Low-Cost Reconfigurable 1 bit Millimeter-Wave Array Antenna for Mobile Terminals

A reconfigurable 1 bit millimeter-wave array antenna for mobile terminals is investigated. The reconfigurable array antenna consists of four reconfigurable 1 bit microstrip patch antenna elements. Each patch antenna element is fed by a slot on the ground. The 1 bit patch antenna element with phase values of -pi and 0 is achieved by selecting the feeding direction of microstrip line. After analyzing the performance of the 1 bit four-element array, a fixed phase is applied to mitigate the negative effects of the 1 bit phase quantized error. The 1 bit four-element arrays with and without the fixed phases are compared in detail. The overlapped -10 dB impedance bandwidth of a prototype array at different beam directions reaches 3 GHz (25-28 GHz). Within the frequency range of 26-28 GHz, the array with the fixed phases can steer the main beam from -34 degrees to 35 degrees without grating lobes. Within these steering beams, the performances of good array gain, moderate sidelobe level, and low cross-polarization level are achieved.