Low Loss Multi-beam Terahertz Transmitarray Antenna for Remote Sensing

A low loss multi-beam transmitarray antenna (MBTA) working at 340 GHz is presented in this paper. In order to eliminate the substrate loss to the terahertz wave, a substrateless all metal unit cell using double hexagon ring slots is designed and calculated. The simulation results show that low transmission loss (mostly better than -1 dB) and full transmission phase range (360°) are achieved. A 14 × 20 focal plane multi-beam transmitarray fed by seven horn feeds is designed by using bifocal theory, which could effectively lower the scanning loss when the feed offset the center of the MBTA focal plane. The MBTA is simulated by commercial electromagnetic software Ansys 18.1, the simulation results show that scanning beams could cover from -15° to +15° with gains more than 25.3 dB, side lobe levels (SLL) lower than -19.3 dB and scanning loss superior to -0.6 dB The terahertz MBTA prototype is currently under fabrication, lithography and deep reactive ion etching (DRIE) processes will be applied to realize microfabrication of the prototype, the fabrication error could reach ±1 μm The microfabrication processes and measured results of the MBTA will be shown on the conference.