Compact dual-/tri-/quad-band bandpass filters with independently frequency-tunable and switchable passbands. Issue 4 (9th May 2021)

• Record Type: Journal Article
• Authors: Li, Zhao; Wang, Litian; He, Ming; Li, Xiaqing; Liang, Zhelong; Wang, Zhipeng
• Is Part Of: International journal of microwave and wireless technologies. Volume 13:Issue 4(2021)
• Page Start: 322
• Page End: 334
• Publication Date: 2021-05-09
• Subjects: tunable dual-/tri-/quad-band filters, -- dual-mode resonator, -- varactor diode, -- independent tunable, -- switchable; Wireless communication systems -- Periodicals; Microwave circuits -- Periodicals; Radio frequency -- Periodicals; 621.381305
• DOI: 10.1017/S1759078720001130
• Languages: English
• ISSNs: 1759-0787

Abstract

Abstract: This paper presents the design of frequency-tunable dual-band, tri-band and quad-band bandpass filters (BPFs). The proposed three BPFs can be independently tuned and individually switched by varying the capacitances of the varactors. In the designed tunable dual-band BPF (TD-BPF), common input/output feed lines are utilized for two tunable dual-mode resonators (TDRs). Further, three TDRs and four TDRs are employed to achieve tunable tri-band BPF (TT-BPF) and tunable quad-band BPF (TQ-BPF), respectively. Then, the TD-BPF and the TT-BPF are fabricated and measured to verify individual tunability and independent switchability. For the TD-BPF, the measurement results show that the center frequency (CF) of the first passband varies from 1.37 to 1.62 GHz, and the CF of the second passband varies from 2.3 to 2.64 GHz. In the measured TT-BPF, the tuning ranges of CFs of three passbands are 1.3–1.5 GHz, 2.36–2.6 GHz, and 3–3.54 GHz, respectively.