JPS5883401A - Antenna - Google Patents

Abstract

PURPOSE:To realize an antenna variable for beam direction with a simple constitution, by combining two antennas orthogonal to each other having the directivity resembling the opened wings of a butterfly. CONSTITUTION:Reception outputs of antennas 31, 32 orthogonal to each other having the directivity resembling the opened wings of a butterfly are inputted to a synthesizer 36 and phase inverters 37, 38 via distributors 33 and 34. The output of the synthesizer 36 is nondirectional and given to a synthesizer 41. The phase inverters 37, 38 are controlled with a switching controller 39 to invert or noninvert the phase of signals from each antenna. A signal synthesizer 40 selects or synthesizes the signals from the inverters 37, 38 under the control of the switching controller 39. The synthesizer 41 synthesizes the signal from the synthesizer 40 and the nondirectional output from the synthesizer 36. Thus, the direction of beam of a cardioid synthesized output of the synthesizer 41 can be changed into eight kinds.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an antenna that can be easily rotated in a beam direction.

Generally, a unidirectional antenna is used to transmit and receive radio waves using an antenna. At this time, in order to obtain the maximum transmission and reception level, the unidirectional antenna beam direction must be directed toward the radio wave arrival direction or the desired transmission direction (hereinafter referred to as the desired direction), and if the reception point or transmission point moves It is necessary to successively orient the μ direction of the antenna beam correctly in the desired direction.

There are two ways to rotate the direction of the antenna beam in the desired direction: mechanically rotating a unidirectional antenna, or electrically rotating the beam direction as in a phased array antenna. However, the disadvantage is that the device is complicated. It is also possible to use an omnidirectional antenna when the desired direction of the antenna beam needs to be changed, but this is likely to cause a decrease in antenna gain and problems with multipath, especially during reception.
There is also the problem that the front-to-back ratio, so-called front-back ratio, cannot be maintained sufficiently.

Traditionally, the front and back directions are in opposite phase with the omnidirectional antenna8.
It is well known that cardioid directivity can be synthesized by combining shape-shaped directional antennas.

An example of this type of antenna is shown in Fig. 1. In Fig. 1, 1 and 2 are typical vertical monoball antennas.

12 is a loop antenna, which is a typical figure-8 directional antenna. Further, 13 indicates a synthesizer. In the case of such a combination antenna, the directivity of the vertical antenna in the horizontal plane is as shown in Figure 2, 21, and the directivity of the loop antenna in the horizontal plane is as shown in 22, so the combined directivity is 2 It becomes a cardioid pattern as shown in Figure 23.

This combination of vertical antenna and loop antenna is used for direction finding, but in this case, to rotate the beam direction of the composite antenna, the loop antenna is mechanically rotated to change the beam direction of the composite pattern. .

Therefore, even in the case of such a composite antenna, a mechanical rotation mechanism is required for K in order to rotate the beam direction, and the device is complicated.

Therefore, it is possible to prepare a number of 8-shaped directional antennas and combine them with other omnidirectional antennas to obtain a cardioid composite pattern in the desired direction, but in this case, the number of desired directions or their phases may be reversed. Even considering this, half the number of antennas would be required.

The present invention relates to an antenna that can electrically rotate the beam direction and eliminates the complexity of the conventional synthetic antenna as described above.
Connect a phase shifter to one side of the distribution terminal of one antenna of two figure-8 directional antennas connected to a divider, and combine the output of the phase shifter with the output of one side of the distribution terminal of the other antenna to perform omnidirectional synthesis. antenna, and further combine the outputs of the remaining terminals of the two-way splitter connected to the above two antennas, or use one of them selectively alone to form a figure-8 directional antenna, and this figure-8 shape By further combining the directional antenna and the omnidirectional composite antenna, an antenna with cardioid directivity can be obtained, and by selectively switching the composite or single figure-8 directional antenna, the direction of the cardioid beam can be changed. It has the feature of being rotatable.

The present invention will be explained below with reference to the drawings. FIG. 3 shows an embodiment of the present invention, in which 31 and 82 are antennas each having a figure-of-eight directivity orthogonal to each other.

38.84 each has 2 dividers, 85 has a phase shifter, and 3
6 is a synthesizer, 87.38 is a phase inverter, 39 is a switching controller, 40 is a selection synthesizer, and 41 is a synthesizer.

The 2-divider 88.84 divides the output of the antenna 31 or 82 into 2
A phase shifter 3''5 is inserted into one side of each output, and the outputs are combined by a combiner 36.The phase shifter 85 is used to make the mutual phases different by 7 in the combiner 36. Since the antennas 81 and 32 are originally spatially orthogonal, the principle is the same as that of a super turns snail antenna, and the output of the combiner 86 becomes omnidirectional.Next, another output of the two-way divider 8184 is phase-inverted. The switching controller 39 controls whether phase inversion is performed or the signal is passed through without phase inversion. I did 3
The outputs of 7.88 are combined by the selection combiner 40, but in this case either one of the outputs is selected under the control of the switching controller 39, or both outputs are combined to form a single output. The output of the selective synthesizer 40 is combined with the output having an omnidirectional pattern of the synthesizer 36, but in order to obtain a cardioid turn, the output level of the selective synthesizer 40 and the synthesizer 36 are combined. It is necessary to match the output levels of 36 degrees, and it is necessary to insert an attenuator or amplifier (not shown) into either one of them for adjustment. It is also necessary that this attenuator or amplifier be linked with a switching controller so as to be able to adjust the difference in output level when either one or the combination of figure-8 antennas is selected.

By doing the above, the outputs of the phase inverters 37 and 38 are divided into two types, and therefore the output of the selection combiner is 37.
Considering the case where the side and side 38 are selected individually or in combination, it is possible to change them into eight types in total, and accordingly, the beam direction of the cardioid type combined output of the combiner 41 can also be changed into eight types.

In the above embodiment, a phase inverter 37.88 was inserted to make it possible to select whether to pass the phase as is or to invert it, but eight different directions of the cardioid beam are required. If not, this phase inverter 87.3
8 may be omitted.

However, in that case, the beam direction can be changed only in three directions because the beam direction is changed by single selection or combination selection by the selection combiner 40.

Further, in the embodiment shown in FIG. 3, the phase inverter is inserted on the side of the figure-8 directional antenna, but it is also conceivable to connect it to the omnidirectional antenna side of the combiner 86 as shown in FIG. In this way, compared to the case of Fig. 8, the phase inverter will be 1
It has the advantage of requiring only one piece. In this case, there are four types of changes in the beam direction of the cardioid type combined output.

As described above, according to the antenna of the present invention, an antenna can be obtained by combining two figure-8-shaped directional antennas that are orthogonal to each other, and there is no need for a mechanically large driving mechanism for changing the desired direction of the antenna. It has great advantages.

[Brief explanation of drawings]

FIG. 1 shows an example of a combination of a vertical monoball antenna and a loop antenna, FIG. 2 shows a combination pattern thereof, and FIGS. 8 and 4 show configuration diagrams of embodiments of the present invention. In the figure, 81 and 82 are antennas with eight-shaped directivity that are orthogonal to each other, and 88 and 34 are two antennas.
85 is a phase shifter, 86 is a combiner, 37.88 is a phase inverter, 39 is a switching controller, 40 is a selection combiner, 4
1 indicates a synthesizer. Agent: Patent Attorney Satoshi Kamiyo 9 10 7'r 2nd A: Figure 3 Antenna Output Tosen

Claims (1)

[Claims] (1) A phase shifter is connected to one side of the distribution terminal of one antenna of two figure-8 directional antennas arranged orthogonally to each other and each has a 2-divider connected to its output end, and its output is connected to the distribution terminal of the other antenna. to form an omnidirectional composite antenna, and further combine the outputs of the remaining terminals of the two-way splitter connected to the two antennas, or selectively select one of them alone. This figure-8-shaped directional antenna and the above non-directional composite antenna are further combined to form an antenna with cardioid-type directivity, and the composite or individual figure-8-shaped directional antenna is used. An antenna characterized in that the direction of an upward cardioid beam can be rotated by selectively switching the antenna.