Quasi-Elliptic Higher-Order Tunable Bandpass Filter With Constant Absolute Bandwidth Using Synchronously Tuned Dual-Mode Resonators
Designing a higher-order tunable bandpass filter (BPF) with constant absolute bandwidth (ABW) and identical passband response at every passband frequency tuning state is considered a challenge. In this paper, we propose quasi-elliptic higher-order tunable BPFs that use synchronously tuned dual-mode...
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Published in | IEEE access Vol. 11; pp. 95051 - 95059 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
Piscataway
IEEE
2023
The Institute of Electrical and Electronics Engineers, Inc. (IEEE) |
Subjects | |
Online Access | Get full text |
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Summary: | Designing a higher-order tunable bandpass filter (BPF) with constant absolute bandwidth (ABW) and identical passband response at every passband frequency tuning state is considered a challenge. In this paper, we propose quasi-elliptic higher-order tunable BPFs that use synchronously tuned dual-mode resonators, which can achieve identical passband frequency response and constant ABW. To achieve identical passband frequency response and constant ABW, all frequency-dependent coupling coefficient and external quality factor are physically realized using series capacitor and shunt varactor. To achieve quasi-elliptic response, transmission zeros are generated at lower and upper sides of passband through cross-coupling between dual-mode resonators. For experimental validation, a prototype of 4th and 6th-order BPFs are designed and fabricated. Experimental results reveal that the passband center frequency of the 4th-order tunable BPF can be tuned from 1.35 to 1.75 GHz (25.82%) with identical passband return loss (RL) of 20 dB and 1-dB constant ABW of 92 ± 1.3 MHz. Similarly, the passband center frequency of 6th-order BPF can be tuned from 1.38 to 1.77 GHz (27.76%) with an identical passband RL of 20 dB and 1-dB constant ABW of 98 ± 1.5 MHz. |
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ISSN: | 2169-3536 2169-3536 |
DOI: | 10.1109/ACCESS.2023.3310934 |