Reconfigurable 2-bit Fixed-Frequency Beam Steering Array Based on Microstrip Line

In this paper, the scanning performance at a fixed frequency of the 2-bit linear array is presented. Then, for the first time, a microstrip line that supports a traveling wave is used as bit phase sources with any bit number to construct reconfigurable fixed-frequency beam steering bit arrays. Using the TM 1n0 (n = 0.5) open cavity as the radiating element, a ten-element reconfigurable 2-bit fixed-frequency beam steering array operating at 5 GHz is designed and fabricated to verify the idea. By sampling two feed points with a separation distance of a quarter wavelength on one side of the microstrip line, the phase states of 0° and -90° are obtained; other two counterpart points on the other side of the line can offer the phase states of -180° and -270°, producing the required 2-bit unit. Five prototypes representing five array configurations show a measured scan range of 94° between -48° and +46° at 5 GHz, and the measured five beams show good quality and consistency: the peak gains range from 10.01 to 12.33 dBi with a gain variation of only 2.32 dB and the 3 dB beam widths vary between 13° and 17°.