One terminal of the radiation conductor elements 51 and 52 is connected through a ground conductor part 9 composed of a through-hole to the ground layer 3, and the radiation conductor elements 51 and 52 are grounded. Thus, two pairs of antenna elements formed by using the bath-face printed circuit board 1 are formed as a grounding reverse L antenna. The outputs of the radiation conductor elements 51 and 52 as linear polarized antenna elements are synthesized by a phase shift synthesizing part 6 with phase difference at 90 deg., and circularly polarized waves are received. Two pairs of antenna elements are formed as the grounding antenna, the radiation conductor elements 51 and 52 are miniaturized, and the antenna system is miniaturized and lightened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises two sets of antenna elements having a structure in which two radiation conductor elements and a ground conductor plate are opposed to each other with a dielectric layer or an air layer thinner than the wavelength therebetween. The present invention relates to an antenna device suitable for being incorporated in a portable wireless device, particularly a mobile wireless device for satellite communication.

[0002]

2. Description of the Related Art Conventionally, there has been provided a printed antenna formed by using a double-sided copper-clad laminated printed circuit board (hereinafter referred to as a double-sided printed circuit board). This printed antenna is a so-called microstrip antenna,
Improvements in photoetching technology have improved the reproducibility of electrical characteristics. Moreover, in the case of this printed antenna, if the dielectric constant of the base material of the double-sided printed circuit board is sufficiently large, there is an advantage that it can be downsized as compared with the case where the dielectric layer is made of air due to the wavelength shortening effect. Therefore, it is particularly applied as a built-in antenna for portable radios and the like.

Conventionally, vertical linearly polarized waves have been used in portable radios, but in recent years, circularly polarized waves using satellites have come to be used especially in mobile communication systems. As this type of circularly polarized printed antenna, the one shown in FIG. 8 has been proposed. In this circularly polarized printed antenna, the radiation conductor layer 2 is formed using the front surface conductor foil of the double-sided printed circuit board 1, and the ground layer 3 is formed using the back surface conductor foil. The insulating layer is used as the dielectric layer 4.

The radiation conductor layer 2 has a length of ½ wavelength (λ /
The radiation conductor elements 5 ₁ and 5 ₂ formed of dipoles as the linearly polarized antenna element 2) are formed so as to be spatially orthogonal to each other. Here, the widths of the radiation conductor elements 5 ₁ and 5 ₂ are formed narrower than the wavelength. The outputs of the respective radiating conductor elements 5 ₁ and 5 ₂ are phase shift combiners (sometimes called hybrids) 6 that operate as 90 ° phase shift combiners.
It is designed to be combined with. The phase shift synthesis output is output from the output terminal 6 a of the phase shift synthesis section 6. In addition, the phase shift combining unit 6 is connected to the ground layer 3 via a terminating resistor 7. Here, a chip resistor is used as the terminating resistor 7, and the terminating resistor 7 and the ground layer 3 are connected by a conductor portion 8 formed of a through hole.

When this circularly polarized printed antenna is used for reception, the outputs of the radiation conductor elements 5 ₁ and 5 ₂ as linearly polarized antenna elements spatially orthogonal to each other are combined with a phase difference of 90 degrees. And receive circularly polarized waves. In addition, for example, when the circularly polarized printed antenna is arranged in a standing manner, the received output of the radiation conductor element 5 ₁ for horizontally polarized wave reception is
By synthesizing the reception output of the radiating conductor element 5 ₂ for vertical polarization reception by delaying the phase by 90 degrees in the phase synthesizing unit 6,
A right-hand circularly polarized signal is received as a whole.

[0006]

By the way, when an attempt is made to equip a portable radio with the printed antenna shown in FIG.
There are the following problems. Since the printed antenna shown in FIG. 8 is a half wavelength type, for example, the dielectric constant is 3.5 and the thickness is 5
When formed using a double-sided printed circuit board 1 of 1 mm, 155
At 0 MHz, the double-sided printed circuit board 1 needs to have a size of about 60 mm square. Also, with this size, the weight becomes heavy. Therefore, it is difficult to apply to a portable wireless device in terms of size and weight.

Further, the phase synthesizing section 6 is formed in a square shape,
Each side requires a quarter wavelength (λ / 4), and in order to form it on the same surface as the radiating conductor elements 5 ₁ and 5 ₂ , the element arrangement of the entire printed antenna and mounting on a portable radio device are required. There is a problem that the above restrictions (such as mounting and fixing) increase. The present invention has been made in view of the above points, and an object thereof is to provide an antenna device that is small and lightweight.

[0008]

In order to achieve the above object, according to the invention of claim 1, two radiating conductor elements and a ground conductor plate are sandwiched by a dielectric layer or an air layer thinner than the wavelength. Facing each other and connecting one end of each radiation conductor to the ground conductor plate to form two sets of ground type antenna elements,
Arranging the grounded antenna element so that at least the ground end side base of the radiating conductor element is orthogonal to each other on the same plane,
A phase shift combining means for combining the outputs of the respective grounded antenna elements with a phase difference of 90 degrees is provided.

According to the second aspect of the invention, in order to achieve the above object, the two radiating conductor elements and the grounding conductor plate are opposed to each other with a dielectric layer or an air layer thinner than the wavelength sandwiched therebetween. One end of the radiating conductor and the grounding conductor plate are connected to form two sets of grounded antenna elements as inverted L-shaped antennas, and at least the bases of the radiating conductor elements on the ground end side are orthogonal to each other on the same plane. A grounded antenna element is arranged, two sets of grounded antenna elements are arranged at intervals of ¼ wavelength, one grounded antenna element is used as a feeding element, and the other grounded antenna element is a non-feeding element. There is.

In the second aspect of the invention, in the case of further miniaturization, as shown in the third aspect, an inductor portion or a capacitance portion may be provided at the tips of the two sets of ground type antenna elements. In order to achieve the above-mentioned object, in the invention of claim 4, the two radiation conductor elements and the ground conductor plate are opposed to each other with a dielectric layer or an air layer thinner than the wavelength interposed therebetween, and One end is connected to the grounding conductor plate to form two sets of grounding type antenna elements as inverse F-type antennas, and the radiation conductor elements are orthogonal to each other in the direction of the main current in the inverse L-type antenna operation mode on the same plane. The two ground-type antenna elements are arranged at an interval of ¼ wavelength, one ground-type antenna element is used as a feeding element, and the other ground-type antenna element is used as a non-ground antenna element. It is used as a power feeding element.

When it is possible to switch between the right-handed circularly polarized wave and the left-handed circularly polarized wave, as described in claim 5, a power feeding unit for feeding power to each radiation conductor element is provided,
It suffices to provide a switching unit for selectively supplying power to the power supply unit of any of the radiation conductor elements.

[0012]

According to the first aspect of the present invention, the two antenna elements are ground type antennas by the above-mentioned structure.
The radiating conductor element can be downsized, and the antenna device can be downsized and lightweight. According to the second aspect of the present invention, the two grounded antenna elements of the two groups are used as the feeding elements and the other grounded antenna element is used as the non-feeding element.
The phase shift combiner is not needed, and the antenna device is further reduced in size and weight.

According to the third aspect of the present invention, it is possible to further reduce the size of the radiating conductor element due to the effect of loading the inductor portion with the inductor or the effect of loading the capacitance portion with the capacitance. According to the invention of claim 4, as in the invention of claim 2, the two ground-type antenna elements of one set are used as the feeding elements and the other ground-type antenna element of the other pair is used as the non-feeding element, so that phase shift synthesis is performed. Therefore, the antenna device is made smaller and lighter.

According to the fifth aspect of the present invention, the two sets of grounded antenna elements can be switched between a feeding element and a non-feeding element and can be switched and used for right-handed circular polarization and left-handed circular polarization.

[0015]

(Embodiment 1) FIG. 1 shows an embodiment of the present invention. This embodiment basically has the same structure as that described with reference to FIG. 8. Therefore, the following description will be made only on the characteristic points of this embodiment, and the same configurations will be denoted by the same reference numerals. Is omitted.

In this embodiment, _one ends of the radiation conductor elements 5 ₁ and 5 ₂ are connected to the ground layer 3 through the ground conductor portion 9 formed of a through hole, and the radiation conductor elements 5 ₁ and 5 ₂ are grounded. . By thus grounding the radiating conductor elements 5 ₁ and 5 ₂ to the ground layer 3, two sets of antenna elements configured by using the double-sided printed circuit board 1 are respectively grounded antennas, more specifically, grounded antennas. It functions as an inverted L antenna.

In the ground type antenna, when the ground layer 3 is not sufficiently larger than the used wavelength, even if the ground type inverted L-shaped antenna is used, the radiation conductor elements 5 ₁ and 5 ₂ facing the ground layer 3 are connected to each other. The horizontally polarized radiation component becomes dominant. Therefore, the radiation conductor elements 5 ₁ and 5 ₂ can have a quarter wavelength. Therefore, by reducing the size of the radiation conductor elements 5 ₁ and 5 ₂ , the size of the double-sided printed circuit board 1 forming the antenna device can be reduced, and the size and weight can be reduced.

However, in the case of the present embodiment, the shape of the phase synthesizing section 6 is the dimension of 1/4 wavelength on one side as in the case of FIG. 8, and the occupied area of this phase synthesizing section 6 does not change. .
Further, in order not to disturb the operation of the radiation conductor element 5 _1, 5 _2, radiating conductor element 5 _1, 5 ₂ phase synthesis unit 6
Need to keep away from. Therefore, in the case of the present embodiment, when the double-sided printed board 1 having a dielectric constant of 3.5 and a thickness of 5 mm is used, the double-sided printed board 1 has a size of about 50 mm square at 1550 MHz.

(Embodiment 2) FIGS. 2A and 2B show another embodiment of the present invention. In the present embodiment, the antenna device is configured without using the phase shift combining unit 6, and the output terminal 1 extended from one of the radiation conductor elements 5 ₁ and 5 _2.
The structure is such that the output is obtained from 0. Further, the radiating conductor element 5 ₁ and the radiating conductor element 5 ₂ are formed with an interval of ¼ wavelength. In such a configuration, the radiation conductor element 5 ₁ serves as a feeding element, and the other radiation conductor element 5 ₂ operates as a non-feeding element.

Now, considering the case where the antenna device of FIG. 2 (a) is erected vertically and the horizontally polarized radio wave is radiated from the radiating conductor element 5 ₁ in the front front direction, the radiating conductor element 5 ₂
Are arranged at a distance of ¼ wavelength, the radio wave radiated from the radiation conductor element 5 ₁ is received with a 90 ° phase delay. Here, the radiating conductor element 5 ₂ are the non-feeding element (no load), the received radio wave is reradiated. That is, a vertically polarized radio wave whose amplitude is almost equal to that of the radio wave radiated from the radiating conductor element 5 ₁ and whose phase is delayed by 90 degrees is re-radiated from the radiating conductor element 5 ₂ . Therefore,
When radio waves are observed from a distance in the front direction, it means that right-handed circularly polarized waves are emitted from the antenna device of this embodiment.

Although the above description is for the case where the antenna is operated as a transmitting antenna, the right-handed circularly polarized wave transmitting antenna effectively operates also as the right-handed circularly polarized wave receiving antenna due to the principle of antenna reversibility. It is clear to do. In addition,
When the left-hand circularly polarized wave, the output terminal 10 formed on the radiating conductor element 5 ₂ side, the radiating conductor element 5 ₂ and the feed element may be a radiation conductor element 5 ₁ and the non-feeding element.

The printed antenna of this embodiment does not need to be provided with the phase-shifting / combining section 6, so that the shape can be further reduced. Note that FIG. 2C shows the double-sided printed circuit board 1 shown in FIG. 2A cut away obliquely, and power is supplied from the ground layer 3 side. If you do this,
When the double-sided printed circuit board 1 having a dielectric constant of 3.5 and a thickness of 5 mm is used, the size of the double-sided printed circuit board 1 can be about 50 × 30 mm at 1550 MHz. The area can be reduced to less than half.

By the way, in this embodiment, the radiation conductor element 5 is used.
₂The non-grounded end of the radiating conductor element 5₁Near the grounded end of
I am doing it. This is a 90 degree phase difference
Selected an element layout that makes the printed antenna smaller.
When the radiating conductor element 5₁, 5 ₂So that the binding of
This is because Fig. 3 shows the circular polarization with the configuration of Fig. 2 (a).
The characteristics when the antenna is manufactured are shown below. Here, FIG.
(A) shows the impedance characteristics of the printed antenna
It is a Smith chart shown, tuning frequency (1550MHz)
In the figure₀, Which is unique to circularly polarized antennas.
The pedestal locus is obtained.

3B and 3C show the reception directional characteristics of the XZ plane and the YZ plane when the X, Y, and Z axes are set for the printed antenna A as shown in FIG. Show each. In FIGS. 3B and 3C, the left-handed single point indicates the reception directional characteristic of the right-handed circularly polarized wave, and the solid line indicates the reception directional characteristic of the left-handed circularly polarized wave. Here, the directional characteristics differ between the XZ plane and the YZ plane at low elevation angles, and the XZ plane is better. However, the cross polarization ratio in the zenith direction (Z-axis direction) is
It is about 15 dB (corresponding to an axial ratio of 3 dB), which is a substantially good characteristic. The gain for the right-hand circularly polarized signal in the zenith direction was +2 dBi.

(Embodiment 3) FIG. 4 shows still another embodiment of the present invention. The printed antenna of this embodiment is shown in FIG.
It is constructed on the basis of the second embodiment shown in (c), and this embodiment is characterized by the shapes of the radiation conductor elements 5 ₁ and 5 ₂ . That is, these radiation conductor elements 5 ₁ ,
By shortening 5 ₂ length, in which was further enables miniaturization.

Specifically, a portion (hereinafter referred to as a base) 5a near the grounded ends of the radiation conductor elements 5 ₁ and 5 ₂ is approximately 1/8.
The length of the wavelength (λ / 8) is set, and each radiation conductor element 5 ₁ , 5 ₂
The base portions 5a are formed so as to be spatially orthogonal to each other. Then, the inductance component is radiated from the side opposite to the ground side of the base 5a (hereinafter referred to as the tip) to the radiating conductor elements 5 ₁ , 5
An inductance portion 5b to be loaded on ₂ is formed. Here, the inductance portion 5b is provided so as to protrude from the tip of the base portion 5a in a direction orthogonal to the base portion 5a, and is formed by bending a plurality of times.

In the grounded antenna, the horizontal polarization directional characteristic is mainly controlled by the current flowing in the portion near the ground end, that is, the base portion 5a. Therefore, by utilizing the point, only radiation conductive element 5 _1, 5 ₂ of the base part 5a spatially orthogonalizing, by shortening the length of the radiating conductor element 5 _1, 5 ₂ by inductance loading effect of the inductance section 5b is there.

FIG. 4B shows the radiation conductor elements 5 ₁ and 5 described above.
_A capacitance portion 5c is provided instead of the _second inductance portion 5b, and the lengths of the radiating conductor elements 5 ₁ and 5 ₂ are shortened due to the capacitance loading effect. With the above structure, the length (B dimension) in the longitudinal direction of the printed antenna shown in FIG. 2C can be shortened to about 2/3. In the case of FIG. 4 as well, by exchanging the feeding element and the non-feeding element, it is possible to receive left-handed circularly polarized waves.

(Fourth Embodiment) Still another embodiment will be described with reference to FIGS. In this embodiment, the electronic switch means is capable of selectively receiving the right-handed circular polarization and the left-handed circular polarization. Radiation conductor element 5 of the present embodiment
₁ , 5 ₂ are switching diodes D ₁ and D ₂ such as PIN diodes and a capacitor C as shown in FIG.
It is connected to the antenna output OUT via. here,
Switching diode D _1, D ₂ are connected in reverse to the radiating conductive element 5 _1, 5 ₂ together, switching diode D ₁ to the common connection point which is respectively connected to the capacitor C,
A bias voltage of D ₂ is applied so that the switching diodes D ₁ and D ₂ are selectively turned on and off.
The capacitor C is for cutting direct current. Further, the bias voltage is changed to the choke coil C by switching the switch SW.
The DC power supplies E ₁ and E _{2 are} applied via H, and the choke coil CH is for high frequency cutting.

The switching diodes D ₁ and D
_As shown in FIG. 6, the copper foil 2 forming the radiation conductor element 5 is partially cut off, and the land 12 is formed in the cutout portion 15.
And a switching diode D is mounted between the land 12 and the radiation conductor element 5. The land 12 is connected to the land 14 provided on the ground layer 3 side by the conductor portion 13 formed of a through hole, and is connected to the subsequent circuit described with reference to FIG.

In FIG. 5, when the switch SW is switched to the a side, the DC power supply E ₁ is applied to the switching diodes D ₁ and D ₂ , the switching diode D ₁ is in the conducting state, and the switching diode D ₂ is in the non-conducting state. Become. Therefore, the radiation conductor element 5 ₁ serves as a feeding element and the radiation conductor element 5 ₂ serves as a parasitic element. Therefore,
In the case of the embodiment described above, it functions as a reception antenna for right-handed circularly polarized waves.

On the contrary, the switch SW is switched to the b side, the DC power source E ₂ is applied to the switching diodes D ₁ and D ₂ , the switching diode D ₁ becomes non-conductive, and the switching diode D ₂ becomes conductive. Therefore, the radiation conductor element 5 ₁ serves as a non-feeding element and the radiation conductor element 5 ₂ serves as a feeding element, and functions as a reception antenna for left-handed circularly polarized waves. This embodiment can be applied to the case where diversity reception is performed in a propagation path with many reflections.

(Fifth Embodiment) FIG. 7 shows still another embodiment. In this embodiment, an inverted F-shaped antenna is used instead of the inverted L-shaped antenna.
It is configured by using a type antenna. Where reverse L
Both the F type antenna and the inverted F type antenna are ground type antennas. However, in the case of the inverted F type antenna, the radiation conductor elements (5 ₁ 'and 5 ₂ ' in FIG. 7) are formed in a rectangular shape, and each side has approximately 1
/ 8 wavelength and the perimeter is 1/2 wavelength.
Therefore, in addition to the function as a plate-shaped inverted L-shaped antenna,
It operates in an operation mode that adds the function of a half-wavelength slot antenna. In the case of this inverted F-type antenna, it operates as a magnetic current antenna in which the decrease in operating gain due to the human body is small,
It is particularly effective when used for a portable wireless device.

Specifically, as shown in FIG. 7, one side is 1
/ 8 wavelength rectangular radiating conductor element 5₁', 5₂’Is formed
Radiating conductor element 5₁At one corner
It is grounded by a grounding conductor portion 9 composed of a roll. Feeding point 11
Is provided near the grounded end. The printer of this embodiment
In the inverted L-shaped antenna mode of the inverted F-shaped antenna in Tena
The main current direction in the figure is the direction indicated by the arrow in the figure. Tsuma
Radiating conductor element 5 ₁, 5₂Through the corner that will be the
Diagonal directions, and the current directions are orthogonal to each other.
It is oriented.

However, the grounding point may be provided at a position indicated by X in the figure. In this case, the main current direction of each radiating conductor element 5 ₁ ′, 5 ₂ ′ is along the long side.
Also in this case, the radiating conductor elements 5 ₁ ′ and 5 ₂ ′ may be formed so that the long sides thereof are orthogonal to each other. In the above description, the case where the antenna device is a printed antenna has been described, but the two radiation conductor elements and the ground conductor plate are opposed to each other with the air layer thinner than the wavelength sandwiched therebetween, and the respective radiation conductors are arranged. It goes without saying that the present invention can also be applied to an antenna device in which two sets of ground type antenna elements are configured by connecting one end of the above to a ground conductor plate.

[0036]

As described above, according to the first aspect of the invention, the two radiation conductor elements and the ground conductor plate are opposed to each other with the dielectric layer or the air layer thinner than the wavelength sandwiched between the two radiation conductor elements. And one end of the ground conductor plate are connected to form two sets of ground type antenna elements, and the ground type antenna elements are arranged so that at least the ground end side bases of the radiating conductor elements are orthogonal to each other on the same plane, Since the phase shift combining means for combining the outputs of the respective grounded antenna elements with a phase difference of 90 degrees is provided, two sets of antenna elements can be grounded antennas, and the radiation conductor element can be downsized. The device can be made smaller and lighter.

According to the second aspect of the invention, the two radiation conductor elements and the ground conductor plate are opposed to each other with the dielectric layer or the air layer thinner than the wavelength sandwiched therebetween, and one end of each radiation conductor and the ground conductor plate. And two are connected to form a grounded antenna element as an inverted L-shaped antenna, and the grounded antenna element is arranged such that at least the ground end side bases of the radiation conductor elements are orthogonal to each other on the same plane. Since two sets of grounded antenna elements are arranged at an interval of ¼ wavelength, one grounded antenna element serves as a feeding element, and the other grounded antenna element serves as a non-feeding element, the phase shift combining unit Is unnecessary, and the size and weight can be further reduced.

According to the third aspect of the present invention, the radiating conductor element is provided by the inductor loading effect of the inductor section or the capacitance loading effect of the capacitance section by providing the inductor section or the capacitance section at the tips of the two sets of ground type antenna elements. Can be further downsized, and further downsized and lightened. In the invention of claim 4, the two radiation conductor elements and the ground conductor plate are opposed to each other with the dielectric layer or the air layer thinner than the wavelength sandwiched therebetween, and one end of each radiation conductor is connected to the ground conductor plate. Then 2
A grounded antenna element as a pair of inverted F-type antennas is configured, and the grounded antenna element is arranged such that the radiation conductor elements are orthogonal to each other on the same plane in the directions of the main current in the inverted L-shaped antenna operation mode. Since two sets of grounded antenna elements are arranged at intervals of ¼ wavelength and one grounded antenna element is used as a feeding element and the other grounded antenna element is used as a non-feeding element, It is not necessary and can be made smaller and lighter.

According to the fifth aspect of the invention, since a power feeding portion for feeding power to each radiation conductor element is provided and a switching means for selectively feeding power to the power feeding portion of any of the radiation conductor elements is provided,
The pair of grounded antenna elements can be switched between a feeding element and a non-feeding element, and can be switched and used for right-handed circular polarization and left-handed circular polarization.

[Brief description of drawings]

1A and 1B are a front view and a sectional view of an embodiment of the present invention.

2A to 2C are a front view of another embodiment, a cross-sectional view, and a front view in the case of further downsizing by changing a method of forming a radiation conductor element.

3A to 3D are Smith charts showing impedance characteristics of the printed antenna of FIG.
A directional pattern on the Z plane, a directional pattern on the YZ plane,
FIG. 3 is an explanatory diagram showing X, Y, and Z axis directions set in the printed antenna.

4 (a) and 4 (b) are front views of yet another embodiment for further miniaturization.

FIG. 5 is a circuit diagram of a main part of still another embodiment.

FIG. 6 is a partial perspective view showing the main structure of the above.

FIG. 7 is a front view of still another embodiment.

8A and 8B are a front view and a sectional view of a conventional example.

[Explanation of symbols]

1 double-sided printed circuit board 2 radiation conductor layer 3 ground layer 4 dielectric layer 5 _1, 5 _2, 5 ₁ ', 5 _2' radiating conductor element 5a base 5b inductance section 5c capacitance section 6 phase synthesis unit 9 ground conductor 10 an output Terminal D ₁ , D ₂ Switching diode SW switch E ₁ , E ₂ DC power supply

Claims (5)

[Claims] 1. A radiation conductor element and a ground conductor plate are opposed to each other with a dielectric layer or an air layer thinner than the wavelength sandwiched therebetween, and one end of each radiation conductor is connected to the ground conductor plate. Two sets of ground-type antenna elements are formed, and the ground-type antenna elements are arranged so that at least the ground end side bases of the radiation conductor elements are orthogonal to each other on the same plane, and the output of each ground-type antenna element is 90 degrees. An antenna device comprising a phase-shift combining means for combining with the phase difference of the above. 2. The two radiation conductor elements and the ground conductor plate are opposed to each other with a dielectric layer or an air layer thinner than the wavelength sandwiched therebetween, and one end of each radiation conductor is connected to the ground conductor plate. Two sets of grounded antenna elements as inverted L-shaped antennas are configured, and the grounded antenna elements are arranged such that at least the bases of the radiation conductor elements on the ground end side are orthogonal to each other on the same plane, and two sets of grounded elements are arranged. 1 type antenna element
An antenna device, which is arranged at intervals of four wavelengths, wherein one grounded antenna element serves as a feeding element and the other grounded antenna element serves as a non-feeding element. 3. The antenna device according to claim 1, wherein an inductor portion or a capacitance portion is provided at the tips of the two sets of grounded antenna elements. 4. The two radiation conductor elements and the ground conductor plate are opposed to each other with a dielectric layer or an air layer thinner than the wavelength sandwiched therebetween, and one end of each radiation conductor is connected to the ground conductor plate. Two sets of grounded antenna elements as inverted F-type antennas are configured, and the grounded antenna elements are arranged so that the radiation conductor elements are orthogonal to each other on the same plane in the directions of the main current in the inverted L-type antenna operation mode. An antenna, characterized in that two sets of grounded antenna elements are arranged at intervals of ¼ wavelength, one grounded antenna element serves as a feeding element, and the other grounded antenna element serves as a non-feeding element. apparatus. 5. The power supply unit for supplying power to each radiation conductor element is provided, and the switching unit for selectively supplying power to the power supply unit of any one of the radiation conductor elements is provided. Item 4. The antenna device according to item 4.