Leakage and ohmic losses investigation in substrate-integrated waveguide

Rectangular waveguide (RW) with sidewalls of vertical conducting cylinders (i.e., substrate-integrated waveguide, SIW) becomes popular with the advent of low-temperature cofired ceramic (LTCC) structure. The formula of leakage loss through the SIW with small cylinders has been found, based on the surface impedance of cylinder walls derived from an analytical MoM. To complete the study of loss, the ohmic loss in the SIW is investigated also in this paper. The theoretical formulas show good agreements with numerical HFSS simulations and the measured data from hardware experiments, demonstrating potential applications to the research and design of some interesting devices such as leaky antennas, etc.