In this paper, half-mode substrate integrated waveguide (HMSIW) bandpass filters with modified complementary split-ring resonators (CSRRs) for the reduction of machining tolerance sensitivity are presented. Profiting from the evanescent-mode resonance operation, the conventional CSRR and its modified versions have been successfully utilized to miniaturize the physical sizes of SIW components. However, few investigations have focused on the fabrication tolerance. Performance of most CSRR-loaded SIW components, as well as their modified versions, is significantly sensitive to the fabrication tolerance. Hence, as the conventional machining process is with large fabrication tolerance, the CSRR-loaded SIW components suffer from limited performance and restrained application practicability. To decrease the influence from the machining tolerance on the components' performance, the slots-embedded CSRR (SECSRR) is proposed and loaded into HMSIW to design evanescent-mode filters. Numerical simulations exhibit that the proposed SECSRR can help to decrease the machining tolerance sensitivity effectively as the fractional frequency offset resulting from the fabrication error is reduced from ±8.11% to ±4.95%, which indicates that the proposed SECSRR is able to improve the suitability of SIW/HMSIW components and circuits for practical radio frequency (RF) and microwave applications.
2. Hong, W., et al., "Half mode substrate integrated waveguide: A new guided wave structure for microwave and millimeter wave application," 2006 Joint 31st International Conference on Infrared Millimeter Waves and 14th International Conference on Terahertz Electronics, 219, Shanghai, China, 2006.
3. Zhai, G., et al., "Folded half mode substrate integrated waveguide 3 dB coupler," IEEE Microwave and Wireless Components Letters, Vol. 18, No. 8, 512-514, Aug. 2008.
doi:10.1109/LMWC.2008.2001006
4. Dong, Y., T. Yang, and T. Itoh, "Substrate integrated waveguide loaded by complementary split-ring resonators and its applications to miniaturized waveguide filters," IEEE Transactions on Microwave Theory and Techniques, Vol. 57, No. 9, 2211-2223, Sep. 2009.
doi:10.1109/TMTT.2009.2027156
5. Zhang, Q., et al., "Compact substrate integrated waveguide (SIW) bandpass filter with complementary split-ring resonators (CSRRs)," IEEE Microwave and Wireless Components Letters, Vol. 20, No. 8, 426-428, Aug. 2010.
doi:10.1109/LMWC.2010.2049258
6. Kang, H. and S. Lim, "Electrically small dual-band reconfigurable complementary split-ring resonator (CSRR)-loaded eighth-mode substrate integrated waveguide (EMSIW) antenna," IEEE Transactions on Antennas and Propagation, Vol. 62, No. 5, 2368-2373, May 2014.
doi:10.1109/TAP.2014.2308532
7. Pradhan, N., K. Subramanian, and R. Barik, "Design of compact substrate integrated waveguide based triple- and quad-band power dividers," IEEE Microwave and Wireless Components Letters, Vol. 31, No. 4, 365-368, Apr. 2021.
doi:10.1109/LMWC.2021.3061693
8. Danaeian, M., K. Afrooz, A. Hakimi, and A. R. Moznebi, "Compact bandpass filter based on SIW loaded by open complementary split-ring resonators," International Journal of RF and Microwave Computer-Aided Engineering, Vol. 26, No. 8, 674-682, Aug. 2016.
doi:10.1002/mmce.21017
9. Danaeian, M., K. Afrooz, and A. Hakimi, "Miniaturization of substrate integrated waveguide filters using novel compact metamaterial unit-cells based on sir technique," AEU - International Journal of Electronics and Communications, Vol. 84, 62-73, Feb. 2018.
doi:10.1016/j.aeue.2017.11.008
10. Danaeian, M., R. Moznebi, and K. Afrooz, "A novel super compact half-mode substrate-integrated waveguide filter using modified complementary split-ring resonator," International Journal of RF and Microwave Computer-Aided Engineering, Vol. 29, No. 6, 21709, 1-8, Feb. 2019.
11. Danaeian, M. and H. Ghayoumi-Zadeh, "Miniaturized substrate integrated waveguide filter using fractal open complementary split-ring resonators," International Journal of RF and Microwave Computer-Aided Engineering, Vol. 28, No. 5, 21249, 1-7, May 2018.
12. Danaeian, M. and K. Afrooz, "Compact metamaterial unit-cell based on stepped-impedance resonator technique and its application to miniaturize substrate integrated waveguide filter and diplexer," International Journal of RF and Microwave Computer Aided Engineering, Vol. 29, No. 2, 21537, 1-9, Feb. 2018.