In this paper, a novel approach has been suggested to obtain an improved spurious-free window for dielectric resonator in microwave integrated circuit environment. In microwave integrated circuit environment, the dielectric resonator placed on a thin dielectric substrate gets located asymmetrically with respect to its shielding enclosure. A reduced separation in frequencies (mode separation) is one of a consequence of this asymmetry that may become a cause of spurious modes. This adverse influence of asymmetry is sought to be compensated by proposing a multi-layer multi-permittivity dielectric resonator structure with several layers of differing permittivity. The suggested approach takes advantage of the fact that the mode separation of a dielectric resonator configuration can be correlated to relevant resonance mode fields. By perturbing the resonance mode fields through the suggested multi-layer multi-permittivity approach, the adverse influence of asymmetry is found to reduce considerably over a comparative conventional ring dielectric resonator in microwave integrated circuit configuration. Still more improvement in mode separation are shown when the shape of the multi-layer multi-permittivity ring dielectric resonator is further modified, suggesting a scope for optimization in present approach.
2. Hunter, I. C., J. D. Rhodes, and V. Dassonville, "Dual-mode filters with conductor-loaded dielectric resonators," IEEE Trans. Microwave Theory Tech., Vol. 47, No. 12, 2304-2311, 1999.
3. Weily, A. R. and A. S. Mohan, "Microwave filters with improved spurious performance based on sandwiched conductor dielectric resonators," IEEE Trans. Microwave Theory Tech., Vol. 49, No. 8, 1501-1507, 2001.
4. Karp, A., H. J. Shaw, and D. K. Winslow, "Circuit properties of microwave dielectric resonators," IEEE Trans. Microwave Theory Tech., Vol. 16, No. 10, 818-828, 1968.
5. Ren, C. L. and Mode suppressor for dielectric resonator filters, "IEEE MTT-S Int. Microwave Symp. Dig.,", 389-391, 1982.
6. Kobayashi, Y. and M. Miura, "Optimum design of shielded dielectric rod and ring resonators for obtaining the best mode separation ," IEEE MTT-S Int. Microwave Symp. Dig., 184-186, 1984.
7. Nishikawa, T., K. Wakino, K. Tsunoda, and Y. Ishikawa, "Dielectric high-power bandpass filter using quarter-cut TE01 image resonator for cellular base stations," IEEE Trans. Microwave Theory Tech., Vol. 35, No. 12, 1150-1155, 1987.
8. Hui, W. K. and I. Wolff, "Dielectric ring-gap resonator for application in MMIC's," IEEE Trans. Microwave Theory Tech., Vol. 39, No. 12, 2061-2068, 1991.
9. Mansour, R. R., "Dual-mode dielectric resonator filters with improved spurious performance," IEEE MTT-S Int. Microwave Symp. Dig., 439-442, 1993.
10. Wang, C., K. A. Zaki, A. E. Atia, and T. G. Dolan, "Dielectric combline resonators and filters," IEEE Trans. Microwave Theory Tech., Vol. 46, No. 12, 2501-2506, 1998.
11. Snyder, R. V. and C. Alvarez, "Filters using a new type of resonator: The partially-metallized dielectric slug," IEEE MTT-S Int. Microwave Symp. Dig., 1029-1032, 1999.
12. Cheng, S.-W. and K. A. Zaki, "Dielectric ring resonator loaded in waveguide and on substrate," IEEE Trans. Microwave Theory Tech., Vol. 39, No. 12, 2069-2076, 1991.
13. Srivastava, K. V., V. V. Mishra, and A. Biswas, "A modified ring dielectric resonator with improved mode separation and its tunability characteristic in MIC environment ," IEEE Trans. Microwave Theory Tech., Vol. 53, No. 6, 1960-1967, 2005.
14. Kirschbaum, H. S. and S. Chen, "A method of producing broad-band circular polarization employing an anisotropic dielectric," IRE Trans. Microwave Theory Tech., Vol. 5, No. 3, 199-203, 1957.
15. Collin, R. E., "A simple artificial anisotropic dielectric medium," IRE Trans. Microwave Theory Tech., Vol. 6, No. 2, 206-209, 1958.
16. Chang, C. T. M., "Circular waveguides lined with artificial anisotropic dielectrics," IEEE Trans. Microwave Theory Tech., Vol. 20, No. 8, 517-523, 1972.
17. Wang, C. and K. A. Zaki, "Generalized multilayer anisotropic dielectric resonators," IEEE Trans. Microwave Theory Tech., Vol. 48, No. 1, 60-66, 2000.
18. Chaudhary, R. K., V. V. Mishra, K. V. Srivastava, and A. Biswas, "Multi-layer multi-permittivity dielectric resonator: A new approach for improved spurious free window ," Proceedings of EuMC, 1194-1197, 2010.
19. Srivastava, K. V., V. V. Mishra, and A. Biswas, "An efficient FDTD algorithm for computation of resonance frequencies of an inhomogeneous cylindrical structure," Proc. Asia Pacific Microwave Conference, 2006.
20. Pullar, R. C., K. Okeneme, and N. M. Alford, "Temperature compensated niobate microwave ceramics with the columbite structure, M2+Nb2O6," Journal of the European Ceramic Society, Vol. 23, 2479-2483, 2003.
21. Leong, K., J. Mazierska, and J. Krupka, "Measurements of Unloaded Q-factor transmission mode dielectric resonators," Proc. International Microwave Symposium, Denver, IEEE MTTS'97 Symposium Digest, 1997.
22. Sucher, M. and J. Fox, Handbook of Microwave Measurements, 3rd Ed., Vol. 2, Wiley, 1963.