Multimode characterization of parallel plate waveguide

Characterization of parallel plate waveguide multimode propagation is investigated for use in sensing and material parameter extraction applications. Broadband and narrowband measurements are presented and compared to finite difference time domain simulations and analytic solutions which use a Fourier transform mode-matching technique. Agreement is observed between simulation and measurement of field patterns, but analytic solutions require estimates of individual mode contributions. Higher order modes contribute both a greater conductive attenuation and higher coupling loss seen in the larger side lobes of the field pattern.