Compact dual band circularly polarized meta‐structured antenna for GPS application

Abstract

AbstractIn 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° 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 λ0 by 0.14 λ0 (krground = 1.28) at L2 band. The measured results show a good agreement with those of simulations.