A Dual-Mode Widebeam Planar Antenna and Its Phased Array Applications

A novel dual-mode widebeam planar antenna is proposed to fulfill the requirements of wide-angle scanning phased array application. It consists of two parallel magnetic dipoles and one electric dipole. The magnetic dipole is a microstrip patch with three shorted edges and the electric dipole is a metal strip with fan-shaped loading. With the utilization of two magnetic dipoles, the bandwidth is enhanced compared to one magnetic dipole. The measured 10-dB impedance bandwidth is 5.3% (5.55-5.85GHz) and the 3 dB beamwidth in E-plane is more than 140° within the whole working band. An array composed of eight elements with 0.23 λ₀ spacing (λ₀ is the free space wavelength of central frequency) is also investigated. The main beam direction of the array can scan from -60° to 60° in E-plane with a gain fluctuation of less than 3 dB and the scanning 3 dB beam can cover a range from -76° to 78°. Good agreement between simulation and measurement is achieved.