volume | PIER Journals

Abstract

A compact microstrip dual-band filter using stepped-impedance resonators (SIRs) is proposed. The ring-type structure is used to minimize the size of the filter, and the location of the input/output excitation port is used to adjust the filter's performance. A dual-band filter has been fabricated and measured to verify the performance of the proposed configuration. The results show that the filter exhibits two passbands, centered at 30.5 GHz and 35.9 GHz, with fractional bandwidths of 7.2% and 5.6%, respectively. The corresponding insertion losses at the center frequencies are 2.7 dB and 3.3 dB. The proposed filter configuration shows great potential for applications in next-generation 5G and satellite communication systems requiring compact and high-performance multi-band filters.

1. Tang, Wei Sheng, Yi-Ming Zhang, Shao Yong Zheng, and Yong Mei Pan, "Low-cost compact inline single-/dual-band filters based on dual-mode dielectric resonators with highly integrated and flexible mixed couplings," IEEE Transactions on Microwave Theory and Techniques, Vol. 73, No. 9, 6589-6602, Sep. 2025.
doi:10.1109/tmtt.2025.3556090 Google Scholar

2. Rao, Jiayu, Pei Ding, Yang Yu, Lei Zhang, and Povilas Vaitukaitis, "Design of controllable dual-band bandpass filter based on dual-mode metal plate coupled resonator," IEEE Microwave and Wireless Technology Letters, Vol. 35, No. 7, 953-956, Jul. 2025.
doi:10.1109/lmwt.2025.3554772 Google Scholar

3. Xie, Wen-Bin, Yi-Hao Ma, Da-Wei Wang, Cheng-Hao Yu, Yue Hu, and Wen-Sheng Zhao, "Compact single-and dual-band balanced high-selectivity bandpass filters based on microstrip resonator loaded substrate integrated waveguide," IEEE Transactions on Electromagnetic Compatibility, Vol. 67, No. 5, 1629-1633, Oct. 2025.
doi:10.1109/temc.2025.3586837 Google Scholar

4. Huang, Xueyu, Wenjie Feng, Kun Tang, Yunfei Cao, Wenquan Che, and Quan Xue, "Miniaturized dual-band filter using D-CRLH resonators with wide stopband and controllable frequencies/bandwidths," IEEE Microwave and Wireless Technology Letters, 1-4, 2025.
doi:10.1109/lmwt.2025.3600634 Google Scholar

5. Lu, Lin-Xi, Wei-Xu Wang, Lei Ma, Wen-Wen Yang, Wei Qin, and Jian-Xin Chen, "Dual-band bandpass filter based on dual-ridged dual-mode dielectric waveguide resonator," IEEE Microwave and Wireless Technology Letters, Vol. 35, No. 10, 1462-1465, Oct. 2025.
doi:10.1109/lmwt.2025.3591397 Google Scholar

6. Li, Jia-Lin, Peng Liu, and Jun-Hao Ye, "Compact dual-mode loop resonators for microwave triplexer applications," Journal of Electrical Engineering, Vol. 74, No. 4, 277-281, 2023.
doi:10.2478/jee-2023-0034 Google Scholar

7. Song, Kaijun, Lele Fang, Qian Li, and Yong Fan, "Compact eight-channel diplexer based on quad-mode stepped impedance resonator," International Journal of Microwave and Wireless Technologies, Vol. 16, No. 10, 1713-1721, 2024.
doi:10.1017/s1759078724000540 Google Scholar

8. Faghir Mirnezami, Seyed Peyman, Mohammadbagher Tavakoli, Farbod Setoudeh, and Ashkan Horri, "Design of a triple band-pass balanced filter based on single-stepped-impedance ring resonator with ultra-wide stopband bandwidth," ETRI Journal, 1-11, 2025.
doi:10.4218/etrij.2024-0376 Google Scholar

9. Shao, Chuan, Rong Cai, Xinnai Zhang, and Kai Xu, "Novel compact wideband bandpass filters with high upper stopband rejection featuring a quadruple-mode resonator," Progress In Electromagnetics Research Letters, Vol. 125, 37-41, 2025.
doi:10.2528/pierl25010402 Google Scholar

10. Zhou, Liguo, Jiang Jiang, Wen Zhang, Ping Kwan Johnny Wong, Bin Xia, Dongwei Zhang, Xudong Bai, and Xilong Lu, "Design of high order HTS duplexer based on SIR structure," IEEE Transactions on Applied Superconductivity, Vol. 33, No. 4, 1-8, 2023.
doi:10.1109/tasc.2023.3248960 Google Scholar

11. Li, Wen Tao, Hao Ran Zhang, Xue Jing Chai, Yong Qiang Hei, Jin Chao Mou, and Xiao Wei Shi, "Compact dual-band balanced-to-unbalanced filtering power divider design with extended common-mode suppression bandwidth," IEEE Microwave and Wireless Components Letters, Vol. 32, No. 6, 511-514, 2022.
doi:10.1109/lmwc.2022.3145021 Google Scholar

12. Yang, Liang, Cheng Lu, Jialin Wang, Shunli Li, Hongxin Zhao, and Xiaoxing Yin, "Postwall-slotline stepped impedance resonator and its application to bandpass filter with improved upper stopband," Electronics, Vol. 11, No. 6, 851, 2022.
doi:10.3390/electronics11060851 Google Scholar

13. Weng, Xiao-Yu, Kai-Da Xu, Ying-Jiang Guo, An-Xue Zhang, and Qiang Chen, "High-selectivity bandpass filter based on two merged ring resonators," Radioengineering, Vol. 30, No. 3, 504-509, 2021.
doi:10.13164/re.2021.0504 Google Scholar

14. Shankar, Earla, Kanaparthi V. Phani Kumar, Vamsi Krishna Velidi, and Slawomir Koziel, "Miniaturized dual-band bandpass filter with wide inter stopband for 5G applications," IEEE Transactions on Circuits and Systems II: Express Briefs, Vol. 71, No. 10, 4461-4465, 2024.
doi:10.1109/tcsii.2024.3395621 Google Scholar

15. Li, Qiwei, Jinyong Fang, Wen Cao, Jing Sun, Jun Ding, Weihao Tie, Feng Wei, Chang Zhai, and Jiangniu Wu, "Optimization and design of balanced BPF based on mixed electric and magnetic couplings," Electronics, Vol. 12, No. 9, 2125, 2023.
doi:10.3390/electronics12092125 Google Scholar

16. Gorur, Ali Kursad, Alper Turkeli, Ceyhun Karpuz, and Adnan Gorur, "Design of a compact microstrip quadruplexer with closely spaced switchable and tunable channels based on asymmetrical dual-mode loop resonators," AEU --- International Journal of Electronics and Communications, Vol. 127, 153421, 2020.
doi:10.1016/j.aeue.2020.153421 Google Scholar

Dr. Wei Zhao

Dr. Mingen Tian

Dr. Ziyan Lu

Dr. Hailong Wang

Dr. Yiming Zhang

Dr. Huali Zhu