Dynamic impedance allocation device, antenna device and dynamic impedance allocation method

Abstract

The invention discloses a dynamic impedance allocation device, an antenna device and a dynamic impedance allocation method, and the structure of the device comprises a main transmission path which is connected with an input / output port; the at least one branch deploying path is connected to the main transmission path in parallel through nodes, and each branch deploying path comprises a variable phase shifter and an open-circuit or short-circuit terminal; by independently adjusting the variable phase shifters, the reflection coefficient of any load impedance is iteratively converged to the matching area of the Smith chart, and dynamic impedance matching is achieved. Compared with the prior art, the impedance allocation device has the dynamic impedance matching capability, solves the problem that a fixed matching network cannot adapt to impedance conversion, solves the systematic technical defects of incapability of continuous adjustment, long-term stability and the like, and can meet the strict requirements of a modern microwave system on broadband and high reliability.

Description

Technical Field

[0001] The present invention relates to an impedance matching device, specifically a dynamic impedance matching device, an antenna device and a dynamic impedance matching method based on a variable stub topology. Background Art

[0002] In the fields of microwave transmission systems and high-frequency circuit design, the reflected wave interference caused by impedance mismatch is the core problem affecting system performance. Reflections caused by problems such as the characteristic impedance difference between the load and the transmission line, and the discontinuity of connectors will lead to problems such as the deterioration of the standing wave ratio, the decrease of power transmission efficiency, and the distortion of measurement signals. To suppress reflections, various impedance matching schemes have been proposed in the industry: using a slotted coaxial cable with an external probe to achieve impedance tuning by axially moving and depth adjusting the probe; using a T-junction or a one-to-two coaxial cable to construct a coaxial shunt stub network, and adjusting the stub reactance by cutting the cable length; in a PCB system, an LC network is often used to construct an L-type, T-type or π-type matching network, and the capacitance and inductance values are adjusted to cancel reflections; using microstrip lines or waveguides to implement open-circuit or short-circuit stubs, and changing the impedance characteristics by adjusting the stub length and position; cutting and pasting copper foil on the slots of the antenna to change the slot size and adjust the antenna impedance.

[0003] Although the above methods have been partially applied to engineering practice, there are still the following technical bottlenecks: the ±5% impedance tolerance caused by PCB processing will cause the actual impedance to deviate by ±10 ohm, and traditional LC networks or fixed stubs cannot dynamically compensate for errors, resulting in mismatch; the insertion position and length of microstrip stubs cannot be adjusted after processing, and cannot meet the requirements of multi-band or dynamic load changes; the slotted coaxial cable structure is prone to unstable contact impedance due to long-term plugging and unplugging wear; the incomplete shielding layer is easy to couple environmental noise. Summary of the Invention

[0004] In order to solve the above technical problems existing in the prior art, the present invention proposes a dynamic impedance matching device, an antenna device and a dynamic impedance matching method based on a variable stub topology. By using a variable phase shifter to replace the fixed stub length, it is possible to achieve impedance matching of the load at any desired frequency without prior knowledge of the load impedance. The specific technical solutions are as follows: A dynamic impedance matching device, which can be connected to any load, includes: A main transmission path, connected to the input / output port, and can integrate a variable phase shifter for adjusting the signal phase; At least one stub matching path, connected in parallel to the main transmission path through a node, and each stub matching path includes a variable phase shifter and an open-circuit or short-circuit terminal; Independently adjusting each variable phase shifter to change the electrical angle of the corresponding stub can iteratively converge the reflection coefficient of any load impedance to the matching region of the Smith chart, realizing dynamic impedance matching.

[0005] Furthermore, the dynamic impedance matching device adopts a single stub structure, including: A first variable phase shifter on the main transmission path, connecting the signal source end and the load; A stub matching path is connected in parallel to the main transmission path through a node, including a second variable phase shifter and an open or short circuit terminal; Adjust the first variable phase shifter and the second variable phase shifter to move the load admittance point along the admittance coordinate system of the Smith chart to the matching point.

[0006] Furthermore, the dynamic impedance matching device adopts a double stub topology structure, including: A first variable phase shifter on the main transmission path, connecting the signal source end and the load; A first stub matching path is connected in parallel to the main transmission path near the signal source side through a first node, including a second variable phase shifter and a first terminal; A second stub matching path is connected in parallel to the main transmission path near the load side through a second node, including a third variable phase shifter and a second terminal; By adjusting the first variable phase shifter, make the signal phase 45°, 90° or 135°, and coordinately adjust the second and third variable phase shifters to gradually approach the admittance point to the matching point.

[0007] Furthermore, the main transmission path of the double stub topology structure further includes a fourth variable phase shifter, located between the first variable phase shifter and the load, and adjust the fourth variable phase shifter to make the signal phase 45°, 90° or 135°.

[0008] Furthermore, the dynamic impedance matching device adopts a triple stub topology structure, including: A first variable phase shifter and a second variable phase shifter on the main transmission path, serially connecting the signal source end and the load; A first stub matching path is connected in parallel to the signal source side of the main transmission path through a first node, including a third variable phase shifter and a first terminal; A second stub matching path is connected in parallel to the middle section of the main transmission path through a second node, including a fourth variable phase shifter and a second terminal; A third stub matching path is connected in parallel to the load side of the main transmission path through a third node, including a fifth variable phase shifter and a third terminal; 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.

[0009] Furthermore, the dynamic impedance matching device adopts a triple stub topology structure, including: The main transmission path connects the signal source end and the load; there are two sections of transmission lines on the main transmission path, and the line lengths of the transmission lines are 1 / 4, 1 / 8, or 3 / 8 of the wavelength. The first stub matching path is connected in parallel to the signal source side of the main transmission path through the first node, and includes a third variable phase shifter and a first terminal. The second stub matching 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 a fourth variable phase shifter and a second terminal. The third stub matching path is connected in parallel to the load side of the main transmission path through the third node, and includes a fifth variable phase shifter and a third terminal.

[0010] Furthermore, the multi-branch parallel connection is realized by a T-joint or a branch transmission line at the node.

[0011] An antenna device includes the dynamic impedance tuning device described above and an antenna connected thereto.

[0012] A dynamic impedance matching method based on a dynamic impedance matching device includes the following steps: (a) Connect the dynamic impedance matching device to the load and the vector network analyzer, measure the reflection coefficient and display it in the admittance coordinate system of the Smith chart. (b) Adjust the variable phase shifter on the main transmission path to move the admittance point to a preset admittance circle. (c) Adjust the variable phase shifters of each stub matching path in sequence to gradually approximate the admittance point to the matching point. (d) If there is a matching dead zone, then by adjusting the additional stub phase shifter, move the admittance point to the adjustable area and repeat steps (b) and (c) until the matching of any load is completed.

[0013] Furthermore, in step (b), the preset admittance circle is the admittance circle of G = 1. In step (c), if the terminal is a short-circuit structure, change the phase to make the admittance point rotate clockwise from the left end to approach the matching point; if the terminal is an open-circuit structure, change the phase to make the admittance point rotate counterclockwise from the right end to approach the matching point.

[0014] Compared with the prior art, the dynamic impedance matching device of the present invention solves systematic 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. Description of the Drawings

[0015] Figure 1 is a schematic diagram of a single stub structure adopted by the dynamic impedance matching device of this embodiment; Figure 2 is a schematic diagram of a double stub topology structure adopted by the dynamic impedance matching device of this embodiment; Figure 3 It is another schematic diagram of the double stub topology adopted by the dynamic impedance matching device of this embodiment; Figure 4 It is a schematic diagram of the triple stub topology adopted by the dynamic impedance matching device of this embodiment; Figures 5 to 7 It is a schematic diagram of the test results of realizing impedance matching by applying the dynamic impedance matching device of this embodiment at different target frequencies. Specific embodiments

[0016] In order to make the purpose, technical solutions and technical effects of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings of the specification and embodiments.

[0017] The present invention discloses a dynamic impedance matching device based on a variable stub topology, which uses a combination of variable phase shifters to construct an impedance matching network, facilitating modular adaptation to different loads and enabling dynamic adjustment of the matching network so that an unknown load operates in a matching state.

[0018] In one embodiment, as Figure 1 shown, the impedance matching network adopts a single stub structure, including: Main transmission path: Connecting the input / output ports, integrated with a first variable phase shifter 111, and both ends of the first variable phase shifter 111 are respectively connected to the signal source end 110 and the load 112.

[0019] Stub matching path: Shunted to the main transmission path through node 12, including a second variable phase shifter 130 and an open or short circuit terminal 131.

[0020] The control logic of this structure is: By independently adjusting the two variable phase shifters, the reflection coefficient of any load impedance is mapped to the matching area of the Smith chart. When the load 112 is purely resistive, the stub matching path can be disabled.

[0021] The process of load impedance matching using the impedance matching device with the above single stub structure is as follows: First step: Connect the signal output end of the impedance matching device to the load and the signal input end to the vector network analyzer; Second step: 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; Third step: Adjust the first variable phase shifter 111 to move the admittance point to the admittance circle with G = 1; Fourth step: Adjust the second variable phase shifter 130. If the terminal 131 is a short circuit structure, change the phase to rotate the admittance point clockwise from the left end. If the terminal 131 is an open circuit structure, change the phase to rotate the admittance point counterclockwise from the right end until reaching the matching point.

[0022] In one embodiment, as Figure 2 shown, the impedance matching network adopts a two-stub topology structure, including: Main transmission path: Connecting the input / output port, integrated with a first variable phase shifter 221, with both ends of the first variable phase shifter 221 connected to the signal source terminal 220 and the load 222 respectively; First stub matching path: Shunted to the main transmission path through the first node 23, located on the signal source side of the main transmission path, including a second variable phase shifter 210 and a first terminal 211.

[0023] Second stub matching path: Shunted to the main transmission path through the second node 24, located on the load side of the main transmission path, including a third variable phase shifter 250 and a second terminal 231.

[0024] Wherein the first variable phase shifter 221 is located between the first node 23 and the second node 24 on the main transmission path.

[0025] Wherein both the first and second terminals can be open or short terminals.

[0026] The structure control logic is: By independently adjusting the three variable phase shifters, the reflection coefficient of any load impedance is mapped to the matching area of the Smith chart; wherein the signal phase adjusted by the first variable phase shifter is matched to 45°, 90° or 135°.

[0027] As Figure 3 shown, on the main transmission path, a fourth variable phase shifter 223 can also be added between the first variable phase shifter 221 and the load 222, and the signal phase adjusted by the fourth variable phase shifter 223 is matched to 45°, 90° or 135°.

[0028] The process of load impedance matching using the above dynamic impedance matching device with a two-stub topology structure is as follows: First step: Connect the signal output end of the dynamic impedance matching device to the load and the signal input end to the vector network analyzer; Second step: 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; Third step: First, adjust the first and third variable phase shifters so that the signal phase angle is 45°, or only connect the first variable phase shifter 221 and adjust the first variable phase shifter 221 so that the signal phase angle is 45°, 90° or 135°; Fourth step: Adjust the third variable phase shifter 250 so that the admittance point approaches the matching point; Fifth step: Then adjust the second variable phase shifter 210 so that the admittance point further approaches the matching point; Sixth step: Repeat the above fourth and fifth steps. If entering the matching dead zone, the first phase shifter or the first and third phase shifters can be adjusted to move the load admittance point out of the dead zone, and then repeat the above fourth and fifth steps until the admittance point reaches the matching point.

[0029] If the terminal is a short - circuit structure, change the phase to make the admittance point rotate clockwise from the left end close to the matching point. If the terminal is an open - circuit structure, change the phase to make the admittance point rotate counter - clockwise from the right end close to the matching point.

[0030] In one embodiment, as Figure 4 shown, the impedance matching network adopts a three - stub topology structure, including: Main transmission path: Connecting the input / output ports, integrated with a first variable phase shifter 321 and a second variable phase shifter 322. After the first variable phase shifter 321 and the second variable phase shifter 322 are connected in series, both ends are respectively connected to the signal source terminal 320 and the load 323.

[0031] First stub matching path: Shunted to the main transmission path through the first node 33, located on the side of the main transmission path close to the signal source, including a third variable phase shifter 310 and a first terminal 311.

[0032] Second stub matching path: Shunted 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, including a fourth variable phase shifter 350 and a second terminal 351.

[0033] Third stub matching path: Shunted to the main transmission path through the third node 36, located on the side of the main transmission path close to the load 323, including a fifth variable phase shifter 370 and a third terminal 371.

[0034] Among them, the first terminal 311, the second terminal 351, and the third terminal 371 can all be open - circuit or short - circuit terminals.

[0035] The regulation logic of this structure is: By independently adjusting the three variable phase shifters, the reflection coefficient of any load impedance is mapped to the matching area of the Smith chart; the signal phase adjusted by the first variable phase shifter 321 should be 45°, 90° or 135° of the impedance to be matched.

[0036] The process of load impedance matching using the dynamic impedance matching device with the above three - stub topology structure is as follows: First step: Connect the signal output end of the impedance matching device to the load, and connect the signal input end to the vector network analyzer; Second step: 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; Step 3: First, adjust the first and second variable phase shifters to make the signal phase angles 45°, 90°, or 135°; Step 4: Adjust the third variable phase shifter 310 to make the admittance point close to the matching point; Step 5: Then, adjust the fourth variable phase shifter 350 to make the admittance point closer to the matching point; Step 6: Repeat the above Step 4 and Step 5 until the admittance point reaches the matching point; 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 area; Step 8: Repeat the above Step 6 to Step 7 until the matching is completed.

[0037] If the terminal is a short - circuit structure, change the phase to make the admittance point rotate clockwise from the left end to approach the matching point. If the terminal is an open - circuit structure, change the phase to make the admittance point rotate counterclockwise from the right end to approach the matching point.

[0038] In one embodiment, the impedance matching network adopts a three - stub topology structure, including: A main transmission path connecting the signal source end and the load; two transmission lines are provided on the main transmission path, and the line lengths of the transmission lines are 1 / 4, 1 / 8, or 3 / 8 of the wavelength; The first stub matching path: connected to the main transmission path in parallel through the first node, located on the side of the main transmission path close to the signal source, including the third variable phase shifter and the first terminal.

[0039] The second stub matching path: connected to the main transmission path in parallel through the second node, located between the two transmission lines, including the fourth variable phase shifter and the second terminal.

[0040] The third stub matching path: connected to the main transmission path in parallel through the third node, located on the side of the main transmission path close to the load, including the fifth variable phase shifter and the third terminal.

[0041] In the above - mentioned embodiment, the node connection is realized by: a T - type joint or a branch transmission line to achieve multi - branch parallel connection, and the transmission line lengths between the branch branches can be freely configured. Coaxial open - circuit / short - circuit switching: The open - circuit and short - circuit can be directly realized by using a dust cap or a short - circuit cap; it can also be realized by an open - circuit / short - circuit switching device, and the open - circuit / short - circuit switching device realizes the switching between the open - circuit and short - circuit states by moving the inner conductor through a sliding or threaded mechanism.

[0042] After the above steps, the impedance of the original load can be adjusted to the matching point at the target frequency to achieve impedance matching, and it can be realized at multiple target frequencies based on the same set of devices. The test results are shown in Figures 5 - 7 . The principle of realizing impedance matching is as follows: In actual work, the impedance of a load often changes with different operating frequencies. To enable the load to operate optimally at different target frequencies, impedance matching is required. For any load impedance , the purpose of achieving impedance matching is to transform its impedance to , so it is necessary to eliminate the imaginary part impedance of the load X l , and adjust the real part impedance R l .

[0043] To achieve this purpose, a stub can be connected in series with the load first to adjust the real part impedance of the load to the characteristic impedance, and the following conditions need to be met: , From this, it can be seen that the equivalent impedance with real part matching can be obtained by changing the transmission line length d or the phase shift constant β to meet the above conditions. Then, on this basis, a stub is inserted to cancel the imaginary part impedance of the input impedance at this time. The final input impedance obtained is , and the conditions to be met are as follows: Open-circuit stub: ; Short-circuit stub: .

[0044] Thus, it can be seen that only by independently adjusting the phase shift constant β or the physical length l on the main transmission line and the stub transmission line can appropriate values be found to achieve impedance matching for any load. To achieve this goal, the present invention introduces a variable phase shifter for adjustment. A variable phase shifter is a phase shifter that can continuously change the phase. A mechanically tuned phase shifter that can change the physical length can be selected, or a numerically controlled step-type phase shifter, a ferrite phase shifter, a MEMS phase shifter, an analog phase shifter, etc. that can change the equivalent phase shift constant can also be selected.

[0045] As mentioned above, only the preferred implementation cases of the present invention are described, and there is no any formal restriction on the present invention. Although the implementation process of the present invention has been described in detail above, for those familiar with the field, they can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacements for some of the technical features. Any modifications, equivalent replacements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A dynamic impedance matching device, characterized in that It can be connected to any load, and the device includes: A main transmission path connecting the input / output ports; At least one stub tuning path connected in parallel to the main transmission path through a node, and each stub tuning path includes a variable phase shifter and an open or short circuit terminal; By independently adjusting each variable phase shifter, the reflection coefficient of any load impedance can be iteratively converged to the matching region on the Smith chart.

2. The dynamic impedance matching device according to claim 1, characterized in that Adopting a single stub structure, including: A first variable phase shifter (111) on the main transmission path, connecting the signal source terminal (110) and the load (112); A stub tuning path is connected in parallel to the main transmission path through a node (12), including a second variable phase shifter (130) and an open or short circuit terminal (131); Adjust the first variable phase shifter (111) and the second variable phase shifter (130) to move the load admittance point to the matching point in the admittance coordinate system of the Smith chart.

3. The dynamic impedance matching device according to claim 1, characterized in that Adopting a double stub topology, including: A first variable phase shifter (221) on the main transmission path, connecting the signal source terminal (220) and the load (222); The first stub tuning path is connected in parallel to the main transmission path near the signal source side through a first node (23), including a second variable phase shifter (210) and a first terminal (211); The second stub tuning path is connected in parallel to the main transmission path near the load side through a second node (24), including a third variable phase shifter (250) and a second terminal (231); By adjusting the first variable phase shifter (221) and coordinately adjusting the second and third variable phase shifters, the admittance point gradually approaches the matching point.

4. The dynamic impedance matching device according to claim 3, wherein The main transmission path further includes a fourth variable phase shifter (223) located between the first variable phase shifter (221) and the load (222).

5. The dynamic impedance matching device according to claim 1, wherein Adopting a triple stub topology, including: A first variable phase shifter (321) and a second variable phase shifter (322) on the main transmission path, connected in series between the signal source terminal (320) and the load (323); The first stub tuning path is connected in parallel to the main transmission path on the signal source side through a first node (33), including a third variable phase shifter (310) and a first terminal (311); The second stub tuning path is connected in parallel to the middle section of the main transmission path through a second node (34), including a fourth variable phase shifter (350) and a second terminal (351); The third stub tuning path is connected in parallel to the main transmission path on the load side through a third node (36), including a fifth variable phase shifter (370) and a third terminal (371); Adjust the first and second variable phase shifters and coordinately adjust the third, fourth, and fifth variable phase shifters to eliminate the matching dead zone.

6. The dynamic impedance matching device according to claim 1, wherein Adopting a triple stub topology, including: The main transmission path connects the signal source terminal (320) and the load (323); There are two transmission lines on the main transmission path, and the line lengths of the transmission lines are 1 / 4, 1 / 8, or 3 / 8 of the wavelength; The first stub tuning path is connected in parallel to the main transmission path on the signal source side through a first node (33), including a third variable phase shifter (310) and a first terminal (311); The second stub matching path is connected in parallel to the middle section of the main transmission path through the second node (34), located between the two transmission lines, and includes a fourth variable phase shifter (350) and a second terminal (351); The third stub matching path is connected in parallel to the load side of the main transmission path through the third node (36), and includes a fifth variable phase shifter (370) and a third terminal (371).

7. The dynamic impedance matching device according to any one of claims 1-6, characterized in that, The nodes achieve multi-branch parallel connection through a T-joint or a branch transmission line.

8. An antenna device, characterized in that, It includes the dynamic impedance tuning device according to any one of claims 1-6 and an antenna connected thereto.

9. A dynamic impedance matching method based on the dynamic impedance matching device described in claim 1, characterized in that, It includes the following steps: (a) Connect the dynamic impedance matching device to a vector network analyzer and any load, measure the reflection coefficient and display it in the admittance coordinate system of the Smith chart; (b) Adjust the variable phase shifter on the main transmission path to move the admittance point to a preset admittance circle at the target frequency; (c) Adjust the variable phase shifters of each stub matching path in sequence to gradually approximate the admittance point to the matching point; (d) If there is a matching dead zone, adjust the variable phase shifter on the stub matching path near the load side, move the admittance point to the adjustable area, and then repeat steps (b) and (c) until the impedance matching of any load is completed.

10. The dynamic impedance matching method according to claim 9, characterized in that, In step (b), the preset admittance circle is the admittance circle with G = 1; in step (c), if the terminal is a short-circuit structure, change the phase to rotate the admittance point clockwise from the left end to approach the matching point, and if the terminal is an open-circuit structure, change the phase to rotate the admittance point counterclockwise from the right end to approach the matching point.

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