Compact Tunable Broadband Filtering Attenuator Based on Variable Resistors

In this letter, a compact microstrip broadband filtering attenuator based on variable resistors is proposed with high-frequency selectivity. It can achieve tunable attenuation characteristics over a broad frequency band by changing the resistance of the variable resistors. Due to the symmetry of the circuit structure, it is analyzed using odd- and even-mode methods. For demonstration, a filtering attenuator prototype is fabricated and measured, which operates from 1.3 to 2.8 GHz and realizes tunable attenuation from 3.26 to 15.61 dB. The results of theoretical calculations, simulations, and measurements agree well with each other, which validates the feasibility of the proposed design.

Automated summary

This letter proposes a compact microstrip broadband filtering attenuator based on variable resistors with high-frequency selectivity. It can achieve tunable attenuation characteristics over a broad frequency band by changing the resistance of the variable resistors. The circuit structure is analyzed using odd- and even-mode methods. A fabricated prototype of the filtering attenuator operates from 1.3 to 2.8 GHz and realizes tunable attenuation from 3.26 to 15.61 dB. The results of theoretical calculations, simulations, and measurements agree well, validating the feasibility of the proposed design.