A Compact Wide-Range Frequency and Bandwidth Reconfigurable Filter

• Published in: IEEE microwave and wireless components letters Vol. 32; no. 11; pp. 1283 - 1286
• Main Authors: Tian, Mingen, Long, Zhihe, Feng, Lijun, He, Leilei, Zhang, Tianliang
• Format: Journal Article
• Language: English
• Published: IEEE 01.11.2022
• Subjects: Bandpass filter (BPF); Bandwidth; Couplings; reconfigurable; Resonant frequency; Resonators; Scattering parameters; Switches; switching diode; Varactors; wide range
• ISSN: 1531-1309; 1558-1764
• DOI: 10.1109/LMWC.2022.3178722

This letter proposes a wide-range reconfigurable bandpass filter (WRBPF) based on the cross-shape triple-mode resonator. Varactor diodes and switching diodes are utilized at the ends of the resonator and the positions of external coupling, which combines the two working modes of the low-frequency band and high-frequency band, greatly broaden the tunable range of the center frequency (<inline-formula> <tex-math notation="LaTeX">f_{0} </tex-math></inline-formula>). When the 3-dB bandwidth of WRBPF is 180 MHz, <inline-formula> <tex-math notation="LaTeX">f_{0} </tex-math></inline-formula> can be adjusted from 0.78 to 1.93 GHz, and the relative adjustment range is 84.9%. When <inline-formula> <tex-math notation="LaTeX">f_{0} </tex-math></inline-formula> is 1.355 GHz, the absolute bandwidth can be adjusted from 110 to 950 MHz, and the relative bandwidth adjustment range is 8.1%-70.1%. Moreover, the circuit size of WRBPF is only <inline-formula> <tex-math notation="LaTeX">0.29\,\,\lambda g\,\,\times 0.22\,\,\lambda g </tex-math></inline-formula>. The experimental results show that WRBPF has not only a simple structure but also an excellent performance.