Broadening the beam-width of microstrip antenna by the induced vertical currents

In this study, a method to broaden the beamwidth of an aperture couple feed microstrip antenna is investigated. Two metal walls are put at the bilateral sides of an original microstrip antenna in the E-plane (xoz-plane). The vertical current on the metal walls is induced by E-field from the horizontal current on the radiating patch of the microstrip antenna. The beamwidth of the antenna is broadened by both the horizontal and vertical currents. A novel wide beamwidth aperture couple feed microstrip antenna (WBMA) is designed according to the proposed method. The simulated and measured reflection coefficients and radiation patterns of the WBMA are presented and compared with the original microstrip antenna. Compared with the original microstrip antenna, the half-power beamwidth (HPBW) is obviously improved, which the HPBW is 236� in the E-plane and 124� in the H-plane at 9.0 GHz. Good radiation characteristics of the new structure antenna have been obtained in the whole operating frequency band.