A dynamic impedance matching device, an antenna device, and a dynamic impedance matching method

Abstract

The application discloses a dynamic impedance matching device, an antenna device and a dynamic impedance matching method, and the structure of the device comprises a main transmission path connected with input / output ports; at least one branch matching path is connected in parallel to the main transmission path through a node, and each branch matching path comprises a variable phase shifter and an open circuit or a short circuit terminal; by independently adjusting each variable phase shifter, the reflection coefficient of any load impedance is iteratively converged to a matching area of a Smith chart, and dynamic impedance matching is realized. Compared with the prior art, the impedance matching device has dynamic impedance matching capability, solves the problem that a fixed matching network cannot adapt to impedance conversion, and solves systematic technical defects such as inability to continuously adjust and long-term stability, and can meet the strict requirements of a modern microwave system on a wide frequency band and high reliability.

Description

Technical Field

[0001] This invention relates to impedance matching devices, specifically a dynamic impedance matching device, antenna device, and dynamic impedance matching method based on variable stub topology. Background Technology

[0002] In the fields of microwave transmission systems and high-frequency circuit design, reflected wave interference caused by impedance mismatch is a core issue affecting system performance. Reflections caused by differences in characteristic impedance between the load and the transmission line, connector discontinuities, etc., can lead to problems such as deterioration of VSWR, decreased power transmission efficiency, and distortion of measurement signals. To suppress reflections, the industry has proposed various impedance matching schemes: using slotted coaxial lines with external probes, and achieving impedance tuning by adjusting the axial movement and depth of the probes; using T-connectors or 1-to-2 coaxial lines to construct parallel stub networks of coaxial lines, and adjusting the stub reactance by cutting the cable length. In PCB systems, LC networks are often used to construct L-type, T-type, or π-type matching networks, and canceling reflections by adjusting the capacitance and inductance values; using microstrip lines or waveguides to implement open or short-circuit stubs, and changing the impedance characteristics by adjusting the length and position of the stubs; cutting and attaching copper foil to the slots on the antenna to change the size of the slots and achieve adjustment of the antenna impedance.

[0003] Although the above methods have been partially applied in engineering practice, the following technical bottlenecks still exist: the ±5% impedance tolerance caused by PCB processing will cause the actual impedance to deviate by ±10 ohms, and traditional LC networks or fixed stubs cannot dynamically compensate for the error, resulting in mismatch; the insertion position and length of microstrip line stubs cannot be adjusted after processing, and cannot meet the needs of multi-band or dynamic load changes; slotted coaxial line structures are prone to unstable contact impedance due to long-term insertion and removal wear; incomplete shielding layers are prone to coupling with environmental noise. Summary of the Invention

[0004] To address the aforementioned technical problems in the existing technology, this invention proposes a dynamic impedance matching device, antenna device, and dynamic impedance matching method based on variable stub topology. By using a variable phase shifter instead of a fixed stub length, impedance matching of the load can be achieved at any desired frequency without prior knowledge of the load impedance. The specific technical solution is as follows:

[0005] A dynamic impedance matching device, capable of connecting any load, includes:

[0006] The main transmission path connects to the input / output ports and can integrate a variable phase shifter for adjusting the signal phase.

[0007] At least one stub allocation path is connected in parallel to the main transmission path through nodes, and each stub allocation path includes a variable phase shifter and an open or short-circuit terminal.

[0008] By independently adjusting each variable phase shifter and changing the electrical angle of its respective branch, the reflection coefficient of any load impedance can be iteratively converged to the matching region of the Smith chart, thus achieving dynamic impedance matching.

[0009] Furthermore, the dynamic impedance matching device adopts a single-stub structure, including:

[0010] The first variable phase shifter on the main transmission path connects the signal source to the load;

[0011] A branch dispatch path is connected in parallel to the main transmission path through nodes, and includes a second variable phase shifter and an open or short-circuit terminal.

[0012] Adjust the first and second variable phase shifters to move the load admittance point to the matching point along the Smith chart admittance coordinate system.

[0013] Furthermore, the dynamic impedance matching device adopts a dual-stub topology, including:

[0014] The first variable phase shifter on the main transmission path connects the signal source to the load;

[0015] The first branch allocation path is connected in parallel to the main transmission path near the signal source through the first node, and includes the second variable phase shifter and the first terminal;

[0016] The second branch allocation path is connected in parallel to the main transmission path near the load side through the second node, and includes the third variable phase shifter and the second terminal;

[0017] By adjusting the first variable phase shifter, the signal phase can be set to 45°, 90°, or 135°, and by coordinating the adjustment of the second and third variable phase shifters, the admittance point can be gradually brought closer to the matching point.

[0018] Furthermore, the main transmission path of the dual-stub topology also includes a fourth variable phase shifter, located between the first variable phase shifter and the load, and the fourth variable phase shifter is adjusted so that the signal phase is 45°, 90° or 135°.

[0019] Furthermore, the dynamic impedance matching device adopts a three-stub topology, including:

[0020] The first and second variable phase shifters on the main transmission path are connected in series between the signal source and the load;

[0021] The first branch allocation path is connected in parallel to the main transmission path signal source side through the first node, and includes the third variable phase shifter and the first terminal;

[0022] The second branch allocation path is connected in parallel to the middle section of the main transmission path through the second node, and includes the fourth variable phase shifter and the second terminal;

[0023] The third branch allocation path is connected in parallel to the load side of the main transmission path through the third node, and includes the fifth variable phase shifter and the third terminal.

[0024] Adjust the first and second variable phase shifters to make the signal phase 45°, 90° or 135°, and coordinately adjust the third, fourth and fifth variable phase shifters to eliminate the matching dead zone.

[0025] Furthermore, the dynamic impedance matching device adopts a three-stub topology, including:

[0026] The main transmission path connects the signal source to the load; two transmission lines are provided on the main transmission path, with the length of the transmission lines being 1 / 4, 1 / 8, or 3 / 8 of the wavelength;

[0027] The first branch allocation path is connected in parallel to the main transmission path signal source side through the first node, and includes the third variable phase shifter and the first terminal;

[0028] The second branch dispatch path is connected in parallel to the middle section of the main transmission path through the second node, located between the two transmission lines, and includes the fourth variable phase shifter and the second terminal.

[0029] The third branch allocation path is connected in parallel to the load side of the main transmission path through the third node, and includes the fifth variable phase shifter and the third terminal.

[0030] Furthermore, the nodes can be connected in parallel with multiple branches via T-connectors or branch transmission lines.

[0031] An antenna device includes the aforementioned dynamic impedance tuning device and an antenna connected thereto.

[0032] A dynamic impedance matching method based on a dynamic impedance matching device includes the following steps:

[0033] (a) Connect the dynamic impedance matching device to the load and the vector network analyzer, measure the reflection coefficient and display it on the Smith chart admittance coordinate system;

[0034] (b) Adjust the variable phase shifter on the main transmission path to move the admittance point to the preset admittance circle;

[0035] (c) Adjust the variable phase shifters of each branch adjustment path in sequence so that the admittance point gradually approaches the matching point;

[0036] (d) If a matching dead zone exists, the admittance point is moved to the adjustable region by adjusting the additional stub phase shifter, and steps (b) and (c) are repeated until the matching of any load is completed.

[0037] Furthermore, in step (b), the preset admittance circle is an admittance circle with G=1. In step (c), if the terminal is a short-circuit structure, the phase is changed to make the admittance point rotate clockwise from the left end to approach the matching point. If the terminal is an open-circuit structure, the phase is changed to make the admittance point rotate counterclockwise from the right end to approach the matching point.

[0038] Compared with existing technologies, the dynamic impedance matching device of the present invention solves systemic technical defects such as processing errors, multi-band compatibility and long-term stability, and can meet the stringent requirements of modern microwave systems for wide bandwidth and high reliability. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the single-stub structure used in the dynamic impedance matching device of this embodiment;

[0040] Figure 2 This is a schematic diagram of a double-stub topology used in the dynamic impedance matching device of this embodiment;

[0041] Figure 3 This is a schematic diagram of another double-stub topology used in the dynamic impedance matching device of this embodiment;

[0042] Figure 4 This is a schematic diagram of the three-stub topology used in the dynamic impedance matching device of this embodiment;

[0043] Figures 5 to 7 This is a schematic diagram illustrating the test results of the application of the dynamic impedance matching device in this embodiment to achieve impedance matching at different target frequencies. Detailed Implementation

[0044] To make the objectives, technical solutions, and technical effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0045] This invention discloses a dynamic impedance matching device based on variable stub topology. It uses a combination of variable phase shifters to construct an impedance matching network, which is convenient for modular adaptation to different loads and can dynamically adjust the matching network so that unknown loads work in a matched state.

[0046] In one embodiment, such as Figure 1 As shown, the impedance matching network adopts a single-stub structure, including:

[0047] Main transmission path: connected to the input / output port, integrating a first variable phase shifter 111, with the two ends of the first variable phase shifter 111 connected to the signal source 110 and the load 112 respectively.

[0048] Branch allocation path: connected in parallel to the main transmission path through node 12, including the second variable phase shifter 130 and open or short-circuit terminal 131.

[0049] The control logic of this structure is as follows: by independently adjusting two variable phase shifters, the reflection coefficient of any load impedance is mapped to the matching region of the Smith chart. When load 112 is purely resistive, the stub matching path can be disabled.

[0050] The process of load impedance matching using the above-mentioned single-stub impedance matching device is as follows:

[0051] Step 1: Connect the signal output terminal of the impedance matching device to the load, and the signal input terminal to the vector network analyzer;

[0052] Step 2: Measure the reflection coefficient Γ of the system load impedance, display it on the Smith chart, and adjust the Smith chart to the admittance coordinate system;

[0053] Step 3: Adjust the first variable phase shifter 111 to move the admittance point to the admittance circle with G=1;

[0054] Step 4: Adjust the second variable phase shifter 130. If the terminal 131 is in a short-circuit structure, change the phase to make the admittance point rotate clockwise from the left end. If the terminal 131 is in an open-circuit structure, change the phase to make the admittance point rotate counterclockwise from the right end until the matching point is reached.

[0055] In one embodiment, such as Figure 2 As shown, the impedance matching network adopts a two-stub topology, including:

[0056] Main transmission path: connected to the input / output port, integrating the first variable phase shifter 221, with the two ends of the first variable phase shifter 221 connected to the signal source terminal 220 and the load 222 respectively;

[0057] The first branch allocation path is connected in parallel to the main transmission path through the first node 23. It is located on the side of the main transmission path close to the signal source and includes the second variable phase shifter 210 and the first terminal 211.

[0058] The second branch allocation path is connected in parallel to the main transmission path through the second node 24. It is located on the main transmission path near the load side and includes the third variable phase shifter 250 and the second terminal 231.

[0059] The first variable phase shifter 221 is located between the first node 23 and the second node 24 on the main transmission path.

[0060] Both the first and second terminals can be open-circuit or short-circuit terminals.

[0061] The control logic of this structure is as follows: by independently adjusting three variable phase shifters, the reflection coefficient of any load impedance is mapped to the matching region of the Smith chart; wherein the signal phase adjusted by the first variable phase shifter is matched to 45°, 90° or 135°.

[0062] like Figure 3 As shown, a fourth variable phase shifter 223 can be added between the first variable phase shifter 221 and the load 222 on the main transmission path. The signal phase adjusted by the fourth variable phase shifter 223 is matched to 45°, 90° or 135°.

[0063] The process of load impedance matching using the dynamic impedance matching device with the above-mentioned double-stub topology is as follows:

[0064] Step 1: Connect the signal output terminal of the dynamic impedance matching device to the load, and the signal input terminal to the vector network analyzer;

[0065] Step 2: Measure the reflection coefficient Γ of the system load impedance, display it on the Smith chart, and adjust the Smith chart to the admittance coordinate system;

[0066] Step 3: First, adjust the first and third variable phase shifters to make the signal phase angle 45°, or only connect the first variable phase shifter 221 and adjust the first variable phase shifter 221 to make the signal phase angle 45°, 90° or 135°.

[0067] Step 4: Adjust the third variable phase shifter 250 so that the admittance point is close to the matching point;

[0068] Step 5: Then adjust the second variable phase shifter 210 to bring the admittance point closer to the matching point;

[0069] Step 6: Repeat steps 4 and 5 above. If you enter the matching dead zone, you can adjust the first phase shifter or the first and third phase shifters to move the load admittance point out of the dead zone. Then repeat steps 4 and 5 above until the admittance point reaches the matching point.

[0070] If the terminal is a short-circuit structure, the phase is changed to make the admittance point rotate clockwise from the left end to approach the matching point. If the terminal is an open-circuit structure, the phase is changed to make the admittance point rotate counterclockwise from the right end to approach the matching point.

[0071] In one embodiment, such as Figure 4 As shown, the impedance matching network adopts a three-stalk topology, including:

[0072] Main transmission path: Connects to the input / output port, integrating a first variable phase shifter 321 and a second variable phase shifter 322. The first variable phase shifter 321 and the second variable phase shifter 322 are connected in series and their two ends are respectively connected to the signal source terminal 320 and the load 323.

[0073] The first branch allocation path is connected in parallel to the main transmission path through the first node 33. It is located on the side of the main transmission path close to the signal source and includes the third variable phase shifter 310 and the first terminal 311.

[0074] The second branch allocation path is connected in parallel to the main transmission path through the second node 34, located between the first variable phase shifter 321 and the second variable phase shifter 322 of the main transmission path, and includes the fourth variable phase shifter 350 and the second terminal 351.

[0075] The third branch allocation path is connected in parallel to the main transmission path through the third node 36. It is located on the main transmission path near the load 323 and includes the fifth variable phase shifter 370 and the third terminal 371.

[0076] The first terminal 311, the second terminal 351, and the third terminal 371 can all be open-circuit or short-circuit terminals.

[0077] The control logic of this structure is as follows: by independently adjusting three variable phase shifters, the reflection coefficient of any load impedance is mapped to the matching region of the Smith chart; wherein the signal phase adjusted by the first variable phase shifter 321 should be matched to 45°, 90° or 135°.

[0078] The process of load impedance matching using the dynamic impedance matching device with the above-mentioned three-stub topology is as follows:

[0079] Step 1: Connect the signal output terminal of the impedance matching device to the load, and the signal input terminal to the vector network analyzer;

[0080] Step 2: Measure the reflection coefficient Γ of the system load impedance, display it on the Smith chart, and adjust the Smith chart to the admittance coordinate system;

[0081] Step 3: First, adjust the first and second variable phase shifters so that the signal phase angle is 45°, 90° or 135°;

[0082] Step 4: Adjust the third variable phase shifter 310 to bring the admittance point close to the matching point;

[0083] Step 5: Then adjust the fourth variable phase shifter 350 to bring the admittance point closer to the matching point;

[0084] Step 6: Repeat steps 4 and 5 above until the admittance point reaches the matching point;

[0085] Step 7: If the above steps enter the "dead zone", change the fifth variable phase shifter 370 to move the admittance point to an adjustable region;

[0086] Step 8: Repeat steps 6 and 7 above until a match is completed.

[0087] If the terminal is a short-circuit structure, the phase is changed to make the admittance point rotate clockwise from the left end to approach the matching point. If the terminal is an open-circuit structure, the phase is changed to make the admittance point rotate counterclockwise from the right end to approach the matching point.

[0088] In one embodiment, the impedance matching network employs a three-stalk topology, comprising:

[0089] The main transmission path connects the signal source to the load; two transmission lines are provided on the main transmission path, with the length of the transmission lines being 1 / 4, 1 / 8, or 3 / 8 of the wavelength;

[0090] The first branch allocation path is connected in parallel to the main transmission path through the first node. It is located on the side of the main transmission path close to the signal source and includes the third variable phase shifter and the first terminal.

[0091] The second branch allocation path: connected in parallel to the main transmission path through the second node, located between the two transmission lines, and includes the fourth variable phase shifter and the second terminal.

[0092] The third branch allocation path: connected in parallel to the main transmission path through the third node, located on the main transmission path near the load side, including the fifth variable phase shifter and the third terminal.

[0093] In the above embodiments, node connections are achieved by using T-connectors or branch transmission lines to realize multiple branches in parallel, and the length of the transmission lines between branches can be freely configured. Coaxial open / short circuit switching: Open and short circuits can be directly achieved using dust caps or short-circuit caps; alternatively, an open / short circuit switching device can be used, which achieves open / short circuit state switching by moving the inner conductor through a sliding or threaded mechanism.

[0094] After the above steps, the impedance of the original load can be adjusted to the matching point at the target frequency, achieving impedance matching. This can be achieved at multiple target frequencies using the same device. Test results are shown below. Figures 5-7 The principle behind impedance matching is as follows:

[0095] In practical applications, the impedance of a load often varies with the operating frequency. Impedance matching is necessary to ensure the load operates optimally at different target frequencies. For any load impedance... The purpose of impedance matching is to transform its impedance to Therefore, it is necessary to eliminate the imaginary part of the load impedance. X l Adjust the real impedance R l .

[0096] To achieve this, a stub can be connected in series with the load to adjust the real impedance of the load to its characteristic impedance, provided the following conditions are met:

[0097] ,

[0098] Therefore, it can be concluded that the transmission line length can be changed. d If the phase shift constant β satisfies the above conditions, the equivalent impedance with real part matching is obtained. Then, a branch is inserted to cancel the imaginary part of the input impedance at this point, resulting in the final input impedance. The following conditions need to be met:

[0099] Pathfinders: ;

[0100] Short-circuit branch: .

[0101] Therefore, it is evident that a suitable value can be found to achieve impedance matching for any load simply by independently adjusting the phase shift constant β or physical length l on the main transmission line and stub transmission line. To achieve this goal, this invention introduces a variable phase shifter for adjustment. A variable phase shifter is a phase shifter capable of continuously changing its phase. Options include mechanically tuned phase shifters capable of changing their physical length, as well as numerically controlled stepper phase shifters, ferrite phase shifters, MEMS phase shifters, and analog phase shifters capable of changing their equivalent phase shift constant.

[0102] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Although the implementation process of the present invention has been described in detail above, those skilled in the art can still modify the technical solutions described in the foregoing examples or make equivalent substitutions for some of the technical features. All modifications and equivalent substitutions made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A dynamic impedance matching device, characterized by, Any load can be connected to the device, which comprises: a main transmission path connecting an input / output port; At least one branch routing path is connected in parallel to the main transmission path through the node, each branch routing path including a variable phase shifter and an open or short terminal; the variable phase shifter is connected to the main transmission path through the node by changing the phase shift constant of the transmission line in the path β Or physical length l Device for continuous phase change independently adjusting each variable phase shifter to iteratively converge the reflection coefficient of any load impedance to a matching region on a Smith chart; the device adopts a double-branch topology, comprising: a first variable phase shifter (221) on the main transmission path connecting a signal source end (220) and a load (222); a first branch adjustment path parallel to the main transmission path near the signal source side through a first node (23), containing a second variable phase shifter (210) and a first terminal (211); a second branch adjustment path parallel to the main transmission path near the load side through a second node (24), containing a third variable phase shifter (250) and a second terminal (231); by adjusting the first variable phase shifter (221) and cooperatively adjusting the second and third variable phase shifters, the admittance point gradually approaches the matching point; the main transmission path further comprises a fourth variable phase shifter (223) between the second node (24) and the load (222).

2. The dynamic impedance matching device of claim 1, wherein, a triple-branch topology is adopted, comprising: a first variable phase shifter (321) and a second variable phase shifter (322) on the main transmission path, connected in series between a signal source end (320) and a load (323); a first branch adjustment path parallel to the main transmission path near the signal source side through a first node (33), containing a third variable phase shifter (310) and a first terminal (311); a second branch adjustment path parallel to the main transmission path through a second node (34), containing a fourth variable phase shifter (350) and a second terminal (351); a third branch adjustment path parallel to the main transmission path near the load side through a third node (36), containing a fifth variable phase shifter (370) and a third terminal (371); adjusting the first and second variable phase shifters and cooperatively adjusting the third, fourth, and fifth variable phase shifters to eliminate the matching dead zone.

3. The dynamic impedance matching device of claim 1, wherein, a triple-branch topology is adopted, comprising: a main transmission path connecting a signal source end (320) and a load (323); two transmission lines are provided on the main transmission path, and the lengths of the transmission lines are 1 / 4, 1 / 8, or 3 / 8 of the wavelength; a first branch adjustment path parallel to the main transmission path near the signal source side through a first node (33), containing a third variable phase shifter (310) and a first terminal (311); a second branch adjustment path parallel to the main transmission path through a second node (34), containing a fourth variable phase shifter (350) and a second terminal (351); a third branch adjustment path parallel to the main transmission path near the load side through a third node (36), containing a fifth variable phase shifter (370) and a third terminal (371).

4. The dynamic impedance matching device of any of claims 1-3, wherein, The nodes are realized by T-junctions or branch transmission lines.

5. An antenna device, characterized by An antenna connected to the dynamic impedance adjustment device of any one of claims 1-3.

6. A dynamic impedance matching method based on the dynamic impedance matching device of claim 1, characterized in that, The method comprises the following steps: (a) connecting the dynamic impedance adjustment device to a vector network analyzer and an arbitrary load, measuring the reflection coefficient, and displaying it on a Smith chart admittance coordinate system; (b) adjusting the variable phase shifter on the main transmission path to move the admittance point to a preset admittance circle at the target frequency; (c) adjusting the variable phase shifters on the branch tuning paths in sequence to gradually approach the matching point; (d) if there is a matching dead zone, adjusting the variable phase shifter on the branch tuning path near the load side to move the admittance point to the adjustable region, and repeating steps (b) and (c) until the impedance matching for any load is completed.

7. The dynamic impedance tuning method of claim 6, wherein, In step (b), the preset admittance circle is an admittance circle with G=1; in step (c), if the terminal is a short-circuit structure, the phase is changed to rotate the admittance point clockwise from the left end to approach the matching point, and if the terminal is an open-circuit structure, the phase is changed to rotate the admittance point counterclockwise from the right end to approach the matching point.

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