CN110401031A - A redefinable microwave device based on phase change materials - Google Patents

Abstract

Microwave device is redefined based on phase-change material the present invention relates to a kind of.Including medium substrate, radiation patch, transmission line, on-off transmission line and two Block- matching units are equipped in the middle part of the top surface of medium substrate；The bottom surface of medium substrate is metal ground plate；The material of on-off transmission line and matching unit is vanadium dioxide；The function of microwave paster antenna is realized using the low conductivity combination of the low conductivity and on-off transmission line of matching unit；Microwave energy fading transmission is formed using the combining properties of high conductivity after on-off transmission line before phase change low conductivity, matching unit phase transformation, realizes the function of microwave attenuator；Frequency selection circuit is constituted together with metal patch using the performance of high conductivity after high conductivity, matching unit phase transformation after on-off transmission line phase transformation, combination forms microwave signal filter transmission, realizes the function of microwave filter.Present invention reduces the cost of microwave device, solves the problems, such as device stack caused by minimizing because of microwave device, improve Electro Magnetic Compatibility.

Description

A redefinable microwave device based on phase change materials

technical field

The invention belongs to the field of microwave antennas, microwave circuits and devices, in particular to a redefinable microwave device capable of conversion and reconfiguration of multiple device functions.

Background technique

In the field of microwave circuits, due to the limitation of electromagnetic distribution and the complexity of electromagnetic wave propagation, it is difficult to realize the multiplexing of microwave circuits by using the reconfigurable way of digital circuits. As early as the 1960s, reconfigurability in the microwave field was proposed. It has been one of the research hotspots for half a century. So far, researchers have achieved the same research on the reconfigurability of microwave devices and circuits. The reconfigurability of microwave device indicators is basically divided into three aspects: 1. Using the reconfigurable properties of the conductivity of phase change materials to select the microwave circuit structure or switch the current path, realize the One or more indicators can be reconfigured based on a device. 2. Through variable microwave devices such as variable resistors and variable capacitors, parameters such as equivalent resistance and capacitance of variable microwave devices are changed to switch microwave circuits to realize the reconstruction of performance indicators. 3. The reconfigurability of the microwave device index is realized by changing the bending or stretching of the carrier to realize the reorganization of the circuit structure. The reconfigurability realized by the above microwave devices mainly focuses on the on-off of the current in the circuit structure or the tuning of the equivalent parameters of the overall structure by changing the locally variable microwave devices. The problems it solves mainly focus on several performance The reconstruction of indicators, such as the reconstruction of the operating frequency band and phase of the same device, has not fundamentally changed the functional definition of the device. The current reconfigurable design method also brings some problems on the basis of realizing the transformation of different indicators of a single device. For example, there are still many device functional units in the microsystem, the circuit area is relatively large, the circuit is complex, and the parasitic effect is serious. . Therefore, it is urgent to consider how to solve the reconfigurable and reusable problem of microwave circuits from a deeper level, and realize general-purpose microwave devices and circuits with more functions and better performance in a simpler, more flexible and more compact way, and shorten microwave circuits. gap with digital circuits.

Contents of the invention

In order to realize the conversion, multiplexing and reconfiguration of the functions of different microwave devices, that is, to realize the redefinition of microwave devices, the present invention provides a redefinable microwave device based on phase change materials.

A redefinable microwave device based on phase change materials includes a dielectric substrate 1, a radiation patch 2 is arranged in the middle of the top surface of the dielectric substrate 1, one end of the radiation patch 2 is connected to one end of a transmission line 3, and the radiation patch 2 The other end is connected to one end of the on-off transmission line 4, the other end of the transmission line 3 is an input port, the other end of the on-off transmission line 4 is an output port, the input port of the transmission line 3 and the output port of the on-off transmission line 4 are respectively located on the sides of the dielectric substrate 1 edge; the radiation patches 2 corresponding to the two sides of one end of the transmission line 4 are respectively embedded with matching units 5; the bottom surface of the dielectric substrate 1 is a metal ground plate 6; during operation, the input port of the transmission line 3 and the on-off transmission line 4 The output ports of each feed through the coaxial connector;

The material of the on-off transmission line 4 and the material of the matching unit 5 are the same phase change material, and the phase change material is vanadium dioxide;

Under room temperature conditions, the combination of the low conductivity of the matching unit 5 and the low conductivity of the on-off transmission line 4 realizes the function of the microwave patch antenna; using the low conductivity of the on-off transmission line 4 before the phase change, when the temperature rises to Above 68°C, the matching unit 5 has high conductivity performance after phase change, and the combination of the two forms microwave energy attenuation transmission, realizing the function of a microwave attenuator; when the temperature rises above 68°C, the on-off transmission line 4 and the matching unit 5 are homogeneous It becomes high-conductivity performance, forms a frequency selection circuit together with the metal patch 2, and realizes the function of a microwave filter.

Further defined technical solutions are as follows:

The material of the dielectric substrate 1 is aluminum oxide, and the materials of the radiation patch 2, the transmission line 3 and the metal ground plate 6 are all copper.

The working band of the microstrip patch antenna is the C band with a wavelength of 58-60mm, the center frequency wavelength _λ0 is 59mm, S11≤-10dB within 5.05GHz to 5.15GHz, and the pattern gain of 5.1GHz is about 1.7dB.

The working frequency band of the microwave attenuator is 4-6GHz, the insertion loss of the two ports is less than -55dB, and the attenuation effect is better.

The working band of the bandpass filter is the C band with a wavelength of 58-60mm, the center frequency wavelength _λ0 is 59mm, the insertion loss of the port is -1dB, and the out-of-band isolation is below -10dB.

When the center frequency wavelength λ ₀ is 59mm,

The length L _b of the dielectric substrate 1 is 0.5λ ₀ , the width W _b is 0.3λ ₀ , the height H _b is 0.5mm, and the thickness H _f0 is 1um;

The length and width of the metal ground plate 6 are equal to the length and width of the dielectric substrate 1;

The length L _f0 of the radiation patch 2 is 0.216λ ₀ , and the width W _f0 is 0.155λ ₀ ;

The length L _f1 of the transmission line 3 is 10.35 mm, and the width W _f1 is 0.5 mm;

The length L _f2 of the on-off transmission line 4 is 10.35 mm, and the width is W _f1 ;

The matching unit 5 has a length L _f3 of 3.2 mm and a width of W _f1 .

Beneficial technical effect of the present invention is embodied in the following aspects:

1. Compared with the previous technology, the previous microwave reconfigurable device is only the same device, and the reconstruction of one or several indicators does not involve the reconfiguration of the device function; while the reconfigurable device proposed by the present invention, It is the reconfiguration of different functions. Under different reconfiguration effects, the reconfiguration between different types or different definitions of microwave devices is realized. The conversion between microwave antenna, microwave attenuator and band-pass filter is realized by using the change of conductivity of vanadium dioxide, a phase change material, before and after the phase change.

2. Compared with the previous technology, the previous phase-change materials were used in reconfigurable microwave circuits and devices, but the phase-change materials were only used as switches, and the conductivity change characteristics of the phase-change materials were not fully utilized to make them generate circuits. Matching function, the invention utilizes the conductivity change characteristic of the phase change material to participate in the matching of the microwave circuit before the phase change, optimizes the structure of the microwave circuit, and enables the phase change material to better exert its phase change performance in the microwave circuit.

3. Compared with the previous technology, the previous phase-change materials or reconfigurable microwave circuits and devices used the phase-change materials as switches. On the same circuit board, different functional circuits were designed, and the switch selection was different. Therefore, the circuit area and volume are too large, which is not conducive to the miniaturization of microwave circuits. The redefinition of device functions by using phase-change materials proposed by the present invention achieves the multiplexing of the same circuit structure, and realizes the transformation of device functions through the difference in electromagnetic field distribution. Therefore, it is essentially different from the previous design ideas, and the circuit area is significant Reduced, device integration has been greatly improved, and at the same time solved the problem of signal crosstalk between devices.

4. Microwave passive devices are mainly divided according to their different selectivity to electromagnetic wave frequency, different energy guidance or radiation, and different phase adjustment. The present invention fully considers the selection of three representative microwave passive devices. The devices are microwave antennas with radiation management functions, microwave attenuators with energy absorption functions, and bandpass filters with frequency selection functions. The "redefinable" of the three microwave passive devices can be realized by integrating them in the same structure.

Description of drawings

Fig. 1 is a schematic diagram of the device structure of the present invention.

FIG. 2 is a top view of the device structure of the present invention and an annotated drawing of the substrate size.

Fig. 3 is a front view of the device structure of the present invention and an annotated diagram of the height dimension of the device.

Figure 4 is an annotated diagram of the internal length and width dimensions of the redefinable device.

Fig. 5 is a graph of gain and return loss for realizing the antenna function according to the present invention.

FIG. 6 is an E/H plane pattern at a frequency point of 5.1 GHz after realizing the antenna function according to the present invention.

Fig. 7 is an insertion loss diagram of the microwave attenuator of the present invention.

Fig. 8 is a graph of return loss and in-band loss of the filter of the present invention.

Serial numbers in the above figure: dielectric substrate 1, radiation patch 2, transmission line 3, on-off transmission line 4, matching unit 5, metal ground plate 6.

Detailed ways

The present invention will be further described through the embodiments below in conjunction with the accompanying drawings.

Example 1

Metal cavity microstrip patch antenna working in the C-band with a wavelength of 58-60mm, the center frequency wavelength λ ₀ is 59mm, the center frequency is 5.1GHz, the lower side frequency is 5.05GHz, and the upper side frequency is 5.15GHz. The working frequency band of the microwave attenuator is 4~6GHz. The working band of the bandpass filter is also the C band with a wavelength of 58-60mm, and the center frequency wavelength _λ0 is 59mm.

Referring to FIG. 1 , a redefinable microwave device based on phase change materials includes a cuboid dielectric substrate 1 , and a radiation patch 2 of copper material with a thickness of 1.5 um is grown in the middle of the top surface of the dielectric substrate 1 . One end of the radiation patch 2 is connected to one end of the transmission line 3, the other end of the radiation patch 2 is connected to one end of the on-off transmission line 4, the other end of the transmission line 3 is an input port, the other end of the on-off transmission line 4 is an output port, and the transmission line The input port of 3 and the output port of the on-off transmission line 4 are respectively located on the edge of the dielectric substrate 1; the radiation patches 2 corresponding to the two sides of one end of the on-off transmission line 4 are respectively embedded with matching units 5; the bottom surface of the dielectric substrate 1 is a metal connection. Floor 6.

The material of the dielectric substrate 1 is aluminum oxide, and the materials of the radiation metal patch 2 , the transmission line 3 and the metal ground plate 6 are all copper. The material of the on-off transmission line 4 and the material of the matching unit are the same phase change material vanadium dioxide.

Referring to Fig. 2 and Fig. 3, the internal dimensions of the dielectric substrate 1: where λ ₀ is 59 mm, the length L _b is 0.5 λ ₀ , the width W _b is 0.3 λ ₀ , and the height H _b is 0.5 mm; the thickness H of the metal ground plate 6 _f0 is 1um; the length and width of the metal ground plate 6 are equal to the length and width of the dielectric substrate 1 .

Referring to Fig. 4, the length L _f0 of the radiating metal patch 2 is 0.216λ ₀ , the width W _f0 is 0.155λ ₀ , and the thickness H _f1 is 1um. The length _Lf1 of the transmission line 3 is 10.35mm, and the width _Wf1 is 0.5mm; the length _Lf2 of the on-off transmission line 4 is 10.35mm, and the width is _Wf1 ; the length _Lf3 of the embedded matching structure of the matching unit 5 is 3.2mm, and the width is W _f1 ; where λ ₀ is the center frequency of the metal cavity microstrip patch antenna; the line width W _f1 is based on the best consideration of impedance matching, which plays a role in suppressing energy reflection.

Referring to FIG. 5 , the curve of antenna S11 parameters changing with frequency. In 5.05GHz to 5.15GHz, S11≤-10dB, S21≤-25dB, the port isolation is very good and also conforms to the narrowband characteristics of the microstrip patch antenna.

Referring to FIG. 6 , the pattern curve of the antenna in this embodiment at 5.1 GHZ fully complies with all indicators of the pattern of the microstrip patch antenna.

Referring to Figure 7, the microwave attenuator completely attenuates the energy of the port in the 4-6GHz frequency band S21≤-55dB, and the microwave attenuator has a better index.

Referring to Figure 8, S11≤-20dB and S21>-1.5dB of the filter at the frequency point of 5.05-5.15GHz; it meets the filter port and insertion loss index.

When the matching unit 5 is used as the matching structure of the microwave antenna before the phase change (low conductivity), the on-off transmission line 4 cannot form effective electromagnetic reflection with the metal ground plate 6 because of its material property of low conductivity, so as to guide the direction of the electromagnetic wave and block the two The function of the high-frequency voltage and current of the port, and the redefinable microwave device realizes the function of the microstrip patch antenna. When the matching unit 5 is converted to a high conductivity after the phase change, the low conductivity of the on-off transmission line 4 attenuates the energy of the input port, so that the redefinable microwave device realizes the function of a microwave attenuator. After being heated, the on-off transmission line 4 forms effective electromagnetic reflection with the metal ground plate 6 with the material properties of high conductivity, guides the direction of the electromagnetic wave and conducts the high-frequency voltage and current function of the two ports, and cooperates with the matching unit 5 to also use high-conductivity after heating. The material property of the rate enables the redefinable microwave device to realize the function of a microwave bandpass filter.

Under the guidance of the concept of redefinition, the phase change material meeting the conditions of the present invention basically has the following characteristics: First, the direction of the electromagnetic wave is significantly affected before and after the phase change, and the transmission path or resonance characteristics of its high-frequency current and voltage can be changed. Secondly, the phase change conditions of the phase change material are simple and convenient, and the phase change material has strong recyclability. Finally, it can be compatible with contemporary integrated circuit technology. At present, phase change materials commonly used in the field of microwave and millimeter waves include graphene, liquid crystal, and vanadium oxide. In the comprehensive comparison, vanadium dioxide is the simplest in the phase transition condition, because the phase transition process can be completed when the external temperature is higher than 68 degrees, and the conductivity of vanadium dioxide before and after the phase transition of sapphire (Al ₂ O ₃ ) substrate is The rate change exceeds 1000 times, and the phase transition process can be completed within 100ns. Finally, the sputtering process used in the preparation of vanadium dioxide is fully compatible with modern integrated circuits. Based on the above advantages, the present invention uses vanadium dioxide as the phase change material for redefinable devices.

The invention can redefine the microwave device. Under the condition of room temperature without heating, both the on-off transmission line 4 and the matching unit 5 maintain the property of low conductivity of vanadium dioxide, and the combination realizes the microwave antenna function. Keep the external temperature above 68°C, heat the matching unit 5 to make it completely phase change, change the conductivity of vanadium dioxide to high conductivity, and keep the external condition of the on-off transmission line 4 without heating and continue to use the phase change material with low conductivity The properties of the rate are combined to realize the function of the microwave attenuator. Simultaneous heating of the on-off transmission line 4 and the matching unit 5 to above 68° C. enables the phase change material to achieve high conductivity properties, and the combination realizes the function of a microwave band-pass filter.

Claims (6)

1. a kind of redefine microwave device based on phase-change material, it is characterised in that: including medium substrate (1), in medium base Radiation patch (2) are equipped in the middle part of the top surface of plate 1, one end of radiation patch (2) is connected to one end of transmission line (3), radiation patch (2) the other end is connected to one end of on-off transmission line (4), and the other end of transmission line (3) is input port, on-off transmission line (4) the other end is output port, and the input port of transmission line (3) and the output port of on-off transmission line (4) are located at Jie The edge of matter substrate (1)；Matching unit (5) are respectively embedded on radiation patch (2) corresponding with one end two sides of transmission line (4)； The bottom surface of the medium substrate (1) is metal ground plate (6)；When work, the input port and on-off of the transmission line (3) are transmitted The output port of line (4) is fed by coaxial connector respectively；

On-off transmission line (4) material and matching unit (5) material are identical phase-change material, and the phase-change material is dioxy Change vanadium；

Under room temperature, the low conductivity combination of the low conductivity and on-off transmission line (4) of the matching unit (5), is realized micro- The function of wave paster antenna；Using the low conductivity of on-off transmission line (4) before phase change, when temperature is increased to 68 DEG C or more, matching The performance of high conductivity, the two combine to form microwave energy fading transmission after unit (5) phase transformation, realize the function of microwave attenuator Energy；When temperature rises to 68 DEG C or more, on-off transmission line (4) and matching unit (5) homogeneously become high conductivity performance, paste with metal Piece 2 constitutes frequency selection circuit together, realizes the function of microwave wave filter.

A kind of microwave device is redefined based on phase-change material 2. according to claim 1, it is characterised in that: given an account of The material of matter substrate (1) is aluminum oxide, and the material of the radiation patch (2), transmission line (3) and metal ground plate (6) is equal For copper.

A kind of microwave device is redefined based on phase-change material 3. according to claim 1, it is characterised in that: described

The service band of micro-strip paster antenna is the C-band of 58~60mm of wavelength, center frequency wavelength λ₀For 59mm, in 5.05GHz The directional diagram gain of S11≤- 10dB in 5.15GHz, 5.1GHz are about 1.7dB.

A kind of microwave device is redefined based on phase-change material 4. according to claim 1, it is characterised in that: described micro- The working frequency range of wave attenuators is that the Insertion Loss of two ports 4~6GHz is less than -55dB, and attenuating is preferable.

A kind of microwave device is redefined based on phase-change material 5. according to claim 1, it is characterised in that: the band The service band of bandpass filter is the C-band of 58~60mm of wavelength, center frequency wavelength λ₀For 59mm, the Insertion Loss -1dB of port, With outer isolation below -10dB.

A kind of microwave device is redefined based on phase-change material 6. according to claim 1, it is characterised in that: work as center Frequency wavelength λ₀When for 59mm,

The length L of the medium substrate (1)_bFor 0.5 λ₀, width W_bFor 0.3 λ₀, height H_bFor 0.5mm, thickness H_f0For 1um；

The length and width of the metal ground plate (6) and the length and width of medium substrate (1) are equal；

The long L of the radiation patch (2)_f0For 0.216 λ₀, wide W _f0For 0.155 λ₀；

The long L of the transmission line (3)_f1For 10.35mm, wide W _f1For 0.5mm；

The long L of the on-off transmission line (4)_f2For 10.35mm, width W _f1；

The long L of the matching unit (5)_f3For 3.2mm, width W _f1。