High-Gain Wideband Leaky-Wave Antenna Excited by Bowtie Element

A leaky-wave antenna with wideband and high-gain characteristics, excited by a rhombic bowtie element with round corners, is derived from a rectangular resonant cavity operating in TM
₁₁₁
mode. In the design procedure, a few particular techniques are used to enhance the antenna impedance bandwidth and gain, such as utilization of bowtie exciter and differentially-fed mechanism. The antenna is fed by a coaxial line, and a transition from microstrip line to parallel strip line (PSL) is utilized to achieve a good differentially-fed structure. With a tradeoff between large impedance bandwidth and high gain, the antenna presents an impedance bandwidth of 41.2% for SWR les 2, a gain of 14 dBi and stable unidirectional radiation patterns. For practical applications, the parametric studies and design guideline are given in the end.