A Study of Metamaterial Based Electrically Small Antenna to Enhance Gain

This is a review paper in which electrically small metamaterial-based antennas are discussed from the industrial point of view using mobile phones as the application example and dual band microstrip antenna with metamaterial structure for dual band operation. The most interesting feature of the design is the ability of enhancing the gain and total efficiency of the antenna without affecting the other important parameters like bandwidth and directivity. The double negative (DNG) properties of metamaterial (-ɛ and -μ) have been proved by simulated S-parameters showing improved results in form of power gain and efficiency. Metamaterial (MTM) in antennas is proposed for better improvement in the impedance bandwidth and reduction in the return loss at operating frequencies. It appears that despite the interesting theoretical findings, the commercial acceptability of these antennas is low. Some of the issues possibly leading to this situation are addressed. Discussion topics range from challenging application environment, through the response of finite-size composite-material samples, all the way to the required constructive criticism and acknowledgement of prior art. Selected issues are discussed in more details, and proposals how to possibly improve the commercial acceptability of metamaterial-based antennas are made.