2026/4/22

【射频通信电路创新论文】

Tunable odd-oder filtering attenuators based on lossy-tuned LC resonators and lossy-tuned feedings using PIN diodes

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• The Key Laboratory of Photonic-Electronic Integration and Communication-Sensing Convergence, School of Information Science and Technology, Southwest Jiaotong University, Chengdu, China

Abstract

This article presents three odd-order lumped LC tunable filtering attenuators based on lossy-tuned resonators and lossy-tuned feedings using PIN diodes. Firstly, odd-order LC bandpass filters are achieved using Chebyshev lowpass filter prototype to bandpass filter transformation. The tunable filtering attenuation with flat passband is then achieved by controlling the resistive losses loaded on the resonators and Input/Output feedings via voltage-controlled PIN diodes. Three prototypes of 3rd-, 5th-, and 7th-order filtering attenuators are designed, fabricated and measured. The 3rd-order filtering attenuator operates at 0.83 GHz with a 3-dB fractional bandwidth (FBW) varying from 48.7% to 47.5% and tunable attenuation varying from 2.4 to 18 dB. The 5th-order one employs an asymmetric structure at 0.685 GHz with FBW varying from 92.2% to 60% and tunable attenuation varying from 2.8 to 29.5 dB. The 7th-order one works at 0.85 GHz with FBW varying from 112.6% to 75.3% and tunable attenuation varying from 2.4 to 30 dB. The measurement results demonstrate the advantages of wide tunable attenuation ranges, good in-band flatness and compact sizes.

Longchuan Liu（博士生 刘隆川）, Qianyin Xiang*, Tunable odd-oder filtering attenuators based on lossy-tuned LC resonators and lossy-tuned feedings using PIN diodes, AEU - International Journal of Electronics and Communications,Available online 21 April 2026, 156345, https://doi.org/10.1016/j.aeue.2026.156345