阅读说明：本技术 一种基于vo2的多功能滤波器 (Based on VO2Multifunctional filter ) 是由 张勇 曹天豪 邓乐 朱华利 胡江 于 2021-06-09 设计创作，主要内容包括：本发明属于微波频段滤波器设计技术领域,具体提供一种基于VO-(2)的多功能滤波器,包括：基板1,设置于基板上依次连接的输入50欧姆微带线2、第一级阻抗匹配结构至第N级阻抗匹配结构、以及输出阻抗匹配结构10,以及分别连接于其尾端的可调VO-(2)枝节对,可调VO-(2)枝节对包括尺寸相同的可调VO-(2)上枝节与可调VO-(2)下枝节。所有可调VO-(2)上枝节工作于第一工作温度,所有可调VO-(2)下枝节工作于第二工作温度；第一工作温度与第二工作温度分别决定了所有可调VO-(2)上枝节与所有可调VO-(2)下枝节的电导率,电导率的变化进一步决定了该滤波器的传输性质,即实现滤波器的多功能调节：既可作为宽带范围内的阻抗匹配过渡结构,也可实现低通滤波、带阻滤波的性质。(The invention belongs to the technical field of microwave frequency band filter design, and particularly provides a VO (voltage-induced volume) based filter 2 The multifunctional filter of (1), comprising: a substrate 1, an input 50 ohm microstrip line 2, a first-stage impedance matching structure to an Nth-stage impedance matching structure, and an output impedance matching structure 10 arranged on the substrate and connected in sequence, and an adjustable VO connected to the tail end of the substrate 2 Branch node pair, adjustable VO 2 The branch node pair comprises adjustable VOs with the same size 2 Upper branch node and adjustable VO 2 And (5) lower branch nodes. All tunable VOs 2 All the adjustable VOs work at the first working temperature 2 The lower branch knot works at a second working temperature; the first working temperature and the second working temperature respectively determine all adjustable VOs 2 Upper branch node and all adjustable VO 2 The conductivity of the lower branch and the change of the conductivity further determine the transmission property of the filter, namely, the multifunctional regulation of the filter is realized: the impedance matching transition structure can be used in a broadband range, and the properties of low-pass filtering and band-stop filtering can be realized.)

1. Based on VO₂The multifunctional filter of (1), comprising: a substrate (1), and an input 50 ohm microstrip line (2) and an input adjustable VO arranged on the substrate₂Branch node pair (3), N-level impedance matching structure and N-level adjustable VO₂A pair of stubs, and an output impedance matching structure (10); the input 50-ohm microstrip line (2), the first-stage impedance matching structure, the Nth-stage impedance matching structure and the output impedance matching structure (10) are sequentially connected and are positioned on a central line of the substrate; VO with adjustable input₂Input adjustable VO with same size of branch node pair₂VO with adjustable upper branch node and input₂Lower branch node, and input adjustable VO₂VO with adjustable upper branch node and input₂The lower branch sections are respectively and vertically connected to the tail end of the input 50 ohm microstrip line; the nth-stage adjustable VO₂N-th-stage adjustable VO with same branch and knot pair₂Upper branch node and nth-stage adjustable VO₂Lower branch node, and nth-stage adjustable VO₂Upper branch node and nth-stage adjustable VO₂The lower branch sections are respectively and vertically connected with the tail end of the nth-stage impedance matching structure; n is 1, 2, N is not less than 4.

2. VO-based according to claim 1₂The multifunctional filter is characterized in that the widths of the input 50-ohm microstrip line (2), the first-stage impedance matching structure and the Nth-stage impedance matching structure are sequentially increased.

3. VO-based according to claim 1₂Is characterized in that the input is adjustable VO₂Upper branch node and first-stage adjustable VO₂Adjustable VO from upper branch node to Nth level₂The upper branch node works at a first working temperature, and the input is adjustable VO₂Lower branch node and first-stage adjustable VO₂Adjustable VO from lower branch node to Nth level₂The lower branch knot works at a second working temperature; when the first working temperature and the second working temperature are both higher than the phase transition temperature, all the VOs can be adjusted₂The branch knot is in a conductor state, and the filter works in a high-low impedance line low-pass filter state; when the first working temperature or the second working temperature is higher than the phase transition temperature, all the VOs are adjustable at the moment₂Upper branch node or adjustable VO₂The lower branch is in a conductor state, and the filter works in a band elimination filter state; when the first working temperature and the second working temperature are both lower than the phase transition temperature, all the VOs can be adjusted₂The filter is directly in an insulation state and works in an impedance matching transition structure state.

Technical Field

The invention belongs to the technical field of microwave frequency band filter design, and particularly relates to a VO (voltage of integration) -based filter₂Multiple functions ofAnd a filter.

Background

In the microwave frequency band, the filter is widely applied to various board-level radio frequency circuits and transceiving components, and has great value in the civil communication field and military application; among them, the microstrip filter is widely used due to its advantages of small size, light weight, wide frequency band, etc. In order to adapt to the communication requirement of multiple frequency bands and reduce the number of filters, the multifunctional filter is an effective solution, and the multifunctional filter can meet the requirements of multiple aspects of a communication system on the premise of not increasing the number of resonators and microstrip branches.

Vanadium dioxide (VO) as phase change material₂) Is an oxide with non-metal phase transition characteristic, and has resistance of 0.1-3 × 10 under external stimulation such as heating, light irradiation, and electric stimulation^-6The omega changes and its phase change process is reversible with changes in electrical, optical, magnetic and lattice structures.

Based on this, the invention is based on vanadium dioxide (VO)₂) The phase change characteristic design of the method is based on VO₂The multifunctional filter of (1).

Disclosure of Invention

The invention aims to solve the problems in the prior art and provide a VO-based photovoltaic (VO)₂The multi-functional filter controls the upper VO and the lower VO respectively₂The temperature of the branches can be adjusted to enable the device to be in different working states, when the temperatures of the upper branches and the lower branches are lower than the phase change temperature by 68 degrees, the filter is in an impedance matching working state, when one side of the temperatures of the upper branches and the lower branches is lower than the phase change temperature by 68 degrees and one side of the temperatures of the upper branches and the lower branches is higher than the phase change temperature by 68 degrees, the filter is in a band elimination filter working state, and when the temperatures of the upper branches and the lower branches are higher than the phase change temperature by 68 degrees, the filter is in a low-pass filter working state.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

based on VO₂The multifunctional filter of (1), comprising: substrate 1, input 50-ohm microstrip line 2 and input adjustable VO (voltage VO) arranged on substrate₂Branch node pair 3, N-level impedance matchingStructure and N-level adjustable VO₂A pair of branches and an output impedance matching structure 10; the input 50-ohm microstrip line 2, the first-stage impedance matching structure, the Nth-stage impedance matching structure and the output impedance matching structure 10 are sequentially connected and are positioned on a central line of the substrate; VO with adjustable input₂Input adjustable VO with same size of branch node pair₂VO with adjustable upper branch node and input₂Lower branch node, and input adjustable VO₂VO with adjustable upper branch node and input₂The lower branch sections are respectively and vertically connected to the tail end of the input 50 ohm microstrip line; the nth-stage adjustable VO₂N-th-stage adjustable VO with same branch and knot pair₂Upper branch node and nth-stage adjustable VO₂Lower branch node, and nth-stage adjustable VO₂Upper branch node and nth-stage adjustable VO₂The lower branch sections are respectively and vertically connected with the tail end of the nth-stage impedance matching structure; n is 1, 2,. and N (N is more than or equal to 4).

Further, the widths of the input 50-ohm microstrip line 2, the first-stage impedance matching structure and the nth-stage impedance matching structure are sequentially increased.

Further, the input is adjustable VO₂Upper branch node and first-stage adjustable VO₂Adjustable VO from upper branch node to Nth level₂The upper branch node works at a first working temperature, and the input is adjustable VO₂Lower branch node and first-stage adjustable VO₂Adjustable VO from lower branch node to Nth level₂The lower branch knot works at a second working temperature; when the first working temperature and the second working temperature are higher than the phase transition temperature, all the VOs are adjustable₂The branch knot is in a conductor state, and the filter works in a high-low impedance line low-pass filter state; when the first working temperature or the second working temperature is higher than the phase transition temperature, all the VOs can be adjusted₂Upper branch node or adjustable VO₂The lower branch is in a conductor state, and the filter works in a band elimination filter state; when the first working temperature and the second working temperature are lower than the phase transition temperature, all the adjustable VOs₂The branches are in an insulation state, and the filter works in an impedance matching transition structure state.

In terms of working principle:

the invention provides a VO-based₂The multi-function filter of (1), wherein,all tunable VOs₂All the adjustable VOs work at the first working temperature₂The lower branch knot works at a second working temperature; VO-based₂The first working temperature and the second working temperature respectively determine all adjustable VOs₂Upper branch node and all adjustable VO₂The conductivity of the lower branch and the change of the conductivity further determine the transmission property of the filter, namely, the multifunctional regulation of the filter is realized: when the first working temperature and the second working temperature are higher than the phase transition temperature (68 ℃), all the adjustable VOs₂The branch knot is in a conductor state, and the filter works in a high-low impedance line low-pass filter state; when the first working temperature or the second working temperature is higher than the phase transition temperature, all the VOs can be adjusted₂Upper branch node or adjustable VO₂The lower branch is in a conductor state, and the filter works in a band elimination filter state; when the first working temperature and the second working temperature are lower than the phase transition temperature, all the adjustable VOs₂The branches are in an insulation state, and the filter works in an impedance matching transition structure state.

Further, each stage of impedance matching structure and each stage of adjustable VO₂The branch pairs are mutually coupled to regulate each VO₂The length and the width of the branch knot enable the working bandwidth of the filter to be expanded so as to meet the requirement of practical application, and the return loss is better; simultaneously, by controlling adjacent VOs at the same side₂The distance between the branches enables electromagnetic waves to be coupled with each other, and the in-band flatness and out-of-band rejection capability of the device in a filter state are further improved.

In conclusion, the beneficial effects of the invention are as follows:

the invention is based on metal oxide VO with phase change property₂The branch knot realizes a multifunctional filter by controlling two working temperatures, can be used as an impedance matching transition structure in a broadband range and can also be used according to VO₂The temperature control characteristic of the device realizes the properties of low-pass filtering and band-stop filtering through the accurate control of the temperature.

Drawings

Fig. 1 is a top view of the multifunctional filter according to the embodiment of the present invention.

Fig. 2 is a structural side view of the multifunctional filter in the embodiment of the present invention.

FIG. 3 is a diagram illustrating the structure of a multifunctional filter according to an embodiment of the present invention; wherein, 1 is a substrate, 2 is an input 50 ohm microstrip line, and 3 is an input adjustable VO₂Branch node pair, 4 is first-stage impedance matching structure, and 5 is first-stage adjustable VO₂Branch node pair, 6 is second-stage impedance matching structure, and 7 is second-stage adjustable VO₂Branch node pair, 8 is third-stage impedance matching structure, 9 is third-stage adjustable VO₂And a branch pair 10 is an output impedance matching structure.

Fig. 4 is a simulation curve of the pull-back loss when the multifunctional filter structure is in the low-pass filter state according to the embodiment of the present invention.

Fig. 5 is a simulation curve of insertion loss when the multifunctional filter structure is in a low-pass filter state according to an embodiment of the present invention.

Fig. 6 is a simulation curve of the return loss when the multifunctional filter structure is in the band-stop filter state in the embodiment of the present invention.

Fig. 7 is an insertion loss simulation curve of the multifunctional filter structure in the state of the band-stop filter according to the embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Example 1

This embodiment provides a VO-based₂The multifunctional filter of (1) is configured as shown in fig. 1 to 3, and includes: substrate 1, input 50-ohm microstrip line 2 and input adjustable VO (voltage VO) arranged on substrate₂Branch node pair 3, first-stage impedance matching structure 4 and first-stage adjustable VO₂Branch node pair 5, second-stage impedance matching structure 6 and second-stage adjustable VO₂Branch node pair 7, third-stage impedance matching structure 8 and third-stage adjustable VO₂A pair of stubs 9 and an output impedance matching structure 10; wherein the input 50 ohm microstrip line 2, the first stageThe impedance matching structure 4, the second-stage impedance matching structure 6, the third-stage impedance matching structure 8 and the output impedance matching structure 10 are connected in sequence and are positioned on the central line of the substrate; VO with adjustable input₂Input-adjustable VO with same size for branch node pair 3₂VO with adjustable upper branch node and input₂Lower branch node, and input adjustable VO₂VO with adjustable upper branch node and input₂The lower branch sections are respectively and vertically connected with the tail end of the input 50 ohm microstrip line, and the first-stage (or second-stage or third-stage) adjustable VO₂The branch node pair is a first-stage (or second-stage or third-stage) adjustable VO with the same size₂Upper branch node and first-stage (or second-stage or third-stage) adjustable VO₂Lower branch node, and first-stage (or second-stage or third-stage) adjustable VO₂Upper branch node and first-stage (or second-stage or third-stage) adjustable VO₂The lower branch nodes are respectively and vertically connected with the tail end of the first-stage (or second-stage or third-stage) impedance matching structure; so that the entire device has a symmetrical structure with respect to the substrate.

It should be noted that, taking the second-stage impedance matching structure as an example, the head end of the second-stage impedance matching structure refers to a connection end of the second-stage impedance matching structure and the first-stage impedance matching structure, and the tail end refers to a connection end of the second-stage impedance matching structure and the third-stage impedance matching structure. In addition, according to different working frequency bands required by designers and different requirements on return loss and insertion loss, the impedance matching structure and the corresponding connected adjustable VO₂The number of levels of the stub pairs, the size (length and width) of the impedance matching structure, and the tunable VO₂The sizes (length and width) of the middle-upper/lower branches of the branch pairs can be flexibly changed until the requirements are met.

According to the system requirement, the temperature of the device can be changed to make VO₂The conductive capacity is changed, so that the device is transited from an insulating state to a metal state, and an S parameter transmission matrix is adjustable through accurate temperature control, so that the device is functionally changed from an impedance transition structure to a low-pass filter, a band-stop filter and an equalizer.

Furthermore, in this embodiment, a Rogers RT/duroid 5880(tm) substrate with a thickness of 0.127mm is selected, and the filter structures shown in fig. 1 and 2 are established in a three-dimensional electromagnetic simulation software High Frequency Structure Simulator (HFSS), and the names and characteristics of the structures are shown in the following table. The lengths and the widths of all the branches and the impedance matching structures (micro-strips) can be adjusted according to needs to realize better return loss and lower insertion loss; the final simulation results are shown in fig. 4 to 7.

Table one: VO-based₂Each structure size of the multifunctional filter

Name of structure	Structural features
		Substrate 1	The length is 13.5mm, the width is 12mm, and the thickness is 0.127mm
Input 50 ohm microstrip line 2	Length 2.5mm, width 0.6mm
		Input-adjustable VO2Branch knot pair 3	Length 3mm, width 0.5mm
First stage impedance matching structure 4	Length 2.8mm, width 0.65mm
		First-stage adjustable VO2Branch knot pair 5	Length 4mm, width 0.8mm
Second stage impedance matching structure 6	Length 3mm, width 1mm
		Second-stage adjustable VO2Branch knot pair 7	Length 3.5mm, width 1mm
Third stage impedance matching structure 8	Length 3.2mm, width 1.2mm
		Third-stage adjustable VO2Branch knot pair 9	Length 3mm, width 1.2mm
Output impedance matching structure 10	Length 2.5mm, width 0.6mm

VO at the upper and lower sides as shown in FIG. 4 and FIG. 5₂The simulation return loss curve and the insertion loss curve when all the branches are in the metal state, VO at the moment₂The bulk conductivity of the branches is 50000siemens/m, and the structure can enable electromagnetic waves of 0-0.5 GHz to pass through without loss at the moment, has good inhibiting effect on high-frequency signals and works in a low-pass filter state; VO at the upper and lower sides as shown in FIG. 6 and FIG. 7₂The simulated return loss curve and the insertion loss curve of the branch in the insulation state and the metal state respectively, and the VO at the moment₂The bulk conductivity of the branches is 140siemens/m, and the structure shows band elimination characteristic at the moment, wherein the stopband of the structure is 0.5-2.5 GHz; therefore, the VO-based provided by the invention₂The multifunctional filter realizes multiple functions in a wide frequency band. VO when the temperature of both sides is 68 ℃ lower than the phase transition temperature₂The conductivity is 140siemens/m, VO₂The branch is in an insulation state, and the filter is in an impedance conversion working state at the moment. When the temperature is 68 degrees higher than the phase transition temperature, the filter is in the low-pass filter working state. When the temperature makes one side of the branches at the two sides in a conductor state,one side is in an insulation state, and the filter is in a band elimination filter working state at the moment. In conclusion, the multifunctional filter realizes the adjustability of multiple working modes.

While the invention has been described with reference to specific embodiments, any feature disclosed in this specification may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise; all of the disclosed features, or all of the method or process steps, may be combined in any combination, except mutually exclusive features and/or steps.