volume | PIER Journals

Abstract

Microstrip-line filters face two major challenges in high-frequency applications. On the one hand, as the operating frequency increases, the resonator length becomes significantly shorter, and when its dimensions become comparable to the line width, the fabrication tolerances deteriorate markedly. However, especially for narrowband filters, the insertion loss becomes more pronounced. To meet the performance requirements of high-frequency narrowband filters in the Ku band, this paper presents the design and implementation of a seventeenth-order hairpin-line bandpass filter utilizing high-temperature superconducting (HTS) materials. The proposed filter operated at a center frequency of 15 GHz with a fractional bandwidth of 2%. By employing a high-permittivity substrate and YBa₂Cu₃O₇ superconducting thin-film technology, a compact structure with dimensions of 27.68 mm × 3.62 mm × 0.5 mm is achieved. The experimental results demonstrate that at 77 K, the filter exhibits an in-band insertion loss below 0.35 dB, a return loss better than 19.5 dB, and stopband suppression exceeding 40 dB, indicating excellent frequency selectivity and out-of-band rejection performance. This work verifies the application potential of HTS materials in high-frequency planar narrowband filters and provides an effective solution for the design of high-performance RF front-ends in the Ku band.

1. Choi, Jin-Young, Jun-Seok Ma, Hyunwoo Oh, and Wook-Sung Kim, "A reconfigurable narrow-band bandpass filter using electrically-coupled open-loop resonators based on liquid crystals," Journal of Physics D: Applied Physics, Vol. 57, No. 46, 465307, 2024.
doi:10.1088/1361-6463/ad6dd0 Google Scholar

2. Das, Tarun Kumar and Sayan Chatterjee, "Multi-spurious harmonics suppression in folded hairpin line bandpass filter by meander spur-line," International Journal of RF and Microwave Computer-Aided Engineering, Vol. 31, No. 11, e22858, 2021.
doi:10.1002/mmce.22858 Google Scholar

3. Feng, Li-Ying and Hong-Xing Zheng, "A miniaturized narrowband bandpass filter with wide stopband using open-loop resonator," Microwave and Optical Technology Letters, Vol. 53, No. 9, 2149-2152, 2011.
doi:10.1002/mop.26206 Google Scholar

4. Liu, Haiwen, Sidong Wang, Jiaxin Kuang, Ruolin Wang, and Hongliang Tian, "Compact HTS narrowband bandpass filter based on spiral D-CRLH resonator," IEEE Transactions on Circuits and Systems II: Express Briefs, Vol. 71, No. 3, 1007-1011, 2024.
doi:10.1109/tcsii.2023.3323859 Google Scholar

5. Jiang, Xuejian, Zhengbin Xu, Jie Xu, Jian Guo, and Cheng Qian, "A miniaturized harmonic reject waveguide filter for ku-band VSAT transmitter," IEEE Access, Vol. 11, 46164-46172, 2023.
doi:10.1109/access.2023.3273120 Google Scholar

6. Malki, Mohamed, Li Yang, and Roberto Gomez-Garcia, "Sharp-rejection in-line groove-gap-waveguide bandpass filter with multiple transmission zeros for Ku-band application," IEEE Microwave and Wireless Technology Letters, Vol. 34, No. 5, 478-481, 2024.
doi:10.1109/lmwt.2024.3379427 Google Scholar

7. Morales-Hernández, Aitor, Miguel Ángel Sánchez-Soriano, Miguel Ferrando-Rocher, Stephan Marini, and Vicente E. Boria, "In-depth study of the corona discharge breakdown thresholds in groove gap waveguides and enhancement strategies for inductive bandpass filters," IEEE Access, Vol. 10, 129149-129162, 2022.
doi:10.1109/access.2022.3228111 Google Scholar

8. Sánchez-Soriano, Miguel Á., Stefano Sirci, J. D. Martínez, and Vicente E. Boria, "Compact dual-mode substrate integrated waveguide coaxial cavity for bandpass filter design," IEEE Microwave and Wireless Components Letters, Vol. 26, No. 6, 386-388, 2016.
doi:10.1109/lmwc.2016.2558651 Google Scholar

9. Máximo-Gutiérrez, Clara, Juan Hinojosa, and Alejandro Álvarez-melcon, "Narrowband and wideband bandpass filters based on empty substrate integrated waveguide loaded with dielectric elements," IEEE Access, Vol. 9, 32094-32105, 2021.
doi:10.1109/access.2021.3060516 Google Scholar

10. Celis, Sebastian, Mohamed Farhat, Abdullah S. Almansouri, Hakan Bagci, and Khaled N. Salama, "Simplified modal-cancellation approach for substrate-integrated-waveguide narrow-band filter design," Electronics, Vol. 9, No. 6, 962, 2020.
doi:10.3390/electronics9060962 Google Scholar

11. Jiao, Meng Ru, Fang Zhu, Peng Chu, Weiliang Yu, and Guo Qing Luo, "Compact hybrid bandpass filters using substrate-integrated waveguide and stripline resonators," IEEE Transactions on Microwave Theory and Techniques, Vol. 72, No. 1, 391-400, 2024.
doi:10.1109/tmtt.2023.3284253 Google Scholar

12. Khan, Arani Ali and Mrinal Kanti Mandal, "Narrowband substrate integrated waveguide bandpass filter with high selectivity," IEEE Microwave and Wireless Components Letters, Vol. 28, No. 5, 416-418, 2018.
doi:10.1109/lmwc.2018.2820605 Google Scholar

13. Liu, Qing, Dongfang Zhou, Yi Zhang, Dewei Zhang, and Dalong Lv, "Substrate integrated waveguide bandpass filters in box-like topology with bypass and direct couplings in diagonal cross-coupling path," IEEE Transactions on Microwave Theory and Techniques, Vol. 67, No. 3, 1014-1022, 2019.
doi:10.1109/tmtt.2018.2889450 Google Scholar

14. Liu, Haiwen, Baoping Ren, Shuangxi Hu, Xuehui Guan, Pin Wen, and Jiaming Tang, "High-order dual-band superconducting bandpass filter with controllable bandwidths and multitransmission zeros," IEEE Transactions on Microwave Theory and Techniques, Vol. 65, No. 10, 3813-3823, 2017.
doi:10.1109/tmtt.2017.2690295 Google Scholar

15. Jin, Shichao, Bin Wei, Bisong Cao, Xiaoping Zhang, Xubo Guo, Huili Peng, Yunlong Piao, and Baoxin Gao, "Design and performance of an ultra-narrowband superconducting filter at UHF band," IEEE Microwave and Wireless Components Letters, Vol. 18, No. 6, 395-397, 2008.
doi:10.1109/lmwc.2008.922624 Google Scholar

16. Yu, Xiao, Weibin Xi, Songtao Wu, and Peiguang Yan, "A 12-pole VHF band high selective high temperature superconducting filter," Superconductor Science and Technology, Vol. 34, No. 1, 015002, 2021.
doi:10.1088/1361-6668/abbec5 Google Scholar

17. Li, Chunguang, Xu Wang, Jia Wang, Liang Sun, and Yusheng He, "Progress on applications of high temperature superconducting microwave filters," Superconductor Science and Technology, Vol. 30, No. 7, 073001, 2017.
doi:10.1088/1361-6668/aa69f1 Google Scholar

18. Tao, Lin, Bin Wei, Xubo Guo, Bisong Cao, and Linan Jiang, "Miniaturized ultra-narrowband superconducting microstrip filter with stable coupling using optimized twin spiral-in-spiral-out resonators," IEEE Transactions on Applied Superconductivity, Vol. 29, No. 6, 1-7, 2019.
doi:10.1109/tasc.2019.2899556 Google Scholar

19. Li, Shunzhou, Jiandong Huang, Qingduan Meng, Liang Sun, Qiang Zhang, Fei Li, Aisheng He, Xueqiang Zhang, Chunguang Li, Hong Li, and Yusheng He, "A 12-pole narrowband highly selective high-temperature superconducting filter for the application in the third-generation wireless communications," IEEE Transactions on Microwave Theory and Techniques, Vol. 55, No. 4, 754-759, 2007.
doi:10.1109/tmtt.2007.892813 Google Scholar

20. Makimoto, M. and S. Yamashita, "Bandpass filters using parallel coupled stripline stepped impedance resonators," IEEE Transactions on Microwave Theory and Techniques, Vol. 28, No. 12, 1413-1417, 1980.
doi:10.1109/tmtt.1980.1130258 Google Scholar

21. Zhang, Xueqiang, Qingduan Meng, Fei Li, Chunguang Li, Shunzhou Li, Aisheng He, Hong Li, and Yusheng He, "A 24-pole high Tc superconducting filter for mobile communication applications," Superconductor Science and Technology, Vol. 19, No. 5, S394-S397, 2006.
doi:10.1088/0953-2048/19/5/S48 Google Scholar

22. Hong, Jia-Sheng and M. J. Lancaster, "Couplings of microstrip square open-loop resonators for cross-coupled planar microwave filters," IEEE Transactions on Microwave Theory and Techniques, Vol. 44, No. 11, 2099-2109, 1996.
doi:10.1109/22.543968 Google Scholar

23. Zhang, Yi, Xiaobang Shang, Fan Zhang, and Jun Xu, "A 3-D printed Ku-band waveguide filter based on novel rotary coupling structure," IEEE Microwave and Wireless Technology Letters, Vol. 33, No. 1, 35-38, 2023.
doi:10.1109/lmwc.2022.3194367 Google Scholar

24. Malki, Mohamed, Li Yang, and Roberto Gómez-García, "Ku-band reflectionless single-and dual-band bandpass filters in groove gap waveguide," IEEE Transactions on Microwave Theory and Techniques, Vol. 73, No. 9, 5813-5827, 2025.
doi:10.1109/tmtt.2024.3487633 Google Scholar

25. Liu, Qing, De-Wei Zhang, Ke Gong, Hang Qian, Wei-Zhe Qu, and Na An, "Single-and dual-band bandpass filters based on multiple-mode folded substrate-integrated waveguide cavities," IEEE Transactions on Microwave Theory and Techniques, Vol. 71, No. 12, 5335-5345, 2023.
doi:10.1109/tmtt.2023.3276058 Google Scholar

26. Yin, Bo, Qianqian Huang, Hongang Hao, and Hongsheng Zhang, "A high-selectivity double-mode SIW bandpass filter utilizing the modified parallel coupled microstrip lines," Electromagnetics, Vol. 41, No. 4, 263-274, 2021.
doi:10.1080/02726343.2021.1928375 Google Scholar

27. Mansour, R. R., B. Jolley, Shen Ye, F. S. Thomson, and V. Dokas, "On the power handling capability of high temperature superconductive filters," IEEE Transactions on Microwave Theory and Techniques, Vol. 44, No. 7, 1322-1338, 1996.
doi:10.1109/22.508237 Google Scholar

28. Booth, J. C., D. A. Rudman, and R. H. Ono, "A self-attenuating superconducting transmission line for use as a microwave power limiter," IEEE Transactions on Applied Superconductivity, Vol. 13, No. 2, 305-310, 2003.
doi:10.1109/tasc.2003.813716 Google Scholar

Dr. Panpan Zhang

Mr. Chenhao Xu

Dr. Yiqiuzi Shen

Dr. Chenchen Wang

Dr. Li Ding