COMPACT SINGLE-FEED CIRCULARLY POLARIZED APERTURE-COUPLED STACK ANTENNA WITH MINKOWSKIISLAND-BASED FRACTAL PATCH

摘要

The authors propose a compact single-feed stack antenna consisting of a Minkowski-island-based (MIB) fractal patch with perturbation, an aperture-coupled structure, and a straight-strip feed line for circular polarization (CP) and unidirectional radiation applications. The MIB fractal configuration with second-order iteration is embedded in the patch for miniaturization. The size reduction of 39.1% is achieved in contrast to the typical patch antenna. This fractal structure applies both dual-mode and orthogonal mode effects simultaneously in the square patch to present bandwidth (BW) and CP characteristics. The stack antenna presents the desired axial ratio (AR) bands of 2.44 GHz with 3-dB BW = 30 MHz (1.2%). The CP is demonstrated with AR spectrum, orthogonal modes distributions, and phase difference. The proposed antenna is successfully simulated and measured with frequency responses, radiation patterns, and current distributions.