JPH0575331A - Plane antenna - Google Patents

Abstract

PURPOSE:To make the plane antenna for mobile communication utilizing an artificial satellite small and to make the band of a frequency characteristic broad. CONSTITUTION:The antenna consists of a radiation element 7 and a ground plate 13 and the radiation element 7 is made up of a couple of conductor wires or microstrip conductors 7a, 7b arranged almost on a plane in spiral and fed from centers 11a, 11b and adjacent winding interval in a radial direction of each spiral is in the relation of logarithmic period and the ground plate is arranged at the rear side of the radiation element at an interval of 1/4 of an operating shortest wavelength electrically.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planar antenna,
In particular, it relates to a planar antenna for mobile communication using an artificial satellite.

[0002]

2. Description of the Related Art Conventionally, since an antenna for mobile communication using an artificial satellite is used while moving,
A device equipped with a device for tracking the satellite so as to point in the direction of the satellite was required.

FIG. 10 shows an example of a mobile communication antenna using this type of artificial satellite. This mobile communication antenna 100 includes a rod-shaped antenna 101 and a mounting portion 102 thereof.
The rod-shaped antenna 101 is a non-tracking type in which a plurality of pairs of conductors are formed in a spiral shape on a rod-shaped insulator and have an inverted conical directivity.

[0004]

However, the above-mentioned conventional antennas are complicated in structure, have a long overall length (because of their height) to be mounted on a moving body, and are modern, light, thin, short and small. There were problems such as not fitting.

The present invention has been made in view of the above points,
The purpose is to solve the above problems, small size and easy to handle,
Another object of the present invention is to provide a planar antenna which is not only convenient to mount on a moving body such as an automobile but also has a wide frequency characteristic.

[0006]

The constitution of the present invention for achieving the above object is as follows (1) and (2). (1) In a planar antenna composed of a radiating element and a ground plane, the radiating element forms a spiral or a plurality of spiral windings composed of a pair of conductor wires or microstrip conductors arranged on a substantially flat surface. , A structure in which power is supplied from the central portion, and adjacent winding intervals in one radial direction of each vortex winding are in a logarithmic periodic relationship, and the outermost circumference of the vortex winding is approximately equal to the longest wavelength used. And the innermost circumference is formed to be approximately equal to the shortest wavelength used, and the ground plane is disposed behind the radiating element at an electrical distance of 1/4 or more of the shortest wavelength used. Is characterized by.

(2) The spiral winding in (1) above is a polygonal spiral winding.

[0008]

The planar antenna constructed as described above has a plurality of vortex windings consisting of a pair of filaments or microstrips as its radiating element, and the vortex windings having adjacent winding intervals in one radial direction. Is in a logarithmic periodic relationship, the outermost circumference of the spiral is formed to be approximately equal to the longest wavelength used, and the innermost circumference is formed to be substantially equal to the shortest used wavelength. The frequency characteristics are ensured, and the ground plane is disposed behind the radiating element at an electrical interval of 1/4 or more of the shortest wavelength used, so that the principle described later allows wideband non-tracking. The antenna has an inverted conical directivity which is preferable for

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be illustratively described in detail below with reference to the drawings. FIG. 1 shows an embodiment of a planar antenna of the present invention, FIG. 1 (A) is a side view of the antenna, and FIG. 1 (B) is a front view thereof. In FIG. 1, 1
Is a planar antenna as a whole, 2 is a feeding part, 3 is a radiating part, and 4 is a mounting part.

FIG. 2 is an enlarged view of the radiating portion 3 of the planar antenna 1 of FIG. 1B, which is a sectional view taken along the line II-II in FIG. 3, and FIG. 3 is a vertical sectional view of the planar antenna 1 of FIG. Is. This figure shows the radiation part 3 for left-handed circular polarization,
Reference numeral 7 is a radiating element composed of a pair of spiral-shaped conductor wires or microstrip conductors 7a and 7b, 8 is a terminating resistor, 9 is a microstrip substrate, and 10 is a protective cover of the radiating element 7. It is a good insulating member.

Reference numerals 11a and 11b denote feed ends to the radiating element 7, which are located substantially at the center of the spirally wound element, and parallel feed lines 12 are provided.
Connected by each. Reference numeral 13 is a ground plate made of a good electric conductor, and the dimension of the distance d from the radiating element 7 has a key that makes the directivity an inverted conical shape.

Now, the configuration, dimensions and operation of the planar antenna in this embodiment will be described below. Figure 4
4A is an explanatory view of a design method for determining the design dimension of the radiating element 7, and FIG. 4B is an enlarged view of a central portion of FIG. 4A.

In the figure, a line 21 is drawn in one radial direction from the center 20 of one spiral conductor 7b of the radiating element 7, and the distance from the center 20 to the first intersection with the spiral conductor 7b is D. _1, and the next intersection from the intersection, that is, around the spiral conductor 7b from the first intersection, then distance to the intersection which intersects and D _2. Each interval in the same manner as the radial line 21, and sequentially D _3, D _4, the spiral conductor 7b, these Aitonaru interval has a spiral shape in the log-periodic relationship.

On the other hand, a line 22 is drawn in the other radial direction from the center 20 of the spiral conductor 7b, the radius to the outermost intersection of the spiral conductor 7b is R _L , and the radius to the innermost intersection is R _H , the outermost circumference length L _L of the spiral conductor 7b is substantially equal to the wavelength λ _L of the lowest frequency f _L used,
Further, when the innermost circumference length l _H of the spiral conductor 7b is made substantially equal to the wavelength λ _H of the maximum frequency f _H used, R _H
The shape and dimensions of the spiral conductor 7b are determined so that the relationship of / λ _H = R _L / λ _L is satisfied. In this case, the spiral conductor 7b may have an Archimedes spiral shape or a polygonal spiral shape as shown in FIG.

Next, as shown in FIG. 3, the ground plane 13 arranged on the rear side of the radiating element 7 has a distance d from the radiating element 7 such that d ≧ λ _H / 4 and d ≧ λ _L / 4. In addition, the central part and the peripheral part may be arranged with a slight taper. The terminating resistor 8 has a value of about 600Ω, and the other end is connected to the conductor ground plane 13 and grounded.

FIG. 5 is an explanatory view of the operating principle of the radiating element 7. Now, taking the case of transmission as an example, the feeding end A
_When the conductor length between A ₂ and A _{3 of} the high frequency current fed from ₁ corresponds to 1/2 of the used wavelength, the direction of the current of that frequency is upward as shown by the arrow.

Since currents of the same frequency fed from the feeding end B ₁ have opposite phases, an upward current as indicated by an arrow flows in the conductor between B ₂ and B ₃ which corresponds to ½ wavelength. .. Therefore, the current vector between the conductors A ₂ and A ₃ and the current vector between the conductors B ₂ and B ₃ are combined to obtain a large upward combined current vector.

Further, the conductor base plate 1 is arranged behind the radiating element 7 with a spacing of about ¼ or more of the wavelength used.
Since the image of the current vector is created in 3,
Electromagnetic waves are emitted in the target direction on the radiating element 7 side.

The target direction has the following meaning and will be described below with reference to FIGS. 6, 7 and 8.
Now, assuming that the planar antenna 1 of the present embodiment is installed horizontally, as shown in FIG. 6, the current vector 25 generated in the radiating element 7 and the image current vector 26 of the opposite phase formed via the ground plane 13 are combined. Thus, the directivity of the antenna 1 is formed. Therefore, when d in FIG. 6, that is, when the distance between the radiating element 7 and the ground plane 13 is electrically set to ¼ of the used wavelength, the synthetic electromagnetic wave is radiated right above.

However, the angle θ of the radiation direction of the electromagnetic wave can be changed by further increasing the d. Regarding the relationship between d and θ, the following relational expression holds when the used wavelength of high frequency is λ. 2dcos θ = λ / 2 Therefore, the value of d for obtaining the desired radiation angle θ can be determined.

FIG. 7 shows an outline of the directivity thus obtained, and 27 in the figure shows the maximum value in the target direction. Further, as can be seen from the figure, this is omnidirectional in the horizontal plane and has the same directivity in any direction, and therefore, an antenna compatible with communication and broadcasting can be obtained without tracking the satellite.

FIG. 8 is a diagram showing an example of the usage situation,
Reference numeral 30 indicates communication and broadcasting satellites, and reference numerals 31 and 32 indicate moving bodies such as automobiles and ships.

Note that the technique of the present invention is not limited to the technique in the above-described embodiment, and may be implemented by means of another aspect having the same function, and the technique of the present invention can be variously modified within the scope of the above configuration. Can be changed or added.

[0024]

As is clear from the above description, according to the planar antenna of the present invention, the directivity of the planar antenna is omnidirectional in the horizontal plane, and the elevation angle in the directivity direction of the vertical plane is changed. And is extremely useful as a non-tracking antenna for mobile units for communication using satellites or broadcasting. Moreover, the frequency characteristic can have a wide band property that can cover an octave.

Further, since the radiating element can be a microstrip, it can be made lighter, thinner and smaller than the conventional antenna, and even if it is mounted on a moving body, physically,
It is possible to provide an antenna that is convenient in appearance.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of a planar antenna of the present invention, FIG. 1 (A) is a side view of the antenna, and FIG. 1 (B) is a front view thereof.

FIG. 2 is an enlarged view of a radiation portion of the planar antenna of FIG. 1B, and is a cross-sectional view taken along the line II-II in FIG.

3 is a vertical cross-sectional view of the planar antenna of FIG.

4A and 4B are explanatory diagrams of a design method for determining a design dimension of a radiating element, FIG. 4A is an overall explanatory diagram, and FIG. 4B is an enlarged explanatory diagram of a central portion thereof.

FIG. 5 is an explanatory diagram of an operating principle of a radiating element.

FIG. 6 is a diagram illustrating the principle of forming an inverted cone-shaped beam pattern.

FIG. 7 is a directivity diagram showing an example of a planar antenna of the present embodiment and an inverted conical beam pattern thereof.

FIG. 8 is a diagram showing an example of a usage situation of the planar antenna of the present embodiment.

FIG. 9 is an example of a case where the radiating element is a polygonal spiral and is an enlarged view of a central portion thereof.

10 is a schematic view showing a conventional mobile communication antenna using an artificial satellite, FIG. 10 (A) is a plan view, and FIG.
(B) is the front view.

[Explanation of symbols]

1 plane antenna 3 radiating part 7 radiating element 7a, 7b spiral conductor 9 microstrip substrate 11a, 11b feeding end 13 base plate 21 radial line D ₁ , D ₂ , D ₃ , D ₄ spacing

Claims (2)

[Claims] 1. A radiating element and a ground plane, wherein the radiating element is formed by a pair of conductor wires or a microstrip conductor, which are arranged in a substantially flat plane, to form a spiral or a plurality of spirals. , A structure in which power is supplied from the central portion, and adjacent winding intervals in one radial direction of each vortex winding are in a logarithmic periodic relationship, and the outermost circumference of the vortex winding is approximately equal to the longest wavelength used. And the innermost circumference is formed to be approximately equal to the shortest wavelength used, and the ground plane is disposed behind the radiating element at an electrical distance of 1/4 or more of the shortest wavelength used. Is a planar antenna. 2. A radiating element and a ground plane, said radiating element forming a single or a plurality of polygonal spirals made of a pair of conductor lines or microstrip conductors arranged in a substantially plane. In addition, the structure is such that power is supplied from the center of the coil, and adjacent winding intervals in one radial direction of each spiral winding have a logarithmic periodic relationship. The wavelength is substantially equal to the innermost circumference, and the innermost circumference is formed to be substantially equal to the shortest wavelength used, and the ground plane is arranged on the rear side of the radiating element at an electrical distance of 1/4 or more of the shortest wavelength used. A flat antenna characterized by being installed.