Bandwidth‐enhanced horizontally polarized omnidirectional slot antenna based on single‐ridge trapezoidal waveguide

Abstract

This letter presents a Ku‐band horizontally polarized (HP) omnidirectional antenna based on single‐ridge trapezoidal waveguide (STW). Four groups of longitudinal slots are etched on a pair of back‐to‐back arranged STWs to achieve the HP omnidirectional radiation performance. The number and distribution of each radiation slot group are optimized to reduce the gain variation. An out‐of‐phase stripline power divider cascaded with two probe‐based vertical power dividers is used to excite all radiating slots in a series‐parallel hybrid structure, which helps to enhance the boresight radiation bandwidth. For demonstration, a prototype covering 14.5 to 15.5 GHz is designed, fabricated, and measured. Experimental results show that the good impedance matching (|S11|←14 dB) and the measured out‐of‐roundness for the omnidirectional radiation pattern are less than 4.4 dB within the desired frequency band. High gain and wideband omnidirectional radiation characteristics can provide a wide range of coverage and good signal transmission performance for outdoor wireless communication systems.