Experimental study of narrow slot, cavity-backed apertures with finite wall conductivity

The authors present results showing the effects of varying conductivity and surface preparations for half-space coupling as well as different loadings of the narrow slot apertures. The coupling through narrow slot apertures having depth was measured for a variety of resonant cavity loadings. The loadings were chosen such that the cavity resonant frequencies were above, near, and below the resonant peak of the half-space coupling curve. Measurements were made in the 2-4-GHz band with vertical polarization. Two cases were considered: the slot radiating into a half-space and a cavity-backed aperture. The half-space coupling was reduced when the slot width decreased and/or the depth was increased. For very narrow slots, the wall loss dominates and this lowers the Q of the aperture. A decrease in Q was observed for a corresponding reduction in conductivity. It was observed that the cavity fields measured were quite large when a resonant structure loaded the aperture.<>