KR0155310B1 - High temperature superconductor microwave duplexer and method thereof - Google Patents

Abstract

The present invention is a part of the multi-channel multiplexer, which is a core component used in wireless and microwave communication systems, and is a high temperature superconductor incorporating a 3-strip right angle coupler of a microstrip branch line and a 2-pole bandpass filter of a parallel coupling line method. It is a kind of subsystem.

The microstrip line high temperature superconducting microwave duplexer of the present invention was implemented through the high temperature superconducting YBCO / MgO epitaxial thin film and micro-shaping process, and the filter signal at the output port had a bandwidth of 36 MHz and a center frequency of ˜10 GHz.

On the other hand, a double-metal (Ti / Ag) ground plane was deposited on the back of the substrate using an electron beam evaporator before the built-in high-temperature superconducting duplexer manufactured in the 4-port type 3-component test-jig and measuring low-temperature microwave characteristics. It was.

Therefore, the high temperature superconducting duplexer has a YBCO / MgO / Ti / Ag structure. The high temperature superconducting duplexer can be used for lossless and dissipative signal processing in wireless and microwave communication components. The microstrip line subsystem is expected to facilitate the development of high temperature superconducting MMICs because it is simple and lightweight.

Description

Microwave HTS duplxer and its fabrication method

1 is a plan view of a high temperature superconducting duplexer of the microstrip wire system according to the present invention.

2 is a circuit diagram of the high temperature superconducting duplexer of the microstrip wire system of FIG.

Figure 3 (a) to (e) is a manufacturing process diagram of a high temperature superconducting duplexer of the microstrip wire system according to the present invention.

* Explanation of symbols for main parts of the drawings

1: single crystal substrate 2: ground plate

3: epitaxial thin film 4: photosensitive film (PR film)

5: photosensitive film pattern 6: high temperature ductile circuit pattern

10,20: 3-dB combiner with first and second branch lines

11, 12, 21, 22: first, fourth, second and third ports (input and output terminals connected to the branch line of the combiner)

13,14,23,24: Parallel coupling line of filter connected with branch line of 3dB coupler (including matching network)

15,25: 3-dB coupler with branch line method

30,40: 2-pde bandpass filter with 1 and 2 parallel coupling lines

The present invention is a microstrip line system that combines a 3-dB coupler and a 2-pole bandpass filter, which are key components of the front end of an RF and microwave band receiver used in a mobile communication system and a satellite communication system. A high temperature superconducting duplexer for microwaves and a method of manufacturing the same.

In recent years, the demand for high-quality communication services has exploded in the fields using radio waves such as mobile communication and satellite communication (broadcasting), and in order to achieve high capacity, improvement of the characteristics and size reduction of various core components constituting the microwave communication system are key tasks. It is emerging. Therefore, in order to effectively utilize the limited radio resources, not only the development of materials with very good microwave characteristics, but also a lot of researches on the development of microwave devices and communication system components (subsystems) that can achieve high performance, high reliability, and miniaturization. Is going on. Microwave applications of high temperature superconductors with excellent microwave properties, lossless and resistive properties are known to be very advantageous for improving the characteristics of communication components. It is recognized that if an optimally designed microwave element (circuit) can be implemented on a high temperature superconducting epitaxial thin film having a very low microwave surface resistance, it will be recognized that miniaturization and high performance of microwave components will be achieved. Therefore, in order to create high-temperature superconducting MMICs for the next generation of microwave communication, characteristics such as size, goodness, and high performance must be superior to existing microwave devices (circuits), and they must be well suited to the radio wave high technology.

The duplexer among the microwave devices is a hybrid passive device that selects and outputs only one specific frequency from a plurality of input frequency signals.

The application principle of directional filters for use in multi-channel multiplexers (subsystems with integrated duplexers) is a conceptually simple and good way to solve the problems associated with multiplexer implementations, but the number of resonators constituting a bandpass filter is large. There is a drawback that the tuning of the ground and the filter is almost impossible. Therefore, the signal is much easier to adjust than the directional filter, and even when the pole number of the bandpass filter is increased (that is, the number of resonators constituting the bandpass filter) to improve the microwave characteristics, In order to implement a good multiplexing communication multiplexer, a connection between a right-angle hybrid coupler and a band-pass filter using a parallel coupling line is also widely used.

However, in order to improve the tuning characteristics through this method, the pole number of the bandpass filter should be increased, but it is physically complicated and in many cases has a disadvantage of being bulky.

Accordingly, the present invention is to provide a duplexer for microwaves and a method for manufacturing the same, which can improve the adjustment characteristics while having a simple structure and a small volume without increasing the number of poles of the band pass filter.

Microwave high temperature superconducting duplexer according to the present invention for achieving the above object is a matching network of a single crystal substrate, a branched-line right-angle 3-dB coupler and a 3-dB coupler (coupler) on one side of the single crystal substrate. Two matching networks connecting the first and fourth ports connected to each other, the branch line of the 3-dB coupler and the parallel coupling line (resonator) of the bandpass filter, and the 3-dB coupler of a quadrilateral on the other side of the single crystal substrate, 3- Output ports (second, third) connected to the branch line of the dB coupler, and matching networks (2) for connecting the parallel coupling line of the bandpass filter, and two parallel coupling lines connected to the 3-dB combiner of the two branch lines. A two-pole bandpass filter (first, second) and a ground plane formed of a Ti / Ag double metal film on the lower surface of the single crystal substrate.

The method for manufacturing a microwave high temperature superconducting duplexer according to the present invention for achieving the above object is a process of depositing an epitaxial thin film by depositing a high temperature superconductivity on top of a single crystal substrate and heat treatment, and cleaning the top of the epitaxial thin film and a photosensitive film Forming a photoresist pattern, forming a photoresist pattern by patterning the photoresist layer, and removing the exposed portion of the epitaxial thin film using the photoresist pattern as an etching mask to form a high temperature superconducting circuit pattern and forming the photoresist pattern. And a step of forming a ground plane formed of a double thin film on the lower surface of the single crystal substrate by using an electron beam evaporator.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a plan view of a duplexer for microwaves according to the present invention.

The microstrip branch line type microwave duplexer has a high coupling degree of 3 dB or more on the single crystal substrate 1 and a 3-dB right angle first and second coupler which is a 4-port type microwave passive element having a center frequency of 11 GHz. (10) (20) Two-pole first and second band pass of parallel-coupled line method with excellent insertion loss and flatness and excellent skirt characteristics up to stop band at bandwidths of 10GHz and 700MHz It is a four-port structured microwave subsystem that combines filters 30 and 40.

The dielectric substrate 1 is a MgO single crystal having a size of 20 mm x 20 mm, excellent microwave characteristics and a dielectric constant of 9.6, and first and second 3-dB right-angle couplers 10, 20, and first and The second two-pole bandpass filter 30, 40 is made of a microstrip wire of a high-temperature pyroelectric epitaxial thin film such as YBa ₂ Cu ₃ O _7-δ (hereinafter referred to as YBCO). The first coupler 10 located on one side of the single crystal substrate 1 is a 3-dB right-angle coupler of the branch line type, and the parallel coupling line of the input / output ports 11, 12 and the band pass filter using the branch line and the matching network ( 13), (14), the second coupler located on the other side on the single crystal substrate 2 is also connected as a 3-dB right angle coupler of the branch line method, the second coupler 20 located on the other side on the single crystal substrate (2) It is a 3-dB right angle coupler of the branch line type, and is connected to the second and third ports 21, 22 and parallel coupling lines 23, 24 of the filter using a branch line and a matching network. The first and second bandpass filters 30 and 40 are two-pole bandpass filters of the parallel coupling line method and are located between two 3-dB couplers of the branch line method. ), Which is included in (14)]. First, second, third, and fourth registrations engaged with the parallel coupling lines of the first, fourth, second, and third ports 11, 12, 21, and 22 and the bandpass filter; The networks 13, 14, 23, and 24 are designed so that the first and second couplers 10, 20 and the first and second bandpass filters 30, 40 match well. All are composed of 50Ω lines.

In addition, the ground plane 2 is formed on the lower surface of the single crystal substrate 1. The ground plane 2 is formed of a double metal thin film of Ti / Ag deposited for minimizing the influence of external electric and magnetic fields as well as good contact and matching with a microwave test fixture.

FIG. 2 is a circuit diagram (principle of operation) of the high temperature superconducting duplexer of the microstrip wire system of FIG.

Referring to Figure 2 will be described the operation of the high temperature superconducting duplexer of the microstrip line method according to the present invention.

As shown in FIG. 2, the microwave duplexer is designed to optimally pass the first and second 3-dB quadrature combiners 10, 20 and the desired frequency to pass the first and second bandpass filters 30, 40. If four frequencies (f _a ), (f _b ), (f _c ), (f _d ) are incident on the first port 11 of the first coupler 10, 3-dB right angle on the left At two branches of the coupler, the energy corresponding to the frequency f _a is divided equally.

The equalized energy passes through the same first and second bandpass filters 30 and 40 and enters two branches of the second coupler 20. At this time, due to the phase relations between the first and second couplers 10 and 20 and the first and second bandpass filters 30 and 40, signals are canceled from each other in the second port 21. Becomes zero.

In addition, all of the energy corresponding to the frequency f _a is collected into the third port 22. On the other hand, the other frequencies f _b , f _c , and f _d are reflected back through the first and second bandpass filters 30 and 40 to the first and second of the first combiner 10. It will enter the matching network 13, 14 again. In this case, the signals are canceled with each other in the first port 11 due to phase relations and become zero, and the energy of all the reflected frequencies is collected in the fourth port 12. The overall operating principle of the microwave duplexer is the same as that of the directional filter, which is widely used in practice. The first and second bandpass filters integrating with the first and second 3-dB combiners 10 and 20 are used. The 30 and 40 have a form of a cascade. However, the signal adjustment is much easier than the directional filter, and the tuning is excellent even when the pole number of the bandpass filter is increased.

3 (a) to (e) is a manufacturing process diagram of a microwave duplexer according to the present invention.

Referring to FIG. 3 (a), the single crystal substrate 1 having excellent microwave characteristics such as MgO is subjected to surface treatment by wet etching or ECR-ion milling.

Referring to FIG. 3 (b), a high temperature superconducting epitaxial thin film 3 such as YBCO is formed by a pulse-laser deposition method. In the above, the epitaxial thin film 3 maintains the pressure in the deposition chamber at about 200 mTorr and deposits the XBCl excimer-laser (wavelength: 308 nm) at a temperature of about 750 ° C. in the deposition chamber. It does not break the vacuum (in-suit method) and grows by heat treatment for about 1 hour while injecting oxygen at about 550 ° C.

Referring to FIG. 3C, after the HMDS (primer) is applied to the epitaxial thin film 3 to clean the surface, the photosensitive film 4 is formed. The photosensitive film 4 is formed by rotating about 30 seconds at 5000 rpm using a spin coater.

Referring to FIG. 3D, the photoresist film 4 is patterned to form the photoresist pattern 5. The photosensitive film pattern 5 is formed by exposing and developing the photosensitive film 4 using a circuit board (mask) to be formed. The exposed portion of the epitaxial thin film 3 is removed using the photoresist pattern 5 as an etching mask to form the high temperature superconducting duplexer pattern 6. In the above, the duplexer pattern 6 includes the first, fourth, second and third ports 11, 12, 21, and 21 of the first and second 3-dB combiners 10 and 20. 22), first, second, third and fourth matching networks 13, 14, 23, 24 and first and second 3-dB combiners 10, 20 and The first and second bandpass filters 30 and 40 are formed to perform one-step etching for three minutes with an etching solution such as EDTA, and to remove the superconducting thin film remaining after the one-step etching. ECR-ion milling is performed in two steps for about 5 minutes to improve the sharpness of the high temperature superconducting duplexer pattern 6.

Referring to FIG. 3E, the photoresist pattern 5 used as the etching mask is removed. Then, a ground plane 2 made of a double thin film of Ti / Ag is formed on the lower surface of the single crystal substrate 1 by using an electron beam evaporator. In the above, silver (Ag) is excellent in electrical conductivity as well as microwave properties, and makes excellent contact and matching with the inner bottom of the test fixture.

As described above, the high temperature superconducting duplexer for microwaves according to the present invention uses a high temperature superconducting YBCO thin film grown on a single crystal substrate of MgO to have a high coupling ratio of 3 dB or more and a branch line type 4-port type microwave having a center frequency of 11 GHz. Two-pole, 3-dB right-angle coupler, a center frequency of 10 GHz, parallel insertion line type, 2-pole band with excellent insertion loss and flatness and excellent skirting characteristic to stop band in the bandwidth of 700 MHz Manufactured by integrating two pass filters.

Therefore, the present invention has an advantage that the manufacturing characteristics can be improved by adjusting the epitaxial thin film by minimizing the number of band pass filters without increasing the number of poles.

Claims (6)

A first 3-dB coupler consisting of a single crystal substrate, a quadrangular 3 dB coupler having a branch line method on one side of the single crystal substrate, and a first and fourth ports connected to a matching network with a branch line of the coupler, and a first and second matching network; And a second 3-dB coupler comprising a quadrilateral 3-dB coupler having a branched line type, a second line and a third port connecting the split line of the coupler, and the third and fourth matching networks to the other side of the single crystal substrate. Microwave including two first and second two-pole bandpass filters manufactured by a parallel coupling line method connected by a matching network between a coupler and a second coupler, and a ground plane formed of a double metal film on a lower surface of the single crystal substrate. High temperature superconducting duplexer. The high temperature superconducting duplexer for microwaves according to claim 1, wherein the single crystal substrate is formed of MgO. _{3. The} high temperature superconducting duplexer according to claim 2, wherein the first and second 3-dB right angle couplers and the first and second two-pole bandpass filters are made of YBa ₂ Cu ₃ O _7-δ epitaxial thin films. 2. The microwave high temperature superconductor duplexer according to claim 1, wherein the two 3-dB quadrature couplers and the two-pole bandpass filter are connected by a branch line and a matching network. Depositing a high temperature superconducting thin film on top of the single crystal substrate and heat treatment to form an epitaxial thin film, washing the upper part of the epitaxial thin film to form a photoresist film, and patterning the photoresist film to form a photoresist pattern And removing the exposed portion of the epitaxial thin film using the photoresist pattern as an etch mask to form a high temperature superconducting circuit (duplexer) pattern and removing the photoresist pattern, and an electron beam evaporator on a lower surface of the single crystal substrate. Method of manufacturing a high temperature superconducting duplexer for microwave through the process of forming a ground plane consisting of a double thin film using. The material of claim 5, wherein the high temperature superconducting circuit pattern is etched by etching dissolution (EDTA) of acetic acid for about 3 minutes and ECR-ion milling is performed for about 5 minutes after the first step of etching. A method of manufacturing a high temperature superconducting duplexer for microwave manufacturing a device as a second step of removing.