JPH11122010A - Primary radiator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a primary radiator for preventing the deterioration of NF through identical channel interference by inhibiting the reception of the radio waves of an uplink by a probe for reception. SOLUTION: The first waveguide 11 of a large diameter whose one side is opened and the second waveguide 12 of a small diameter whose first waveguide side is opened on the concentric back are arranged in a column. While a first probe 21 for the reception is arranged at a distance of 1/4 of a wavelength λd of the radio waves of a downlink from a first waveguide terminating end face 11a in the first waveguide 11, a second probe 22 terminated by a terminating resistor is arranged at a distance of 1/4 of the wavelength λu of the uplink radio waves from the terminating end face 12a of the second waveguide in the second waveguide 12. The radio waves of the downlink are received by the first probe, and the radio waves of the uplink are terminated by the second probe.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a primary radiator, and more particularly to a primary radiator for preventing NF deterioration due to an uplink radio wave transmitted from an earth station.

[0002]

2. Description of the Related Art A VSAT (Very Small A) equipped with an earth station for transmitting and receiving to and from satellites using a micro parabolic antenna.
In satellite communication systems such as (pertue Terminal), for example,
In the case of Asia / Oceania, the frequency of the radio wave (uplink) transmitted from the earth station to the satellite is fu = 14
It is determined that a frequency band of fd = 12 GHz is used for a frequency of a radio wave (downlink) transmitted from a satellite and received by an earth station using a GHz band. Conventionally, as shown in FIG. 3, a primary radiator for receiving radio waves (downlink) from this satellite has a downlink radio wave wavelength λd from a terminal surface 10a of a waveguide 10 opening on one side. The probe 20 is arranged at a distance of ４, and the signal processing board 3 for connecting the probe 20 is arranged outside the waveguide 10.
Then, as shown in FIG. 3, the signal processing board 3
An RF amplifier 3a, a band-pass filter 3b composed of a pattern on a substrate, a local oscillator 3c, a mixer 3d,
By disposing the IF amplifier 3e, the probe 2
The radio wave received at 0 is converted to an intermediate frequency and output. However, in this configuration, since the probe 20 is arranged at a distance of の of the radio wave wavelength λd of the downlink from the end face 10 a of the waveguide 10, the wavelength of the radio wave incident on the waveguide 20 The downlink radio wave of λd has the same phase as the radio wave reflected by the probe 20 at the terminal surface 1a, and can resonate and be received by the probe 20.
Although the uplink radio wave of the wavelength λh is also attenuated, it is received by the probe 2 and the difference | nfu between the integral multiple nfu of the uplink radio frequency fu and the integral multiple mfl of the oscillation frequency fl of the local oscillator 3c. −mfl | matches the intermediate frequency fIF, causing co-channel interference and deteriorating the NF of the receiving converter. Therefore, the probe 20
Attenuates the radio wave frequency fu of the uplink received in the above, but since the band-pass filter 3b is formed by a pattern on the substrate, there is a problem that there is a limit in increasing the attenuation characteristic. .

[0003]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and prevents a receiving probe from receiving an uplink radio wave, thereby reducing N-channel interference caused by co-channel interference.
It is an object of the present invention to provide a primary radiator in which deterioration of F is prevented.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention uses a VSAT (Very Small Ape) equipped with an earth station for transmitting and receiving to and from a satellite using a micro parabolic antenna.
rtue Terminal) is a receiving-only primary radiator that receives radio waves from a satellite of a satellite communication system such as a satellite communication system, and has a large-diameter first waveguide opening on one side, and A small-diameter second waveguide opening on the waveguide side is arranged in tandem, and a downlink radio wave transmitted from a satellite and received by an earth station is received by the first waveguide, and the second waveguide is received by the second waveguide. It is a primary radiator that terminates uplink radio waves transmitted from an earth station and received by a satellite.

[0005] The first waveguide is located at a boundary between the first waveguide and the second waveguide, that is, at a distance of 1/4 of the wavelength of the downlink radio wave from the end face of the first waveguide. A first probe for reception is arranged, and a second probe terminated with a terminating resistor at a distance of １ ／ of the wavelength of the uplink radio wave from the terminating surface of the second waveguide to the second waveguide. The first probe receives a downlink radio wave, and the second probe terminates an uplink radio wave.

The inner diameter of the second waveguide is set so that the cutoff frequency is higher than the frequency of the downlink radio wave and lower than the frequency of the uplink radio wave.

The first waveguide and the second waveguide are rectangular waveguides or circular waveguides.

[0008]

As described above, in the primary radiator of the present invention, a large-diameter first waveguide opening on one side, and the first waveguide side being concentric with the inside of the first waveguide. A small-diameter second waveguide that is open is arranged in tandem, a downlink radio wave transmitted from a satellite and received by an earth station is received by the first waveguide, and transmitted from an earth station by a second waveguide. By terminating the uplink radio wave received by the satellite, the uplink radio wave reflected by the second waveguide is prevented from returning to the first waveguide.

The first waveguide has a boundary between the first waveguide and the second waveguide, that is, one-fourth of the wavelength of the downlink radio wave from the terminal end surface of the first waveguide. 1st for receiving in distance
While the second waveguide is placed in the second waveguide.
1/4 of the wavelength of the radio wave of the uplink from the end face of the waveguide
The second probe terminated with a terminating resistor is placed at a distance of.
The radio wave incident on the first waveguide and the radio wave reflected on the terminal end surface of the first waveguide are in phase and resonated and received, while the radio wave on the uplink is transmitted by the second probe to the second waveguide. The radio wave incident on the terminal and the radio wave reflected by the terminal end surface of the first waveguide are in phase and resonated and received. The second probe terminates and consumes the radio wave of the uplink, and is transmitted to the first waveguide. Without returning
The first probe does not receive uplink radio waves. Also, the inner diameter of the second waveguide is set so that the cutoff frequency is higher than the frequency of the downlink radio wave and lower than the frequency of the uplink radio wave, so that the second waveguide is The radio wave is not guided, but the radio wave more than the frequency of the uplink radio wave is guided. Therefore, the radio wave of the downlink is all reflected at the terminal surface of the first waveguide, and only the radio wave of the uplink is transmitted to the second waveguide. It is guided to the wave tube and terminated and consumed by the second probe.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A primary radiator according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a side sectional view showing an embodiment of a primary radiator according to the present invention, and FIG. 2 is a block diagram showing a circuit configuration of the signal processing board. Reference numeral 11 denotes a first waveguide formed in a square or a circle, 12 denotes an opening at the back of the first waveguide 11 and is arranged concentrically in a row.
This is a second waveguide having a smaller diameter and also formed in a square or a circle. The inner diameter of the second waveguide 12 is set to a value such that the cutoff frequency is higher than the frequency of the downlink radio wave and lower than the frequency of the uplink radio wave. For example, in the case of a rectangular waveguide, the length L1 of its long side is set to a value shorter than 1/2 of the wavelength λd of the downlink radio wave and longer than 1/2 of the wavelength λu of the uplink radio wave. . The first waveguide 11 includes the first waveguide 1.
From the boundary surface between the first and second waveguides 12, that is, from the end surface 11 a of the first waveguide 1, the wavelength λd of the downlink radio wave is 1
The first probe 21 is arranged at a distance of / 4 from the terminal surface 12a of the second waveguide 12 to the second waveguide 12. The second probe 22 is arranged at a distance of. Further, a signal processing board 3 connected to the first probe 21 and the second probe 22 is disposed outside the first waveguide 11 and the second waveguide 12.

A signal processing circuit shown in FIG. 2 is arranged on the signal processing board 3. An RF amplifier 3a amplifies an RF signal from the first probe 21. A signal amplifier 3b is amplified by the RF amplifier 3a. A band-pass filter that passes a downlink radio frequency fd from the RF signal, 3c is a local oscillator, 3d is a signal of the downlink frequency fd from the band-pass filter 3b, and a local oscillation signal from the local oscillator 3c is added to the signal. Mixer for converting to frequency fIF, 3
e amplifies the IF signal from the mixer 3d and outputs it to the output terminal 3
This is an IF amplifier output from f. 3g is a terminating resistor connected between the second probe 22 and the ground.

The operation of the above configuration will now be described. Radio waves are reflected from a reflector such as a parabolic antenna (not shown) and input from an input satellite through an opening of the first waveguide. Among these radio waves, the downlink radio wave transmitted from the satellite is resonated because the incident wave from the aperture of the first probe 21 and the reflected wave reflected from the end face 11a of the first waveguide are in phase. To power the first probe 21
The signal is received and input to the RF amplifier 3a of the signal processing board 3. On the other hand, an uplink radio wave is input from the opening of the second waveguide 12, and the second probe 22 converts the incident wave from the opening and the reflected wave reflected by the terminal surface 12 a of the second waveguide 12. In phase, resonance occurs, power is supplied to the second probe 22, received, terminated by the terminating resistor 3 g of the signal processing board 3, and consumed. Therefore, the uplink radio wave does not return to the first waveguide 11, and the first probe 21 cannot receive the uplink radio wave.

The inner diameter of the second waveguide 12 is set so that the cut-off frequency fc is higher than the frequency fd of the downlink radio wave and lower than the frequency fu of the uplink radio wave. Does not guide the downlink radio wave, but guides the radio wave whose frequency is higher than the frequency fu of the uplink radio wave, so that the downlink radio wave is completely reflected by the terminal surface 11a of the first waveguide 11. Only the uplink radio waves are guided to the second waveguide 12, terminated and consumed by the second probe 22.

The downlink signal received by the first probe 21 is amplified by the RF amplifier 3a of the signal processing board 3, selected by the band-pass filter 3b, and converted to the intermediate frequency fIF by the mixer 3d. The signal is amplified by the IF amplifier 3e and an IF signal is output from the output terminal 3f.
Further, as described above, the uplink signal received by the second probe 22 is terminated and consumed by the terminating resistor 3g of the signal processing board 3.

[0015]

As described above, according to the primary radiator of the present invention, a large-diameter first waveguide having one side open,
Concentrically behind the second waveguide, a small-diameter second waveguide opening on the first waveguide side is provided.
Waveguides are arranged in tandem, the first waveguide receives downlink radio waves transmitted from a satellite and received by an earth station,
By terminating the uplink radio wave transmitted from the earth station by the waveguide and received by the satellite, the uplink radio wave reflected by the second waveguide is prevented from returning to the first waveguide. A first waveguide is provided at a boundary between the first waveguide and the second waveguide, that is, at a distance of 1/4 of a wavelength of a downlink radio wave from an end surface of the first waveguide. While one probe is arranged, a second probe terminated by a terminating resistor is arranged in the second waveguide at a distance of 1/4 of the wavelength of the radio wave of the uplink from the end surface of the second waveguide. As a result, the radio wave of the downlink becomes the same phase as the radio wave incident on the first waveguide by the first probe and the radio wave reflected at the end face of the first waveguide, resonates, and is received by the first probe. can do. On the other hand, the radio wave of the uplink is the second probe, and the radio wave incident on the second waveguide and the radio wave reflected on the terminal surface of the first waveguide are in phase and resonated and received. In this case, since the uplink radio wave is terminated and consumed, and is not returned to the first waveguide, the first probe cannot receive the uplink radio wave. Also, the inner diameter of the second waveguide is set so that the cutoff frequency is higher than the frequency of the downlink radio wave and lower than the frequency of the uplink radio wave, so that the second waveguide is The radio wave of the frequency higher than the frequency of the uplink radio wave is guided without guiding the radio wave of the uplink, so that the radio wave of the downlink is all reflected at the end face of the first waveguide and can be received by the first probe, Is guided to the second waveguide, is terminated and consumed by the second probe, and cannot be received by the first probe. Therefore, it is possible to provide a primary radiator in which the receiving probe does not receive the radio wave of the uplink and the NF is prevented from being deteriorated due to the co-channel interference.

[Brief description of the drawings]

FIG. 1A is a front view showing one embodiment of a primary radiator according to the present invention, and FIG.

FIG. 2 is a block diagram showing a signal processing circuit of a signal processing board of a primary radiator according to the present invention.

3A is a front view showing a conventional primary radiator, FIG.
(B) is a side sectional view.

FIG. 4 is a block diagram showing a signal processing circuit of a signal processing board of a conventional primary radiator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 1st waveguide 11a Termination surface 12 2nd waveguide 12a Termination surface 21 1st probe 22 2nd probe 3 Signal processing board 3a RF amplifier 3b Bandpass filter 3c Local oscillator 3d Mixer 3e IF amplifier 3f Output terminal 3g Termination resistance λd Radio wave wavelength of downlink λu Radio wave wavelength of uplink L1 Length of long side of second waveguide

Claims (5)

[Claims] 1. A VSAT (Very Small A) equipped with an earth station for transmitting and receiving to and from a satellite using an ultra-small parabolic antenna.
A primary radiator for receiving radio waves from a satellite of a satellite communication system such as a pertue terminal). The primary radiator has a large-diameter first waveguide opening on one side, and the first waveguide is concentric with the first waveguide. A small-diameter second waveguide opening on the waveguide side is arranged in tandem, and a downlink radio wave transmitted from a satellite and received by an earth station is received by the first waveguide, and the second waveguide is received by the second waveguide. A primary radiator that terminates an uplink radio wave transmitted from an earth station and received by a satellite. 2. The first waveguide has a boundary between the first waveguide and the second waveguide, that is, one-fourth of the wavelength of the radio wave of the downlink from the end face of the first waveguide. While a first probe for reception is arranged at a distance, the second waveguide is terminated with a terminating resistor at a distance of 1/4 of the wavelength of the radio wave of the uplink from a terminating surface of the second waveguide. The primary radiator according to claim 1, wherein a second probe is arranged, the first probe receives a downlink radio wave, and the second probe terminates an uplink radio wave. . 3. An internal diameter of the second waveguide is set such that a cutoff frequency is higher than a frequency of a downlink radio wave and lower than a frequency of an uplink radio wave. Primary radiator. 4. The apparatus according to claim 1, wherein said first waveguide and said second waveguide are rectangular waveguides.
Primary radiator as described. 5. The method according to claim 1, wherein the first waveguide and the second waveguide are circular waveguides.
Primary radiator as described.