This paper proposes a new method to produce and reconfigure transmission zero(s) (TZ(s)). The TZs are constructed by using lumped elements in series with dielectric resonators, which is different from conventional methods such as introducing a cross coupling between nonadjacent resonators and mixed coupling between adjacent resonators. The proposed filter consists of two dielectric resonators, a capacitor, an inductor, two PIN diodes, etc. Two PIN diodes are used as switches to realize reconfigurable TZ(s). The mechanism is analyzed theoretically. An equivalent schematic diagram is simulated by using ADS software. The simulated results show that the structure can realize four response states, i.e., no TZ in the stopband, one TZ in the lower stopband, one TZ in the upper stopband, and two TZs in both sides of the stopband of the filter, respectively. The dielectric resonators (DRs) were made of dielectric ceramics with high dielectric constant of about 92. The filter was fabricated on a dielectric substrate and measured by using a vector network analyzer and double regulated DC power supply.
"A Novel Switchable Dielectric Bandpass Filter with Reconfigurable Transmission Zeros," Progress In Electromagnetics Research Letters,
Vol. 103, 57-63, 2022. doi:10.2528/PIERL22010606
1. Cao, L., L. Wang, and L. Yin, "Progress in electrically tunable microwave bandpass filters," Electronic Components & Materials in Chinese, Vol. 27, No. 2, 9-17, 2019.
2. Lan, B.-Z., Y. Qu, C.-J. Guo, et al. "A fully reconfigurable bandpass-to-notch filter with wide bandwidth tuning range based on external quality factor tuning and multiple-mode resonator," Microw. Opt. Technol. Lett., Vol. 61, No. 5, 1253-1258, 2019. doi:10.1002/mop.31725
3. Kingsly, S., M. Kanagasabai, M. G. N. Alsath, et al. "Compact frequency and bandwidth tunable bandpass-bandstop microstrip filter," Microw. Wirel. Compon. Lett., Vol. 28, No. 9, 786-788, 2018. doi:10.1109/LMWC.2018.2858005
4. Schuster, C., A. Wiens, F. Schmidt, et al. "Performance analysis of reconfigurable bandpass filters with continuously tunable center frequency and bandwidth," IEEE Transactions on Microwave Theory and Techniques, Vol. 65, No. 11, 4573-4584, 2017. doi:10.1109/TMTT.2017.2742479
5. Lin, W., K. Zhou, and K. Wu, "Tunable bandpass filters with one switch-able transmission zero by only tuning resonances," IEEE Microwave and Wireless Components Letters, Vol. 31, No. 2, 105, Feb. 2021. doi:10.1109/LMWC.2020.3039915
6. Fu, M., Q. Feng, Q. Xiang, and N. Jiang, "Fully tunable filter with cross coupling and reconfigurable transmission zero," Int. J. RF Microw. Comput. Aided. Eng., e22407, 2020.
8. Chiou, Y.-C. and G. M. Rebeiz, "A tunable three-pole 1.5-2.2-GHz bandpass filter with bandwidth and transmission zero control," IEEE Transactions on Microwave Theory and Techniques, Vol. 59, No. 11, 2872-2878, 2011. doi:10.1109/TMTT.2011.2164619
9. Cao, L. Z., Z.-J. Li, D. Deng, et al. "A tunable bandpass filter with bandwidth or transmission zeros control," International Conference on Microwave and Millimeter Wave Technology, 1-3, 2021.
10. Fathelbab, W. M. and M. B. Steer, "A reconfigurable bandpass filter for RF/microwave multifunctional systems," IEEE Transactions on Microwave Theory and Techniques, Vol. 53, No. 3, 1111-1116, 2005. doi:10.1109/TMTT.2005.843502
11. Tsai, H.-J., B.-C. Huang, N.-W. Chen, et al. "A reconfigurable bandpass filter based on a varactor-perturbed, T-shaped dual-mode resonator," IEEE Microwave and Wireless Components Letters, Vol. 24, No. 5, 297299, 2014. doi:10.1109/LMWC.2014.2306893
12. Cao, L., J. Hu, and L. Yin, "Compact coaxial dielectric bandpass filter with load-source coupling," 2015 Asia-Pacific Microwave Conference (APMC), Vol. 2, 1-3, 2015.