A Broadband Artificial Material for Gain Enhancement of Antipodal Tapered Slot Antenna

A broadband artificial material composed of non-resonant parallel-line unit cells is proposed to enhance the gain of an antipodal tapered slot antenna (ATSA). The artificial material, whose effective refractive index is lower than that of the substrate on which the antenna is printed, will act as a regular lens in beam focusing. In order to investigate the gain enhancement effect of the material, a combination of the proposed material with an ATSA is made by locating the material in front of the antenna. Simulation results indicate that the gain of the antenna has been enhanced significantly and increasing the dimension of the material in the radiation direction leads to a higher gain without destroying its broadband characteristic. The original and the artificial material loaded ATSAs are designed and fabricated with the measurement results showing that the gain of the original ATSA has been increased by 1.3-3.6 dB in the measurement bandwidth of 6-19 GHz.