Fundamental Superstrate Effects on Printed Circuit Antenna Efficiency

Printed circuit antennas integrated on typically used substrates such as quartz, GaAs or Si exhibit low radiation efficiency due to surface wave effects in the substrate (e.g., a GaAs substrate yields on optimum radiation efficiency of e/sub s/ /spl sime/ 28%). It is demonstrated in this paper that e/sub s/ = 100% is feasible with practical materials either by using a magnetic superstrata layer or by integrating the antennas on the lower side of a dielectric superstrata (such as GaAs), while in this case, the substrate is merely a supporting layer with lower dielectric constant. The effect of the composite layer is to eliminate surface waves, provided the layer thicknesses are chosen properly.