A Three-dimensional Compact Propeller-shaped Circularly Polarized Ceiling Antenna

Abstract

A three-dimensional compact propeller-shaped circularly polarized ceiling-mounted antenna loaded by inverted L-shaped slot is proposed in this paper. This three-dimensional structure has a small size, single feed and half-plane radiation mode. The antenna is composed of four alternately welded radiating elements and a disc reflector. Each radiating element is formed by etching a rectangular microstrip radiating patch and a trapezoidal microstrip radiating patch on the surface of the substrate. The four radiating elements are welded vertically on the disc reflector. The back of the disc reflector has the ground plane. The antenna is fed coaxially through the via in the center of the disc reflector. The result demonstrates that the 10-dB impedance fractional bandwidth achieves 66.3% (4.4-8.94 GHz). The 3-dB axial ratio fractional bandwidth is 2.2% (6.44-6.58 GHz). The radiation characteristic is close to half-space radiation on the xoz plane and the yoz plane. The peak gain of the antenna is 3.22 dBi. The simulation and measurement results are in good agreement. With its compact structure, effective coverage, miniaturization, etc., the antenna is very suitable for applications such as biomedical monitoring equipment and short-rangeradio communications.