Tunable microstrip filter and design method thereof

Abstract

The invention discloses a tunable microstrip filter and a design method of the tunable microstrip filter. The tunable microstrip filter comprises a plurality groups of parallel coupling lines. One end of each group of coupling lines is in short circuit, and the other end of each group of coupling lines is grounded after passing through a lumped capacitor, wherein the lumped capacitor is a voltage controlled variable capacitance diode. A manufacturing method of the tunable microstrip filter comprises the steps of normalizing a low-pass filter, searching a list for the order n of the filter to determine the normalization parameter of the normalized low-pass filter, working out the relevant parameter values of the filter according to the normalization parameter, working out the interval S and the width W of each group of parallel coupling lines of the microstrip filter by searching a list, and working out the length L of each group of parallel coupling lines. According to the tunable microstrip filter, the voltage controlled variable capacitance diode is used for replacing a common capacitor, the two ends of the voltage controlled variable capacitance diode are connected with the output ends of the digital-analogue conversion circuit respectively, and as long as a corresponding binary-system high or low level is output, the wanted analog voltage can be obtained; in this way, the center frequency of the microstrip filter is changed, tuning of the filter is achieved, the basic performance is good, and use is convenient.

Description

technical field [0001] The invention belongs to the field of filter production, in particular to a tunable microstrip filter and a design method thereof. Background technique [0002] In the new century, wireless communication technologies around the world have developed rapidly. While these technologies bring us convenience, they also raise new questions for us. Because within the limited spectrum range, the spectrum of wireless communication signals is getting wider and wider, resulting in more and more crowded spectrum occupancy. Therefore, in order to adapt to the status quo of signals with increasingly wider frequency spectrum and faster and faster frequency jumps, electronically tuned filter technology has emerged as the times require. [0003] Electrically tuned filters are widely used in radar transceiver systems, which are located after the front-end antenna of the receiver and before the mixer to filter out interference and image signals. More importantly, moder...

AI Technical Summary

Problems solved by technology

Because within the limited spectrum range, the spectrum of wireless communication signals is getting wider and wider, resulting in more and more crowded spectrum occupancy

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