volume | PIER Journals

Abstract

A CPW (coplanar waveguide) bandpass filter based on spiral-shaped DGSs (defected ground structures) which can be used in the 5G band is proposed. Two pairs of face-to-face symmetrical spiral-shaped DGSs are added to the ground planes of a CPW main transmission line. A cross-shaped notch is adopted in the central strip of the CPW main transmission line to generate the passband, while two m-shaped DGSs are brought in to improve the passband performance of the filter. The measured results show that the central frequency is 3.54 GHz, and the 3-dB bandwidth is from 3.29 GHz to 3.79 GHz. The filter has a 10.1% bandwidth with a return loss better than 10 dB from 3.35 GHz to 3.71 GHz, and the insertion loss is less than 2.0 dB in the passband. Besides, there are two transmission zeros near the passband at 2.45 GHz and 4.81 GHz, which can improve the stopband rejection.

1. Firmansyah, T., S. Praptodinoyo, R. Wiryadinata, et al. "Dual-wideband bandpass filter using folded cross-stub stepped impedance resonator," Microw. Opt. Technol. Lett., Vol. 59, No. 11, 2929-2934, 2017.
doi:10.1002/mop.30848

2. Lin, L., B. Wu, T. Su, et al. "Design of tri-band bandpass filter using novel hexa-mode stub-loaded ring resonator," Microw. Opt. Technol. Lett., Vol. 57, No. 9, 2005-2008, 2015.
doi:10.1002/mop.29252

3. Qin, W., J. Cai, Y. Li, and J. Chen, "Wideband tunable bandpass filter using optimized varactor-loaded SIRs," IEEE Microw. Wirel. Compon. Lett., Vol. 27, No. 9, 812-814, 2017.
doi:10.1109/LMWC.2017.2734848

4. Gholipour, V., S. M. M. Moshiri, A. Alighanbari, and A. Yahaghi, "Highly selective wideband bandpass filter using combined microstrip/coplanar waveguide structure," Electronics Letters, Vol. 52, No. 13, 1145-1147, 2016.
doi:10.1049/el.2016.0835

5. Xiao, J., M. Zhu, J. Ma, and J. Hong, "Conductor-backed CPW bandpass filters with electromagnetic couplings," IEEE Microw. Wirel. Compon. Lett., Vol. 26, No. 6, 401-403, 2016.
doi:10.1109/LMWC.2016.2562641

6. Yang, B., H. J. Qian, Y. Shu, and X. Luo, "Compact bandpass filter with wide stopband using slow-wave CPW resonator with back-to-back coupled-scheme," IEEE International Symposium on Radio-Frequency Integration Technology (RFIT), 13-15, Seoul, South Korea, 2017.

7. Chen, Z., et al., "A high efficiency band-pass filter based on CPW and quasi-spoof surface plasmon polaritons," IEEE Access, Vol. 8, 4311-4317, 2020.
doi:10.1109/ACCESS.2019.2963062

8. Letavin, D. A. and V. A. Chechetkin, "Miniature microwave bandpass filter with two circular spiral resonators," International Conference on Advances in Computing, Communications and Informatics (ICACCI), 2315-2317, Jaipur, 2016.

9. Chang, Y.-C., P.-Y. Wang, S. S. H. Hsu, et al. "A V-band CPW bandpass filter with controllable transmission zeros in integrated passive devices (IPD) technology," IEEE MTT-S International Microwave Symposium, 1-3, San Francisco, CA, 2016.

10. Peng, B., et al., "Compact quad-mode bandpass filter based on quad-mode DGS resonator," IEEE Microw. Wirel. Compon. Lett., Vol. 26, No. 4, 234-236, 2016.
doi:10.1109/LMWC.2016.2537053

11. Ahn, D., J. S. Park, C. S. Kim, et al. "A design of the low-pass filter using the novel microstrip defected ground structure," IEEE Trans. Microwave Theory Tech., Vol. 49, No. 1, 86-93, 2001.
doi:10.1109/22.899965

12. Xiao, J.-K., X. Qi, H. Wang, and J. Ma, "High selective balanced bandpass filters using endconnected conductor-backed coplanar waveguide," IEEE Access, Vol. 7, 16184-16193, 2019.
doi:10.1109/ACCESS.2019.2893607

Dr. Wen Huang

Dr. Lu Li

Dr. Liang Li

Dr. Jinsheng Dong