Investigations on Waveguide-fed Slot Antenna: Equivalent Network Representation

ABSTRACT

The paper presents investigations on equivalent network representation of displaced narrow longitudinal slot as the length of the slot is varied over the range 0·44–1·5 λ. It is shown that the scattering coefficients (symmetrical, antisymmetrical and unsymmetrical) as also the discontinuities in terminal voltages and currents corresponding to the equivalent network depend upon the nature of the field distribution (odd, even or general) in the slot. The equivalent network is realizable in the form of a T or a π. The T and π-networks may be approximated by shunt and series elements respectively. From the elements of the T and π-equivalent networks, the important parameters such as scattering coefficients and scattering metrix and hence the effect of the slot on the wave propagating down the waveguide have been found. Further, a knowledge of the above parameters provides information regarding the change in the nature of field distribution in the slot with change in its length.