MILLIMETER-WAVE WIDE BEAMWIDTH APERTURE-COUPLED ANTENNA DESIGNED BY MODE SYNTHESIS

Abstract

In this letter, a wide beamwidth aperture-coupled antenna is designed by mode synthesis at the millimeter-wave frequency. To obtain the wide beamwidth, a TM010 mode and a zeroth-order resonance mode of a metamaterial antenna are combined. A theoretical equation of synthesized radiation pattern is derived to find the conditions to obtain the widest E-plane half power beamwidth (HPBW). By utilizing the equation, the optimal phase difference and injected power ratio to two antennas are found. The results are verified by a derived equivalent circuit and a full wave simulator. In addition, an aperture-coupled feed that has an advantage to minimize the interference between a feed and an antenna has been used. Finally, the antenna with wide beamwidth is designed and fabricated at 35 GHz. The radiation efficiency and E-plane HPBW of the designed antenna are simulated as 86.7% and 138 degrees, respectively, which roughly agree with the measured results. (C) 2015 Wiley Periodicals, Inc.