Prediction of radiation patterns of the CRLH leaky-wave antennas by different approaches

In this paper, new approaches for predicting the radiation patterns of composite right/left-handed (CRLH) leaky-wave antenna (LWA) are proposed and compared with the conventional approaches. The conventional approach for fast calculating the scanning angle of main beam, as well as the conventional array factor (AF) approach based on isotropic point sources for calculating the radiation pattern, has low accuracy when the scanning angle or observing angle approaches to the axial directions. To solve this problem, an improved AF approach is proposed, which has taken into account the influence of non-isotropic point source in each period of the CRLH structure. In addition, a traveling-wave line-source approach is also presented, which is very simple but efficient and accurate for the computation of the radiation patterns of CRLH LWAs.