[01] Abdessamed Chinig, Microwave Group, Faculty of Sciences and Techniques, Hassan 1st University, Settat, Morocco.

In this paper, a compact microstrip diplexer is proposed for Wimax and DCS applications at 2.5 GHz and 1710-1880 MHz respectively. The microstrip diplexer consists of two band-pass filters operating at different frequency bands and a coupled-junction. Each filter is formed by a meander-line resonator and two Input/Output feed lines. The frequency response of each filter can be easily controlled by modifying the dimensions of the meander-line resonators. ADS and CST-MWS solvers have been used to characterize the response of the diplexer. Good electrical performances are obtained after an optimization of the proposed circuit. The microstrip diplexer presents an insertion loss of 2.3 dB a return loss of 30 dB and an isolation between the two filters better than 22 dB for an overall size of 25×32 mm².

Band-Pass Filter, Diplexer, Meander-Line Resonators, Microstrip, Isolation

[01] Liu, Y., Feng, C., Bai, N., Sun, X., Hu, Y., Liao, F., & Feng, J. (2016, April). Meta-material absorber for microstrip meander-line slow wave structure. In Vacuum Electronics Conference (IVEC), 2016 IEEE International (pp. 1-2). IEEE. [02] Sumathy, M., Christie, L., Datta, S. K., & Kumar, L. (2012, April). Analysis of a W-band meander-line slow-wave structure for millimeter-wave traveling-wave tubes. In Vacuum Electronics Conference (IVEC), 2012 IEEE Thirteenth International (pp. 461-462). IEEE. [03] Chang, W. S., & Chang, C. Y. (2012). A high slow-wave factor microstrip structure with simple design formulas and its application to microwave circuit design. IEEE Transactions on Microwave Theory and Techniques, 60(11), 3376-3383. [04] Kamal, S., & Chaudhari, A. A. (2017). Printed Meander Line MIMO Antenna Integrated with Air Gap, DGS and RIS: A Low Mutual Coupling Design for LTE Applications. Progress In Electromagnetics Research C, 71, 149-159. [05] Agrawal, T., & Srivastava, S. (2017). Compact MIMO Antenna for Multiband Mobile Applications. Journal of Microwaves, Optoelectronics and Electromagnetic Applications (JMOe), 16(2), 542-552. [06] Kumar, A., Choudhary, D. K., & Chaudhary, R. K. (2017). Metamaterial Tri-Band Bandpass Filter Using Meander-Line with Rectangular-Stub. Progress In Electromagnetics Research Letters, 66, 121-126. [07] Ali, W. A. E., & Boutejdar, A. (2017). Design of Low-Pass Filter Using Meander Inductor and U-Form Hi-Lo Topology with High Compactness Factor for L-Band Applications. Progress In Electromagnetics Research M, 55, 95-107. [08] Chiu, H. C., Lai, C. H., & Ma, T. G. (2012, June). Miniaturized rat-race coupler with out-of-band suppression using double-layer synthesized coplanar waveguides. In Microwave Symposium Digest (MTT), 2012 IEEE MTT-S International (pp. 1-3). IEEE. [09] Lou, J. W., Li Guomin Yang, M., Adams, X. Y., & Sun, N. X. (2013). Compact Low-Loss Wideband and High-Power Handling Phase Shifters Wave Frequency-Scanning Applications. IEEE Antennas and Wireless Propagation Letters, 12, 116-119. [10] Chakraborty, A., Kundu, A., Dhar, S., Maity, S., Chatterjee, S., & Gupta, B. (2011, September). Compact K-band distributed RF MEMS phase shifter based on high-speed switched capacitors. In Mediterranean Microwave Symposium (MMS), 2011 11th (pp. 25-28). IEEE. [11] Chen, W. K. (Ed.). (2002). The circuits and filters handbook. CRC Press.