Leaf-Shaped Bowtie Slot Antenna Array for Application in Beam Scanning

In this paper, a circular 4×4 Butler Matrix based on microstrip line is designed and applied to a 4-element linear array of leaf-shaped bowtie slot antenna. This antenna structure is designed to operate within 27GHz to 29GHz. The circular butler matrix is used in order to eliminate crossover element. On the top of antenna array, a dielectric superstrate with high dielectric constant is used to improve impedance bandwidth and gain. Those antenna characteristics are evaluated by using Finite Different Time Domain (FDTD) method. From the simulated results, -10dB impedance bandwidth is within 27GHz to 28.5GHz and the antenna can scan the beam within 9° to -13° along E-plane.