The miniaturization of conventional ring resonators is demonstrated by forcing a voltage minimum at one end of the resonator. In addition, the resonator is loaded with a capacitance to achieve further miniaturization and reducing its sensitivity to substrate thickness tolerance. The final resonator is 73% smaller than a conventional ring resonator and has a tenfold decrease in sensitivity to substrate thickness variations. Using this resonator a 4-pole quasi-elliptic filter is fabricated showing good agreement between simulation and experimental results.
2. Rouchard, F., New classes of microstrip resonators for HTS microwave filter applications, IEEE International Microwave Symposium Digest, 1023-1026, Baltimore, MD, 1998.
3. Gorur, A., "A novel dual-mode bandpass filter with wide stopband using the properties of microstrip open-loop resonator," IEEE Microwave and Wireless Components Letters, Vol. 12, 386-388, 2002.
doi:10.1109/LMWC.2002.804560
4. Wolff, I. and V. K. Tripathi, "The microstrip open ring resonator," IEEE Transactions on Microwave Theory and Techniques, Vol. 32, 102-107, 1984.
doi:10.1109/TMTT.1984.1132619
5. Zhu, L., P. M. Wecowski, and K. Wu, "New planar dual-mode filter using cross-slotted patch resonator for simultaneous size and loss reduction," IEEE Transactions on Microwave Theory and Techniques, Vol. 47, 650-654, 1999.
doi:10.1109/22.763171
6. Hong, J. S., E. P. McErlean, and B. Karyamapudi, "Eighteen pole superconducting CQ filter for future wireless applications," IEE Proceedings on Microwaves Antennas and Propagation, Vol. 153, 205-211, 2006.
doi:10.1049/ip-map:20050043
7. Vendik, I., et al., "Design of trimmingless narrowband planar HTS filters," Springer Journal of Superconductivity and Novel Magnetism, Vol. 14, 21-28, 2001.
doi:10.1023/A:1007871903562
8. Zhou, J., M. J. Lancaster, and F. Huang, "HTS coplanar meander line resonator filters with suppressed slot line mode," IEEE Transactions on Applied Superconductivity, Vol. 14, 28-32, 2004.
doi:10.1109/TASC.2004.824327
9. Corona-Chavez, A., M. J. Lancaster, and H. T. Su, "HTS quasi-elliptic filter using capacitive-loaded cross-shape resonators with low sensitivity to substrate thickness," IEEE Transactions on Microwave Theory and Techniques, Vol. 55, 117-120, 2007.
doi:10.1109/TMTT.2006.888577
10. Wadell, B. C., Transmissión Line Design Handbook, Artech House, 1991.
11. Sonnet software, v.12.
12. Pettenpaul, E., H. Kaputsa, A. Weisgerber, H. Mampe, J. Lunginsland, and I. Wolff, "CAD models of lumped elements on GaAs up to 18 GHz," IEEE Transactions on Microwave Theory and Techniques, Vol. 36, 294-304, 1988.
doi:10.1109/22.3518
13. Hong, J.-S. and M. J. Lancaster, Microstrip Filters for RF/microwave Applications, John Wiley and Sons, 2001.
doi:10.1002/0471221619