JP3328494B2 - Phase control array antenna - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna used in a portable radio, and more particularly to an array antenna having a plurality of elements mounted on a portable radio in a frequency band of 2 GHz or more.

[0002]

2. Description of the Related Art In recent years, portable radios, such as cellular telephones in the 900 MHz band, have rapidly become widespread with the expansion of service areas, lower prices of apparatuses, and lowering of call costs. However, there are many situations where the radio wave level from the base station is low, and the call quality is not always good. These problems can be compensated if the antenna directivity can be changed arbitrarily. That is, if the directivity of the antenna can always be controlled by the transmission / reception circuit so as to have the maximum gain in the radio wave arrival direction, the communication quality can be improved. The present invention is based on the above-mentioned idea.
In a portable radio device in the GHz band, by controlling the phases of a plurality of antenna elements, the antenna directivity and gain are improved, and a phase control array antenna capable of always performing communication with optimal transmission / reception sensitivity is provided. Is what you do.

Hereinafter, an antenna of a conventional portable radio will be described with reference to the drawings. Figure 1 shows a conventional 900M
FIG. 1 is a schematic diagram of a portable wireless device in the Hz band, 1 is an external antenna such as a whip antenna that can be housed inside a housing 12, 2 is a built-in antenna provided inside the housing, 3 is an external antenna 1. And an antenna switch for switching the connection between the antenna and the built-in antenna 2. Reference numeral 4 denotes a transmission / reception circuit.

[0004] The operation of the antenna of the conventional portable radio device configured as described above will be briefly described below.
In ordinary wireless communication, when waiting for an incoming call with the external antenna 1 housed in the housing, or when the received electric field level is strong and good communication is possible even with the built-in antenna 2, FIG.
As shown in (1), the built-in antenna 2 and the transmission / reception circuit 4 are connected by the antenna changeover switch 3 to perform communication.

[0005] When transmitting from a carrier, the external antenna 1 is pulled out of the housing 12 and the antenna changeover switch 3 is connected to the external antenna 1 to perform communication. In addition, the reception levels of both the external antenna 1 and the built-in antenna 2 are compared, and the optimum one is selected.

[0006]

However, in a conventional portable wireless device of the 900 MHz band or the 1.5 GHz band, the external antenna 1 is housed in a housing, and when the built-in antenna is in operation, the external antenna 1 is placed in a standby state such as a pocket or bag. The reception characteristics may be poor when the device is placed in a desk or placed on a desk, and even during transmission, the portable radio is generally used at an arbitrary angle. Therefore, there is a problem that the transmission characteristics are not always optimal.

SUMMARY OF THE INVENTION An object of the present invention has been made in view of the fact that an antenna does not always maintain optimum transmission / reception characteristics under various circumstances which are problems of the related art. Control for a portable wireless device in a band, which can electrically control the phase of the signal fed to each antenna by a plurality of antenna elements and always have the optimal antenna directivity and gain corresponding to the direction of arrival of radio waves An object of the present invention is to provide an array antenna.

[0008]

A phase control array antenna for a portable radio according to the present invention comprises a plurality of antenna elements provided on one surface outside a housing of the portable radio, and a plurality of antenna elements. A plurality of phase shifters connected to each,
The received electric field strength of each of the plurality of antenna elements is represented by X
・ Each vertical and horizontal deviation of three planes based on each direction of YZ
A transmission / reception circuit that detects the direction of arrival of the radio wave by detecting from the correspondence relationship with the wave component characteristic, such that the gain of the plurality of antenna elements is maximized corresponding to the direction of arrival of the radio wave determined by the transmission / reception circuit. And a controller for controlling the phases of the plurality of phase shifters, respectively.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The basic circuit configuration of the present invention will be described below with reference to the drawings. FIG. 2 is a configuration diagram showing a basic configuration of the present invention. In FIG. 2, 5A surrounded by a broken line
NT1, ANT2,... ANTn are antenna elements, respectively, and are arranged with an element interval d therebetween. [Phi ₁ of 6 surrounded by the broken line, Φ _2, ..., the [Phi _n, a plurality of antenna elements ANT1, ANT2, a phase shifter which is connected to ... each ANTn. The phase shifter 6 corrects the phase delay and adjusts the phase according to the distance d between the antenna elements, and is electrically controlled by the controller 9.

Reference numeral 7 denotes a transmission / reception signal distributor / combiner.
For example, it is constituted by a strip line or the like, and is connected to the transmission / reception circuit 8 to distribute and combine power evenly. In addition, in the transmission / reception circuit 8, in addition to processing of transmission / reception signals, X ·
Vertical and horizontal polarization components of three planes based on each direction of YZ
There is a table of minute characteristics, and correspondence with this table
The reception electric field level is detected from the relationship, the arrival direction of the electric wave based on the state where the portable wireless device housing 12 is placed is determined from the maximum level, and a signal is sent to the controller 9. Controller 9
The directivity of the antenna 5 to the normal by controlling the phase of the phase shifter 6 in response to the arrival direction of the determined radio wave,
The gain can be kept optimal.

Next, FIG. 3 shows an external front view of the simplest configuration using two antenna elements in the embodiment of the present invention. In the figure, 13 and 14 are external antennas, for example,
A metal conductor having a diameter of about 2 mm is used as a core wire and fixed with a resin cover. In this embodiment, the two external antennas 13 and 14 are arranged parallel to the upper surface of the portable radio housing 12 at a fixed interval d (approximately の of the wavelength λ), and there is no built-in antenna. The length of the external antennas 13 and 14 is about one eighth of the wavelength λ. For example, in the case of 2 GHz, the length of the two external antennas 13 and 14 is about 25 mm and the distance d
Is about 50 mm.

FIG. 4 is a circuit block diagram of the embodiment of FIG. 3 of the present invention. In the figure, 13 and 14 are external antennas,
15 is a phase shifter, 16 is a distributor / synthesizer, 17 is a transmission / reception circuit,
18 is a controller. In this embodiment, the antenna element is 2
Therefore, only one of them is provided with the phase shifter 15. Next, in this embodiment, in each of the X, Y, and Z directions,
The measured characteristics of the relationship between the phase difference and the antenna maximum gain in three planes based on the three planes are shown in FIGS. FIG. 5 shows the characteristics when the portable radio is upright (XY plane), and FIG. 6 shows the characteristics when the radio is flattened (YZ plane). Also,
Figure 7 shows the characteristics when the radios sideways (Z- X plane). The horizontal axis of these FIGS. 5 to 7 is two external antennas 1.
The vertical axis represents the antenna gain, which represents the phase difference between the excitation currents 3 and 14. The characteristics of the solid line show the characteristics of the vertical polarization component at 1.9 GHz, and the characteristics of the broken line show the characteristics of the horizontal polarization component. From these figures, it can be seen that the excitations of the two antenna elements are in-phase (phase difference 0degr) both when the portable wireless device casing 12 is upright (XY plane) and when the portable wireless device casing 12 is lying down (YZ plane).
ess), it can be seen that the antenna gain is maximum and thus optimal. Similarly, when the portable wireless device housing 12 is turned over (ZX plane), the antenna gain becomes maximum when the phase difference is set to 180 degrees.

[0013] FIG. 8 is a comparison of the antenna directivity of the conventional one antenna element and the embodiment in portable radio housing 12 is Hira倒 <br/> to the state (Y-Z plane) FIG. From this figure, it can be seen that the present embodiment shown by the broken line has improved both the maximum gain and the average gain by about 5 dB over the conventional one shown by the solid line. These effects apply to the entire space, and are achieved by detecting the direction of arrival of the radio wave by the transmission / reception circuit 17 and controlling the phase so that the antenna directivity is oriented in that direction.

In the above embodiment, the case where the antenna element is two external antennas has been described. However, the same effect can be obtained when a plurality of external antenna elements are used. It is clear that the same effect can be obtained by applying a combination of a plurality of external antenna elements and a built-in antenna element.

[0015]

As described above, by practicing the present invention, the optimum antenna directivity and gain can always be maintained corresponding to the direction of arrival of radio waves, so that the effect is extremely large in practical use.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a conventional portable wireless device.

FIG. 2 is a diagram illustrating an example of a basic circuit configuration according to the present invention.

FIG. 3 is an external front view of one embodiment of the present invention.

FIG. 4 is a circuit configuration diagram of the embodiment of FIG. 4 of the present invention.

FIG. 5 is a diagram showing the X of the portable wireless device in the embodiment of FIG. 4 of the present invention;
-The relationship between the phase difference on the Y plane and the antenna maximum gain.

FIG. 6 is a diagram illustrating a portable wireless device according to the embodiment of FIG. 4 according to the present invention;
-The relationship between the phase difference on the Z plane and the antenna maximum gain.

FIG. 7 shows the Z of the portable wireless device in the embodiment of FIG. 4 of the present invention.
-The relationship between the phase difference on the Y plane and the antenna maximum gain.

FIG. 8 shows a comparison of antenna directivity between a single conventional antenna element and the present embodiment in a state where the portable wireless device housing 12 is flattened (YZ plane).

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 external antenna 2 built-in antenna 3 antenna switch 4 transmission / reception circuit 5 plural antenna elements 6 plural phase shifters 7 distributor / combiner 8 transmission / reception circuit 9 controller 12 portable radio housing 13, 14 external antenna 15 phase shifter 16 Distributor / combiner 17 Transmitter / receiver circuit 18 Controller

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Kinami Sasaki 3-14-20 Higashinakano, Nakano-ku, Tokyo International Electric Company (56) References JP-A-52-102610 (JP, A) JP-A 63-208306 (JP, A) JP-A 5-31386 (JP, U) JP-A 1-162913 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01Q 3 / 00-3/46 H01Q 21/00-21/30 H01Q 23/00

Claims (2)

(57) [Claims] A plurality of antenna elements provided on one outer surface of a housing of the portable wireless device; a plurality of phase shifters connected to each of the plurality of antenna elements; Each received electric field strength in X, Y, Z directions
With vertical and horizontal polarization component characteristics of three planes based on
And a transmission / reception circuit for detecting the direction of arrival of the radio wave by detecting from the response, the plurality of phase shifts so that the gain of the plurality of antenna elements is maximized corresponding to the direction of arrival of the radio wave determined by the transmission / reception circuit A phase control array antenna comprising a controller for controlling the phase of each device. 2. The plurality of antenna elements are linear antennas whose lengths are set to ８ of the wavelength of the operating frequency, and the mutual installation interval of the plurality of antenna elements is the wavelength of the operating frequency. 2. The array according to claim 1, wherein the array is set to 1/4 of
2. The phase control array antenna according to 1.