volume | PIER Journals

Abstract

This study presents an equivalent circuit and a design of an H-plane waveguide bandpass filter (BPF) with chamfer. Traditionally, only thin inductive diaphragm with no chamfers considered in the direct-coupled cavity theory, but this will lead to difficulties in the BPF manufacturing. During manufacturing process the chamfer cannot be avoided, and its equivalent circuit and effects on frequency shifting are investigated in this paper. A new design method is proposed in order to compensate the effect of chamfer in the half-wavelength resonator connection between the inductance diaphragm and the waveguide. A modified empirical formula and corresponding procedure are provided for designing such filters. The working center frequency and 3 dB bandwidths (BW) are simulated considering different chamfer radius. The simulated center frequencies are 18 GHz, 26 GHz, 34 GHz and 42 GHz, and BWs are 2.265%, 2.5%, 10%, 15% and 20%. Results show that the modified formula, which conforms better with the simulated results, is superior to the traditional formula. Two H-plane waveguide BPFs are manufactured with center frequency 26 GHz with 2.5% BW and 34 GHz with 2.265% BW. The results of the modified formula are in good agreement with measured ones.

1. Sinclair, G. N., R. N. Anderton, and R. Appleby, "Outdoor passive millimeter wave security screening," 2001 IEEE 35th International Carnahan on Security Technology, 172-179, 2001.
doi:10.1109/.2001.962830

2. Wang, N.-N., J.-H. Qiu, and W.-B. Deng, "Development status of millimeter wave imaging systems for concealed detection," Infrared Technology, Vol. 31, No. 3, 129-135, China, 2009.

3. Nanzer, J. A. and R. L. Rogers, "Human presence detection using millimetre-wave radiometry," IEEE Trans. Microw. Theory & Tech., Vol. 55, No. 12, 2727-2733, 2007.
doi:10.1109/TMTT.2007.909872

4. Xue, Y., J. Miao, G. Wan, A. Hu, and F. Zhao, "Prototype development of an 8mm band 2-dimensional aperture synthesis radiometer," 2008 International Geoscience and Remote Sensing Symposium, Boston, 2008.

5. Zheng, C., X. Yao, A. Hu, and J. Miao, "A passive millimeter-wave imager used for concealed weapon detection," Progress In Electromagnetics Research B, Vol. 46, 279-297, 2013.

6. Zheng, C., X. Yao, A. Hu, and J. Miao, "Statistical power measurement unit for an 8 mm-band two dimensional synthetic aperture interferometric radiometer BHU-2D," Progress In Electromagnetics Research M, Vol. 27, 119-128, 2012.
doi:10.2528/PIERM12101506

7. Yang, B.-H., Z.-P. Li, T.-F. Yu, et al. "Design of receiver used for passive millimeter waveimaging system," TELKOMNIKA, Vol. 12, No. 1, 98-105, 2014.

8. Li, L., K. Wu, and P. Russer, "On the thru-reflect-line (TRL) numerical calibration and error analysis for parameter extraction of circuit model," International Journal of RF and Microwave Computer-Aided Engineering, Vol. 16, No. 5, 470-482, 2006.
doi:10.1002/mmce.20167

9. Zhang, J., Z. Li, C. Zheng, X. Yao, B. Yang, and J. Miao, "Local oscillator uncorrelated phase noiseanalysis for millimeter-wave passive imager BHU-2D frequency synthesizer," Progress In Electromagnetics Research B, Vol. 54, 89-106, 2013.

10. Usher, J. and W. J. R. Hoefer, "Tunable microwave and millimeter-wave band-pass filter," IEEE Trans. Microwave Theory and Techniques, Vol. 39, 643-653, Apr. 1991.

11. Zhao, M., Y. Fan, and . Zhang, "A W-band low loss E-plane type waveguide band-pass filter," IEEE 2007 International Symposium on Microwave, Antenna, Propagation and EMC Technologies for Wireless Communications, 355-357, 2007.
doi:10.1109/MAPE.2007.4393621

12. Zhao, M. and Y. Fan, "A Ka band low loss wideband E-plane waveguide filter," Proceedings of 2011 4th IEEE International Symposium on Microwave, Antenna, Propagation and EMC Technologies for Wireless Communications, MAPE 2011, 802-804, 2011.
doi:10.1109/MAPE.2011.6156221

13. Lorente, J. A, C. Ernst, and A. A. Melcon, "Rigorous derivation of lossy equivalent circuit for narrowband waveguide direct-coupled-cavity filters," IET Microw. Antennas Propag., Vol. 7, No. 4, 251-258, 2013.
doi:10.1049/iet-map.2012.0283

14. Bahl, I. and P. Bhartia, Microwave Solid State Circuit Design, John Wiley & Sons Inc., 2003.

15. Levy, R., "Theory of direct-coupled-cavity filters," IEE Transactions on Microwave Theory and Techniques, Vol. 15, No. 6, 340-347, 1967.
doi:10.1109/TMTT.1967.1126471

16. Yang, B.-H., G. Mehdi, A. Hu, et al. "The round-ended design and measurement of all symmetric edge-coupledbandpass filter," Progress In Electromagnetics Research C, Vol. 136, 17-27, 2013.

Dr. Baohua Yang

Dr. Zhi-Ping Li

Dr. Jin Zhang

Dr. Xianxun Yao

Dr. Cheng Zheng

Dr. Xiaozhou Shang

Dr. Jungang Miao