Novel Compact Dual-Band Bandpass Filter Based on Multilayer Liquid Crystal Polymer Substrate

doi:10.1007/s12204-023-2659-y

Abstract

Abstract: In this paper, a compact defected ground structure loaded ultra high frequency dual-band bandpass filter is designed and implemented based on multilayer liquid crystal polymer technology. This novel filter is simply composed with several lumped and semi-lumped elements, to create a dual-passband response. In order to enhance the out-of-band rejection, a feedback capacitor Cz at the in/out ports of the filter is introduced, and four transmission zeros (TZs) are obtained outside the pass band. Furthermore, the position of TZs can be determined by adjusting the value of Cz. The schematic and design process of the filter are given in this paper. The center frequencies of dual-band bandpass filter are 0.9GHz and 2.45GHz, and the 3-dB bandwidths are 13.7% and 14.3%, respectively. The circuit size is 11mm × 9.5mm × 0.193mm. The proposed filter has been fabricated and tested, and the measured result is in good agreement with the simulation result.

Key words: dual-band bandpass filter, multilayer liquid crystal polymer, defected ground structure

摘要： 本文基于多层液晶聚合物技术，设计并实现了一款加载缺陷接地结构的紧凑型超高频双通带带通滤波器。该新型滤波器通过集总元件和半集总元件设计组合，产生了双通带响应。为了增强其带外抑制，在滤波器的输入合输出端口之间引入了反馈电容Cz，使其通带外产生了四个传输零点。同时，该滤波器可以通过调整Cz的值来调整传输零点的位置。文中给出了滤波器的原理图和设计过程。该双通带带通滤波器的两个中心频率分别为0.9 GHz和2.45 GHz，3 dB带宽分别为13.7%和14.3%，电路尺寸为 11 mm×9.5 mm×0.193 mm。最后对滤波器进行了制作和测试，实测结果与仿真结果吻合较好。

关键词: 双通带带通滤波器，多层液晶聚合物，缺陷地结构

CLC Number:

TN713

Liu Weihong, Liu Qingran. Novel Compact Dual-Band Bandpass Filter Based on Multilayer Liquid Crystal Polymer Substrate[J]. J Shanghai Jiaotong Univ Sci, 2025, 30(2): 233-238.

References

[1] ZHANG X Y, CHEN J X, XUE Q, et al. Dual-band bandpass filters using stub-loaded resonators [J]. IEEE Microwave and Wireless Components Letters, 2007, 17(8): 583-585.
[2] MONDAL P, MANDAL M K. Design of dual-band bandpass filters using stub-loaded open-loop resonators [J]. IEEE Transactions on Microwave Theory and Techniques, 2008, 56(1): 150-155.
[3] KIM C H, CHANG K. Independently controllable dual-band bandpass filters using asymmetric steppedimpedance resonators [J]. IEEE Transactions on Microwave Theory and Techniques, 2011, 59(12): 3037- 3047.
[4] TANG J M, LIU H W, YANG Y. Compact widestopband dual-band balanced filter using an electromagnetically coupled SIR pair with controllable transmission zeros and bandwidths [J]. IEEE Transactions on Circuits and Systems II : Express Briefs, 2020, 67(11): 2357-2361.
[5] SINGH V, KILLAMSETTY V K, MUKHERJEE B. Compact dual-band BPF with wide stopband using stub-loaded spiral stepped-impedance resonator [J]. Electronics Letters, 2016, 52(22): 1860-1862.
[6] SHI J, XUE Q. Dual-band and wide-stopband singleband balanced bandpass filters with high selectivity and common-mode suppression [J]. IEEE Transactions on Microwave Theory and Techniques, 2010, 58(8): 2204-2212.
[7] PUCEL R A. Design considerations for monolithic microwave circuits [J]. IEEE Transactions on Microwave Theory and Techniques, 1981, 29(6): 513-534.
[8] HAO Z C, HONG J S. Ultra wideband bandpass filter using embedded stepped impedance resonators on multilayer liquid crystal polymer substrate [J]. IEEE Microwave and Wireless Components Letters, 2008, 18(9): 581-583.
[9] THOMPSON D C, TANTOT O, JALLAGEAS H, et al. Characterization of liquid crystal polymer (LCP) material and transmission lines on LCP substrates from 30 to 110 GHz [J]. IEEE Transactions on Microwave Theory and Techniques, 2004, 52(4): 1343- 1352.
[10] TENTZERIS M M, LASKAR J, PAPAPOLYMEROU J, et al. 3-D-integrated RF and millimeter-wave functions and modules using liquid crystal polymer (LCP) system-on-package technology [J]. IEEE Transactions on Advanced Packaging, 2004, 27(2): 332-340.
[11] HAO Z C, HONG J S. Compact wide stopband ultra wideband bandpass filter using multilayer liquid crystal polymer technology [J]. IEEE Microwave and Wireless Components Letters, 2009, 19(5): 290-292.
[12] POURZADI A, ISAPOUR A, KOUKI A. Design of compact dual-band LTCC second-order Chebyshev bandpass filters using a direct synthesis approach [J]. IEEE Transactions on Microwave Theory and Techniques, 2019, 67(4): 1441-1451.
[13] YEUNG L K,WU K L. A compact second-order LTCC bandpass filter with two finite transmission zeros [J]. IEEE Transactions on Microwave Theory and Techniques, 2003, 51(2): 337-341.
[14] BAIRAVASUBRAMANIAN R, PINEL S, PAPAPOLYMEROU J, et al. Dual-band filters for WLAN applications on liquid crystal polymer technology [C]//IEEE MTT-S International Microwave Symposium Digest. Long Beach: IEEE, 2005: 533-536.
[15] CERVERA F J, HONG J S. Compact self-packaged dual-band filter using multilayer liquid crystal polymer technology [J]. IEEE Transactions on Microwave Theory and Techniques, 2014, 62(11): 2618-2625.
[16] ZHANG X Y, CHAN C H, XUE Q, et al. Dualband bandpass filter with controllable bandwidths using two coupling paths [J]. IEEE Microwave and Wireless Components Letters, 2010, 20(11): 616-618.