Metamaterial Assisted Multi-Wide Band Electrically Small Antennas

Metamaterials have gained significant interest in antenna technology nowadays due to their exceptional features. This article presents metamaterial (MTM) based two new antennas with a vision to precisely enhance the number of bands and maintain a suitable bandwidth level. A sequential rise in band numbers from 2 to 4 and then to 5 is noticed by the applications of split-ring resonator (SRR) and complementary structure of dual negative metamaterial (dual NG-MTM) in a standard patch antenna. Initially, a dual NG-MTM was attached at the back of the patch antenna and it presented four separate bands at 2 GHz, 6.8 GHz, 9.1 GHz, and 9.6 GHz, respectively with comparatively larger bandwidth. At last, inclusion of an SRR takes the band-width to another level in addition to providing five bands and its electrical size is then compact as 0.22λ<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</inf> × 0.19λ<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</inf> × 0.0006λ<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</inf>, with a ka (antenna size indicator) value of less than 1. These extraordinary features of the above-mentioned MTM antennas lead to promising applications including television broadcasting and 5G system.