volume | PIER Journals

Abstract

This paper presents a compact electrically tunable bandpass filter with continuous control of center frequency and bandwidth independently. The filter consists of two coaxial dielectric resonators loaded with two varactors for center frequency tuning. A symmetrical Y-type capacitor network used for tuning bandwidth is proposed. A prototype made of dielectric ceramics with dielectric constant of 88 has been designed, fabricated and measured. The center frequency varies from 0.562 GHz to 0.845 GHz and 3 dB bandwidth is tuned from 117 MHz to 194 MHz at the center frequency of 845 MHz. A constant absolute bandwidth of 141 MHz is realized by varying simultaneously bias voltages. The volume of fabricated filter containing bias networks is 24×22×6.5 mm³ (0.045λ₀×0.041λ₀×0.012λ₀). The measured results agree with the simulation outcome.

1. Chen, Anrong and Tao Yang, "A microstrip bandpass filter with tunable bandwidth and center frequency," Microwave and Optical Technology Letters, Vol. 63, No. 9, 2333-2336, 2021.

2. Sánchez-Renedo, M., R. Gómez-García, JI Alonso, and C. Briso-Rodríguez, "Tunable combline filter with continuous control of center frequency and bandwidth," IEEE Transactions on Microwave Theory and Techniques, Vol. 53, No. 1, 191-199, Jan. 2005.
doi:10.1109/TMTT.2004.839309

3. Hong, J.-S. and C. Briso-Rodríguez, Tunable and Reconfig urable Filters, in Microstrip Filters for RF Microwave Applications, 564-569, John Wiley & Sons, Inc., 2011.
doi:10.1002/9780470937297

4. Bandyopadhyay, Anjan, Pankaj Sarkar, and Rowdra Ghatak, "A bandwidth reconfigurable bandpass filter for ultrawideband and wideband applications," IEEE Transactions on Circuits and Systems Ii-express Briefs, Vol. 69, No. 6, 2747-2751, Jun. 2022.
doi:10.1109/TCSII.2022.3167028

5. Arain, Salman, Abdul Quddious, Symeon Nikolaou, and Photos Vryonides, "Demonstration of reconfigurable bpfs with wide tuning bandwidth range using 3λ/4 open- and λ/2 short-ended stubs," Technologies, Vol. 8, No. 1, Mar. 2020.
doi:10.3390/technologies8010014

6. Kawai, Kunihiro, Hiroshi Okazaki, and Shoichi Narahashi, "Center frequency and bandwidth independently tunable filter using mems digitally tunable capacitors," 2014 Xxxith Ursi General Assembly and Scientific Symposium (URSI GASS), China, Aug. 2014.

7. Sanchez-Soriano, Miguel A., Roberto Gomez-Garcia, German Torregrosa-Penalva, and Enrique Bronchalo, "Reconfigurable-bandwidth bandpass filter within 10-50%," IET Microwaves Antennas & Propagation, Vol. 7, No. 7, 502-509, May 2013.
doi:10.1049/iet-map.2012.0274

8. Liu, B., F. Wei, H. Zhang, X. Shi, and H. Lin, "A tunable bandpass filter with switchable bandwidth," Journal of Electromagnetic Waves and Applications, Vol. 25, No. 2-3, 223-232, 2011.
doi:10.1163/156939311794362704

9. Gentili, Fabrizio, Luca Pelliccia, Fabrizio Cacciamani, Paola Farinelli, and Roberto Sorrentino, "RF MEMS bandwidth-reconfigurable hairpin filters," 2012 Asia-pacific Microwave Conference (APMC 2012), 735-737, Kaohsiung, Taiwan, Dec. 2012.

10. Mao, Jin-Rong, Wai-Wa Choi, Kam-Weng Tam, Wen Quan Che, and Quan Xue, "Tunable bandpass filter design based on external quality factor tuning and multiple mode resonators for wideband applications," IEEE Transactions on Microwave Theory and Techniques, Vol. 61, No. 7, 2574-2584, Jul. 2013.
doi:10.1109/TMTT.2013.2264684

11. Chao, Shih-Fong, Wei-Cheng Lin, and Che-You Kuo, "Bandpass filter with tunable bandwidth using triple-mode H-type resonator," 2014 International Symposium on Next-generation Electronics (ISNE), Chang Gung Univ, Taoyuan, May 2014.

12. Chaudhary, Girdhari, Yongchae Jeong, and Jongsik Lim, "Dual-band bandpass filter with independently tunable center frequencies and bandwidths," IEEE Transactions on Microwave Theory and Techniques, Vol. 61, No. 1, 1, 107-116, Jan. 2013.
doi:10.1109/TMTT.2012.2222910

13. Huang, Xiaoguo, Quanyuan Feng, and Qianyin Xiang, "Bandpass filter with tunable bandwidth using quadruple-mode stub-loaded resonator," IEEE Microwave and Wireless Components Letters, Vol. 22, No. 4, 176-178, Apr. 2012.
doi:10.1109/LMWC.2012.2188280

14. Jia, Ding-Hong, Quanyuan Feng, Xiao-Guo Huang, and Qian-Yin Xiang, "A novel tri-mode bandwidth tunable filter with harmonic suppression," Progress In Electromagnetics Research C, Vol. 34, 183-194, 2013.

15. Tsai, Hsuan-Ju, Nan-Wei Chen, and Shyh-Kang Jeng, "Center frequency and bandwidth controllable microstrip bandpass filter design using loop-shaped dual-mode resonator," IEEE Transactions on Microwave Theory and Techniques, Vol. 61, No. 10, 3590-3600, Oct. 2013.
doi:10.1109/TMTT.2013.2280129

16. Wei, Zhihua, Tao Yang, Pei-Ling Chi, Xilin Zhang, and Ruimin Xu, "A 10.23-15.7-ghz varactor-tuned microstrip bandpass filter with highly flexible reconfigurability," IEEE Transactions on Microwave Theory and Techniques, Vol. 69, No. 10, 4499-4509, Oct. 2021.
doi:10.1109/TMTT.2021.3098835

17. Fan, Maoyu, Kaijun Song, and Yong Fan, "Reconfigurable bandpass filter with wide-range bandwidth and frequency control," IEEE Transactions on Circuits and Systems Ii-express Briefs, Vol. 68, No. 6, 1758-1762, Jun. 2021.
doi:10.1109/TCSII.2020.3040190

18. Chiou, Yi-Chyun and Gabriel M. Rebeiz, "Tunable 1.55-2.1 ghz 4-pole elliptic bandpass filter with bandwidth control and > 50 db rejection for wireless systems," IEEE Transactions on Microwave Theory and Techniques, Vol. 61, No. 1, 1, 117-124, Jan. 2013.
doi:10.1109/TMTT.2012.2227789

19. Schuster, Christian, Alex Wiens, Florian Schmidt, Matthias Nickel, Martin Schuessler, Rolf Jakoby, and Holger Maune, "Performance analysis of reconfigurable bandpass filters with continuously tunable center frequency and bandwidth," IEEE Transactions on Microwave Theory and Techniques, Vol. 65, No. 11, 2, SI, 4572-4583, Nov. 2017.
doi:10.1109/TMTT.2017.2742479

20. Tang, Wenxing and Jiasheng Hong, "Reconfigurable microstrip combline filter with tunable center frequency and bandwidth," Asia-pacific Microwave Conference 2011, 1162-1165, Engineers Australia, Melbourne, Dec. 2011.

21. Wang, Hao, Akash Anand, and Xiaoguang Liu, "A miniature 800-1100-MHz tunable filter with high-Q ceramic coaxial resonators and commercial RF-MEMS tunable digital capacitors," 2017 IEEE 18th Wireless and Microwave Technology Conference (WAMICON), 1-3, Cocoa Beach, Fl, Apr. 2017.

22. Cao, Liangzu, Guangwen Li, Jian Hu, and Lixia Yin, "A miniaturized tunable bandpass filter with constant fractional bandwidth," Progress In Electromagnetics Research C, Vol. 57, 89-97, 2015.

23. Cao, Liangzu, Junmei Yan, and Lixia Yin, "A compact tunable dielectric filter with constant absolute bandwidth," 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT2018), 1-3, China, May 2018.

24. Huang, Fengxi, Siamak Fouladi, and Raafat R. Mansour, "High-Q tunable dielectric resonator filters using MEMS technology," IEEE Transactions on Microwave Theory and Techniques, Vol. 59, No. 12, 2, SI, 3401-3409, Dec. 2011.
doi:10.1109/TMTT.2011.2171984

25. Yan, Winter Dong and Raafat R. Mansour, "Tunable dielectric resonator bandpass filter with embedded MEMS tuning elements," IEEE Transactions on Microwave Theory and Techniques, Vol. 55, No. 1, 154-160, Jan. 2007.
doi:10.1109/TMTT.2006.888582

26. Pozar, David M and R. Mansour, Microwave Engineering, John Wiley & Sons, Inc., New Jersey, 2011.

27. Hong, J.-S. and R. Mansour, Coupled Resonator Circuits, in Microstrip Filters for RF Microwave Applications, 3rd Ed., 244-262, John Wiley & Sons, Inc., New Jersey, 2011.

28. Torregrosa-Penalva, G., G. Lopez-Risueno, and J. Alonso, "A simple method to design wide-band electronically tunable combline filters," ” IEEE Transactions on Microwave Theory and Techniques, Vol. 50, No. 1, 172-177, 2002.
doi:10.1109/22.981262

Professor Liangzu Cao

Dr. Lixia Yin