Method of Auxiliary Sources for Analyzing Half-Mode Substrate Integrated Waveguide

A new numerical method based on the method of auxiliary sources (MAS) is presented for analyzing the propagation characteristics of the EH1 mode of a half-mode substrate integrated waveguide (HMSIW). A set of filament auxiliary sources are located on a cylinder surface inside the shorting-via of the HMSIW for representing the current in the shorting-via, and matching points are located on the surface of the shorting-via. Due to the periodicity of the HMSIW, only one period needs to be concerned, and the field resulting from the auxiliary sources in one period is expanded into a series of space harmonics. A transverse equivalent network is introduced to represent the transverse wave of each space harmonic inside the HMSIW, and then the Green's function is deduced. Hence, the propagation wavenumber is calculated accurately and efficiently. The calculated results agree very well with those obtained with other methods.