2-Bit reconfigurable circularly-polarized unit-cell at Ka-band

We present here the design and numerical results of a circularly-polarized electronically reconfigurable unit-cell with a 2-bit phase resolution. This unit-cell, whose size (length χ width χ height) is 5.1×5.1×1.3 mm ³ , operates at Ka-band. It comprises six metal layers printed on three RT/Duroid 6002 dielectric substrates and two bonding films. Four p-i-n diodes are soldered on the two radiating elements printed on the top and bottom layers of the dielectric stack in order to control the transmission phase. Thus 0°, 90°, 180°, and 270° phase states are achieved by properly switching the p-i-n diodes. Fractional 3-dB transmission bandwidths of 10.3%, 12.4%, 9.7%, and 13.1% have been achieved at 29 GHz for the 0°, 90°, 180°, and 270° phase states, respectively; while the insertion losses at 29 GHz varies between 1.1 dB and 1.3 dB.