JPH08250919A - Portable earth station equipment - Google Patents

Abstract

PURPOSE: To simplify the adjustment of an azimuth angle and an elevation angle of an antenna and of matching a turning angle of a plane antenna with a polarization angle of a radio wave from a communication satellite. CONSTITUTION: A turntable 720 is turned by refering to an azimuth indicated by an azimuth magnet 716 to direct a main body section 710 to the azimuth of a communication satellite. Then one end of an elevating angle adjustment bar 706 is fitted to a support member 717, and the support member 717 is stepwise slid along a slide groove 718 by refering an angle indicated by a slope meter 705 to make an elevating angle of an antenna 200 matching an elevation angle of the communication satellite. Then a polarization angle adjustment screw 703 is loosened and the antenna is moved along a guide groove 704 and then the polarization angle adjustment screw 703 is tightened. Thus, the angle of a direction of the antenna 200 perpendicular to the direction of the communication satellite matches a polarization angle of a radio wave received from the communication satellite.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an earth station in satellite communication, and more particularly to installation of a plane antenna in a portable earth station.

[0002]

2. Description of the Related Art As a portable earth station using a plane antenna, an earth station for Inmarsat service is known. The frequency band of the radio wave used in this Intel Matte Service is the L band, and the polarization is circular polarization.

Here, since the attenuation of radio waves by rain is small in the frequency band of the L band, the gain of the transmitting antenna of the earth station may be relatively small. Further, since the inter-satellite interference can be reduced by making the gain of the transmitting antenna relatively small, it is not necessary to orient the transmitting antenna strictly to the satellite. Further, when circularly polarized waves are used, it is not necessary to adjust the rotation angle of the plane antenna of the earth station to match the polarization angle. Therefore, in the earth station in Inmarsat service, the orientation of the antenna can be adjusted relatively easily.

[0004]

However, the linearly polarized K
When u-band radio waves are used, the attenuation of the radio waves is not so small that the gain of the transmitting antenna of the earth station cannot be reduced.
It is necessary to orient the transmitting antenna strictly to the satellite. Further, since the linearly polarized wave is used, it is necessary to adjust the rotation angle of the plane antenna of the earth station to match the polarization angle.

However, in the conventional portable earth station, the rotation angle of the plane antenna of the earth station cannot be adjusted. Therefore, it cannot be applied to satellite communication using linearly polarized radio waves.

Therefore, an object of the present invention is to provide a portable earth station which can be applied to satellite communication using linearly polarized radio waves. Also,

[0007]

[Means for Solving the Problems] To achieve the above object,
The present invention relates to an earth station device for transmitting and receiving radio waves to and from a satellite, the main body containing a transmission / reception circuit, a plane antenna, and a rotation direction having an axis perpendicular to an antenna surface of the plane antenna as a rotation axis. And a connecting member for connecting the planar antenna to the main body so that the planar antenna can rotate within a predetermined rotation angle range.

[0008]

According to the earth station apparatus of the present invention, the plane antenna can be rotated within the predetermined rotation angle range by the connecting member in the rotation direction about the axis perpendicular to the antenna surface as the rotation axis. As described above, since the plane antenna is connected to the main body, the rotation of the plane antenna can easily adjust the rotation angle of the plane antenna to the polarization angle. It can also be applied to satellite communications using linearly polarized radio waves.

[0009]

Embodiments of the satellite communication system according to the present invention will be described below.

FIG. 1 shows the configuration of a satellite communication system according to this embodiment.

In the figure, 101 is a communication satellite, 102 is a center station, 107 is a portable earth station, 104 is an extension telephone and 10
Reference numeral 5 is a public communication network, and 103 is a PBX connected to the public communication network 105. The PBX 103 is a private branch exchange having a plurality of extensions installed in a premises such as a business office, and accommodates a plurality of extension telephones 104 in the premises.

In such a configuration, the center station 102
Accommodates 20 extension lines of the PBX 103. Each portable earth station 107 has one extension and one that the PBX 103 accommodates.
Corresponding to pair 1, the center station 102 relays each extension to the portable earth station 107 corresponding to the extension. Between the center station 102 and the portable earth station 107, there is a TDM between the center station 102 and each portable earth station 107.
A signal is transmitted by a (time division multiplex) method. Further, a signal is transmitted from each portable earth station 107 to the center station 102 by CDM (code division multiplexing) using a spread spectrum system. That is, for transmission from each portable earth station 107 to the center station 102, 2 M of Ku band (14 GHz) is used.
A band of Hz is prepared. And each portable earth station 107
From the center station 102 to the C station using this 2 MHz band.
The signal is transmitted by DM.

From each portable earth station 107 to the center station 102
The frequency band of the communication satellite 101 used for transmission to the mobile station and the frequency band of the communication satellite 101 used for transmission from the center station 102 to each portable earth station 107 are constantly secured. In addition, the portable earth station is miniaturized so that it can be carried manually or by auto-buy.

With such a configuration, the telephone connected to the public network 105 or the extension telephone 104 directly connected to the PBX 103 is similar to the case of communicating with the extension telephone 104 connected to the PBX 103 in the event of a disaster such as an earthquake. By the procedure, it is possible to communicate with the portable earth station 107 that has been carried to the disaster area. Therefore, it is possible to quickly collect information on the disaster area from the telephone connected to the public network 105 or the extension telephone 104. Further, in the present system, since the existing PBX exchange function is used as the system exchange function, the introduction of the present system is easier than the case of introducing a completely independent system dedicated to a disaster. Also,
Furthermore, regardless of the disaster situation such as public communication network, PBX
Communication between the extension telephone 104 directly connected to the extension of 103 and the portable earth station 107 can be ensured. Moreover, the extension telephone 104 that communicates with the portable earth station 107 does not have to be a dedicated one, and may be used as the normal extension telephone 104.

Here, the transmission format used by the center station 102 for transmission and the transmission format used by each portable earth station 107 for transmission will be described.

First, the transmission format used by the center station 102 for transmission will be described.

FIG. 2 shows a transmission format used by the center station 102 for transmission.

As shown in the figure, the center station 102 repeatedly executes a cycle of time-division-multiplexing and transmitting one reference frame and one portable earth station 107 frame per portable earth station 107. .

The reference frame is for all portable earth stations 10
The frame received at step 7 includes a frame mark, an identifier, a center station ID, and control data. The frame mark is pattern data for recognizing the reference frame in the portable earth station 107, the identifier represents that the frame is the reference frame, and the center station ID is the reference frame. Indicates the ID of the center station that transmitted the frame. Further, the control data represents the contents of common control performed on all the portable earth stations 107.

Next, the portable earth station frame is a frame received by each portable earth station 107, and includes a frame mark, a portable earth station ID, a permission flag, and a message.
Data. The frame mark is pattern data for the portable earth station 107 to recognize the frame for the portable earth station, and the portable earth station ID is for receiving the frame for the portable earth station. Portable Earth Station 107
The permission flag is a portable earth station I.
This is a flag for instructing the portable earth station 107 specified by D whether or not to permit transmission. Next, the message data is a message I indicating the type of message and the message.
D. In this embodiment, the center station 102
As the message to be transmitted from the portable earth station 107 to the portable earth station 107, voice data, control data, ringing tone data and busy tone data are sent. A unique value is added to each data as a message ID.

Next, the transmission format used by each portable earth station 107 for transmission will be described.

FIG. 3 shows a transmission format used by each portable earth station 107 for transmission.

As shown, each portable earth station 107
Repeatedly transmits the transmission frame. Each portable earth station 1
The transmission frame transmitted by 07 is transmitted by the CDM method by spread spectrum as described above.

The transmission frame is composed of a frame mark, a portable earth station ID, and message data. Frame
The mark is pattern data for identifying the transmission frame at the center station 102, and the portable earth station ID is the portable earth station 107 that transmitted the transmission frame.
It is information indicating the identification of the. Next, the message data is
It is composed of a message and a message ID indicating the type of message. In this embodiment, the portable earth station 107
From the message to the center station 102, voice data, dial information, and on-hook / off-hook information are sent. A unique value is added to each data as a message ID.

Next, details of the portable earth station 107 will be described.

FIG. 4 shows the configuration of the transmission / reception system of the portable earth station 107.

As shown, the portable earth station 107 is
Antenna 200, transceiver 210, line connection control unit 23
0, telephone section 240, control section 250, selection sections 251, 25
2, a display 260, and an input unit 270.

Further, the transceiver 210 includes a modulator 213,
Spread spectrum encoder 214, up-converter 21
5, a transmission amplifier 216, a reception amplifier 217, a down converter 218, a demodulator 219, a demultiplexer 222, a reception level detector 223, and a frequency filter 221. Although not shown, the telephone unit 240 includes a handset, a dial key, a ringer for outputting a ringing tone, and the like.

In such a structure, the portable earth station 1
Reception of the signal from the center station 102 at 07 is performed as follows.

That is, the Ku band (14 GHz) signal from the center station 102 received by the antenna 200 is attenuated by the frequency filter at a component of 14 GHz or more,
The signal is amplified by the reception amplifier 217 and converted by the down converter 218 into a signal having a frequency of 1 GHz.
The signal converted to the frequency of 1 GHz is demodulated by the demodulator 219 and output to the demultiplexer 222.

From the received signal, the demultiplexer 222 uses the above-mentioned reference frame and portable station ID as its own I
Separate the portable earth station frame with D and pass it to the selection section. After performing the error correction processing of the passed frame, the selecting unit 251 contents the reference frame, the permission flag in the frame for the portable earth station, and the frame for the portable earth station. The control data in the message data of
The voice data, the ringing tone data, and the voice tone data in the message data of the frame for the portable earth station are sent to the line connection control unit 230. Here, the types of these data are identified by the message ID.

The control unit 250 displays on the display 260 and each unit according to the received reference frame center station ID, control data, permission flag in the frame for portable earth station, and control data. Control the behavior of. For example, when the permission flag indicates that transmission is not permitted,
The transmitter / receiver 200 is controlled to suppress the transmission, and the selection unit 253 is prohibited from sending each data to the line connection control unit 230. Further, the received center station ID is displayed on the display 260.

On the other hand, the line connection control unit 230 has the selection unit 2
Depending on the contents of the data received from 51, the telephone unit 240
Control. The control of the telephone section 240 is performed by outputting a ringing tone according to the ringing tone data from the ringer and a beeper.
This includes sending a beep sound to the handset included in the telephone unit 240 in accordance with the sound data, decoding the voice data, and sending a voice signal represented by the voice data to the handset included in the telephone unit 240. Be done.

The signal amplified by the reception amplifier 217 is also sent to the reception level detector 223. The reception level detector 223 detects the level of the frame mark portion in the received signal and sends it to the control unit 250. Control unit 2
The display unit 50 displays the level transmitted from the reception level detector 223 on the display unit 260 in response to the input from the input unit 271.

On the other hand, the portable earth station 107 to the center station 1
The transmission to 02 is performed as follows.

That is, the telephone section 240 outputs to the line connection control section 230 a voice signal input to the handset, a signal indicating the on-hook / off-hook state of the handset, and a signal indicating the input content from the dial key. . The line connection control section 230 adds a message ID to these signals, creates message data of voice data, dial information, and on-hook / off-hook information and sends it to the selecting section 252. On the other hand, the control unit 250 sends the message data in which the message ID is added to the control data sent to the center station 102 to the selection unit 252.

The selecting unit 252 appropriately adds an error correction code or the like to each received message data, and then adds the portable earth station ID and frame mark of its own station to the above-mentioned transmission frame. -, And sends them to the modulator 213 sequentially.

The modulator 213 modulates the received transmission frame into a signal having a frequency of 1 GHz. This modulated signal is spread-spectrum coded by the spread spectrum coder 214 so that its spectrum is spread within the band of 2 MHz. The spread spectrum coded signal is then converted by the up-converter 215 into a Ku band signal, that is, a signal with a frequency of 14 GHz,
The signal is amplified by the transmission amplifier 21 and sent to the antenna 200. The antenna transmits this amplified signal to the communication satellite.

Next, the configuration of the center station 102 will be described.

The configuration of the center station 102 is shown in FIG.

As shown in the figure, the center station 102 includes an antenna 300, a transceiver 310, and a subscriber line connection controller 32.
0, a control unit 330, and selection units 340 and 350.

The transmitter / receiver 310 receives a signal sent from each portable earth station 107 by the antenna 300 via the communication satellite using the Ku band, demodulates and decodes the signal, and each portable earth station 107 receives the signal. Of the transmission frame and sent to the selection unit 340. The selection unit 340 performs error correction processing on the transmission frame for each of the separated portable earth stations 107, and at the same time displays a message for the control data included in the transmission frame.
The message data and the portable earth station ID are sent to the control unit 330, and for other message data, the portable earth station ID included in the transmission frame and the conversion preset by the control unit 330 are transmitted. A line corresponding to the extension corresponding to the portable earth station ID included in the transmission frame is selected based on the correspondence between the type earth station ID and the extension and is sent to the subscriber line connection control unit 320 from this. . The subscriber line connection control unit 320 controls the extension assigned to each portable earth station 107, that is, the extension corresponding to the line receiving the message data, according to the content of the received message data. This extension control includes direct current loop control of the extension according to on-hook / off-hook information received as message data from the corresponding portable earth station 107, output of the extension of DTMF sound according to dial key information, and the like. , Audio data decoding and extension output.

On the contrary, the subscriber line connection control section 320 detects the state of the extension for each extension. That is, for example, the presence / absence of a ringing tone signal on the extension and the presence / absence of a beep sound are detected. Then, in accordance with the detected state, ringing tone data and page tone data are generated,
The message data in which the message ID is added to these is sent to the selection unit 350 via the line corresponding to the extension line. Also, the voice signal received from the extension is encoded, and the message data in which the message ID is added to the encoded voice data is sent to the selection unit 350.

The control unit 330 also controls each portable earth station 1
Message data in which a message ID is added to each control data individually sent to 07 is sent to the selection section 350 together with the portable earth station ID of the portable earth station 107 to which the message data is sent. Further, the control unit 330 creates the above-mentioned reference frame and sends it to the selection unit 350. The selection unit 350 receives the message data corresponding to each extension received from the subscriber line connection control unit 320 and the control unit 330.
Receives individual message data for each portable earth pole from. Then, regarding the message data received from the subscriber line connection control section 320, the control section 3 is previously set.
Based on the correspondence between the extension and the portable earth station ID set by 30, the message data for each portable earth pole from the control unit 330 is sent together with the portable earth station ID from the portable earth station ID sent together. The earth station 107 recognizes the portable earth station ID, adds an error correction code to each of the destination portable earth stations 107, and adds the recognized portable earth station ID to each portable earth station 107. Create a portable earth station frame for station 107. Then, these and the reference frame received from the control unit 330 are time-division multiplexed and sent to the transceiver 310. The transceiver 310 modulates the received frame signal and transmits it to a communication satellite. Here, the control unit 330 creates the above-mentioned basic frame and control data according to the operation of the operator performed via the input unit 360.

With the above configuration, the center station 10
2 relays not only the payload information but also the information for controlling the extension call between the PBX 103 and the portable earth station 107, so that the portable earth station 107 can be operated just like an ordinary extension telephone. It will be available.
In the above example, a PBX having the most general analog telephone line interface as an extension interface is assumed as the PBX 102, and ringing tone data or a beep tone is used as information for controlling a call. Center station 10 for data, on-hook / off-hook information and dial information
2 and the portable earth station, and the extension and the portable earth station 107 were controlled based on these. However, the information sent and received for call control and the control based on these are PBX10.
It changes according to the extension interface of 2. For example, P
If the extension interface of the BX 102 is the basic interface of ISDN, the call control information of the D channel or the synchronization information of the layer 1 level may be used as the information transmitted and received for call control.

Further, with the above configuration, the center station and each portable earth station 107 can mutually exchange control data.

Therefore, the extension is not assigned to each portable earth station 107 from the beginning, but the control unit 25 of the activated portable earth station 107 is activated when the system is started up.
0 transmits a connection request as control data, and the control unit 330 of the center station that receives the connection request sends the selection request to the selection units 340 and 350.
By notifying the correspondence between the extension and the portable earth station ID,
The extension is assigned to the portable earth station that has transmitted the connection request, and then the permission flag described above is set to a value indicating permission of transmission and transmitted to the portable earth station that has transmitted the connection request. May be allowed to be called.

Further, since the center station 102 can remotely control each portable earth station 107 by using the control data and the permission flag, any portable earth station 107 can be selected as the portable earth station 107 for communication. You can Therefore,
For example, a plurality of center stations 102 may be provided as shown in FIG. 6, and each center station 102 may communicate with any one of the plurality of mobile earth stations 107. However, in this case, the specific center station 1
02, the portable earth station 107 with which the center station communicates is designated to each center station via the communication path 120. In this case, the control unit 330 of each center station 102
By notifying the selection units 340 and 350 of the correspondence between the extension and the portable earth station ID, the extension is dynamically assigned to the portable earth station. As described above, even if the center station with which the portable earth station 107 communicates is not fixed, each portable earth station 107 displays the received center station ID on the display 260 as described above. Therefore, the user can recognize the center station with which he / she communicates.

Next, the portable earth station 10 used in this embodiment.
The structure of No. 7 will be described.

FIG. 7 shows the appearance of the portable earth station 107.

As shown, the portable earth station 107
It has a trunk type structure composed of a lid part 700 and a main body part 710 connected by a hinge 713, and the figure shows a state where the lid of the trunk is closed. As shown, the trunk has a handle 711 for easy carrying and a latch mechanism 7 for holding the lid in a closed state.
12 are provided. A turntable 720 for rotating the main body in the horizontal direction is provided at the bottom of the main body 710, and the main body 710 is rotated by rotating the head (knob) 721 of the worm gear. Can be fixed by rotating it in any direction.

FIG. 8 shows a lid portion 70 of the portable earth station 107.
Shows 0 open.

As shown in the figure, the lid 700 of the portable earth station 107 is composed of an antenna support plate 701 pivotally attached to the main body 710 by a hinge 713, and an antenna 200 attached to the antenna support plate 701. . That is,
The outer wall of lid 700 also serves as an antenna. Antenna 2
Reference numeral 00 denotes a planar antenna, and as shown in FIG. 9, the antenna support plate 701 is attached by a pivot 702 so as to be rotatable along the upper surface of the antenna support plate 701, and the antenna 200 is fixed by a polarization angle adjusting screw 703. It can be rotated and fixed at any angle. FIG. 10 shows a cross-sectional view of the planar antenna and the antenna support plate taken along a vertical cross section passing through the pivot 702. Polarization angle adjusting screw 70 in the figure
By rotating 3 along the guide groove 704 and tightening the polarization angle adjusting screw 703, the antenna 200 can be fixed at a desired angle.

Further, in addition to this, the inclinometer 705, the above-mentioned receiving amplifier 217, etc. are attached to the antenna supporting plate 701 as shown in the figure. In addition, the antenna support plate 70
1, an elevation angle adjusting bar 706 is pivotally attached.

Next, the transmitter / receiver 714 of the telephone section 240, the display 260, the dial key 715 of the telephone section 240, the input section 270 including a function key, and the compass 716 are provided on the upper surface of the main body section 710. Has been.
A holding member 717 that holds one end of the elevation angle adjusting bar 706 swingably is provided so that it can be slid stepwise along the slide groove 718.

The elevation angle adjusting bar 706 is detached from the holding material 717 when the lid 700 is closed, and is housed between the main body 710 and the lid 700. On the other hand, when giving an elevation angle to the antenna 200, it is attached to the holding member 717. With one end of the elevation adjustment bar 706 attached to the holding member 717,
The elevation angle of the antenna 200 can be adjusted by gradually sliding the holding agent 717 along the slide groove 718.

Next, a lower portion of the main body 710 is provided with a turret for rotating the main body 710 in the horizontal direction as described above.
Table 720 is provided, and by using this, the main body can be rotated and fixed in an arbitrary direction. FIG. 11 shows a sectional view of this turntable. The turn table 720 includes a bearing table 723 pivotally attached to the main body 710 by a pivot 722, a gear wheel rotating with the main body on the bearing table, and a cover fixed to the bearing table. 724 and the main body 710
And a worm gear 721 meshed with the gear 725. A part of the head (knob) of the worm gear 721 is exposed from an opening provided in the cover so that the user can freely rotate it. In such a configuration,
With the rotation of the gear 721, the gear 725 moves to the main body 710.
Rotate horizontally with.

Now, the portable earth station 107 according to this embodiment.
Receives a Ku band linearly polarized wave from a communication satellite. Therefore, before carrying out communication using the portable earth station 107, the antenna 200 is directed to the azimuth and elevation angle of the antenna surface of the antenna 200 and the communication satellite 101, and the antenna is rotated so as to match the polarization direction of the linearly polarized wave. Need to let.

According to the portable earth station 107 of this embodiment, such a planar antenna can be adjusted as follows. That is, first, referring to the direction indicated by the direction magnet 716,
Rotate the worm gear 721 to move the main body 710 to the communication satellite 1
Turn to the direction of 06. Next, one end of the elevation angle adjusting bar 706 is attached to the holding member 717, and the holding member 717 is stepwise slid along the slide groove 718 with reference to the angle indicated by the inclinometer 705 to set the elevation angle of the antenna 200 to that of the communication satellite. To match. Then, by loosening the polarization angle adjusting screw 703, moving it along the guide groove 704, and tightening the polarization angle adjusting screw 703, the angle of the antenna 200 perpendicular to the communication satellite direction is received from the communication satellite 106. Adjust to the polarization angle of the radio wave.

Here, since the azimuth, elevation angle, and polarization angle of the communication satellite can be obtained from the current position by calculation, the above operation allows the orientation and rotation angle of the antenna to be appropriately set appropriately. However, in actual use, fine adjustment of the orientation of the antenna 106 is required. According to the portable earth station 107 according to the present embodiment, this fine adjustment can be performed with reference to the level of the received radio wave displayed on the display 260 as described above. That is, when the display of the reception level is requested from the input unit 271, the control unit 250 displays the level transmitted from the reception level detector 223 on the display unit 2.
Since it is displayed on 60, the orientation of the main body 710, the antenna 20
The elevation angle of 0 and the rotation angle may be finely adjusted.

Next, the antenna 20 of the portable earth station 107
0 will be described.

FIG. 12 shows the structure of the antenna 200.

In the figure, 1a is a slot plate made of a conductive member such as an aluminum plate or a steel plate, and 2a is a slot formed in the conductive member. 3a, 3b, 3c and 3d are foam members having a low dielectric constant and are spacers. 4a, 5
a is a low loss film substrate. Reference numerals 4b and 5b denote linear polarization antenna elements, which are formed on the film substrates 4a and 5a by etching, printing with conductive ink, or the like.

Like 1a, 1b is a slot plate made of a conductive material such as an aluminum plate and a steel plate, and 2b is 2a.
And a slot formed in the conductive member. or,
Reference numeral 4c is a feeder line for the array antenna element 4b formed on the low loss film substrate 4a, and 5c is a feeder line for feeding the array antenna element 5b formed on the low loss film substrate 5a. Reference numeral 6 is a filter circuit formed on the film substrate, and 1c is a ground conductor made of a conductive member such as an aluminum plate or a steel plate.

The array antenna formed on the film substrate 4a is a receiving antenna, and the array antenna formed on the film substrate 5a is a transmitting antenna. In the planar antenna according to the present embodiment, the linear polarized antenna element 4b of the receiving antenna is excited by the radio wave of the receiving frequency, and the linear polarized antenna element 5b of the transmitting antenna is excited by the radio frequency of the transmitting antenna and radiates the radio wave. The frequencies of the received radio wave and the transmitted radio wave are different, and the polarization planes of both radio waves are orthogonal. Radio waves pass through slots 2a and 2b, respectively. Or, it is reflected by the ground conductor 1c.

The excited linearly polarized antenna element 4b functions as one antenna element with the slots 2a and 2b and the linearly polarized antenna element 5b, and the linearly polarized antenna element 5b has the elements 2a and 2b. The linearly polarized antenna elements of the slots and 4b function as one antenna element.
The size of the antenna element is independently determined regardless of the number of antenna elements and the interval between the antenna elements, and specifically,
It is determined from the permittivity of the medium around the antenna element and the resonance condition of the radio wave used. For example, when a rectangular patch antenna element is used, the length of the antenna element with respect to the excitation direction of the antenna element is about 0.5 normalized by the wavelength of radio waves when the medium around the antenna element is a vacuum. become.

Here, since the electric field vibration directions of the linearly polarized radio waves radiated from the antenna element 5b are orthogonal to the electric field vibration directions of the linearly polarized radio wave received by the antenna element 4b, they are mutually opposite. It does not receive radio waves. However, the radio wave radiated from the linearly polarized antenna element 5b is
Since it has a slight vibration direction component of the electric field orthogonal to the excitation direction of the antenna element, it is received by the antenna element 4b having the excitation direction of the electric field orthogonal to the excitation direction of the antenna element.

For example, the power of the transmission frequency band radiated from the transmission antenna is 1 W and the isolation is 35 dB.
Then, it is expected that, out of the power of 30 dBm transmitted from the transmission antenna, the power of -5 dBm will be received by the reception antenna.

If this electric power enters the above-mentioned receiving amplifier as it is, it becomes impossible to receive the electric wave which should be originally received from the communication satellite. Therefore, when the allowable input level of the transmission frequency band of the receiving amplifier is -35 dBm, 30 dB
A frequency filter with a blocking amount of must be placed in front of the receiving amplifier. However, it is not desirable to use such a high-performance frequency filter in terms of price and size.

Therefore, in this embodiment, for this reason, a pattern having the same structure as the antenna element is formed on the same surface as the receiving antenna surface.
The transmission filter 6 is formed, so that the transmission frequency component is attenuated to some extent. By doing so, it is possible to eliminate the need for a frequency filter in the preceding stage of the receiving amplifier, or to make the amount of blocking smaller than in the past.

For example, if a pattern filter having the same amount as the antenna element and a blocking amount of 30 dB is formed on the same surface as the antenna surface, the frequency filter to be arranged in front of the receiving amplifier becomes unnecessary.

Here, the shape of the pattern filter 6 is shown in FIG.
3, FIG. 14 and FIG.

In FIG. 13, 6a to 6i are strip lines having different characteristic impedances. 13, FIG. 14, and FIG. 15 are half-wavelength coupling filters, respectively. These are formed as a part of the power supply line 4c. That is,
The received signal of the receiving antenna is input from the point a on the power feeding line 4c, passes through the pattern filter 6, and passes through the point b on the power feeding line 4c.
Output from The design of the frequency characteristics of such a pattern filter is described in detail in "Communication Microwave Circuit" (edited by The Institute of Electronics, Information and Communication Engineers) P101-P103.

In this example, the pattern filter is provided only on the receiving antenna surface, but the pattern filter may be provided on the transmitting antenna surface. For example, a noise component having a frequency lower than 14 GHz (for example, 13 GHz) generated by the characteristics of the transmission amplifier may be formed by a pattern filter provided on the power feeding line 5c of the transmission antenna.

Here, FIG. 16 shows the connection between the planar antenna and the transceiver 210 described above. 20 in the figure
Reference numeral 0 is a planar antenna in which the pattern filter 6 is formed on the receiving antenna surface, and the frequency filter 221 has a waveguide having an input / output unit for inputting a radio wave obtained by coaxial waveguide conversion 11a of the output of the feed line 4c. Is a waveguide filter. Further, the reception amplifier 217 is also a waveguide type amplifier, but includes a conversion unit that converts an output into an electric signal. Further, the output of the transmission amplifier 216 is once converted into a radio wave by coaxial waveguide conversion, then 11b, and converted again.
1c is input to the power supply line 5c as an electric signal.

Now, the antenna 20 according to the present embodiment.
The directivity characteristic of 0 will be described.

The directional characteristic F of the array antenna is an array factor f representing a term including the directional characteristic g of the antenna element, the spatial arrangement of each antenna element, the feed amplitude, and the feed phase.
Is expressed by the following equation 1.

[0078]

[Equation 1]

Here, the zenith angle is θ indicating the inclination from the axis perpendicular to the antenna plane as in the coordinate system shown in FIG. 17, and it is on the antenna plane and indicates the angle from the x-axis on the antenna plane. Is the azimuth angle.

First, for the sake of simplicity, consider the array factor f of a linear array antenna only when a plurality of antenna elements are arranged along a straight line along the x-axis at equal intervals and the azimuth angle φ is zero. In this case, it is assumed that the intended communication satellite is located on the line connecting the azimuth angles of 0 degree and 180 degrees.
The number of antenna elements is N, and the antenna element spacing is d.
When power is fed to each antenna element at the same amplitude and the same phase, the array factor f is expressed by the following equation 2. In this case, since the feeding phase for each antenna element is the same for all the antenna elements, the peak of the directional characteristic is in the vertical direction with respect to the plane on which the antenna is arranged. That is, since the peak of the directional characteristic is oriented in the direction of θ = 0 and the phase is the same for all the antenna elements, the antenna efficiency can be increased and the antenna aperture area can be reduced.

[0081]

[Equation 2]

In Expression 2, k represents the free space wave number of the radio wave, and j represents the imaginary number. Since Equation 2 is the sum of geometric progressions, it can be rewritten as Equation 3 below.

[0083]

(Equation 3)

Therefore, if the above Equation 3 becomes _{0 in} the direction of a certain specific direction θ ₀ , F (θ ₀ ) representing the directivity characteristic in the θ ₀ direction becomes 0 (this is called a null point) from Equation 1. ,
not emit radio waves theta ₀ direction or the directional characteristic does not receive the radio waves from the theta ₀ direction. Since the numerator on the right-hand side of Equation 3 needs to be 0 in order for Equation 3 to become 0, the following Equation 4
Should be satisfied.

[0085]

[Equation 4]

In Expression 4, m represents an integer other than 0. Number 4
According to, no radio wave is emitted in the θ ₀ direction, or
In order not to receive the radio wave from the θ ₀ direction, the number N of antenna elements and the distance d between antenna elements are set so as to satisfy the relationship expressed by the following equation 5 between the number N of antenna elements and the distance d between antenna elements. You know that you should decide.

[0087]

(Equation 5)

[0088] Thus, in relation represented by about a few 5, be determined a number of antenna elements N and the antenna spacing d, does not emit radio wave to theta ₀ direction or a reception intensity of a radio wave from theta ₀ direction Can be made smaller.

By the above method, the number of antenna elements and
FIG. 18 shows a conceptual diagram of directional characteristics when the antenna element spacing is determined. In FIG. 18, reference numeral 71 is a communication satellite with which a transceiver equipped with an antenna attempts to communicate, and 72 is a non-purpose communication satellite with which communication is not performed.
It is a communication satellite in the adjacent position. Reference numeral 73 denotes an antenna aperture plane, and 74 denotes a directional characteristic showing the intensity of the radio wave that can be radiated by the antenna or how much the received radio wave can be collected. As can be seen from FIG. 18, according to the present invention, in order to reduce the intensity of the radio wave emitted in the direction of the communication satellite 72 at the adjacent position or the intensity of the radio wave received from the adjacent satellite 72, the intensity of the radio wave indicated in the directional characteristic is reduced. The valley where the intensity becomes small will be directed toward the communication satellite at the adjacent position. That is, by setting the direction of θ _{0 to} the direction of the adjacent satellite 72 and determining the number of antenna elements and the spacing between the antenna elements, the directional characteristic in the direction of θ ₀ can be made the null point.

Further, the larger the number of antenna elements and the larger the size of the plane on which the antennas are arranged, the larger the peak size of the directivity characteristic can be made. For this reason, the number of antenna elements and the interval may be determined so as to have a peak of directional characteristics that enables communication with a communication satellite with which communication is desired.

As described above, since the feeding phase and the feeding amplitude for the antenna element can be made the same, the antenna efficiency can be improved. In addition, compared to the size of the antenna when the feed lobe amplitude and feed phase are made non-uniform so as to reduce the size of the entire side lobe for communication satellites in adjacent positions, the feed amplitude and feed phase are not uniform. Therefore, it is possible to reduce the size because the unequal distributor and the like required for the above are unnecessary.

In this embodiment, in FIG. 12, the number of antenna elements and the distance between the antenna elements are determined by the equation 5.
For example, as shown in FIG. 19, when there are eight antenna elements in the horizontal direction, radio wave interference of adjacent satellites from the horizontal direction, that is, when the azimuth angle φ = 0 and the zenith angle θ ₀ is 13.2 degrees. In order to prevent the receiver 10 from receiving it (at the time of transmission, to prevent radio wave interference from being exerted on an adjacent satellite in the direction of the zenith angle θ ₀ of 13.2 degrees), N is calculated from the equation (5). 8,
When θ ₀ is 13.2 degrees and m is 1, d / λ is 0.54
7, or m may be set to 2 and d / λ may be set to 1.095. Here, λ represents the free space wavelength of the radio wave. Here, although the antenna element spacing d / λ is determined strictly from Equation 5 as 0.547, it may be slightly shifted due to the mutual coupling between the antenna elements.

Next, the antenna elements are arranged in the lateral direction, that is, in the azimuth angle φ = 0 direction, and when there are 32 elements, they are arranged at the following intervals. The zenith angle θ ₀ is 4.4 degrees and 8.8.
In order to prevent the receiver 10 from receiving the radio wave interference of the adjacent satellites from the three directions of 13.2 degrees and 13.2 degrees, N is set to 32 in Equation 5 and m is set when θ ₀ is 4.4 degrees. Is set to 2, m is set to 4 in the case of 8.8 degrees, and m is set to 6 in the case of 13.2 degrees. As a result, d / λ is
0.815 for 4.4 degrees and 0.8 for 8.8 degrees
In case of 17 and 13.2 degrees, it becomes 0.821. Therefore,
32 antenna elements are arranged in the horizontal direction, and θ ₀ is 4.4 degrees and 8.8 in a direction in which 32 antenna elements are arranged.
In order to reduce the radio wave interference that the receiver 10 receives from the adjacent satellites in the three directions of 13.2 degrees and 13.2 degrees, the antenna element interval d / λ may be arbitrarily selected between 0.815 and 0.821. .

Up to this point, the case where 32 elements are arranged in the horizontal direction has been shown, but the same can be said for the vertical direction. Even when 16 elements are arranged in the vertical direction, the direction in which the 16 antenna elements are arranged, that is, in the direction of φ = 90 degrees, θ ₀ is three directions of 4.4 degrees, 8.8 degrees, and 13.2 degrees. In order to reduce the radio wave interference received by the receiver 10 from the adjacent satellite, N is set to 16 in the equation (5). When θ ₀ is 4.4 degrees, d / λ is 0.815 when m is 1, and θ ₀ is 8.
In case of 8 degrees, when m is 2, d / λ becomes 0.817, and θ
_{When 0} is 13.2 degrees, d / λ is 0.821 when m is 3.
Becomes Therefore, the antenna element is 1 in the direction of φ = 90 degrees.
Even when 6 elements are arranged side by side, in order to reduce the radio wave interference received by the receiver 10 from adjacent satellites in 3 directions, the azimuth angle φ
As in the case where 32 antenna elements are arranged in the direction of = 0, the vertical antenna element spacing d / λ is 0.81.
It may be arbitrarily selected from 5 to 0.821.

According to such a method of determining the antenna element spacing, when a total of 512 elements of 32 × 16 elements are arrayed in a grid, the element spacing in the direction in which the 32 element antenna elements are arrayed. d / λ is 0.815
From 0.821 to 0.821, the element spacing d / λ in the direction in which 16 antenna elements are arranged is 0.817 to 0.8.
821 may be arbitrarily selected. In this case, 16
The elements may be arranged in the vertical direction and the 32 elements may be arranged in the horizontal direction at the same element intervals. That is, the grid-like vertical and horizontal intervals are made equal to the obtained intervals between the antenna elements. In this case, since the element spacing is the same in both the vertical direction and the horizontal direction, it is possible to use whichever is used in the x-axis direction. The elements may be arranged at different arrangement intervals between the above-mentioned element intervals in the vertical direction and the horizontal direction. In this example, m in Equation 5 is determined in order to arrange the array element spacing d / λ in the vertical and horizontal directions as close as possible to 0.82, but the value of m is naturally an integer other than 0, and , Both lateral directions can be arbitrarily determined. For example, if N is 32 in the horizontal direction, m is 1 when θ ₀ is 4.4 degrees, m is 2 when 8.8 degrees, and m is 3 when it is 13.2 degrees. Good. As a result, d / λ is 0.407 in the case of 4.4 degrees, 0.409 in the case of 8.8 degrees, and 0.411 in the case of 13.2 degrees, respectively. In this case, the vertical element arrangement interval d / λ is about 0.8, and the horizontal element arrangement interval d / λ.
It is also possible to set λ to around 0.41. Even in this case, it is possible to set the directional characteristic to the null point in the adjacent satellite communication direction.

Here, the directivity characteristics of the number of antenna elements and the spacing between the antenna elements described above are shown in FIGS.
This will be described with reference to FIG.

FIG. 20, FIG. 21 and FIG. 22 are layout diagrams of the antenna. 20, FIG. 21 and FIG.
Both the vertical axis and the horizontal axis are values normalized by frequency, and the spacing of the array is shown by d / λ, and the squares show the antenna elements. Figure 2
0 indicates a state in which eight elements are arranged in a straight line in the x-axis direction,
FIG. 21 shows a state where 16 elements are arranged in a straight line in the x-axis direction, and FIG. 22 shows an antenna arrangement when 32 elements are arranged in the x-axis direction and 16 elements are arranged in a y-axis in a grid pattern. ing. In this case, the size of the antenna element is a square with one side being approximately 0.5 standardized by the wavelength of the radio wave, and the antenna element interval is a value between 0.815λ and 0.821λ.

23 and 24 show the far-field directional characteristics of radio waves radiated from the antenna element array shown in FIG.
Shown in In FIG. 23, the intensity of the radio wave radiated from the array antenna is shown by the shade of the shadow, the azimuth angle φ (0 to 360 degrees) is shown in the circular circumferential direction, and φ is a line connecting 0 degrees and 180 degrees. Shows the x-axis in FIG. 8, and the line connecting φ with 90 degrees and 270 degrees shows the y-axis in FIG. Also,
A circle indicated by a dotted line in a concentric pattern from the center of the circle indicates the inclination from the vertical axis of the antenna surface, that is, the zenith angle θ,
The concentric circles are marked by dotted lines with a zenith angle of 18 degrees from the center to the outer side, and the outermost circle has a zenith angle of 90 degrees.

In FIG. 23, there are a total of 13 peaks showing the peak of absolute gain on the x-axis where the antenna elements are arranged, that is, on the straight line connecting φ from 0 ° to 180 °,
There is only one mountain on the y-axis that is orthogonal to the axis where the antenna elements are arranged, that is, on the straight line that connects φ with 90 degrees and 270 degrees. Hereinafter, a mountain with a zenith angle θ of 0 is referred to as a main beam, a mountain with a zenith angle θ of other than 0 is referred to as a side lobe, and a valley between mountains is referred to as a null point. In this way, when the antenna elements are arranged on a straight line in the azimuth direction in which the satellite is located, the directional characteristics in the plane cut by the straight line become sharp, and the null point and side Robes and alternates appear.

Further, FIG. 24 shows a directional pattern when the directional pattern in FIG. 23 is cut by a straight line connecting φ with 0 ° and 180 °. In FIG. 24, the horizontal axis represents the zenith angle θ, and the vertical axis represents the absolute gain which is a unit of the intensity of the radiated radio wave. As can be seen from FIG. 24, the null points, which are the valleys of the radio field intensity, are formed at approximately 8.8 degrees and 13.2 degrees of the zenith angle. According to the present embodiment, as described above, since the null point determines the interval between the antenna elements so as to match the direction of the satellite at the position adjacent to the target satellite, It does not receive radio waves from a certain satellite and is not affected by them.

Similarly, the directional characteristics of the array antenna when 16 antenna elements shown in FIG. 21 are arranged are shown in FIG.
5 and FIG. 26, and FIG. 27 and FIG. 28 show the directional characteristics of the array antenna of the array of 32 element × 16 element antenna elements shown in FIG. Comparing the directional characteristics shown in FIG. 23 and FIG. 25, when the number of antenna elements is increased from 8 elements to 16 elements, the directional characteristics (the distance between the side lobes and the null points) become more dense on the x-axis. You can see that On the other hand, it can be seen that the directional characteristics on the y-axis do not change between 8 elements and 16 elements. Similar to FIG. 24, FIG. 26 shows a directional pattern when the directional pattern in FIG. 25 is cut by a straight line connecting φ with 0 degrees and 180 degrees. In FIG. 26, it can be seen that the null points, which are the valleys of the radio field intensity, are formed at approximately 4.4 degrees, 8.8 degrees, and 13.2 degrees of the zenith angle.

Further, in FIGS. 27 and 28, x
Since 32 antenna elements are arranged on the axis and 16 antenna elements are arranged on the y axis in a lattice pattern, in the directional characteristic diagram shown in FIG. 27, φ is a direction connecting 0 ° and 180 °, and φ is 90 °. It can be seen that the intervals between the side lobes and the null points appear closely in both the direction connecting the degrees and 270 degrees. Figure 2
8 shows the directional characteristics in FIG.
The directional characteristic figure when it cuts by the straight line which connects 0 degree and 180 degrees is shown. In FIG. 28, a second null point is located at a position where the zenith angle θ is 4.4 degrees, and a fourth null point is located at a position where the zenith angle θ is 8.8 degrees.
It can be seen that there is a sixth null point at the 13.2 degree position. Further, at this time, the directional characteristic diagram on the straight line connecting φ between 90 degrees and 270 degrees is almost the same as the directional characteristic diagram shown in FIG.

As described above, by increasing the number of antenna elements, the directional characteristics of the antenna (the distance between the side lobe and the null point) can be made close. Furthermore, by arranging the antenna elements in a grid pattern, the directional characteristics of the antenna can be made dense in both the x-axis and the y-axis directions.

[0104]

As described above, according to the present invention, it is possible to provide a portable earth station which can be applied to satellite communication using linearly polarized radio waves.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a satellite communication system.

FIG. 2 is a diagram showing a transmission format of a center station.

FIG. 3 is a diagram showing a transmission format of a portable earth station.

FIG. 4 is a block diagram showing a configuration of a portable earth station.

FIG. 5 is a block diagram showing a configuration of a center station.

FIG. 6 is a diagram showing another configuration of the satellite communication system.

FIG. 7 is a perspective view showing an appearance of a portable earth station.

FIG. 8 is a perspective view showing an appearance of a portable earth station.

FIG. 9 is a perspective view showing an appearance of a portable earth station.

FIG. 10 is a cross-sectional view showing a cross section of a connection portion between an antenna and an antenna support plate.

FIG. 11 is a cross-sectional view showing a cross section of the turn table.

FIG. 12 is a diagram showing a structure of an antenna.

FIG. 13 is a diagram showing a pattern example of a pattern filter.

FIG. 14 is a diagram showing a pattern example of a pattern filter.

FIG. 15 is a diagram showing a pattern example of a pattern filter.

FIG. 16 is a diagram showing a connecting portion between an antenna and a transceiver.

FIG. 17 is a diagram showing a coordinate system used in the detailed description of the present invention.

FIG. 18 is a diagram showing a far-field directional characteristic of an antenna required in satellite communication.

FIG. 19 is a diagram showing an antenna having an 8 × 8 antenna element.

FIG. 20 is a layout diagram of antenna elements in the case of eight elements.

FIG. 21 is a layout diagram of antenna elements in the case of 16 elements.

FIG. 22 is a layout diagram of antenna elements in the case of 32 elements × 16 elements.

23 is a far-field directional characteristic diagram of radio waves radiated from the antenna element array shown in FIG. 20.

FIG. 24 is a far-field directional characteristic diagram of radio waves radiated from the antenna element array shown in FIG. 20.

FIG. 25 is a far-field directional characteristic diagram of radio waves radiated from the antenna element array shown in FIG. 21.

FIG. 26 is a far-field directional characteristic diagram of radio waves radiated from the antenna element array shown in FIG. 21.

FIG. 27 is a far-field directional characteristic diagram of radio waves radiated from the antenna element array shown in FIG. 22.

FIG. 28 is a far-field directional characteristic diagram of radio waves radiated from the antenna element array shown in FIG. 22.

[Explanation of symbols]

 101 Communication Satellite 102 Center Station 103 PBX 104 Extension Telephone 105 Public Communication Network 107 Portable Earth Station 200 Antenna 700 Lid 710 Main Body 720 Turntable 701 Antenna Support Plate 702 Axis 703 Polarization Angle Adjustment Screw 704 Guide Groove 706 Elevation angle adjusting bar 717 Holding material 718 Slide groove

Claims (4)

[Claims] 1. A portable earth station device for transmitting and receiving radio waves to and from a satellite, the main body containing a transmitting / receiving circuit, a planar antenna, and an axis perpendicular to an antenna surface of the planar antenna as a rotation axis. And a connecting member for connecting the planar antenna to the main body so that the planar antenna can be rotated in a rotation direction within a predetermined rotation angle range. 2. A portable earth station device for transmitting and receiving radio waves to and from a satellite, comprising a main body containing a transmitting / receiving circuit, a planar antenna, and the planar surface supporting and supporting the planar antenna. A support member that is rotatably connected to the main body in a rotation direction that changes the elevation angle of the antenna, and the planar antenna rotates in a predetermined direction in a rotation direction that has an axis perpendicular to the antenna surface of the planar antenna as a rotation axis. An earth station device, comprising: a connecting member that connects the planar antenna to the support member so as to be rotatable within an angular range. 3. The earth station apparatus according to claim 1, further comprising a turntable provided at a lower portion of the main body for rotating the main body in a horizontal direction. Earth station equipment. 4. The earth station device according to claim 2, wherein the support member is arranged such that the antenna surface of the planar antenna supported by the support member is located on a top surface of the main body portion with respect to an upper surface of the main body portion. The earth station device, wherein the earth station device is rotatably connected to the main body portion to a position where a predetermined angle is formed.