Broadband Circularly Polarized Crossed-Dipole Antenna With a Single Asymmetrical Cross-Loop

Abstract

This letter presents a broadband cavity-backed circularly polarized (CP) crossed-dipole antenna encircled by a novel asymmetrical cross-loop. By using the single parasitic cross-loop, the antenna has a simple structure and a compact configuration. More importantly, it produces additional two CP modes. The suitable combination of the crossed dipole and the crossloop provides broadband CP operation. The measured results show that the proposed antenna with an overall dimension of 1.1λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 1.1λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.28λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> (in terms of the CP center frequency) features broadband CP characteristics of an impedance bandwidth with S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> <; -10 dB from 3.14 to 6.34 GHz (67.5%) and a 3 dB axialratio bandwidth from 3.83 to 6.62 GHz (53.4%). A unidirectional right-hand circular-polarized radiation pattern with a peak gain of 10.62 dBi is achieved over the CP operating band.