Design procedure for a forward-fire/backward-fire longitudinal slot array in rectangular waveguide

An analytical design procedure for a new type of traveling-wave-fed rectangular waveguide slot array is presented. This array is shown to have an invariant squint angle for the main beam. The array consists of a waveguide terminated in matched loads at both ends, with longitudinal slots in the upper broadwall used as the radiating elements. A transverse coupling slot is cut in the lower broadwall at the center of the antenna, dividing it into two traveling-wave linear arrays, each with different element spacings. The inputs of both halves are excited by the coupling slot. An analysis algorithm is used to predict the antenna bandwidth. A test antenna consisting of 66 slots was designed to operate at 10.0 GHz. After fabrication, the antenna was placed in a far-field test range. Azimuth and elevation patterns, the input VSWR (voltage standing wave ratio), and the power absorbed into the loads at the ends of the array were measured.<>