Design and measurement of a parallel plate slot array antenna fed by a rectangular coaxial line

We propose a parallel plate slot array antenna fed by a rectangular coaxial line, which can simplify the electrical contact between the bottom plate of the parallel plate and the rectangular coaxial line. We adopt hard walls at the both side walls of the parallel plate in order to excite a quasi-transverse electromagnetic (TEM) wave. We analyze the overall structure of the antenna, and measure its prototype. The measured bandwidth for VSWR less than 1.5 is 2.1%, and the antenna efficiency is 50.5% at 4.859 GHz where the reflection is minimized.