Compact wideband printed antenna with circularly polarized tilted beam radiation using a Quasi-Radiator

Abstract

This paper presents a new compact wideband printed antenna with circularly polarized (CP) tilted beam radiation using a quasi-radiator. To achieve size compactness and tilted CP performance, the radiation patch of a conventional monopole is loaded by a fork-slot, and a shorting via is used to connect the corners of rectangular patch and partial ground plane together. The fabricated prototype has an |S11| < −10 dB of 60.9% (1.2–2.25 GHz), an AR < 3 dB of 25.7% (1.55–2 GHz), a peak gain of 3.7 dBi, a compact size of 0.186λ0 × 0.186λ0 × 0.008λ0 at the lowest frequency with CP radiation, a right-handed CP beam at θ = −42°, and a left-handed CP radiation at θ = −134° in the elevation plane. The antenna is analyzed using characteristic mode analysis (CMA) to figure out the orthogonal modes and working principle of CP radiation. The antenna benefits include low-profile, simple structure, easy fabrication, large tilt angle, and stable radiation patterns over entire bandwidth.