The synthesis of surface reactance using an artificial dielectric

A thin artificial dielectric layer consisting of a rectangular array of closely spaced, thin conductive cylinders (pins), was constructed above a perfectly conducting ground plane. The reactance of the surface was measured at 4.8 GHz for a variety of pin heights and dielectric embedding material by measuring the height-gain profile of a transverse magnetic (TM) surface wave launched across it. Design equations using the theories of artifical dielectrics and propagation in anisotropic media are given. These can be used to predict the surface reactance providing a correction factor accounting for fringing fields at the tops of the pins is included. Using an embedding dielectric tends to reduce this fringing effect.