Reconfigurable 1-bit Fixed-Frequency Beam-Scanning Array With Ultra-Thin Thickness and Small Cross Section Using Microstrip Line as Phase Shifters

Reconfigurable bit array offers a cost-effective and low-loss solution for beam scanning. This communication proposes a reconfigurable 1-bit fixed-frequency beam-scanning array using a long microstrip line as the excitation source and phase shifters simultaneously, leading to the merits of ultra-thin thickness and small cross section. The reconfigurable 1-bit unit consists of two symmetric open cavities. Two rows of p-i-n diodes are located between the radiating elements and microstrip line to obtain 1-bit quantized phases (0°/180°). The isotropic array is simulated using MATLAB to obtain an appropriate unit spacing of 16 mm at 5 GHz. A 16-unit reconfigurable 1-bit beam-scanning array at 5 GHz is fabricated. The results indicate that the proposed reconfigurable 1-bit array achieves a scanning range of 92° from −43° to 49° with the maximum peak gain of 10.7 dBi and a scan loss of only 2.2 dB. All the cross-polarized levels are better than 13 dB and the average sidelobe is 5.6 dB. Benefiting from the use of the microstrip line without extra phase shifter, the width of the antenna array is less than λ₀ and the profile is only 0.04λ₀ . The proposed design has great potential for beam-scanning application in restricted space.