Compact dual band circularly polarized meta-structured antenna forGPSapplication

Abstract

In this letter, a dual band circularly polarized (CP) meta-structured antenna is designed by -1 mode for L1 band and mu-zero resonance mode for L2 band, respectively. The antenna consists of two kinds of unit cells which have four unit elements for -1 mode and mu-zero resonance mode, respectively, in order to utilize the limited space efficiently, and to maximize the gain. Since two modes of -1 mode and mu-zero resonance mode operate like as loop antenna, these are fed by magnetic coupling of an aperture, simultaneously. In order to reduce mutual coupling between two modes, the orientation of -1 mode antennas are tilted by 45 degrees from that of MZR mode antennas. In this arrangement, magnetic fields with two directions are needed to excite all unit elements, simultaneously. Thus, a cross shaped asymmetric aperture is employed. The RHCP gain of the antenna is measured to be 0.59 dBic at L1 band and -0.02 dBic at L2 band, respectively. The size of the antenna is only 0.14 lambda(0)by 0.14 lambda(0)(kr(ground)= 1.28) at L2 band. The measured results show a good agreement with those of simulations.