JPH0441602Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an antenna sharing device that combines input radio waves of frequencies ₁ and ₂ and outputs the synthesized signal to the antenna side.

[Prior Art] Conventionally, when combining input radio waves of frequencies _{1 and 2} , an antenna sharing device as shown in FIG. 2 has been used. In this antenna sharing device, first, second, third, and fourth ports 3a, 3
It is equipped with a 3 dB directional coupler 3 having frequencies ₁ , 3 c, and 3 _d .
A non-reflection terminator 4 that absorbs the synthesized wave is connected to the third port 3c to which the obtained synthesized wave is output, and the obtained synthesized wave is output. The antenna 5 was connected to the fourth port 3d.

In such an antenna sharing device, the frequency input to the first and second ports 3a and 3b
The radio waves ₁ and ₂ are combined by a 3 dB directional coupler 3, and the resulting combined wave is output to a non-reflection terminator 4 and an antenna 5. The composite wave input to the non-reflection terminator 4 is
It is absorbed by the non-reflection terminator 4. The composite wave input to the antenna 5 is radiated into the air by the antenna 5.

At this time, as is well known, intermodulation waves (hereinafter referred to as IM waves) are generated by the film resistance of the non-reflection terminator 4 and the like.

When this IM wave leaks into the antenna 5 via the 3 dB directional coupler 3, it becomes noise and interferes with communication.

The IM wave _o ' (n is the order) generated in the case of two _- wave synthesis is ₃ '= _21-2 , ₅ '= _{31-22 ...}

Conventionally, in order to suppress IM waves generated in the non-reflection terminator 4, the non-reflection terminator 4 is used as shown in FIG.
A method has been adopted in which a high-loss cable 6 is attached to the front stage of the high-loss cable 6, and the IM wave generated by the non-reflection terminator 4 is attenuated by the high-loss cable 6.

[Problems to be solved by the invention] However, when the high-loss cable 6 is used, it is necessary to make it long in order to attenuate the IM waves, and there is a problem that the cable becomes large. Further, when the applied power becomes high, it is necessary to coat the high-loss cable 6 with oil to cool it, resulting in a problem that the cable becomes larger and more expensive.

The purpose of this invention is to suppress the increase in size as much as possible.
An object of the present invention is to provide an antenna sharing device equipped with a non-reflection terminator that can attenuate IM waves.

[Means for Solving the Problems] To explain the configuration of the present invention to achieve the above object, the present invention includes a 3dB directional coupler having first, second, third, and fourth ports. The third port is configured to combine radio waves of frequencies ₁ and ₂ inputted to the first and second ports using the 3 dB directional coupler to form a composite wave, and output the resulting composite wave. A non-reflection terminator that absorbs the composite wave is connected to the fourth port, and the fourth port outputs the resulting composite wave.
In an antenna sharing device in which an antenna is connected to a port of the device, the non-reflection terminator reflects an IM wave generated at the non-reflection termination between its input terminal and the non-reflection termination. The present invention is characterized in that it is provided with a bandpass filter section for filtering the signal and returning it to the non-reflection terminator.

[Function] In this way, as a non-reflection terminator connected to the third port of the 3dB directional coupler, between the input terminal and the non-reflection terminator, there is a
If a structure is used in which a bandpass filter section is provided that reflects the IM wave and returns it to the non-reflection terminator, the IM wave generated at the non-reflection terminator will be reflected by the bandpass filter section. The light then returns to the non-reflection termination and is absorbed.

In addition, in such antenna sharing equipment, 3dB
There is no need to connect a high-loss cable between the directional coupler and the non-reflection terminator, and the antenna sharing device can be made smaller and less expensive.

[Embodiment] Hereinafter, an embodiment of the antenna sharing device according to the present invention will be described in detail with reference to the drawings.

The overall configuration of the antenna sharing device of this embodiment is as follows:
This is similar to the antenna sharing device shown in FIG. In the antenna sharing device of this embodiment, the 3dB directional coupler 3
As the non-reflection terminator 4 connected to the third port 3c of the device, a structure shown in FIG. 1 is used.

The non-reflection terminator 4 is configured between its input terminal 7 and the non-reflection termination 8 to generate a signal at the non-reflection termination 8.
The structure includes a bandpass filter section 9 that reflects the IM wave and returns it to the non-reflection termination section 8.

The input terminal 7 has an outer conductor portion 7A and a center conductor portion 7.
It has a coaxial structure with B.

In the non-reflection termination section 8, a film resistor section 8B is provided at the center of the case 8A with one end fixed to the inner wall of the case 8A, and a center conductor terminal 8C is connected to the other end of the film resistor section 8B. The center conductor terminal 8C is led out of the case 8A via an insulator 8D, and a heat radiation fin 8E is protruded from the outside of the case 8A.

In the bandpass filter section 9, a plurality of resonant rods 9B are cantilever-supported and provided in multiple stages from the inlet to the outlet on one side of the case 9A, and these resonant rods 9
Corresponding to B, screw-shaped adjustment elements 9C are provided on the other surface of the case 9A, and each adjustment element 9
C is provided with a stator 9D made of a nut for fixing at the adjusted position, and an input/output loop 9E connecting the center conductor part 7B of the input terminal 7 and the resonance rod 9B at the input end and the input/output loop 9E at the entrance. An insulator 9F is provided to insulate the output end from the case 9A, and an input/output loop 9G connecting the resonant rod 9B at the output end and the center conductor terminal 8C of the non-reflection termination section 8 is provided at the exit.

In such a non-reflection terminator 4, when the bandpass filter section 9 is adjusted using the adjustment element 9C so that the synthesized wave input from the input terminal 7 passes, the synthesized wave passes through the bandpass filter section 9. The heat is converted into heat and absorbed by the film resistance section 8B of the non-reflection termination section 8. At this time, even if an IM wave is generated from the film resistor section 8B, the IM wave is reflected by the bandpass filter section 9 toward the non-reflection termination section 8 and is consumed again by the film resistor section 8B. As described above, according to the present invention, the IM wave can be confined within the non-reflection termination section 8. Further, by increasing the loss of the bandpass filter section 9, the IM wave generated at the non-reflection termination section 8 can be suppressed. In this way, since the amount of attenuation of the IM wave level can be set by changing the number of stages of the bandpass filter section 9, the non-reflection terminator 4 can be extremely miniaturized, and the amount of attenuation can be easily set.

[Effect of the invention] As explained above, in the antenna sharing device according to the invention, the input terminal serves as a non-reflection terminator connected to the third port of the 3 dB directional coupler that combines radio waves of frequencies ₁ and ₂ . Since a structure is used in which a band-pass filter section is provided between the non-reflection termination section and the non-reflection termination section, which reflects the IM wave generated at the non-reflection termination section and returns it to the non-reflection termination section. The IM wave generated at the non-reflection terminal part of the non-reflection terminator can be confined and absorbed within the non-reflection terminator. In addition, with the antenna sharing device of this invention, 3dB
There is no need to connect a high-loss cable between the directional coupler and the non-reflection terminator, and the antenna sharing device can be made smaller and less expensive.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional view showing an embodiment of a non-reflection terminator used in the antenna sharing device according to the present invention;
The figure is a wiring diagram of the antenna sharing device, and FIG. 3 is a partial vertical cross-sectional view showing the connection state of a conventional non-reflection terminator and a high-loss cable. 3...3dB directional coupler, 3a...first port, 3b...second port, 3c...third port, 3d...fourth port, 4...non-reflection terminator, 5 ...Antenna, 7...Input terminal, 8...Reflection-free termination section, 9...Band-pass filter section.

Claims (1)

[Claims for utility model registration] 3dB with 1st, 2nd, 3rd, and 4th ports
A directional coupler is provided, and the radio waves of frequencies ₁ and ₂ input to the first and second ports are combined by the 3 dB directional coupler to form a composite wave, and the resulting composite wave is output. A non-reflection terminator that absorbs the synthesized wave is connected to the third port, and an antenna is connected to the fourth port from which the resulting synthesized wave is output. In the antenna sharing device, the non-reflection terminator includes a bandpass filter between its input terminal and the non-reflection terminator that reflects intermodulation waves generated at the non-reflection terminator and returns it to the non-reflection terminator. An antenna sharing device characterized by being provided with a section.