JPH08167807A - Diversity antenna system for mobile object communication - Google Patents

Abstract

PURPOSE: To attain fine diversity control by comparatively simple constitution by arraying three antenna elements like an equilateral triangle. CONSTITUTION: Three antenna elements 1 to 3 are arrayed on the vertexes of an equilateral triangle mutually with an interval of half wavelength. A phase shift control parat 4 is arranged on feeding routes for the elements 1 to 3. The control part 4 selects two elements out of the three elements 1 to 3 and applies phase-shifted feed with an optional phase difference to the two selected elements. At the time of receiving, the control part 4 receives receiving signals from the two elements with a phase difference. In addition, the control part 4 executes feed control by inverting the phase difference between the two antenna elements. Consequently six directional patterns in total can be obtained from the control part 4. A feed control part 6 controls transmitting/receiving operation based upon a compared result signal from a comparator circuit 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diversity type antenna for mobile communication which prevents deterioration of communication quality due to multipath fading or the like.

[0002]

2. Description of the Related Art Antennas used for mobile communication are
An antenna that uses two antenna elements to perform space diversity, polarization diversity, and the like is used to reduce multipath fading and to cope with changes in the radio environment due to movement. In addition, a beam tilt antenna or the like that controls the directivity by increasing the number of antenna elements to perform phase-shift power feeding is also used.

[0003]

However, in the methods such as the spatial diversity by the two elements or the directional diversity by the directivity combination as described above, the diversity is used in the indoor or outdoor skyscrapers with large multipath fading. There was a drawback that there were too few choices to expect an effect and we could not handle it.

Further, in order to increase the control options, the number of antenna elements must be increased, and there is a drawback that the antenna device as a whole must be made huge.

An object of the present invention is to provide a diversity antenna device which can obtain an effective diversity effect by various options of control with a compact structure without significantly increasing the number of antenna elements.

[0006]

According to the first invention (claim 1) of the present application, a plurality of antenna elements, a comparison device for comparing the received power from each antenna element, a power feeding power of each element, a power feeding A diversity type antenna device for mobile communication, comprising: a power feeding control device for controlling a phase shift;
By using a triangular array in which one antenna element is arranged at each apex of an equilateral triangle, it is possible to reduce the array configuration of three elements and to relatively simplify the power feeding circuit configuration when performing phase shift power feeding. Become.

In the second invention (claim 3) of the present application, the space diversity is performed by the three antenna elements arranged in the above-mentioned equilateral triangle, so that the volume of the entire antenna is not extremely increased and the multipath It becomes possible to perform more precise diversity control with respect to deterioration of communication quality and communication speed due to fading or the like.

In the third invention (claim 3) of the present application, since the element array is an equilateral triangle when performing phase-shift feeding using two of the above-mentioned three antenna elements, it is comparatively possible. It is possible to obtain a total of 6 directivities from the combination of the selected two elements and the inversion of the feeding phase, despite the small-scale configuration. It is possible to perform diverse diversity control.

In the fourth invention (claim 4) of the present application, it is possible to obtain a plurality of directivities by performing phase-shift feeding to the above-mentioned three antenna elements and changing the value of the given phase difference. Particularly, by combining with the above-described third and fourth inventions, it becomes possible to perform more detailed diversity control.

[0010]

1 is a block diagram showing the configuration of an embodiment of the present invention.

In this embodiment, the three antenna elements 1 to 3 are, for example, dipole antennas,
As shown by the broken lines in the figure, they are arranged at the vertices of equilateral triangles. Further, the antenna elements 1 to 3 are arranged with an interval of a half wavelength (λ / 2).

Further, a phase shift control section 4 is provided in the feeding paths of these antenna elements 1 to 3. The phase shift control unit 4 selects any two elements from the antenna elements 1 to 3 and performs phase shift power feeding on the selected two elements with an arbitrary phase difference (for example, 120 °). ing. That is, at the time of transmission, with respect to the power supply signals to the two antenna elements, by means such as a capacitor or a coil,
Power is supplied with the phase difference, and at the time of reception, the received signals from the two antenna elements are received with the phase difference.

Further, the phase shift controller 4 inverts the phase difference between the two antenna elements to control power feeding. As a result, it is possible to obtain a total of six directivity patterns from the combination of the selected two elements and the inversion of the feeding phase from the phase shift control unit 4, and the received signals according to each directivity pattern are output to the subsequent stage. Is output to the comparison circuit 5.

The comparison circuit 5 compares the six reception signals from the phase shift control section 4 based on the six directivity patterns, and notifies the power supply control device 6 of a comparison result signal indicating the best reception state.

The power supply control device 6 judges the optimum directivity pattern based on the comparison result signal from the comparison circuit 5,
Control is performed so that transmission / reception operation is performed using the phase difference with the corresponding antenna element.

As described above, the selection of the directivity pattern is performed based on the received signal at the time of reception. Based on the directivity pattern determined at the time of reception, a common directivity pattern is also used at the time of transmission. It is used for transmission.

However, when the transmission is performed for the first time, it is not possible to determine the directivity pattern by the received signal at that time. Therefore, for example, the transmission is performed using one predetermined directivity pattern, Alternatively, the transmission is performed in the state without directivity, and the directivity pattern as described above is selected in the subsequent receiving operation.

2 to 4 (a) to 4 (f) are explanatory views showing models of directivity patterns obtained when two-element phase-shift power feeding is performed in a diversity antenna for a mobile body using a dipole antenna as described above. It is a figure.

As described above, in this example, power is fed with an element spacing of a half wavelength and a phase difference of 120 ° so that each directivity pattern has two maximum gain directions and two null points. It has a direction.

By selecting two elements from the three elements, three types of pattern orientations can be obtained, and by feeding each of them in opposite phases, a total of six directivities can be obtained.

Therefore, by comparing these directivity patterns and switching the directivity patterns, fine diversity control is possible.

The above-mentioned embodiment is the first aspect of the present invention.
Although the description will be centered on the items 1 and 3, it is possible to similarly implement the other claims by using the configuration and the control method disclosed in this embodiment.

That is, it is possible to perform the space diversity according to claim 2 by individually comparing the received powers of the antenna elements 1 to 3 in the comparison circuit 5 and selecting the one having the highest sensitivity. In addition, for the three antenna elements, phase-shift feeding control is performed with a plurality of types of phase differences,
The control of claim 4 is obtained by selecting the most efficient directivity pattern.

Further, by combining these with the control of the above-mentioned embodiment, it is possible to obtain a wider variety of choices of directivity patterns, and it is possible to perform diversity control adaptable to various radio wave environments.

[0025]

As described above, according to the present invention,
By arranging the three antenna elements in an equilateral triangle,
With a relatively simple configuration, it is possible to have many directivities, so without enlarging the antenna configuration,
It becomes possible to perform more detailed diversity control.

[Brief description of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an example of a directivity pattern in the above embodiment.

FIG. 3 is an explanatory diagram showing an example of a directivity pattern in the above embodiment.

FIG. 4 is an explanatory diagram showing an example of a directivity pattern in the above embodiment.

[Explanation of symbols]

 1 to 3 ... Antenna element, 4 ... Phase shift control section, 5 ... Comparison circuit, 6 ... Feeding control device.

Claims (4)

[Claims] 1. A diversity system for mobile communication, comprising: a plurality of antenna elements; a comparison device for comparing received power from each antenna element; and a power feeding control device for controlling power feeding power of each element and power feeding phase shift. An antenna device, wherein a triangular array in which three antenna elements are arranged at respective vertices of an equilateral triangle is used. 2. The diversity antenna device according to claim 1, wherein spatial diversity is performed by selecting and using one of the three antenna elements having the highest sensitivity by the comparison device. 3. The directivity in a desired direction according to claim 1, wherein any two elements of the three antenna elements are used to perform phase-shift power feeding with an arbitrary phase difference by the power feeding control device. A diversity antenna device, characterized in that, while obtaining a pattern, received power of each directivity pattern based on the combination of the elements is compared by the comparison device, and the most efficient directivity pattern is selected. 4. The power feeding control device according to claim 1, wherein the power feeding control device feeds phase shift power to the three antenna elements with an arbitrary phase difference to obtain a directivity pattern in a desired direction. A diversity antenna device, characterized in that received power of each directivity pattern based on the phase difference is compared by the comparison device and the most efficient directivity pattern is selected.