JPH05102897A - Diversity antenna - Google Patents

Abstract

PURPOSE:To provide the compact diversity antenna for mobile object communication reducing the influence of fading. CONSTITUTION:On one face of an insulated substrate 1, a conductive layer 10 is formed while forming a notch 5 axially symmetrically almost at 120 deg. and on the other face of the insulated substrate 1, a line 6 for feeding a notch antenna is formed. The line 6 for feeding is composed of a circular line equipped with a step 6a for adjusting the phase of the excitation of the notch, and feeding is executed to one terminal. A conductive base plate 2 is arranged almost parallelly to the insulated substrate 1, and a feeding rod 4 is connected to the central part of the conductive layer 10. The conductive layer 10 and the base plate 2 is short-circuited through a matching pin 3 to adjust an input impedance. The matching pin 3 is press-formed integrally with the base plate 2. The notch antenna is formed by the notch 5 and the line 6 for feeding, and a capacity load type pole antenna is formed by the feeding rod 4, base plate 2, conductive layer 10 and matching pin 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diversity antenna, and more particularly to a plane type diversity antenna suitable for mobile communication.

[0002]

2. Description of the Related Art Various mobile communication systems such as car telephones employ various diversity systems such as space diversity, power density reception, and polarization diversity in order to prevent the effects of fading caused by complicated terrain and obstacles. ..

[0003]

In the conventional space diversity system in which the antennas of the same polarization are spatially displaced by 90 ° in phase and signals selected from antennas in good condition are used while being selected. The antennas are placed at 90 ° out of phase. Therefore, there is a drawback that the installation space becomes large.

In the power density receiving system and the polarization diversity system, a slot antenna and a monopole antenna are combined, and two antennas are spatially arranged at the same position, so that the antenna becomes large. is there. Therefore, the conventional diversity type antenna has a drawback that it is not suitable for a mobile communication antenna that is required to be small. The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a small-sized antenna for mobile communication which is less affected by fading. Another object of the present invention is to provide a small diversity antenna.

[0005]

In order to achieve the above object, an antenna according to a first aspect of the present invention is formed on an insulating substrate and one surface of the insulating substrate, and a notch is formed at an axis of approximately 120 °. A conductive layer, and a feeding line formed on the other surface of the insulating substrate for exciting the notches in phases shifted by 120 °.

Also, according to the antenna of the second aspect of the present invention, an insulating substrate, and a conductive layer formed on one surface of the insulating substrate and having a plurality of notches formed in the circumferential direction,
An annular feeding line is formed on the other surface of the insulating substrate so as to overlap the notch, is fed to one end of the notch, and has a step of adjusting the phase of excitation of each notch.

[0007]

With the above structure, according to the antenna of the first aspect of the present invention, the number of 12
A notch antenna is arranged on the 0 ° axis. Therefore, the area occupied by the notch antenna can be reduced as compared with the conventional case where the notch antenna is arranged on the 90 ° axis. Further, with the above configuration, according to the antenna of the second aspect of the present invention, the notch antenna can be excited by the power feeding line having a simple configuration.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A mobile communication antenna according to an embodiment of the present invention will be described below with reference to the drawings. (First embodiment)

The antenna according to this embodiment is an antenna for receiving a power density by combining a capacitive loading monopole antenna with a matching pin, which is a planar antenna, and a notch antenna.

FIG. 1A is a plan view of an antenna according to this embodiment, and FIG. 1B is a sectional view taken along line AA of FIG. 1A. 2 is an exploded perspective view of the antenna shown in FIGS. 1A and 1B, and FIG. 3 is an enlarged view of the vicinity of the input impedance matching pin of this embodiment.

This antenna is composed of a metallic rod 4, a dielectric substrate 1 fixed to the upper end of the metallic rod 4, and a metal base plate 2 which is arranged substantially in parallel at a predetermined distance. The center of the dielectric substrate 1 having a shape (hexagonal shape in this embodiment) corresponding to the reception or transmission frequency is fixed to the upper end of the metal feed rod 4. Further, the lower end of the power feeding rod 4 is fixed to the center of the main plate 2 via an insulator 7.

A fan-shaped notch 5 is formed on the lower surface of the dielectric substrate 1.
The metal film 10 in which the (cut) is formed in 120 ° axial symmetry
Is fixed. The power supply rod 4 is connected to approximately the center of the metal film 10. An annular (C-shaped) strip line 6 for feeding power to the notch 5 is fixed to the upper surface of the dielectric substrate 1.

The reason for forming three notches 5 with 120 ° axial symmetry is to excite each with a phase difference of 120 ° and to obtain omnidirectionality in the horizontal plane. Since the notch 5 is excited with a phase difference of 120 °, the annular strip line 6 has
A wide step 6a is arranged on the 120 ° axis. This step 6a matches the input impedance so that the phase of the current supplied to each notch 5 is shifted by 120 °.

The metal film 10 and the annular strip line 6 are
For example, both surfaces of the dielectric substrate 1 are metal-plated, and the formed metal plating is etched to form. A support portion 3 is integrally formed on the base plate 2 by pressing on a 120 ° axis symmetrical object. The supporting part 3 is bent, and the tip thereof is the metal film 1.
It is fixed to 0 by soldering, spot welding, or the like.
The supporting portion 3 has a role of fixing the dielectric substrate 1 to the ground plane 2 and a function of a matching pin for adjusting the input impedance of the capacitive loading type monopole antenna.

The center conductor of a power feeding coaxial cable 16 for a capacitive loading type monopole antenna is connected to the power feeding rod 4 and the outer conductor of the power feeding coaxial cable is connected to the main plate 2 through a connector 11.

As shown enlarged in FIG. 3, the center conductor 13 of the coaxial cable 12 for feeding the notch antenna is insulated from the metal film 10, penetrates the dielectric substrate 10 and is connected to one end of the feeding strip line 6. Connected. The outer conductor 14 of the power feeding coaxial cable 12 is fixed to the support body 3 by a clamp 15, soldering, welding, or the like. As a result, the fixing of the coaxial cable 12 to the antenna and the connection of the outer conductor 14 and the ground plane 2 are simultaneously achieved.

1 to 3, a capacitive loading type monopole antenna with a matching pin is formed from a feeding rod 4, a metal film 10, a support (matching pin) 3, and a ground plate 2, and a notch 5 and an annular strip line 6 are formed. A notch antenna is formed from the. A diversity antenna is composed of these two antennas. For example, when transmitting, power is supplied to both antennas through both coaxial cables 11 and 16, and when receiving,
Use the output of the antenna with the better condition or a combination of the outputs of both antennas.

The current supplied from the power feeding rod 4 flows toward the support 3 which is a matching pin. Therefore, the current flowing through the metal film 10 is concentrated on the line connecting the power feeding rod 4 and the support body 3, and has only a radial component. Therefore, even if the notch 5 is provided at the illustrated position, it does not affect the operation of the capacitance loaded monopole antenna with the matching pin.

The capacitance loaded monopole antenna with a matching pin is an antenna sensitive to an electric field, and the notch 5 is an antenna sensitive to a magnetic field. Therefore, according to the above configuration,
Since the antenna sensitive to the electric field and the antenna sensitive to the magnetic field are spatially arranged at the same position, it becomes possible to receive the power density with the planar antenna.

By making the notch 5 fan-shaped,
The frequency band required for the notch antenna is obtained. If the shape of the notch 5 is increased, the electrical volume of the capacitance loaded monopole antenna with a matching pin is decreased and the resonance frequency is increased.

In the configurations of FIGS. 1 to 3, the three notches are arranged offset by 120 ° and they are excited in phases shifted by 120 °, so that omnidirectionality in the horizontal plane is achieved. Further, since the number of notches is three, the occupied area of the notch antenna is smaller than the conventional one, and the antenna can be easily downsized. Further, it becomes possible to receive the power density with the planar antenna. Therefore,
The antenna of this embodiment is suitable as an antenna for mobile communication. (Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIG.

FIG. 4A is a plan view of the antenna according to this embodiment, and FIG. 4B is a side view. This example
It is an example in which the notch antenna of the first embodiment is modified, and an example is shown in which a feeding circuit is individually provided in the notch 5. Note that FIG.
In FIGS. 3A and 3B, the same parts as those in FIGS.

In this embodiment, as shown in FIG. 4A, a linear strip line 21 is arranged for each notch 5 instead of the annular strip line 6 shown in FIG. Each straight stripline 21 extends from above the support 3 across the corresponding notch 5. As shown in FIG. 4B, one end P of each linear strip line 21 is connected to the phase circuit 22 via the coaxial cable 24, and the phase circuit 22 is connected to the branch circuit 23.
The output of the transmitter (not shown) is branched into three by the branch circuit 23 and supplied to the phase circuit 22. The phase circuit 22 adds a phase difference of 120 ° to each signal, supplies the signals to the corresponding linear strip lines 21 in the phases of 0 °, 120 °, and 240 °, and excites the corresponding notch 5.

Also in the configuration of FIG. 4, omnidirectionality in the horizontal plane is achieved, the occupied area of the notch antenna is smaller than the conventional one, and the antenna can be easily downsized.
It becomes possible to receive power density. Therefore, the antenna of this embodiment is also suitable as an antenna for mobile communication. (Third embodiment)

A third embodiment of the present invention will be described with reference to FIG. FIG. 5 is a plan view of the antenna according to the third embodiment. In FIG. 5, the same parts as those in FIGS. This embodiment is an example in which the feed circuit of the notch antenna according to the first embodiment is improved.

In this embodiment, as shown in FIG.
Instead of the annular strip line 6 shown in FIG. 1, a radial strip line 26 is arranged on one surface of the dielectric substrate 1, and each tip of the radial strip line 26 is a stub. By adjusting the length of the radial strip line 26, the phase of excitation of each notch is 0 °, 120 °,
Set to 240 °. The strip line 26 and the feeding coaxial cable are connected at the feeding point P as shown in FIG.

Also in the configuration of FIG. 5, omnidirectionality in the horizontal plane is achieved, the antenna can be easily downsized, and power density reception can be performed, which is suitable as an antenna for mobile communication. ..

Although the power feeding rod 4 and the coaxial cable 16 are connected using the connector 7 in FIG. 1, the outer conductor 3 of the coaxial cable 16 is connected to the main plate 2 as shown in FIG.
1 may be directly fixed by the clamp 32 or the like, the internal conductor 33 may be pulled out, and fixed to the power feeding rod 4.
The cable clamp 32 can be integrally formed by pressing the base plate 2 as shown in FIG. 7, for example. If the outer conductor of the coaxial cable is fixed by the clamp 32, the fixing of the coaxial cable 16 and the connection between the outer conductor and the ground plane 2 are achieved at the same time. Further, as shown in FIG. 6, the coaxial cable 1
You may draw out the center conductor of 6 and use this as a power feeding rod.

The present invention is not limited to the above embodiment. For example, in the above description, the power supply strip lines 6, 21, 26 and the metal film 10 are formed, for example, by forming a metal film on the dielectric substrate 10 and etching the metal film. However, the present invention is not limited to this, and the feeding strip lines 6 and 2 formed separately from the dielectric substrate 10.
1, 26 and the metal film 10 may be fixed to the dielectric substrate 10. In addition, the present invention is not limited to the above embodiment, and various modifications can be made.

[0030]

As described above, according to the present invention, since the notch is fan-shaped, the band of the notch antenna can be widened. Further, since the notch is provided for the 120 ° axis target, the area of the notch antenna can be made smaller than the conventional diversity antenna in which the notch is arranged for the 90 ° axis target, and the electrical volume of the capacitive loading type monopole antenna can be effectively made. It can be taken and the antenna can be miniaturized. Further, if the feeding circuit of the notch antenna is C-shaped (annular) having a step for phase adjustment, it is possible to feed the notch antenna with a simple configuration.

[Brief description of drawings]

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

FIG. 2 is an exploded perspective view of the antenna shown in FIG.

3 is a cross-sectional view showing a configuration of a power feeding portion of the antenna shown in FIG.

FIG. 4 is a diagram showing an antenna according to a second embodiment of the present invention.

FIG. 5 is a plan view showing an antenna according to a third embodiment of the present invention.

6 is a diagram showing a modification of the antenna shown in FIG.

FIG. 7 is a diagram showing an example of a cable clamp.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Dielectric substrate, 2 ... Lower plate, 3 ... Support part (impedance matching pin), 4 ... Rod, 5 ... Notch, 6 ... C-shaped strip line, 6a ... Step, 7 ... Connector, 1
1, 16, 24 ... Coaxial cable, 13 ... Central conductor, 14
... outer conductor, 15 ... wire clamp, 21 ... power feeding strip line, 22 ... phase circuit, 23 ... branch circuit, 26 ...
Radiant strip line, 32 ... Cable clamp.

Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location H04B 7/02 9199-5K (72) Inventor Hiroyuki Arai 4-10-10 Koishikawa, Bunkyo-ku, Tokyo Academic Academy Heights 301

Claims (3)

[Claims] 1. An insulating substrate, a conductive layer which is formed on one surface of the insulating substrate and has three notches that are symmetrical with respect to an axis of 120 °, and another notch formed on the other surface of the insulating substrate.
An antenna characterized in that it is provided with a feed line that excites in a phase shifted by °. 2. A conductive ground plate arranged substantially parallel to the insulating substrate, a power feed rod connected to the conductive layer, and a matching pin for connecting the conductive layer and the ground plate and adjusting an input impedance. The antenna according to claim 1, further comprising: the matching pin formed integrally with the ground plane. 3. An insulating substrate, a conductive layer formed on one surface of the insulating substrate and having a plurality of notches formed in a circumferential direction of the substrate, and another surface of the insulating substrate overlapping the notch. An antenna, which is formed, is fed to one end thereof, and has an annular feeding line having steps for adjusting the phase of excitation of each notch.