Left-handed medium effect on the characteristics of a circular patch antenna

Much work on the improvement of the performance of patch antennas has been published. Most of the solutions proposed use an array of several antennas. The main disadvantages of this method come from the feeding of each antenna and from the coupling between each element. Our study shows that enhancement of the performance of a patch antenna is possible without the use of an array of several elements. The approach described makes use of a left-handed medium (LHM) placed above a single patch antenna. A homogenization procedure of the LHM has been done in order to extract its effective parameters. These parameters have then been used in order to design a patch working at a frequency where the LHM presents low losses. An improvement of the gain by 2.8 dB is achieved and a more directional antenna is obtained. For such an improvement, two antennas would have to be used and, hence, we have avoided the feeding and inter-element coupling problems. In the case of a LHM with lower losses, the gain of the antenna is about 12 dB.