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

Abstract

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 <inline-formula><tex-math notation= LaTeX >$\\text{5.8}\\,\\text{GHz}$</tex-math></inline-formula>. Measurements show that the array exhibits a field of view of <inline-formula><tex-math notation= LaTeX >$\\pm{\\text{30}}^\\circ$</tex-math></inline-formula> in elevation over the <inline-formula><tex-math notation= LaTeX >$\\text{5.4}\\text{--}\\text{6.2}\\,\\text{GHz}$</tex-math></inline-formula> band, with an active reflection coefficient for the central elements better than <inline-formula><tex-math notation= LaTeX >$-{\\text{10 dB}}$</tex-math></inline-formula>.