Use of a surface wave cell and an optically modulated scatterer to evaluate the propagation properties of surface waves

This paper describes a new method for measuring the propagation properties of the surface waves supported by a metal-backed planar layered substrate (infinite plane surface waves). The measurement method utilizes a partially filled rectangular waveguide cell, within which the modes mimic the propagation of a surface wave along an infinite plane. The surface wave is observed using an optically modulated scatterer (OMS). Measured data at 10 GHz of the surface waves supported by low loss and lossy substrates are presented, and good agreement between predicted and measured data is found. The advantages of combining the waveguide cell and OMS to characterize surface waves are: 1) the OMS is small and perturbs the surface waves only minimally; 2) the sample dimensions of the waveguide cell are modest; 3) the measurement environment is well defined electromagnetically; and 4)only a very pure mono-modal surface wave is permitted to propagate in the waveguide cell.