Reduced Sideband Levels in Time-Modulated Arrays Using Half-Power Sub-Arraying Techniques

A new approach to reducing the sidebands levels and power losses in the harmonic patterns of time-modulated linear arrays is presented. The approach is based on reducing the static element weights of the outer elements of a linear array using simple 3 dB power dividers. This approach allows the relative switch-on times of the outer elements of the array to be increased which reduces the transients in the time-domain output from the array and results in lower sideband levels. Numerical results are presented to illustrate and compare the approach to conventional switching schemes.