Input impedances of centre-fed slot aerials near half-wave resonance

Slot radiators of various widths were fed via balanced parallel-rod transmission lines connected near the centre points of opposite edges of the slots. Series components of impedance at the feed points were measured for each slot at a number of frequencies, including that at which the length of the slot was ¿¿. In the first set of experiments the slot was free to radiate on both sides of the metal sheet in which it was cut. Further measurements are described in which the dimensions of the slot were kept constant whilst rectangular cavities of various dimensions were placed symmetrically behind the slot so as to prevent radiation from one face of the metal sheet.