Method for rapidly determining passive intermodulation level of cavity filter

Abstract

The invention relates to a method for rapidly determining a passive intermodulation level of a cavity filter. The method comprises the following steps: firstly equally dividing a cavity filter contact part, carrying out frequency domain electromagnetic field simulation twice at two carrier frequencies, and respectively obtaining surface currents of the contact part; then determining voltage drop of each part of the contact part by combining contact resistance, and determining nonlinear current of each part according to nonlinear current-voltage characteristics of the contact part; and finally taking the nonlinear current as excitation, carrying out electromagnetic simulation at a passive intermodulation frequency, and finally determining the passive intermodulation power level of a port of the cavity filter, so that quick determination of the passive intermodulation level of the cavity filter is realized. The method provided by the invention can be used for solving the problem of the passive intermodulation simulation of the cavity filter, and passive intermodulation performance of the cavity filter can be effectively simulated and optimized.

Description

technical field [0001] The invention belongs to the field of passive intermodulation of microwave components, and relates to a method for determining the passive intermodulation level of a cavity filter. Background technique [0002] Passive-Intermodulation (PIM) refers to the combination of carrier frequency due to the mutual modulation of carrier signals due to the nonlinearity of microwave passive components when two or more carriers are input under high power conditions. A phenomenon in which products fall into the receive passband and cause interference. When the intermodulation level is low, it will increase the noise floor of the received signal, reduce the signal-to-noise ratio of the receiver, and increase the bit error rate; when the intermodulation level is further increased, it will affect the normal operation of the entire communication system. Forced to reduce power usage, or divide the use of channels; in severe cases, intermodulation products will flood the ...

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Problems solved by technology

[0003] At present, the passive intermodulation characteristics of microwave components can only be tested and verified after the design, processing, and commissioning of the product are completed. As a result, the passive intermodulation performance of the product cannot be guaranteed. Once the passive intermodulation performance does not meet the requirements, Then the product needs to be redesigned, processed, tested, and sometimes even repeated many times. Therefore, the passive intermodulation performance has seriously restricted the development of low passive intermodulation and high-power microwave components.

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