W-band High-gain Hybrid-fed Microstrip Patch Array with Low Sidelobe Patterns

A W-band hybrid-fed mictrostrip patch array for advanced real-time imaging applications has been proposed in the article. It is fed by a novel hybrid feeding network with lower loss compared with the parallel-fed network. The proposed array is composed of 16 series-fed taper microstrip patch subarrays with Chebyshev amplitude tapering. The series-fed subarray is fed symmetrically in the midpoint to achieve non-dispersive patterns at different frequencies. In order to decrease the transmission loss, a hybrid feeding network is de-signed to replace the multi-level parallel one between series-fed subarrays. The tapering distribution is determined by the width of the quarter wave impedance transformer in the hybrid feeding network. Simulation results show that the antenna array achieves an impedance bandwidth of greater than 6 GHz and a gain of greater than 26.8 dBi. The side-lobe level of the pattern at the center frequency is -22.5 dB and -22.4 dB in E- and H-planes, respectively.