Miniaturized Wideband Bandpass Filter based on Capacitor-loaded One-eighth Wavelength Coupled Line
Keywords:
Bandpass filter, capacitors, coupled line, miniaturized, widebandAbstract
A novel miniaturized wideband bandpass filter (BPF) using capacitor-loaded microstrip coupled line is proposed. The capacitors are loaded in parallel and series to the coupled line, which makes the filter just require one one-eighth wavelength coupled line and achieve filtering response with multiple transmission poles (TPs) and transmission zeros (TZs). Compared with the state-of-the-art microstrip wideband BPFs, the proposed filter has the advantages of compact size and simple structure. A prototype centered at 1.47 GHz with the 3-dB fractional bandwidth of 86.5% is demonstrated, which exhibits the compact size of 0.003λ2/g (λg is the guided wavelength at the center frequency) and the minimum insertion loss of 0.37 dB.
Downloads
References
Y. Wu, L. Cui, W. Zhang, L. Jiao, Z. Zhuang, and Y. Liu, “High performance single-ended wideband and balanced bandpass filters loaded with steppedimpedance stubs,” IEEE Access, vol. 5, pp. 5972- 5981, May 2017.
F. Wei, Z. D. Wang, F. Yang, and X. W. Shi, “Compact UWB BPF with triple-notched bands based on stub loaded resonator,” Electronics Letters, vol. 49, no. 2, pp. 124-126, Jan. 2013.
R. Li and L. Zhu, “Compact UWB bandpass filter using stub-loaded multiple-mode resonator,” IEEE Microwave and Wireless Components Letters, vol. 17, no. 1, pp. 40-42, Jan. 2007.
Q. X. Chu, X. H. Wu, and X. K. Tian, “Novel UWB bandpass filters using stub-loaded multiple-mode resonator,” IEEE Microwave and Wireless Components Letters, vol. 21, no. 8, pp. 403-405, Aug. 2011.
X. Y. Zhang, Y.-W. Zhang, and Q. Xue, “Compact band-notched UWB filter using parallel resonators with a dielectric overlay,” IEEE Microwave and Wireless Components Letters, vol. 23, no. 5, pp. 252-254, May 2013.
L. Gao, X. Y. Zhang, and Q. Xue, “Compact tri-band bandpass filter using novel eight-mode resonator for 5G WiFi application,” IEEE Microwave and Wireless Components Letters, vol. 25, no. 10, pp. 660-662, Oct. 2015.
B. Zhang, Y. Wu, and Y. Liu, “Wideband singleended and differential bandpass filters based on terminated coupled line structures,” IEEE Transactions on Microwave Theory and Techniques, vol. 65, no. 3, pp. 761-774, Mar. 2017.
X. Xia, X. Cheng, F. Chen, and X. Deng, “Compact UWB bandpass filter with sharp roll-off using APCL structure,” Electronics Letters, vol. 54, no. 4, pp. 223-225, May 2018.
X. Y. Zhang, X. Dai, H.-L. Kao, B.-H. Wei, Z. Y. Cai, and Q. Xue, “Compact LTCC bandpass filter with wide stopband using discriminating coupling,” IEEE Transactions on Components Packaging and Manufacturing Technology, vol. 4, no. 4, pp. 656- 663, Apr. 2014.
S. W. Ren, H. L. Peng, J. F. Mao, and A. M. Gao, “Compact quasi-elliptic wideband bandpass filter using cross-coupled multiple-mode resonator,” IEEE Microwave and Wireless Components Letters, vol. 22, no. 8, pp. 397-399, Aug. 2012.
J. Zhou, Y. Chiang, and W. Che, “Wideband bandpass filter based on ring resonator with high selectivity and multiple transmission zeros,” Electronics Letters, vol. 50, no, 5, pp. 384-386, Feb. 2014.
W. Feng, X. Gao, W. Che, and Q. Xue, “Bandpass filter loaded with open stubs using dual-mode ring resonator,” IEEE Microwave and Wireless Components Letters, vol. 25, no. 5, pp. 295-297, May 2015.
J. Xu, Y.X. Ji, C. Miao, and W. Wu, “Compact single-/dual-wideband BPF using stubs loaded SIR (SsLSIR),” IEEE Microwave and Wireless Components Letters, vol. 23, pp. 338-340, July 2013.
Q. X. Chu and X. K. Tian, “Design of UWB bandpass filter using stepped-impedance stubloaded resonator,” IEEE Microwave and Wireless Components Letters, vol. 20, no. 9, pp. 501-503, Sep. 2010.
F. Li, W. Che, L. Gu, and Q. Xue, “Broadband bandpass filter with wide upper stopband using stub-loaded multiple-mode resonators,” Electronics Letters, vol. 49, no. 13, pp. 818-820, June 2013.
F. Wei, W. T. Li, X. W. Shi, and Q. L. Huang, “Compact UWB bandpass filter with triple-notched bands using triple-mode stepped impedance resonator,” IEEE Microwave and Wireless Components Letters, vol. 22, no. 10, pp. 512-514, Oct. 2012.
L. Li and Z. Li, “Side-coupled shorted microstrip line for compact quasi-elliptic wideband bandpass filter design,” IEEE Microwave and Wireless Components Letters, vol. 20, no. 6, pp. 322-324, June 2010.
J. Xu, Y.-X. Ji, W. Wu, and C. Miao, “Design of miniaturized microstrip LPF and wideband BPF with ultra-wide stopband,” IEEE Microwave and Wireless Components Letters, vol. 23, no. 8, pp. 397-399, Aug. 2013.
C.-H. Liang and C.-Y. Chang, “Compact wideband bandpass filters using stepped-impedance resonators and interdigital coupling structures,” IEEE Microwave and Wireless Components Letters, vol. 19, no. 9, pp. 551-553, Sep. 2009.
J. Dong, J. Shi, and K. Xu, “Compact wideband differential bandpass filter using coupled microstrip lines and capacitors,” IEEE Microwave and Wireless Components Letters, vol. 29, no. 7, pp. 444-446, June 2019.