| This dissertation presents the analytical design procedure for a new type of traveling-wave-fed rectangular waveguide slot array. Compared to other waveguide slot arrays, this array is expected to have wider bandwidth and 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. The radiating slots are modelled as shunt elements on an equivalent transmission line, and the electric field in each slot is assumed to be an equiphase, half cosinusoid. 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. The antenna design procedure consists of (1) obtaining the aperture distribution, (2) collecting a sample of self-admittance data large enough to characterize slots needed in the design and curvefitting this data, and (3) determining the required slot offsets and lengths to generate the aperture distribution found in (1). All three of these steps are performed analytically. Once the antenna dimensions are determined, the design procedure is inverted so that the aperture distribution versus frequency becomes the unknown. Then, as the frequency of operation is varied, the antenna pattern can be characterized, and the antenna bandwidth determined analytically. Finally, an antenna is designed and built using the procedure. The pattern of the antenna is measured, and the experimental data obtained are compared to the theoretical predictions. |
