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.