A method for decreasing the loss in substrate integrated waveguide (SIW) structures is introduced. In this method, the dielectric substrate is partially removed. Accordingly, dielectric loss reduction has been explicated analytically. Its equivalence to the rectangular waveguide of solid walls which is partially filled with dielectric has been identified. A novel topology for demonstrating the idea is established and a low loss three port substrate integrated waveguide power divider is presented. This SIW power divider shows lower loss than conventional SIW power dividers. Proper TRL standards are realized for removing the effect of transition and/or matching sections in measurement process. For a low-loss three-port PSIW power divider, the return loss below 10 dB and transmission coefficients between -3 dB to -3.5 dB from 8.75 GHz to 10 GHz have been achieved. The measured amplitude imbalance is less than ±0.2 dB, and the measured phase difference between <S21 and <S31 is about 40 in the same frequency band.
2. Ke, W., D. Deslandes, and Y. Cassivi, "The substrate integrated circuits --- A new concept for high-frequency electronics and optoelectronics," 6th International Conference on Telecommunications in Modern Satellite, Cable and Broadcasting Service, TELSIKS 2003 , Vol. 1, P-III-P-X, 2003.
3. Germain, S., D. Deslandes, and K. Wu, "Development of substrate integrated waveguide power dividers," Canadian Conference on Electrical and Computer Engineering, IEEE CCECE 2003, Vol. 3, 1921-1924, 2003.
4. Deslandes, D., "Design equations for tapered microstrip-to-substrate integrated waveguide transitions," 2010 IEEE MTT-S International Microwave Symposium Digest (MTT), 704-707, 2010.
5. Bozzi, M., L. Perregrini, and W. Ke, "Modeling of conductor, dielectric, and radiation losses in substrate integrated waveguide by the boundary integral-resonant mode expansion method," IEEE Transactions on Microwave Theory and Techniques, Vol. 56, 3153-3161, 2008.
6. Ranjkesh, N. and M. Shahabadi, "Reduction of dielectric losses in substrate integrated waveguide," Electronics Letters, Vol. 42, No. 21, 1230-1231, 2006.
7. Kaijun, S., F. Yong, and Z. Yonghong, "Eight-way substrate integrated waveguide power divider with low insertion loss ," IEEE Transactions on Microwave Theory and Techniques, Vol. 56, 1473-1477, 2008.
8. Songnan, Y. and A. E. Fathy, "Synthesis of an arbitrary power split ratio divider using substrate integrated waveguides," IEEE/MTT-S International Microwave Symposium , 427-430, 2007.
9. Ning, Y., C. Caloz, and W. Ke, "Substrate integrated waveguide power divider based on multimode interference imaging," 2008 IEEE MTT-S International Microwave Symposium Digest, 883-886, 2008.
10. Mohammadi, P. and S. Demir, "Two layers substrate integrated waveguide power divider," 2011 XXXth URSI General Assembly and Scientific Symposium, 1-4, 2011.
11. Eom, D., J. Byun, and H.-Y. Lee, "Multi-layer four-way out-of-phase power divider for substrate integrated waveguide applications," IEEE MTT-S International Microwave Symposium Digest, MTT'09, 477-480, 2009.
12. Smith, N. A. and R. Abhari, "Compact substrate integrated waveguide Wilkinson power dividers," IEEE Antennas and Propagation Society International Symposium, APSURSI'09, 1-4, 2009.
13. Wenjie, F., C. Wenquan, and D. Kuan, "Compact planar magic-T using E-plane substrate integrated waveguide (SIW) power divider and slotline transition ," IEEE Microwave and Wireless Components Letters, Vol. 20, 331-333, 2010.
14. Harrington, R. F., Time Harmonic Electromagnetic Fields, Wiley-IEEE Press, 2001.
15. Che, K. D. W., D. Wang, and Y. L. Chow, "Analytical equivalence between substrate-integrated waveguide and rectangular waveguide," IET Microw. Antennas Propag., Vol. 2, No. 1, 2008.
16. Mohammadi, P. and S. Demir, "Multi-layer substrate integrated waveguide E-plane power divider ," Progress In Electromagnetics Research C, Vol. 30, 159-172, 2012.
17. Marcuvitz, N., Waveguide Handbook, McGraw-Hill Book Company, Inc., 1951.