JP2014036331A - Antenna device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve high sensitivity of a reception system while preventing superposition of the strain component due to interference wave, or the like, on an input signal, and to continue operation even in a situation where a filter is not cooled to cryogenic state.SOLUTION: An antenna device includes a normal conducting line 613 composed of a normal conducting material, and configured by forming a plurality of branch lines by stubs in the main line, a plurality of band elimination filters 6121-612m corresponding to a plurality of transmission frequencies, respectively, and bonding wires 6141-614m for connecting the plurality of band elimination filters 6121-612m and the plurality of branch lines, respectively. Upon occurrence of interference of unwanted waves, the band elimination filter 612 suppresses the signals due to unwanted waves by making the plurality of band elimination filters 6121-612m, corresponding to the frequency of the unwanted waves, function.

Description

  Embodiments described herein relate generally to an antenna device used as a receiving antenna of a radar, a communication system, a microwave radiometer, or a radio wave receiving system.

  As a measure for improving the performance of a system having a signal receiving function such as a radar or a communication system, there is a high sensitivity of a receiving system by reducing a system noise temperature. In general, the system noise temperature is dominated by transmission loss from an antenna to a low noise amplifier (LNA) and internal noise generated by the LNA. Therefore, an electric circuit such as a transmission line from the antenna to the LNA or a reception filter. Furthermore, the LNA is housed in a heat insulating container such as a vacuum container, and provided with a cooling means for cooling the LNA to a superconducting state, thereby reducing the transmission loss from the antenna to the LNA close to zero. An antenna device has been devised that reduces the internal noise and increases the sensitivity of the receiving system.

  In addition, in an antenna device that reduces the transmission loss from the antenna to the LNA, reduces the internal noise of the LNA, and increases the sensitivity of the reception system, in order to remove unwanted wave interference such as interference signals, the input side of the LNA An antenna device has been devised that includes a duplexer that frequency-separates reception systems for the required number of reception frequencies, and that configures a reception circuit such as an LNA for each separated reception system.

  The branching filter is composed of a plurality of bandpass filters made of a superconducting material, and a narrowband signal is input for each separated reception system by using a narrowband filter that can extract only the instantaneous band to be used. It is configured as follows. As a result, when unnecessary wave interference such as jamming waves occurs in a device that determines and operates a plurality of transmittable frequencies (transmission channels) in advance, such as a radar device, other transmission channels that do not interfere with each other By selecting and performing transmission / reception, unnecessary wave interference is avoided.

JP 2000-236206 A

  However, in the conventional antenna device, if the superconducting material cannot be cooled to the cryogenic temperature where the superconducting material becomes superconductive or the cooling means such as the refrigerator breaks down and becomes superconducting, it can be demultiplexed. Transmission loss in a plurality of band-pass filters constituting the device increases. The reception signal is cut off due to the increase of the transmission loss, and the antenna device has a problem that the operation cannot be continued.

  Therefore, in the present embodiment, even when unnecessary wave interference such as an interference signal occurs, it is possible to achieve high sensitivity of the reception system while preventing the distortion component due to the interference signal or the like from being superimposed on the reception signal. An object of the present invention is to provide an antenna device that can continue operation even if the filter is not cooled to a cryogenic state.

  According to this embodiment, the antenna device forms a plurality of branch lines on an antenna unit that receives a signal transmitted at an arbitrary transmission frequency among a plurality of transmission frequencies and a main line formed of a normal conductive material. A normal conduction line, a plurality of band elimination filters formed of a superconducting material and corresponding to each of a plurality of reception frequencies, and a connection means for selectively connecting each of the plurality of band elimination filters and the plurality of branch lines. A band elimination filter unit comprising: an amplifier that amplifies the reception signal extracted by the band elimination filter unit with low noise; and a heat insulating container that houses the band elimination filter unit and the amplifier and shields heat from the outside, Cooling means for cooling the band elimination filter unit and the amplifier accommodated in the heat insulating container to a cryogenic temperature.

It is a block diagram which shows the structure of the antenna apparatus which concerns on this embodiment. It is a figure which shows an example of a structure of the zone | band removal filter part shown in FIG. It is a characteristic view which shows the filter characteristic of the zone | band removal filter part shown in FIG.

  Hereinafter, embodiments will be described with reference to the drawings.

  FIG. 1 is a block diagram showing the configuration of the antenna device according to the present embodiment.

  As shown in FIG. 1, the antenna device includes n antenna elements T1 to Tn arranged in an array, a distributor 1, transmission phase shifters 21 to 2n, transmission amplifiers 31 to 3n, and transmission filters 41 to 4n. , A transmission system including transmission / reception switchers 51 to 5n, reception circuits 61 to 6n, a reception phase shifter 71 to 7n, and a synthesizer 8, a vacuum vessel 9, and a refrigerator 10.

  FIG. 1 shows only the configuration of the receiving circuit 61, and the other receiving circuits 62 to 6 n have the same configuration as the receiving circuit 61. In the drawings showing the subsequent embodiments, the same description is omitted.

  The transmission system and the reception system are provided with n antenna elements corresponding to the number n of antenna elements, and the output terminals of the transmission system and the input terminals of the reception system are respectively corresponding antenna elements via transmission / reception switchers 51 to 5n. Connected to T1 to Tn.

  The distributor 1 receives a transmission signal generated by a transmission signal generation device (not shown) and distributes this transmission signal to n systems. The transmission signal generation device generates a transmission signal by selecting one of the plurality of transmission channels.

  Each of the transmission phase shifters 21 to 2n receives the transmission signal distributed by the distributor 1, and performs desired phase control on the transmission signal.

  The transmission amplifiers 31 to 3n receive the transmission signals output from the corresponding transmission phase shifters 21 to 2n, respectively, and amplify the power of the transmission signals with a desired gain.

  The transmission filters 41 to 4n receive the transmission signals output from the corresponding transmission amplifiers 31 to 3n, respectively, and extract desired transmission frequency band components from the transmission signals.

  The transmission / reception switchers 51 to 5n are for switching the transmission system and the reception system for the corresponding antenna elements T1 to Tn, and use, for example, a circulator or a coaxial switch.

  The reception circuits 61 to 6n include a limiter 611, a BRF unit 612 including a plurality of band rejection filters (BRF: Band Rejection Filter, hereinafter referred to as BRF) 6121 to 612m, and an LNA (low noise amplifier) 615. .

  The limiter 611 receives the reception signal output from the transmission / reception switchers 51 to 5n, limits the signal level of the reception signal, and performs subsequent over-input protection to the BRF unit 612 and the LNA 615.

  The BRF unit 612 includes a plurality of BRFs 6121 to 612m having different frequency rejection bands and a normal conducting line 613 for transmitting a reception signal, and selectively transmits each BRF 6121 to 612m to the normal conducting line 613 for transmission. The unwanted wave signal component is suppressed by limiting the frequency band in which unwanted wave interference occurs from the received signal.

  FIG. 2 is a diagram illustrating an example of the configuration of the BRF unit 612 illustrated in FIG.

  The normal conductive line 613 is constructed on an alumina substrate, which is a normal conductive material, and is composed of a main line made of a normal conductive material such as a copper thin film and a plurality of branch lines made of a stub made of a normal conductive material in the same manner as the main line. The

  The BRFs 6121 to 612m are installed on a MgO (magnesium oxide) substrate, which is a superconducting material, and use a superconducting BRF made of a superconducting material such as a YBCO (yttrium-based superconductor) thin film. The BRFs 6121 to 612m are subordinately connected to the plurality of branch lines by connecting means such as bonding wires 6141 to 614m.

  Here, the normal conducting material, the superconducting material, and the connecting means are presented as examples, and the scope of the present embodiment is not limited thereby.

  From FIG. 2, for example, a signal received by the antenna element T <b> 1 is input from the input side to the normal conducting line 613 via the limiter 611. At this time, when unnecessary wave interference such as an interference signal occurs in the received signal, the received signal corresponds to the frequency of the interference wave among the plurality of BRFs 6121 to 612m connected by the stubs of the normal conduction line 613. By causing the BRF to function, the frequency component of the interference wave is suppressed from the received signal.

  FIG. 3 is a characteristic diagram showing filter characteristics of the BRF unit 612 shown in FIG.

  In FIG. 3, the BRF unit 612 has a plurality of filter characteristics with respect to a wide radar frequency band like a radar device, for example. The number of filter characteristics of the BRF unit 612 is the same as a plurality of narrow-band transmittable frequencies (transmission channels) included in the radar apparatus. Here, m filter characteristics are provided for m transmission channels. Yes. That is, each of the plurality of BRFs 6121 to 612m has a filter characteristic that blocks the frequency band for each transmission channel. Here, for example, when an interference wave is generated in the frequency band f2 shown in FIG. 3, the BRF corresponding to f2 is caused to function. Thereby, since the loss of the frequency band of f2 increases in the reception signal passing through the normal conducting line 613, the signal of the frequency band of f2 is suppressed, and the interference wave is suppressed. For example, a diode is used for the BRFs 6121 to 612m of the BRF unit 612. In this case, the loss in a desired frequency band can be increased by controlling the applied voltage so that the diode is turned on and off.

  Further, the branch line (line to which the superconducting BRF is connected) configured in the normal conductive line 613 is configured by a stub or the like with the characteristic impedance viewed from the normal conductive line 613 opened. As a result, even when the superconducting BRF is not cooled to a cryogenic temperature at which the superconducting BRF is in a superconducting state, the operation can be continued only with the normal conducting line 613. In this case, the signal from the input side in FIG. 3 is propagated to the output side by the normal conducting line 613, each superconducting BRF end that does not operate is opened, and the propagation signal can obtain stable characteristics.

  The plurality of BRFs 6121 to 612m of the BRF unit 612 are selected so that only the BRF of the frequency to be suppressed functions according to a control signal from an antenna controller (not shown).

  The LNA 615 receives the reception signal output from the BRF unit 612 and amplifies the reception signal with low noise. The reception phase shifters 71 to 7n receive the reception signal output from the LNA 615 and perform desired phase control on the reception signal. The synthesizer 8 receives the received signals that have been subjected to phase control by the receiving phase shifters 71 to 7n, and synthesizes these received signals.

  The vacuum container 9 accommodates the receiving circuits 61 to 6n, and insulates and keeps the temperature of the contents by making the inside vacuum. The vacuum vessel 9 is a vessel for insulating the surroundings where the superconducting material is disposed in a vacuum state for the purpose of efficiently maintaining a cryogenic temperature. For this reason, at least the periphery where the superconducting material is disposed has an airtight structure including an interface connector and the like.

  The refrigerator 10 is a means for cooling the transmission line in the vacuum vessel 9 and the receiving circuits 61 to 6n at an extremely low temperature.

  The processing operation of the above configuration will be described below.

  First, at the time of transmission, when a transmission signal by an arbitrary transmission channel is input, this transmission signal is distributed and supplied to each of the transmission phase shifters 21 to 2n arranged in an array by the distributor 1, and each transmission signal is transmitted. After phase control according to the excitation distribution of the transmission beam is performed by the credit phase shifters 21 to 2n, power is amplified by the transmission amplifiers 31 to 3n, unnecessary wave components are suppressed by the transmission filters 41 to 4n, and transmission / reception is performed. It is radiated | emitted to space from antenna element T1-Tn via the switchers 51-5n. Here, as the frequency of the input transmission signal, one frequency of a plurality of transmission channels is selected by a transmission signal generator (not shown).

  At the time of reception, signals received by the antenna elements T1 to Tn are input to the reception system via the transmission / reception switchers 51 to 5n, and the amplitude is limited by the limiter 611 accommodated in the vacuum vessel 9. After that, the data is input to the BRF unit 612 composed of a plurality of BRFs 6121 to 612m. The output signal from the BRF unit 612 is amplified with low noise by the LNA 613, phase-controlled in accordance with the directivity characteristics of the received beam by the phase shifters for reception 71 to 7 n, and then combined by the combiner 8. The signals are combined and output as a receive beam.

  As described above, the antenna device according to the embodiment includes the reception system made of the normal conductive material and the BRFs 6121 to 612m made of the superconductive material connected to the reception system in the vacuum vessel 9. This makes it possible to suppress interference waves when unnecessary waves such as interference signals interfere, and at the same time to cool the superconductive material to a cryogenic temperature, a refrigerator, etc. Even when the cooling means fails and the cryogenic state cannot be maintained, the operation can be continued with the receiving system made of the normal material.

  Therefore, the antenna device of the present embodiment prevents distortion components due to interference signals and the like from being superimposed on the reception signal even when unnecessary wave interference such as interference signals occurs, and further cools the reception circuits 61 to 6n by the cooling means. As a result, it is possible to achieve high sensitivity of the receiving system.

  In addition, when the BRFs 6121 to 612m are not cooled to a cryogenic state, the antenna device is opened from the normal transmission line and does not affect the characteristics of the reception system, so that the operation of the antenna device can be continued.

  The antenna device can be applied to any of a mechanical rotating array antenna that does not use a phase shifter and a phased array antenna having a phase shifter for each antenna element or subarray.

  1 shows a block diagram of a configuration in which a plurality of receiving systems are integrated in the vacuum vessel 9, but the vacuum vessel 9 may be divided for each circuit corresponding to the antenna elements T1 to Tn. . Further, the refrigerator 10 may be divided in accordance with this.

  In the above embodiment, an antenna device including a plurality of antennas T1 to Tn arranged in an array is described. However, as n = 1 (when the antenna element has one configuration), the distributor 1, The transmission phase shifters 21 to 2n, the reception phase shifters 71 to 7n, and the combiner 8 may be omitted.

  The limiter 611 shown in FIG. 2 may be disposed outside the vacuum vessel 9. Further, a band pass filter (BPF) may be disposed in the receiving system made of a normal conductive material in order to suppress interference waves such as interference waves other than a wide reception band such as a radar band. This may be either before input of the limiter 611 or after output.

  As mentioned above, although embodiment was described, this embodiment is shown as an example and is not intending limiting the range of invention. This embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. This embodiment and its modifications are included in the scope of the present invention and the gist thereof, and are also included in the invention described in the claims and the equivalent scope thereof.

  DESCRIPTION OF SYMBOLS 1 ... Distributor, 21-2n ... Transmission phase shifter, 31-3n ... Transmission amplifier, 41-4n ... Transmission filter, 51-5n ... Transmission / reception switching device, 61-6n ... Reception circuit, 611 ... Limiter, 612 ... Band elimination filter unit, 6121 to 612m ... BRF (band elimination filter), 613 ... normal conduction line, 6141 to 614m ... bonding wire, 615 ... LNA (low noise amplifier), 71-7n ... reception phase shifter, 8 ... Synthesizer, 9 ... vacuum container, 10 ... freezer.

Claims (5)

An antenna unit for receiving a signal transmitted at an arbitrary transmission frequency among a plurality of transmission frequencies;
A normal line that forms a plurality of branch lines on the main line formed of a normal material; and
A band elimination filter formed of a superconducting material and including a plurality of band elimination filters corresponding to each of the plurality of transmission frequencies, and connection means for selectively connecting the plurality of band elimination filters and the plurality of branch lines. And
An amplifier that amplifies the received signal extracted by the band elimination filter unit with low noise;
A heat insulating container that houses the band elimination filter unit and the amplifier and blocks heat from outside;
An antenna device comprising: the band elimination filter unit housed in the heat insulation container; and a cooling means for cooling the amplifier to a cryogenic temperature.   The antenna apparatus according to claim 1, wherein the antenna unit is an array antenna formed by arranging a plurality of antenna elements in an array. A superconducting material is used for at least a part of the band elimination filter part,
The antenna apparatus according to claim 1, wherein the heat insulating container is in a vacuum state around at least a superconducting material of the band elimination filter unit.   The antenna device according to claim 1, wherein a diode is used as the plurality of band elimination filters.   The antenna device according to claim 2, wherein the heat insulating container is divided for each reception system corresponding to each of the plurality of antenna elements.

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