阅读说明：本技术 一种s21传输矩阵可调的宽带带阻滤波器 (S21Transmission matrix adjustable broadband band-stop filter ) 是由 张勇 曹天豪 朱华利 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S-(21)传输矩阵可调的宽带带阻滤波器；包括：基板1,设置于基板上的依次连接的输入50欧姆微带线2、输入阻抗渐变过渡结构3、枝节连接微带线4、输出阻抗渐变过渡结构5及输出50欧姆微带线6,以及依次连接于枝节连接微带线上的输入枝节、周期性枝节、输出枝节,所述输入枝节、周期性枝节、输出枝节分别由金属枝节与VO-2枝节连接构成。本发明利用输入枝节、周期性枝节、输出枝节中VO-2枝节的相变特征,通过滤波器工作温度的有效调节,实现滤波器的S-(21)传输矩阵可调；既可作为宽带范围内的直通器件,又可通过工作温度的精准控制来充当均衡器,还可作为带阻滤波器工作。(The invention belongs to the technical field of microwave frequency band filter design, and particularly provides an S 21 A transmission matrix adjustable broadband band-stop filter; the method comprises the following steps: the microstrip line structure comprises a substrate 1, an input 50-ohm microstrip line 2, an input impedance gradual transition structure 3, a branch connection microstrip line 4, an output impedance gradual transition structure 5 and an output 50-ohm microstrip line 6 which are arranged on the substrate and connected in sequence, and an input branch, a periodic branch and an output branch which are connected to the branch connection microstrip line in sequence, wherein the input branch, the periodic branch and the output branch are respectively composed of a metal branch and a VO (voltage of vacuum) 2 The branches are connected. The invention utilizes VO in input branch, periodic branch and output branch 2 The phase change characteristic of the branch knot realizes the S of the filter by effectively adjusting the working temperature of the filter 21 The transmission matrix is adjustable; the band-pass filter can be used as a through device in a broadband range, can be used as an equalizer through the accurate control of the working temperature, and can also be used as a band-stop filter.)

1. S₂₁A transmission matrix adjustable wideband band reject filter comprising: the device comprises a substrate (1), and an input 50-ohm microstrip line (2), an input impedance gradual transition structure (3), a branch connection microstrip line (4), an output impedance gradual transition structure (5), an output 50-ohm microstrip line (6), an input metal matching branch (7) and an input VO which are arranged on the substrate₂Matching branches (8), periodic metal branches (9) and periodic VO₂Branch (10), output metal matching branch (11), and output VO₂Matching branches (12); the microstrip line structure is characterized in that the input 50-ohm microstrip line (2), the input impedance gradual change transition structure (3), the branch connection microstrip line (4), the output impedance gradual change transition structure (5) and the output 50-ohm microstrip line (6) are sequentially connected; the input metal matches with the branch (7) and the input VO₂The width of the matching branch (8) is the same and the matching branch is connected to form an input branch, and the output metal matching branch (11) and the output VO₂The width of the matching branches (12) is the same and the matching branches are connected to form an output branch, and the periodic metal branches (9) and the periodic VO₂The branches (10) have the same width and are connected to form periodic branches; the input metal branch knot and the output metal branch knot are respectively connected to the head end and the tail end of the branch knot connecting microstrip line, and a plurality of periodic branch knots are arranged between the input metal branch knot and the output metal branch knot at equal intervals; the input metal matching branch (7), the periodic metal branch (9) and the output metal matching branch (11) are respectively and vertically connected to the branch connecting microstrip line (4).

2. S according to claim 1₂₁The transmission matrix adjustable broadband band-stop filter is characterized in that the input stub and the output stub have the same structure and size, the input impedance gradual change transition structure (3) and the output impedance gradual change transition structure (5) have the same structure and size, and the input 50-ohm microstrip line (2) and the output 50-ohm microstrip line (6) have the same structure and size.

3. S according to claim 1₂₁The broadband band-stop filter with the adjustable transmission matrix is characterized in that the widths of the input 50-ohm microstrip line (2) and the output 50-ohm microstrip line (6) are 3/4 of the width of the branch-joint microstrip line (4).

4. S according to claim 1₂₁The transmission matrix adjustable broadband band elimination filter is characterized in that the widths of the input branches and the output branches are smaller than the width of the periodic branches.

5. S according to claim 1₂₁The broadband band-stop filter with the adjustable transmission matrix is characterized in that in the periodic branches, periodic VOs₂The length of the branch (10) is 1.8 times of the length of the periodic metal branch (9).

Technical Field

The invention belongs to the technical field of microwave frequency band filter design, and particularly relates to an S₂₁A transmission matrix adjustable broadband band-stop 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. At present, once most of microstrip filters are designed and processed, transmission matrixes of the microstrip filters are determined, and in order to expand the application width of the filters in radio frequency circuits, it is necessary to realize that S parameter transmission curves of the filters are adjustable.

In order to meet the communication requirement of multiple frequency bands and reduce the number of filters, the multiband filter is a solution, but the number of resonators needs to be increased or a more complex design method needs to be used for each frequency band of the multiband filter; however, S₂₁The transmission matrix adjustable broadband band-stop filter can meet the requirement of multiple frequency bands of a communication system on the premise of not increasing the number of resonators. 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^-6Omega varies with changes in electrical, optical, magnetic and lattice structures, and the phase change process is reversible.

The invention is therefore based on vanadium dioxide (VO)₂) Is designed to obtain S₂₁The transmission matrix is adjustable, and the broadband band-stop filter meets the requirement of multiple frequency bands of a communication system.

Disclosure of Invention

The present invention is directed to solving the above problems in the prior art by providing a S₂₁Transmission matrix adjustable broadband band-stop filter by using vanadium dioxide (VO)₂) The phase change characteristic of the metal oxide can change the conductivity of the branch so as to realize different S at different temperatures₂₁And (5) transmitting the matrix.

In order to achieve the purpose, the invention adopts the technical scheme that:

s₂₁A transmission matrix adjustable wideband band reject filter comprising: the device comprises a substrate 1, and an input 50-ohm microstrip line 2, an input impedance gradual transition structure 3, a branch connection microstrip line 4, an output impedance gradual transition structure 5, an output 50-ohm microstrip line 6, an input metal matching branch 7 and an input VO which are arranged on the substrate₂Matching branch 8, periodic metal branch 9 and periodic VO₂Branch 10, output metal matching branch 11, output VO₂Matching the branches 12; the microstrip line structure is characterized in that an input 50-ohm microstrip line 2, an input impedance gradual change transition structure 3, a branch connection microstrip line 4, an output impedance gradual change transition structure 5 and an output 50-ohm microstrip line 6 are sequentially connected; input metal matching branch 7 and input VO₂The matching branches 8 have the same width and are connected to form an input branch, and the output metal matching branch 11 and the output VO₂The matching branches 12 have the same width and are connected to form an output branch, and the periodic metal branch 9 and the periodic VO₂The branches 10 have the same width and are connected to form periodic branches; the input metal branch knot and the output metal branch knot are respectively connected to the head end and the tail end of the branch knot connecting microstrip line, and a plurality of periodic branch knots are arranged between the input metal branch knot and the output metal branch knot at equal intervals; the input metal matching branch 7, the periodic metal branch 9 and the output metal matching branch 11 are respectively and vertically connected with the branch connecting microstrip line 4.

Further, the input stub and the output stub have the same structure and size, the input impedance gradual change transition structure 3 and the output impedance gradual change transition structure 5 have the same structure and size, and the input 50-ohm microstrip line 2 and the output 50-ohm microstrip line 6 have the same structure and size.

Furthermore, the widths of the input 50-ohm microstrip line 2 and the output 50-ohm microstrip line 6 are 3/4 of the width of the stub connection microstrip line 4.

Further, the width of the input branch and the output branch is smaller than that of the periodic branch.

Further, in the periodic branch, a periodic VO₂The length of the branches 10 is 1.8 times the length of the periodic metal branches 9.

In terms of working principle:

s of the broadband band-stop filter in the invention₂₁The adjustable transmission matrix is determined based on the working temperature of the device, and the working temperature determines VO in the input branch and the output branch₂The conductivity of the branches and the change of the conductivity further determine the transmission property of the filter, thereby realizing the S of the filter₂₁The transmission matrix is adjustable; VO when the working temperature is 68 ℃ lower than the phase transition temperature₂The device is in an insulation state, the conductivity is very low, and the device has the property of a straight-through microstrip line, so that electromagnetic waves can pass through without damage; VO when the working temperature is increased to more than 68 DEG C₂The conductivity rises rapidly from the insulating state to the metallic state, at which point the device operates in the band stop filter state.

Furthermore, the impedance gradual change transition structure is connected with the input, the output and the middle periodic structure, so that the working bandwidth is expanded, the return loss is better, and the transmission loss is reduced; input, output and periodic branches at VO₂When the branches are in a metal state, the filter works in a band-resistance state, and electromagnetic waves are mutually coupled between adjacent branches during transmission, so that the rectangular coefficient of the filter is improved.

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

the present invention provides a method for producing S₂₁A transmission matrix adjustable broadband band-stop filter is based on a metal oxide VO₂Designing the structure of the device through the branch node and passing through the metal oxide VO₂The phase change characteristic of the microstrip filter₂₁The transmission matrix is adjustable; the invention can be used as a through device in a broadband range and can be based on VO₂The device acts as an equalizer through the accurate control of the working temperature, the equalization precision is only limited by the temperature control precision at the moment, and when the temperature is raised to make VO₂When the device is in the metal state, the device is in the working state of the band elimination filter.

Drawings

FIG. 1 shows an example of S of the present invention₂₁Structural top view of the broadband band-stop filter with adjustable transmission matrix.

FIG. 2 shows an embodiment of the present invention S₂₁The side view of the structure of the broadband band-stop filter with the adjustable transmission matrix.

FIG. 3 shows an embodiment of the present invention S₂₁The transmission matrix is adjustable and the structure of the broadband band-stop filter is schematic; wherein, 1 is Rogers RT/duroid 5880(tm) substrate, 2 is input 50 ohm microstrip line, and 3 is input impedance gradual transition structure4 is a branch-connected microstrip line, 5 is an output impedance gradual transition structure, 6 is an output 50-ohm microstrip line, 7 is an input metal matching branch structure, and 8 is an input VO₂Matching branch structure, 9 is periodic metal branch structure, and 10 is periodic VO₂A branch structure 11 of output metal matched with the branch structure and 12 of output VO₂Matching the branch structure.

FIG. 4 shows VO in the embodiment of the present invention₂Return loss curve of the filter in the metallic state.

FIG. 5 shows VO in the embodiment of the present invention₂The insertion loss curve of the filter in the metallic state.

FIG. 6 shows VO in the embodiment of the present invention₂Return loss curve of the filter in the isolated state.

FIG. 7 shows the VO values of the embodiment of the present invention₂The insertion loss curve of the filter in the insulating state.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more clearly apparent, the present invention is further described in detail below 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-based₂S of₂₁The structure of the broadband band-stop filter with the adjustable transmission matrix is shown in figures 1-3, and the broadband band-stop filter comprises: the device comprises a substrate 1, and an input 50-ohm microstrip line 2, an input impedance gradual transition structure 3, a branch connection microstrip line 4, an output impedance gradual transition structure 5, an output 50-ohm microstrip line 6, an input metal matching branch 7 and an input VO which are arranged on the substrate₂Matching branch 8, periodic metal branch 9 and periodic VO₂Branch 10, output metal matching branch 11, output VO₂Matching the branches 12; the input 50-ohm microstrip line 2, the input impedance gradual change transition structure 3, the branch connection microstrip line 4, the output impedance gradual change transition structure 5 and the output 50-ohm microstrip line 6 are sequentially connected; input metal matching branch 7 and input VO₂Matching branchSection 8, output metal matching branch section 11 and output VO₂The width of the matching branches 12 is the same, and the input metal matching branch 7 and the input VO are identical₂The matching branches 8 are connected to form an input branch, an output metal matching branch 11 and an output V O₂The matching branches 12 are connected to form output branches; the periodic metal branch 9 and the periodic VO₂The branches 10 have the same width and are connected to form periodic branches; the input metal branch knot and the output metal branch knot are respectively connected to the head end and the tail end of the branch knot connecting microstrip line, and a plurality of periodic branch knots are arranged between the input metal branch knot and the output metal branch knot at equal intervals; the input metal matching branch 7, the periodic metal branch 9 and the output metal matching branch 11 are respectively and vertically connected with the branch connecting microstrip line 4.

It should be noted that the input stub and the output stub have the same structure and size, the input impedance gradual change transition structure 3 and the output impedance gradual change transition structure 5 have the same structure and size, and the input 50 ohm microstrip line 2 and the output 50 ohm microstrip line 6 have the same structure and size, so that the broadband band elimination filter has a symmetrical structure; the head end of the branch section connecting microstrip line 4 is connected with the connecting end of the microstrip line and the input impedance gradual change transition structure, and the tail end of the branch section connecting microstrip line 4 is connected with the connecting end of the microstrip line and the output impedance gradual change transition structure.

In addition, the above-mentioned VO-based₂S of₂₁The transmission matrix adjustable broadband band-stop filter has periodic metal branches and periodic VO according to different working frequency bands required by designers and different requirements on return loss and insertion loss₂The length, width, number and period distance of the branches can be flexibly changed until the requirements are met.

In terms of working principle, the working temperature of the device is adjusted according to the system requirement, so that VO (vacuum) is realized₂The conductive capability is changed, so that the transition from an insulating state to a metal state is realized; enabling the device S by precise temperature control₂₁The transmission matrix is adjustable, and the function of the device can be changed from direct connection to a filter and an equalizer.

Furthermore, this embodimentA0.254 mm thick Rogers RT/duroid 5880(tm) substrate is selected as a substrate, and the filter Structure shown in FIGS. 1 and 2 is established in a three-dimensional electromagnetic simulation software High Frequency Structure Simulator (HFSS), wherein the names and characteristics of the structures are shown in the following table I. When the practical application design is carried out, the length and the width of each branch and each microstrip can be adjusted according to the requirement to realize better return loss and lower insertion loss, VO₂The branches and the metal branches are tightly connected to improve the adjustability of the device; the simulation results are shown in fig. 4 to 7.

Table one: s21 transmission matrix adjustable broadband filter each structure size

When VO is shown in FIG. 4 and FIG. 5 respectively₂The simulated return loss curve and the insertion loss curve of the device when the branch node is in the metal state, VO at the moment₂The bulk conductivity of the branch knot is 50000siemens/m, and the structure has a good inhibition effect on electromagnetic waves of 3-7 GHz; when VO is shown in FIG. 6 and FIG. 7 respectively₂The simulated return loss curve and the insertion loss curve of the device when the branch node is in an insulation state, VO at the moment₂The bulk conductivity of the branches is 140siemens/m, and the structure shows a straight-through characteristic at the moment, so that electromagnetic waves at 1-10 GHz can pass through the structure without damage, and the matching characteristic is excellent; thus, the invention provides S₂₁The transmission matrix adjustable broadband band-stop filter has good straight-through characteristic and band-stop characteristic respectively at proper temperature, and realizes S₂₁And the transmission matrix is adjustable.

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.