An experimental study of the slot aerial and the three-element collinear array of slot aerials

The principle of complementarity is reviewed with particular reference to its application to the study of slot transmission lines and slot aerials. The conventional techniques for making measurements on transmission lines are shown to be applicable to a two-slot line that is used to centre-drive a slot aerial. The complementary normalized impedance of such an aerial as a function of its half length, and the distributions of the electric and magnetic field along it, have been measured and are described. The experimental results for the slot aerial are compared with the approximately complementary ones derived theoretically for a centre-driven cylindrical aerial. The effect of the finite thickness of the earth screen in which the slot line and aerial are cut is discussed. A similar study is described for a threeelement collinear array of slot aerials.