A 200 GHz Switchable Beam-Steering Phased Array Using Lens-Coupled Annular-Slot Antennas

We report the design and simulation of a THz switchable beam-steering phased array using lens-coupled annular-slot antennas (ASA). For a prototype demonstration, the antenna employed was designed on a high resistivity Si substrate with a radius of 106 um, and a gap width of 6 um (with return loss of 31.8 dB, and 10 dB bandwidth of 13%) for operation at 200 GHz. To achieve a reasonably low side lobe level, a 1×5 array with an element spacing of 0.56λ is utilized. The array is then attached to an extended hemi-spherical Si lens with a radius of 5 mm for high antenna efficiency in the THz region and the succeeding antenna elements are fed by a Nolen matrix and a high performance optically controlled switch network. By switching the input ports of the Nolen matrix, equal magnitude and unique progressive phase difference can be generated for feeding the antennas and steering the antenna beam. The simulation results show that five different beam angles (i.e., -33°, -15°, 0°, 15°, 33°) with the gain of around 15 dB can be achieved. The lens-coupled phased array has great potentials for advanced THz imaging and communication applications.