Method for computer aided design of microwave filter

Abstract

The invention discloses a method for the computer aided design of a microwave filter. The method comprises the following steps of: 1) determining the size of a resonator according to the center frequency of the filter; 2) determining a group of standard delay amounts Gamma1, Gamma2, ..., GammaN according to the bandwidth and order N of the filter; 3) simulating a single-port network consisting ofan input port and a first-order resonator, and regulating the physical size of the first-order resonator to make the port delay characteristic of the network meets Gamma1; 4) adding a second-order resonator, and regulating the physical sizes of the first-order and second-order resonators to make the port delay of the network meets Gamma2; 5) by parity of reasoning, obtaining the physical sizes ofa half of resonators; and 6) mirroring the resonators with the regulated physical sizes to obtain the sizes of the other half of resonators to finish the design of the filter. In the method, the delay characteristic of the single-port filter is utilized, and the method has the advantages of small calculated amount and high efficiency as well as high center frequency and bandwidth setting accuracy, and is particularly suitable for the computer aided design (CAD) of the high-order microwave filter.

Description

technical field [0001] The invention belongs to the technical field of analog signal processing, in particular to a computer-aided design (CAD) method of a microwave filter. Background technique [0002] In recent years, commercial microwave / RF circuit computer-aided design (CAD) software, especially full-wave electromagnetic field simulation (Full-Wave Electromagnetic) software, has developed very rapidly. These commercial software can be used for microwave filter design, modeling, and simulation , and finally the actual microwave filter can be made according to the software design model. In the past ten years, the speed and memory of computers have doubled every two years. The rapid development of these commercial software is mainly due to the rapid increase in the processing speed of computers. For microwave / RF circuit design software, its simulation algorithms include FDTD, MOM, FEM, IE / BEM, etc. These algorithms need to take up a lot of memory space in the process of c...

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Problems solved by technology

In practical applications, since this method does not consider the coupling effects of non-adjacent resonators and the effect of shifting the center frequency of each resonator in the filter due to resonator coupling, the filter is obtained by using this method Generally, the frequency characteristic is far from the ideal result, which greatly increases the workload of subsequent fine-tuning of the physical size. Moreover, the fine-tuning simulation process lacks directionality and mainly relies on manual experience, especially in the simulation design of high-order filters. The workload will increase sharply, and the work efficiency will be greatly reduced.

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