A simple method for designing a triple-mode bandpass filter is presented in this paper. Triple-mode is achieved by using half-mode substrate integrated waveguide (HMSIW) cavity.Three perturbation metal vias were introduced for shifting resonant modes.The resonant frequencies of these modes can be adjusted by the location and the diameter of perturbation vias properly. In order to improve the out-of-band rejection, the CPW-to-SIW transition was added. A triple-mode HMSIW filter with the center frequency of 13 GHz was designed and fabricated. The measured fractional bandwidth is 35% with a transmission zero located at 20.4 GHz. Good agreement is observed between simulation and measurement.
2. Balalem, A., et al., "Realization of a microstrip triple-mode bandpass filter using a square-loop resonator," IEEE International Microwave Symposium Digest, 849-852, 2009.
3. Deslandes, D. and K. Wu, "Integrated microstrip and rectangular waveguide in planar form," IEEE Microwave and Wireless Components Letters, Vol. 11, No. 2, 68-70, 2001.
4. Liu, B., et al., "Half mode substrate integrated waveguide (HM-SIW) 3-dB coupler," IEEE Microwave and Wireless Components Letters, Vol. 17, No. 1, 22-24, 2007.
5. Chen, X. P., K. Wu, and Z. L. Li, "Dual-band and triple-band substrate integrated waveguide filters with Chebyshev and quasi-elliptic responses," IEEE Transactions on Microwave Theory and Techniques, Vol. 55, No. 12, 2569-2578, 2007.
6. Deng, K., et al., "A compact planar bandpass filter with wide out-of-band rejection implemented by substrate-integrated waveguide and complementary split-ring resonator," Microwave and Optical Technology Letters, Vol. 53, No. 7, 1483-1487, 2011.
7. Cheng, F., et al., "A compact dual-band bandpass SIW filter," Journal of Electromagnetic Waves and Applications, Vol. 27, No. 3, 338-344, 2013.
8. Gong, K., et al., "C-band bandpass filter based on half mode substrate integrated waveguide (HMSIW) cavities," IEEE Asia Pacific Microwave Conference, APMC 2009, 2591-2594, 2009.
9. Zhou, S., et al., "A novel X-band half mode substrate integrated waveguide (HMSIW) bandpass filter," IEEE Asia Pacific Microwave Conference, APMC 2009, 1387-1389, 2009.
10. Liu, W. and F. Liu, "A highly selective super-wide bandpass filter by cascading HMSIW with asymmetric defected ground structure," 2010 International Conference on IEEE Microwave and Millimeter Wave Technology (ICMMT), 77-80, 2010.
11. Cassivi, Y., et al., "Dispersion characteristics of substrate integrated rectangular waveguide," IEEE Microwave and Wireless Components Letters, Vol. 12, No. 9, 333-335, 2002.
12. Shen, W., W. Y. Yin, and X. W. Sun, "Compact substrate integrated waveguide (SIW) filter with defected ground structure," IEEE Microwave and Wireless Components Letters, Vol. 21, No. 2, 83-85, 2011.