Antipodal Vivaldi Antenna with enhanced gain and improved radiation patterns for 5G-IoT applications using metamaterial and Substrate Integrated Waveguide

An analysis of a novel antipodal Vivaldi antenna (AVA) with constant high gain and enhanced radiation patterns is presented in this paper. The antenna consists of a 1 × 4 AVA array, fed by substrate integrated waveguide (SIW). Next, the corrugations are added to the AVA array with SIW (AVAS) to increase the gain up to 1.5 dBi. Further gain enhancement and radiation pattern improvement are achieved by incorporating square-shaped split-ring resonator (SRR) metamaterial at the aperture of the AVAS array with corrugations (AVAS-C). The designed AVAS-C array with metamaterial (AVAS-CM) provides an enhanced gain of 16.2 ± 0.8 dBi over the 37.9 GHz to 45 GHz frequency range. Also, the proposed AVAS-CM array gives stable radiation patterns. Its front-to-back ratio (FBR) is above 21.3 dB, the sidelobe level (SLL) is below −13.6 dB, and E-plane beam titling is ±1∘. In compact devices, an antenna with low FBR and SLLs is essential to avoid radiations in the wanted directions to alleviate the degradation of electronic components. This paper presents the first time use of the SIW technique for improving the radiation pattern characteristics of the AVA array. Experimental and simulated results show that it is suitable for compact 5G-IoT devices.