volume | PIER Journals

Abstract

We present a revised Cauchy method to accurately extract the high quality factor of dielectric resonators from measurements. Since the losses displace all the zeros and poles of the transfer function horizontally to the left in the complex plane, the accurate evaluation of the unloaded quality factor of microwave resonators can be achieved based on the complex frequency transformation. The results show that if the three-point method is employed, the accuracy of the quality factor values deteriorates when the input/output coupling is strong. Nevertheless, a nearly constant factor value can be obtained by our proposed technique whether the input/output couplings are weak or strong. This algorithm provides an alternative method to measure the unloaded quality factor when the signal-to-noise ratio is high.

1. Pozar, D. M., Microwave Engineering, 3rd Ed., Wiley, 2005.

2. Chua, L. H. and D. Mirshekar-Syahkal, "Accurate and direct characterization of high-Q microwave resonators using one-port measurement," IEEE Trans. Microw. Theory Tech., Vol. 51, No. 3, 978-985, 2003.
doi:10.1109/TMTT.2003.808711

3. Cameron, R. J., C. M. Kudsia, and R. R. Mansour, Microwave Filters for Communication Systems, Wiley, 2007.

4. Wang, P., L. H. Chua, and D. Mirshekar-Syahkal, "Accurate characterization of low-Q microwave resonator using critical-points method," IEEE Trans. Microw. Theory Tech., Vol. 53, No. 1, 349-353, 2005.
doi:10.1109/TMTT.2004.839931

5. Kwok, R. S. and J. F. Liang, "Characterization of high-Q resonators for microwave-filter applications," IEEE Trans. Microw. Theory Tech., Vol. 47, No. 1, 111-114, 1999.
doi:10.1109/22.740093

6. Leong, K. and J. Mazierska, "Precise measurements of the Q factor of dielectric resonators in the transmission mode --- Accounting for noise, crosstalk, delay of uncalibrated lines, coupling loss, and coupling reactance," IEEE Trans. Microw. Theory Tech., Vol. 50, No. 9, 2115-2127, 2002.
doi:10.1109/TMTT.2002.802324

7. Wang, R., J. Xu, C. L. Wei, M.-Y. Wang, and X.-C. Zhang, "Improved extraction of coupling matrix and unloaded Q from S-parameters of lossy resonator filters," Progress In Electromagnetics Research, Vol. 120, 67-81, 2011.
doi:10.2528/PIER11072804

8. Garcia-Lamperez, A., T. K. Sarkar, and M. S. Palma, "Generation of accurate rational models of lossy systems using the Cauchy method," IEEE Microw. Wireless Compon. Lett., Vol. 14, No. 10, 490-492, 2004.
doi:10.1109/LMWC.2004.834576

9. Garcia-Lamperez, A., S. Llorente-Romano, M. Salazar-Palma, and T. K. Sarkar, "Efficient electromagnetic optimization of microwave filters and multiplexers using rational models," IEEE Trans. Microw. Theory Tech., Vol. 52, No. 2, 508-521, 2004.
doi:10.1109/TMTT.2003.822021

10. Macchiarella, G., "Extraction of unloaded and coupling matrix from measurement on filters with large losses," IEEE Microw. Wireless Compon. Lett., Vol. 20, No. 6, 307-309, Jun. 2010.
doi:10.1109/LMWC.2010.2047455

11. Adve, R. S., T. K. Sarkar, S. M. Rao, E. K. Miller, and D. R. Pflug, "Application of the Cauchy method for extrapolating/interpolating narrow-band system responses," IEEE Trans. Microw. Theory Tech., Vol. 45, 837-845, May 1997.
doi:10.1109/22.575608

12. Wang, R. and J. Xu, "Extracting coupling matrix and unloaded Q from scattering parameters of lossy filters," Progress In Electromagnetics Research, Vol. 115, 303-315, 2011.
doi:10.2528/PIER11021604

13. Chu, Q.-X., X. Ouyang, H. Wang, and F.-C. Chen, "TE01σ-mode dielectric-resonator filters with controllable transmission zeros," IEEE Trans. Microw. Theory. Tech., Vol. 61, 1086-1094, 2013.
doi:10.1109/TMTT.2013.2238551

Dr. Dajun Lei

Mr. Feng Qiu

Dr. Jinggui Zhang

Dr. Hui Dong

Dr. Zhenhua Tang

Dr. Jian-Quan Huang

Dr. Ming Yao

Prof. Qing-Xin Chu