A Multi-Reconfigurable CLL-Loaded Planar Monopole Antenna

Abstract

In this paper, multi-reconfiguration capabilities of a planar monopole antenna with two switchable capacitively loaded loops (CLLs), as near field resonant parasitic elements, are introduced. The idea is to apply the CLLs not only to minimize the dimensions of the antenna, but also to present multiple resonances, which can be satisfactorily chosen by applying switches placed across six gaps of the CLLs. By changing the switched states, it is feasible to obtain different reconfigurations such as frequency agility (from 1.5 to 2.9 GHz), polarization diversity (with circular polarization bandwidth from 1.59 to 1.72 GHz), and various shapes of the radiation patterns and beam directions (change in the ±30° y-direction) of the antenna. The transmutation of polarization designs from their linear counterparts to left hand and right hand circular polarizations by introducing an asymmetry in the configuration of the two-CLLs is also represented. The prototypes of the proposed antenna are fabricated and tested. The measured reflection coefficient, radiation pattern, gain and axial ratio results are presented and compared to the corresponding simulated values.