High-Gain, Circularly-Polarized THz Antenna With Proper Modeling of Structures With Thin Metallic Walls

In the paper, a corporate feed antenna array with slot radiators and a layer of polarizing patches is designed to operate at 350 GHz. The antenna is conceived as a silicon structure fully metalized by gold. Different methods for modeling thin gold layers at terahertz frequencies are compared and the optimum approaches are chosen depending on the thickness of the metal layer and its relation to the skin depth. Two designed antenna arrays are in 2 x 2 and 4 x 4 configuration, radiate circularly polarized waves, and have high gains of 13.8 dBic and 18.4 dBic, respectively. Antenna arrays have a low profile of only 1.3 lambda(0). Cheaper and more available manufacturing technology is presented and discussed in detail together with the measurement results of three manufactured prototypes. Small deviations between the simulated results and the measured ones are obtained due to a lower surface roughness, which is confirmed by the scanning probe microscope. Comparison with state-of-the-art antenna arrays demonstrates that the proposed arrays excel in easy/lowcost manufacturing, high gain, circular polarization with good axial-ratio bandwidth, compact size, and the possibility to easily extend the array into a larger version.