Theory of frequency scanning of antennas

This paper presents the theory of180 for a linear array and Tchebycheff array by frequency variation and discusses the relationships between the linear array theory and theω- of periodic structures. Each element is excited by a slow-wave structure which is either nondispersive or dispersive. At a center frequency, the spacing is an integral multiple of guide wavelengthMλc. It is shown that this is in fact the -Mth space harmonic in the so-called forbidden region, and all the other harmonics are slow. For a given frequency range, the necessary phase velocity and other parameters are determined in order to obtain180 without causing other main beams, and the example is carried out for theX-band frequency range.