Analysis of broadside and end-fire linear arrays of slot antennas

Abstract

Based on the analytical exposition presented here, which covers the formulation for both broadside and ordinary end-fire arrays of slot antennas, inflection design curves computed and which describe the profiles of the radiation patterns and the directivity for the foregoing two categories of arrays, are easily obtainable. Investigated are the behaviours of those important parameters under varying conditions. It is shown that when subjected to the same conditions, ordinary end-fire linear array of rectangular slots is more directive than the broadside array. Indeed, directivities of 13dB and 9.5dB are obtained here for ordinary end-fire and broadside arrays, respectively, when the inter-element separation is 0.25λ. What led to the emergence of the array theory proposed in this paper are three-fold. First, is the expression derived for the field radiated by an elemental slot consisting of the hybrid sum of the primary and secondary patterns radiated. Second, is the formulation of the array factor which multiplies the field radiated by an elemental slot from which the total field radiated by the array unfolds. Lastly, is the formulation for the determination of the directivity of the array of slots. It is also shown that the directivity of the array is a function of frequency, inter-element separation and the phase shift among the elements of the array.