JP4068521B2 - Superconducting duplexer device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a superconducting duplexer device, and more particularly to a superconducting duplexer device including a filter circuit for separating a high-frequency transmission / reception signal by connecting to a transmission / reception antenna. This type of duplexer apparatus is suitable for use in a transmission / reception unit of a base station in mobile communication.
[0002]
[Prior art]
In mobile communication, a transmission / reception antenna is often shared, and a duplexer device that separates a high-frequency transmission / reception signal by a filter circuit is required. Filter characteristics that remove signals in unnecessary frequency bands and pass only signals in necessary frequency bands are ideal characteristics as the passing characteristics (S ₂₁ ) become steeper, and for that purpose, resonance that constitutes the filter is performed. It is necessary to increase the number of stages n.
[0003]
In this respect, if the filter is made of a superconductor, the conductor loss can be made much smaller than that of a normal metal. For example, even when n = 15, the loss can be extremely small, such as 0.15 dB. Then, since a power of about several tens of watts from the transmission wave tends to go around to the reception filter side, the superconductor filter has a drawback of lacking power resistance.
[0004]
Under such circumstances, conventionally, there is known a duplexer apparatus in which a superconducting filter 10 is provided on the receiving side after a transmission / reception wave is separated by a room temperature type duplexer 20 (Patent Document 1). However, since the loss of the room temperature duplexer 20 and the connection cable is added in advance, the advantage of low loss by the superconducting filter 10 is lost.
[0005]
In addition, in the related art, a reception filter in which n resonators are configured by superconducting microstrip lines, and the width of 1 or m (n> m) resonators on the shared antenna side is transmitted from the shared antenna side. The thing thickened so that sufficient tolerance with respect to electric power may be acquired is known (patent document 2). However, it is good if the transmission power from the shared antenna side is not so high, but it cannot be fully used in applications where a large transmission power of about several tens of watts is circulated from the shared antenna side, for example, in a base station.
[0006]
In addition, a band rejection filter that restricts the passage of signals in the frequency bands f1 and f2 adjacent to a desired band of a high-frequency signal has been conventionally formed by a non-superconducting material that does not lower the conductivity due to heat generation. One having a first line 20 and second lines 21 and 22 for a resonator formed of a superconducting material and resonating with an adjacent frequency is known (Patent Document 3). However, since the loss due to the non-superconducting material line 20 is constantly added, the merit of low loss due to the superconducting filters 21 and 22 is lost.
[0007]
[Patent Document 1]
JP 2000-252853 A (summary, figure).
[0008]
[Patent Document 2]
JP-A-11-68404 (summary, figure).
[0009]
[Patent Document 3]
JP 2000-269754 (summary, FIG. 9).
[0010]
[Problems to be solved by the invention]
As described above, in the past, in view of the low power resistance of superconductors, especially in applications such as base stations where large transmission power is applied, a transmission / reception filter is integrated into one superconducting duplexer device. It was not considered to make up.
[0011]
The present invention has been made in view of the above-mentioned problems of the prior art, and the object of the present invention is to provide a superconducting duplexer device that can achieve extremely low loss and high performance by integrating a superconductor transmitting / receiving filter. Is to provide.
[0012]
[Means for Solving the Problems]
The above problem is solved by the configuration of FIG. That is, the superconducting duplexer device according to the present invention (1) is a common dielectric having a ground layer 22 on the back surface in the superconducting duplexer device for separating a high-frequency transmission / reception signal by connecting to the transmitting / receiving antenna 10. A filter circuit formed of a superconducting microstrip line formed on a substrate 21; a transmission filter 3 that passes a transmission signal component of a required transmission bandwidth; and a reception filter 5 that passes a reception signal component of a required reception bandwidth; provided in front of the reception filter 5, the with suppressing the echo component of the signal from the transmission filter 3 to the reception filter 5 and the suppression filter 4 composed of a superconductor, the critical temperature following a whole these And a refrigerator to be held in the machine .
[0013]
According to the present invention (1), the suppression filter 4 composed of a superconductor for suppressing the sneak component of the signal from the transmission filter 3 to the reception filter 5 is provided in the preceding stage of the reception filter 5, Even if a relatively large transmission power reaches the receiving side, this can be sufficiently suppressed with low heat generation. Therefore, the reception filter 5 can sufficiently perform its original function as a reception filter without destroying the superconducting state. Moreover, since the suppression filter 4 is a superconductor, the loss in the reception band is extremely small, and the loss of the entire duplexer device is sufficiently small.
[0014]
In the present invention (2), in the present invention (1), as shown in FIG. 2, for example, the suppression filter 32 (corresponding to 4 in FIG. 1) includes one or more planar resonators 32a, It is composed of a large-area bandpass filter (BPF) with 32b interposed, and its pass characteristic is wider than that of the reception filter 33 (corresponding to 5 in FIG. 1) and has a gentle attenuation characteristic. is there. Therefore, even if a relatively large transmission power wraps around the receiving side, unnecessary components can be sufficiently reflected in a state where current is dispersed by the large-area resonators 32a and 32b. Can be sufficiently suppressed.
[0015]
In the present invention (3), in the present invention (1), as shown in FIG. 6, for example, the suppression filter 35 (corresponding to 4 in FIG. 1) includes one or more planar resonators along the receiving strip line. The band stop filter (BRF) is a large area type in which 35a and 35b are combined, and the stop bandwidth is wider than the required transmission bandwidth. Therefore, even if a relatively large transmission power wraps around the receiving side, the unnecessary component can be sufficiently absorbed in a state where the current is dispersed by the large area resonators 35a and 35b. Can be sufficiently suppressed.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a plurality of preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the same reference numerals denote the same or corresponding parts throughout the drawings. Also, this superconducting duplexer device is suitable for application to a base station device of a mobile communication system.
[0017]
FIG. 2 is a diagram for explaining the superconducting duplexer device according to the first embodiment, showing a case where each superconducting filter circuit formed on a single dielectric substrate is constituted by a band pass filter (BPF). Yes.
[0018]
In the figure, 20a is a superconducting duplexer according to the first embodiment, 10 is a transmission / reception antenna (ANT), 21 is a common (single) dielectric substrate made of magnesium oxide MgO, and 22 is formed on the entire back surface. A grounded layer 24, a superconducting microstrip transmission line formed on the surface of the substrate 21, 31 a transmission filter (BPF) for passing a transmission signal component Tx having a required transmission bandwidth, and 33 a required reception band A reception filter (BPF) 32 that allows the reception signal component Rx having a width to pass therethrough is provided in a preceding stage of the reception filter 33, and a suppression filter (BPF) for suppressing a sneak component of the signal from the transmission filter 31 to the reception filter 33, Reference numeral 40 denotes a refrigerator for maintaining the entire superconducting duplexer circuit at a superconducting critical temperature (93K) or lower.
[0019]
For example, a YBCO-based oxide superconducting film having a film thickness of about 300 to 1000 nm is formed on an MgO (εr = 9.7) substrate 21 by sputtering or the like, the back surface is a ground layer, and various planar circuit filters on the surface. Form a pattern.
[0020]
An example transmission filter 31 is a large-area band-pass filter (BPF) in which disk (disk) type resonators 31a and 31b are interposed on a transmission strip line. The power of the transmission wave Tx is about 50 dBm (100 W) at the maximum, but in each of the resonators 31a and 31b, the current density is sufficiently dispersed due to its large area, and thus deviates from the critical current and critical temperature during operation. The superconducting state is sufficiently maintained.
[0021]
Note that square resonators 31a and 31b may be used instead of the disk resonators 31a and 31b. Moreover, if it is a large area type | mold, the pattern of various well-known band pass filter circuits other than the above can be employ | adopted. Furthermore, the number of stages of the transmission filter 31 can be selected according to the required band pass characteristics.
[0022]
The suppression filter 32 as an example is a large-area band-pass filter (BPF) in which square resonators 32a and 32b are interposed on the reception strip line. Even if the transmission power sneaking into the reception system is about several tens of watts, the current density is sufficiently dispersed by the large area of each of the resonators 32a and 32b. The superconducting state is sufficiently maintained.
[0023]
Instead of the square resonators 32a and 32b, disk (disk) resonators 32a and 32b may be used. Moreover, if it is a large area type | mold, the pattern of various well-known band pass filter circuits other than the above can be employ | adopted. In consideration of the fact that the transmission power that wraps around the reception system is relatively smaller than that of the transmission system, various types of smaller band-pass filter circuit patterns can be adopted as the suppression filter 32. Furthermore, although the number of stages of the suppression filter 32 can be selected in accordance with the required band pass characteristics, in this embodiment, two stages are used in order to minimize the pass loss in the previous stage.
[0024]
The reception filter 33 in the example is configured by arranging a plurality of hairpin resonators having λ / 2 wavelengths on a reception strip line. Although the figure shows the case where the number of stages is n = 9, even when n = 15, the loss can be made extremely small as 0.15 dB, and an extremely sharp band-pass characteristic can be obtained. In the hairpin resonator 33, since the current is concentrated in the vicinity of the λ / 4 wavelength of each resonator central portion, heat is generated in that portion. However, since the power of the received wave is at most about 0 dBm (1 mW), Superconducting state is maintained. The reception filter 33 is not limited to the hairpin resonator, and may be, for example, a spiral resonator having a reduced size.
[0025]
FIG. 3 shows band characteristics of the superconducting duplexer device according to the first embodiment. In the figure, the characteristic 31C of the transmission filter 31 is the pass bandwidth fT1 to fT2, the characteristic 32C of the suppression filter 32 is the pass bandwidth fR1 to fR2, and the characteristic 33C of the reception filter 33 is the pass bandwidth fR3 to fR4. Preferably, the passband widths fR1 to fR2 of the suppression filter 32 are wider than the passband widths fR3 to fR4 of the reception filter 33, and have a gentle attenuation characteristic. Therefore, the suppression filter 32 can be configured with a small number of stages, and the sneak current from the transmission wave can be sufficiently suppressed.
[0026]
In such a configuration, the transmitted wave that has passed through the transmission filter 31 tries to flow into the suppression filter 32. However, since fT1 to fT2 are in the attenuation region when viewed from the suppression filter 32, they pass through the suppression filter 32 and are received. The power flowing into the filter 33 is sufficiently suppressed. At this time, since the suppression filter 32 is a large area type resonator, the superconducting state does not collapse. On the other hand, the reception filter 33 has a pass bandwidth of fR3 to fR4, and this band is a reception band on the system. Since the reception filter 33 is a hairpin type that is small and can increase the number of filter stages, a steep attenuation characteristic 33C is obtained.
[0027]
FIG. 4 is a diagram for explaining the superconducting duplexer device 20b according to the second embodiment, and shows a case where a band rejection type transmission filter 34 is employed instead of the transmission filter 31 of FIG. The transmission filter 34 of this example is a large area type band rejection filter (BJF) in which planar resonators 34a and 34b are coupled at each λ / 4 wavelength along the transmission strip line. Although the power of the transmission wave Tx is about 100 W at the maximum, the current density is sufficiently dispersed by the large area in each of the resonators 34a and 34b, so that the critical current and the critical temperature are not deviated during operation. The superconducting state is sufficiently maintained.
[0028]
In addition, if it is a large area type | mold, the pattern of various well-known band stop filter circuits besides the above can be employ | adopted. Normally, the unnecessary wave component included in the transmission wave Tx is about 30 to 50 dB smaller than the transmission level, so that the resonators 34a and 34b need not have a particularly large area to disperse the current. Also, the number of stages of the transmission filter 34 can be selected according to the required band rejection characteristic.
[0029]
FIG. 5 shows the band characteristics of the superconducting duplexer device according to the second embodiment. In the figure, the transmission filter 34 includes resonator elements 34a and 34b. The band stop characteristic of the resonator 34a is 34Ca, and the band stop characteristic of the resonator 34b is 34Cb. Therefore, the substantial pass characteristic of the transmission filter 34 is the pass bandwidth fT1 to fT2. The pass characteristics of the other suppression filters 32 and reception filters 33 may be the same as those described in FIG.
[0030]
In such a configuration, the transmission wave that has passed through the transmission filter 34 tries to flow into the suppression filter 32. However, since the substantial pass bandwidths fT1 to fT2 are in the attenuation region as viewed from the suppression filter 32, the suppression filter The power that passes through 32 and flows into the reception filter 33 is sufficiently suppressed. At this time, since the suppression filter 32 is a large area type resonator, the superconducting state does not collapse. On the other hand, since the reception filter 33 is a hairpin type that is small and can increase the number of filter stages, a steep attenuation characteristic 33C is obtained.
[0031]
FIG. 6 is a diagram for explaining a superconducting duplexer device 20c according to the third embodiment, and shows a case where a band rejection type suppression filter 35 is employed instead of the suppression filter 32 of FIG. The suppression filter 35 in this example is a large-area band-rejection filter (BRF) in which one or more planar resonators 35a and 35b are coupled along the reception strip line. In the example of FIG. 6, the example using the hairpin type | mold resonators 35a and 35b of a suitable area is shown. Also, the number of stages of the suppression filter 35 can be selected according to the required band rejection characteristics.
[0032]
Note that the suppression filter 35 in this example needs to suppress most of the transmission wave sneak power, and therefore a large-area filter is used. However, in the case of a large area type, various known band elimination filter circuit patterns other than the above can be adopted. For example, another example of the band rejection filter 36 is shown in FIG.
[0033]
FIG. 7 shows band characteristics of the superconducting duplexer device according to the third embodiment. In the figure, the pass characteristic 35C of the suppression filter 35 is the stop bandwidth fT3 to fT4, which is wider than the required transmission bandwidth fT1 to fT2. The pass characteristics of the other transmission filters 31 and reception filters 33 may be the same as those described in FIG.
[0034]
In such a configuration, a part of the transmission wave that has passed through the transmission filter 31 tends to sneak toward the suppression filter 35, but the sneak component is sufficiently attenuated by the suppression filter 35. The power flowing in is sufficiently suppressed. At this time, since the suppression filter 35 is a large-area resonator, the superconducting state does not collapse. On the other hand, since the reception filter 33 is a hairpin type that is small and can increase the number of filter stages, a steep attenuation characteristic 33C is obtained.
[0035]
In addition, although several embodiment suitable for the said invention was described, it cannot be overemphasized that the structure of each part and various changes can be performed within the range which does not deviate from this invention thought.
[0036]
(Supplementary note 1) In a superconducting duplexer device for separating a high-frequency transmission / reception signal by connecting to a transmitting / receiving antenna, a superconducting microstrip line formed on a common dielectric substrate having a ground layer on the back surface A filter circuit that passes a transmission signal component of a required transmission bandwidth, a reception filter that passes a reception signal component of a required reception bandwidth, and is provided in a stage preceding the reception filter and receives from the transmission filter A superconducting duplexer device comprising: a suppression filter for suppressing a sneak component of a signal to the filter, and maintaining the whole of the filter below a critical temperature.
[0037]
(Supplementary note 2) The superconducting duplexer device according to supplementary note 1, wherein the transmission filter comprises a large-area type band-pass filter in which one or more planar resonators are interposed on a transmission strip line.
[0038]
(Supplementary note 3) The superconducting duplexer device according to supplementary note 1, wherein the transmission filter includes a large area type band rejection filter in which a plurality of planar resonators are coupled along a transmission strip line.
[0039]
(Supplementary Note 4) The suppression filter is composed of a large-area bandpass filter in which one or more planar resonators are interposed on the reception strip line, and its pass characteristic is wider than the passband width of the reception filter. The superconducting duplexer device according to appendix 1, wherein the device has a gentle damping characteristic.
[0040]
(Supplementary Note 5) The suppression filter is composed of a large area type band stop filter in which one or more planar resonators are coupled along the reception strip line, and the stop bandwidth is wider than the required transmission bandwidth. The superconducting duplexer device according to Supplementary Note 1, wherein:
[0041]
【The invention's effect】
As described above, according to the present invention, a superconductor transmission / reception filter can be integrated into a single superconducting duplexer device, which contributes significantly to improving the performance of the superconducting duplexer device. large.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating the principle of the present invention.
FIG. 2 is a diagram illustrating a superconducting duplexer device according to a first embodiment.
FIG. 3 is a diagram illustrating band characteristics of the superconducting duplexer device according to the first embodiment.
FIG. 4 is a diagram illustrating a superconducting duplexer device according to a second embodiment.
FIG. 5 is a diagram for explaining band characteristics of a superconducting duplexer device according to a second embodiment;
FIG. 6 is a diagram for explaining a superconducting duplexer device according to a third embodiment;
FIG. 7 is a diagram for explaining band characteristics of a superconducting duplexer device according to a third embodiment;
FIG. 8 is a diagram illustrating a band rejection filter according to another embodiment.
[Explanation of symbols]
20 Superconducting duplexer 10 Transmitting and receiving antenna (ANT)
21 Dielectric substrate 22 Ground layer 24 Transmission line 31, 34 Transmission filter 33 Reception filter 32, 35 Suppression filter 40 Refrigerator

Claims (3)

In a superconducting duplexer device that is connected to a transmission / reception antenna and separates high-frequency transmission / reception signals,
A filter circuit using a superconducting microstrip line formed on a common dielectric substrate having a ground layer on the back, a transmission filter for passing a transmission signal component of a required transmission bandwidth, and a reception signal of a required reception bandwidth a reception filter for passing components, provided in front of the reception filter, a suppression filter which is constituted by a superconductor with suppressing the echo component of the signal to the reception filter from the transmission filter, the total of these A superconducting duplexer apparatus comprising: a refrigerator that is maintained below a critical temperature.   The suppression filter is a large-area type bandpass filter in which one or more planar resonators are interposed on the reception strip line, and its pass characteristic is wider than the passband width of the reception filter and has a gentle attenuation characteristic. The superconducting duplexer device according to claim 1, comprising:   The suppression filter is composed of a large area type band stop filter in which one or more planar resonators are coupled along the reception strip line, and the stop bandwidth is wider than the required transmission bandwidth. The superconducting duplexer device according to claim 1.

Images