Compact multi-band loop antennas using CPW-based CRLH quarter-wave type resonators

Abstract

In this paper, a novel approach to design compact multi-band loop antennas is proposed. This type of antennas is composed of coplanar waveguide (CPW)-based composite right/left- handed (CRLH) quarter-wave type resonators, and developed on a vialess single layer. Both size reduction and low frequency ratios have been achieved, profiting from the employment of quarter-wave resonators and the high nonlinearity in the left-handed region of CRLH transmission line (TL) dispersion diagram. A sample prototype operating at three negative modes (1.92/2.15/2.64 GHz) with an overall size of 29 × 21.3 × 1.0mm3 was manufactured and measured. Measured results show good agreement with EM simulation, exhibiting good impedance matching as well as stably omni-directional radiation patterns at the three operating modes.