Study on isolation and radiation behaviours of a 34 x 34 array-antennas based on SIW and metasurface properties for applications in terahertz band over 125-300 GHz

This paper describes the feasibility of conceptual design of a 34 x 34 array antenna for operation at Terahertz over a frequency range of 125-300 GHz for S-11 <= -10dB, which corresponds a fractional bandwidth of 82.35%. Each radiation element constituting the array consists of a square patch of dimensions of 2 x 2 mm(2) that are excited by a matched microstrip line. Each patch is isolated from each other with metallic via-holes, which are implemented based on the substrate integrated waveguide (SIW) technique. This technique is shown to effectively reduce mutual coupling between adjacent radiation elements that can otherwise undermine the arrays radiation gain and pattern. Periphery of each patch is embedded with circular dielectric slots, which are created based on the metasurface concept to enhance the radiation gain and efficiency performances. With the proposed approaches (1) the mutual coupling is suppressed on average by 25dB over its operating frequency range, and (2) the effective aperture area of the array antenna is extended without increase in the array's physical dimensions. Radiation gain and efficiency of the proposed array antenna over its operating range vary from 7.51 dBi to 40.08 dBi, and from 70.51% to 90.11%, respectively. Improvement in gain and efficiency of approximately 60% and 30%, respectively, is achieved with the inclusion of the metasurafce slots. The proposed 34 x 34 array antenna is proper candidate for applications in Terahertz wireless communication systems.