An $8\times 4$ Continuous Transverse Stub Array Fed by Coaxial Ports

Continuous transverse stub arrays are wideband, wide-scanning antennas consisting of an arrangement of long slots or parallel-plate waveguide apertures radiating in free space. A line source is generally required to feed these arrays. Here, we show that such a line source can be created over the radiating aperture using a two-dimensional (2-D) arrangement of coaxial probe transitions. The coaxial transitions are directly integrated into the parallel-plate waveguides feeding the slots. Such a solution avoids using quasi-optical systems or bulky corporate networks to feed the array. The proposed 2-D feeding scheme also allows steering the main beam of the array. This is an additional benefit with respect to previous designs for which scanning was limited to a single plane. An array of 8 × 4 elements validates the concept at $\text{5.8}\,\text{GHz}$ . Measurements show that the array exhibits a field of view of $\pm{\text{30}}^\circ$ in elevation over the $\text{5.4}\text{--}\text{6.2}\,\text{GHz}$ band, with an active reflection coefficient for the central elements better than $-{\text{10 dB}}$ .