RF and mm wave filterssuffers from a common problem of asymmetries in filters transmission response caused by unwanted field couplings between individual resonators. In this paper, unwanted or spurious couplings between non-adjacent resonators are identified in the filter network from the simulation stage and mitigated to the extent possible. A 4-pole Quasi Elliptic Planar Band Pass Filter is fabricated at 48.5 GHz on a Liquid Crystal Polymer (LCP) substrate. An improvement of 6 dB in side lobe imbalance in filter transmission response is obtained. Effect of spurious coupling on band pass filters transmission response is demonstrated through EM simulation. Commensurate measurement results are presented.
2. Thompson, D. C., J. Papapolymerou, and M. M. Tentzeris, "High temperature dielectric stability of liquid crystal polymer at mm-wave frequencies," IEEE Microwave and Wireless Components Letters, Vol. 15, No. 9, 561-563, Sept. 2005.
doi:10.1109/LMWC.2005.855369
3. Thompson, D. C., O. Tantot, H. Jallageas, G. E. Ponchak, M. M. Tentzeris, and J. Papapolymerou, "Characterization of liquid crystal polymer (LCP) material and transmission lines on LCP substrates from 30 to 110 GHz," IEEE Transactions on Microwave Theory and Techniques, Vol. 52, No. 4, 1343-1352, Apr. 2004.
doi:10.1109/TMTT.2004.825738
4., Rogers Corporation advanced circuit materials website: http://www.rogerscorporation.com/acm/index.html.
5. Zou, G., H. Gronqvist, P. Starski, and J. Liu, "High frequency characteristics of liquid crystal polymer for system in a package application," IEEE 8th Int. Advanced Packaging Materials Symp., 337-341, Mar. 2002.
6. Bairavasubramanian, R. and J. Papapolymerou, "Multilayer quasi-elliptic filters using dual-mode resonators on liquid crystal polymer technology," IEEE MTT-S International Microwave Symposium Digest, 549-552, Jun. 2007.
7. Cameron, R. J., C. M. Kudsia, and R. R. Mansour, Microwave Filters for Communication Systems, J. Wiley & Sons, New Jersey, 2007.
8. Matthaei, G. L., L. Young, and E. M. T. Jones, Microwave Filters, Impedance-Matching Networks, and Coupling Structure, 3rd Ed., McGraw-Hill Book Company, 1964.
9. Kudsia, C., R. Cameron, and W. C. Tang, "Innovation in microwave filters and multiplexing networks for communication satellite systems," IEEE Transactions on Microwave Theory and Techniques, Vol. 40, 1133-1149, Jun. 1992.
doi:10.1109/22.141345
10. Gupta, V., T. V. Gajjar, K. K. Pathan, and Y. H. Dave, "Spurious coupling compensation through iris structure in coax cavity filters," 2016 Asia-Pacific Microwave Conference (APMC), 1-3, 2016, DOI: 10.1109/APMC.2016.7931416.
11. Luhaib, S., N. Somjit, and I. C. Hunter, "Improvement of the stopband spurious window for a dual-mode dielectric resonator filter by new coupling technique," International Journal of Electronics, Vol. 105, No. 11, 1805-1815, 2018, DOI: 10.1080/00207217.2018.1482008.
doi:10.1080/00207217.2018.1482008
12. Zhang, W., Z. Yao, J. Zhang, E. S. Kim, and N. Y. Kim, "A compact dual-mode bandpass filter with high out-of-band suppression using a stub-loaded resonator based on the GaAs IPD process," Electronics, Vol. 9, No. 5, 712, 2020, DOI: 10.3390/electronics9050712.
doi:10.3390/electronics9050712
13. Amari, S., M. Bekheit, and F. Seyfert, "Notes on bandpass filters whose inter-resonator coupling coefficients are linear functions of frequency," 2008 IEEE MTT-S International Microwave Symposium Digest, 1207-1210, Atlanta, GA, USA, 2008.
14. Zhang, R. and R. R. Mansour, "Low-cost dielectric-resonator filters with improved spurious performance," IEEE Transactions on Microwave Theory and Techniques, Vol. 55, No. 10, 2168-2175, Oct. 2007.
doi:10.1109/TMTT.2007.906540
15. Mansour, R. R., "Dual-mode dielectric resonator filters with improved spurious performance," 1993 IEEE MTT-S International Microwave Symposium Digest, Vol. 1, 439-442, Atlanta, GA, USA, 1993.
16. Goussetis, G. and D. Budimir, "Compact ridged waveguide filters with improved stopband performance," 2003 IEEE MTT-S International Microwave Symposium Digest, Vol. 2, 953-956, Philadelphia, PA, USA, 2003.
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