An equivalent matching method for variable non-frequency-variant network port impedance in the frequency domain

Abstract

The present invention discloses an equivalent matching method for a variable non-frequency-variable network port impedance in the frequency domain, comprising five steps, wherein the first step is to determine at which single frequency point the entire network operates, the second step is to determine the physical quantity affecting the network port impedance and the variation range of the physical quantity, the third step is to determine the correspondence between the network port impedance and the physical quantity and the variation range of the corresponding network port impedance, the fourth step is to select a suitable narrowband frequency variation range centered on the working frequency point of the network, the fifth step is to set the one-to-one correspondence between the physical quantity and the frequency according to the variation range of the physical quantity and the frequency variation range obtained in the second and fourth steps, and the network port impedance that varies with the physical quantity in step S3 is equivalent to the port impedance that varies with the frequency, and is matched in the frequency domain. The invention is applicable to the scenario where one or more physical quantities act simultaneously, and converts the non-frequency domain impedance matching problem under the influence of one or more physical quantities into the traditional frequency domain impedance matching problem, and is very convenient to use in the analysis and design of microwave millimeter wave circuits, thereby improving the design efficiency.

Description

Technical Field

[0001] The invention relates to the field of radio frequency and microwave millimeter wave technology, and in particular to an equivalent matching method for variable non-frequency-variable network port impedance in the frequency domain. Background Art

[0002] Impedance matching method is one of the most important technical issues in RF and microwave millimeter wave circuits and systems. This method can reduce the reflection of the input, output and connection of each component of the system, thereby improving the transmission efficiency and working stability of the system. In early circuit design, in most cases we only consider the impact of frequency changes on the port impedance of the circuit network. Therefore, so far, the method for matching the impedance that changes with frequency is very mature. With the rapid development of modern RF and microwave millimeter wave circuit systems, the system has proposed more complex functions and higher electrical performance indicators for each component. Among them, the port impedance of many circuit networks needs to consider not only the impact of frequency changes, but also the impact of one or more other different physical quantities. In order to adapt to the development of modern RF and microwave millimeter wave circuit systems, more and more people are paying attention to the method of studying how to efficiently and accurately match the port impedance of the circuit network that changes with multiple physical quantities.

[0003] The existing variable non-frequency-variable port impedance matching methods mainly solve the problem of matching the port impedance change caused by the input power change when the network with nonlinear load works at a single frequency point. The main methods are as follows:

[0004] The first method is to use a T-junction to connect two rectifier branches with variable port impedance in parallel, and adjust the impedance compression network on the two parallel branches to make the port impedance change more smoothly with power. This method reduces the impedance variation range to be matched, which is beneficial to matching; but it does not fundamentally solve the problem of impedance variation, and also limits the matching network structure, affecting the matching effect (J.Xu and DSRicketts, "An Efficient, Watt-Level Microwave Rectifier Using an Impedance Compression Network (ICN) With Applications in Outphasing Energy Recovery Systems," IEEE Microwave and Wireless Components Letters, vol. 23, no. 10, pp. 542-544, Oct. 2013).

[0005] The second method uses two parallel branches for current diversion, and the impedance is processed by the capacitors and inductors on the two branches. The impedance compression is achieved by making the imaginary impedance cancel each other and the real impedance change smoothly. However, this method still only reduces the range of port impedance change, does not fundamentally solve the problem of impedance change, and also limits the matching network structure, affecting the matching effect (K. Niotaki, A. Georgiadis, A. Collado and JSVardakas, "Dual-Band Resistance Compression Networks for Improved Rectifier Performance," IEEE Transactions on Microwave Theory and Techniques, vol. 62, no. 12, pp. 3512-3521, Dec. 2014)

[0006] The third method is the iterative optimization method often used in engineering practice. This method is to select a power point in the input power variation range to excite the circuit network, and match the network port impedance at this input power point; at the same time, observe the matching effect of the matching network at other power points. Select the power point with poor matching effect and re-match the circuit. By repeating the above steps, the matching network is continuously optimized, and then matching is achieved within the entire input power range. The main disadvantages of this method are the following two points: one is that this method requires multiple iterative optimizations, which leads to a longer design cycle for the entire circuit; the other is that if the network port impedance varies too much within the input power variation range, it is difficult to determine an optimal matching network to achieve matching of the network port impedance within the entire input power variation range. Summary of the invention

[0007] The purpose of the present invention is to solve the problem of impedance matching of radio frequency and microwave millimeter wave circuit system networks under the influence of various physical quantities, and to propose an equivalent matching method of variable non-frequency-variant network port impedance in the frequency domain.

[0008] To achieve the above object, the method adopted by the present invention comprises the following steps:

[0009] S1. Determine at which single frequency the entire network works;

[0010] S2. Determine the physical quantity that affects the impedance of the network port and the variation range of the physical quantity;

[0011] S3, determining the corresponding relationship between the network port impedance and the physical quantity and the variation range of the corresponding network port impedance;

[0012] S4, selecting a suitable narrowband frequency variation range centered on the network operating frequency point;

[0013] S5. According to the physical quantity variation range of step S2 and the frequency variation range of step S4, a one-to-one correspondence between the physical quantity and the frequency is set, and the network port impedance that varies with the physical quantity in step S3 is equivalent to the port impedance that varies with the frequency, and matching is performed in the frequency domain;

[0014] The network port impedance in step S2 includes a network input port impedance and a network output port impedance.

[0015] The physical quantity that affects the network port impedance in step S2 does not include frequency.

[0016] Furthermore, in the frequency domain equivalent matching method of the variable non-frequency-variant network port impedance, the step S4 requires that the selected frequency variation range is small enough so that the network S parameters within the narrowband frequency range remain substantially unchanged compared to the single frequency point.

[0017] The principle of the present invention is: for radio frequency and microwave millimeter wave networks, the network port impedance will not only change with the change of frequency, but also with the change of other physical quantities. When the network works at a single frequency point or does not consider the frequency response, in order to achieve network port impedance matching very conveniently and simply under different physical quantity change conditions, the present invention proposes a new solution; first, the change range of the corresponding network port impedance within a certain physical quantity change range is obtained, and then a narrowband frequency interval centered on the working frequency point of the network is selected. According to the previously determined physical quantity change range and the selected narrowband frequency interval, the one-to-one correspondence between the physical quantity and the frequency is set, and the network port impedance that changes with the physical quantity is equivalent to the port impedance that changes with the frequency, and is matched in the frequency domain. Since the bandwidth of the selected frequency interval is extremely narrow, the physical quantity change caused by the frequency change is negligible; at the same time, the selected narrowband frequency interval is small enough to ensure that the network S parameters in the frequency interval remain basically unchanged compared with the single frequency point.

[0018] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0019] The present invention solves the problem of how to match the network port impedance that changes under the influence of multiple external physical quantities when the network works at a single frequency point or does not consider the frequency response. The advantage of the present invention is that the network port impedance that changes under the influence of other external physical quantities is equivalent to matching in a narrowband frequency range centered on the working frequency point of the network; the range of change of the physical quantity that affects the impedance change and the selected frequency range are matched one by one, and at the same time, the network port impedance that changes with the physical quantity is equivalent to the port impedance that changes with the frequency, so as to realize the conversion of impedance from non-frequency domain to frequency domain, match the port impedance in the frequency domain, and avoid the limitations of matching such as impedance compression method; at the same time, because the selected frequency interval is small enough, the impedance change caused by frequency change and the change of other frequency-varying physical quantities are negligible, which ensures the accuracy of the method; the invention converts the non-frequency domain impedance matching of the network port into our traditional frequency domain impedance matching, making the impedance matching design of the network port under the influence of multiple physical quantities very simple, thereby improving the design efficiency of microwave millimeter wave circuits. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The invention provides an equivalent matching method of a variable non-frequency-variable network port impedance in the frequency domain;

[0021] Figure 2 It is a step diagram of the equivalent matching method of the variable non-frequency-variant network port impedance in the frequency domain according to the first embodiment of the present invention;

[0022] Markings in the figure: step one S1, step two S2, step three S3, step four S4, step five S5. DETAILED DESCRIPTION

[0023] In order to make the purpose, problem to be solved and method of the present invention clearer, the present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0024] Embodiment 1:

[0025] Figure 2The method step diagram of a specific embodiment of the present invention, wherein step S1 determines that the operating frequency of the entire network is 5 GHz; step S2 determines that the physical quantity affecting the network port impedance is the input power and its variation range is -20 dBm to 0 dBm; step S3 determines the corresponding relationship between the network port impedance and the input power and the corresponding network port impedance variation range; step S4 selects a suitable frequency variation range with 5 GHz as the center frequency, which is 4.999 GHz to 5.001 GHz; step S5 sets the one-to-one correspondence between input power and frequency to a linear relationship based on the physical quantity variation range of step S2 and the frequency variation range of step S4, and the network port impedance that varies with the input power in step S3 is equivalent to the port impedance that varies with the frequency, and matches it in the frequency domain.

[0026] Embodiment 2:

[0027] In this embodiment, the input power physical quantity that affects the network port impedance in step S2 is changed to the external environment temperature, and the other parts are completely the same as those in the first embodiment, and the functions of the present invention can still be achieved.

[0028] Embodiment three:

[0029] In this embodiment, the physical quantity of input power that affects the impedance of the network port in step S2 is changed to the external environment humidity, and the other parts are completely the same as those in the first embodiment, and the functions of the present invention can still be achieved.

[0030] Embodiment 4:

[0031] In this embodiment, the input power physical quantity that affects the network port impedance in step S2 is changed into the input voltage amplitude, and the other parts are completely the same as those in the first embodiment, and the functions of the present invention can still be realized.

[0032] Embodiment five:

[0033] In this embodiment, the input power physical quantity that affects the network port impedance in step S2 is changed to the external environment pressure, and the other parts are exactly the same as those in the first embodiment, and the functions of the present invention can still be achieved.

[0034] Embodiment six:

[0035] In this embodiment, the physical quantity affecting the impedance of the network port in step S2 is changed from one physical quantity change to multiple physical quantity changes at the same time, and the other parts are completely the same as those in the first embodiment, and the functions of the present invention can still be realized.

[0036] Embodiment seven:

[0037] In this embodiment, the linear correspondence between the input power and the frequency in step S5 is changed into a nonlinear correspondence, and the other parts are completely the same as those in the first embodiment, and the functions of the present invention can still be realized.

[0038] Embodiment eight:

[0039] In this embodiment, the operation in step S1 is changed from a single frequency point to a very narrow bandwidth, ensuring that the center frequency of the bandwidth is still the original single frequency point frequency, and in the process of changing the frequency range, the network S parameters within the selected narrowband frequency range remain basically unchanged with the single frequency point, and the other parts are exactly the same as in embodiment 1, and the functions of the present invention can still be realized.

[0040] It can be seen from the above eight embodiments that the present invention has the following advantages:

[0041] Wide application scenarios and strong universality. The frequency domain equivalent matching method of the network port impedance proposed in the present invention can complete the network port impedance matching in combination with the traditional frequency domain impedance matching method under the influence of a variety of different physical quantities, such as input power and temperature changes, as long as the frequency response change of the network can be ignored. Therefore, this method has a wide range of application scenarios in the analysis and design of RF and microwave millimeter wave networks, and also greatly improves the design efficiency of RF and microwave millimeter wave systems.

[0042] The method is simple. The frequency domain equivalent matching method of the network port impedance proposed by the present invention includes fewer steps, and at the same time, the network port impedance matching problem under the influence of one or more physical quantities is converted into a traditional frequency domain impedance matching problem, which greatly simplifies the matching design of the radio frequency and microwave millimeter wave network, thereby saving cost and time for the design of the radio frequency and microwave millimeter wave system.

[0043] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific variations and combinations that do not deviate from the essence of the present invention based on the technical revelations disclosed by the present invention, and these variations and combinations are still within the protection scope of the present invention.

Claims

1. A method for equivalent matching of variable non-frequency-variant network port impedance in the frequency domain, comprising the following steps: S1. Determine at which single frequency the entire network works; S2. Determine the physical quantity that affects the impedance of the network port and the variation range of the physical quantity; S3, determining the corresponding relationship between the network port impedance and the physical quantity and the variation range of the corresponding network port impedance; S4, selecting a suitable narrowband frequency variation range centered on the network operating frequency point; S5. According to the physical quantity variation range of step S2 and the frequency variation range of step S4, a one-to-one correspondence between the physical quantity and the frequency is set, and the network port impedance that varies with the physical quantity in step S3 is equivalent to the port impedance that varies with the frequency, and matching is performed in the frequency domain; The network port impedance in step S2 includes a network input port impedance and a network output port impedance; The physical quantity that affects the network port impedance in step S2 does not include frequency.

2. The method for equivalent matching of variable non-frequency-variant network port impedance in the frequency domain as described in claim 1, wherein the step S4 requires that the selected frequency variation range is small enough so that the network S parameters within the narrowband frequency range remain substantially unchanged compared to the single frequency point.

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