Design of a Circularly Polarized Broadband Slot Antenna for Base Station
Applications
Abstract
In this paper, a circularly polarized broadband slot antenna is designed
for base station applications. The antenna is built on a square-shaped
FR4 epoxy substrate that measures 60mm in length and 1mm in height with
a relative permittivity of 4.4. The ground plane has a recessed slot,
and the feeding mechanism employs an offset microstrip line. The slot
enables circular polarization and optimal impedance matching, which are
enhanced further by offset feeding and the addition of stubs to create a
composite-shaped patch. With an impedance bandwidth of 106% (1.28
GHz-4.16 GHz) and an axial ratio bandwidth of 69% (1.71 GHz-3.51 GHz),
the CP broadband slot antenna effectively covers popular mobile
communication bands such as GSM 1800, GSM 1900, 3G/LTE 2100, 3G/LTE
2300, 4G/LTE 2500, and 2.4 GHz Wi-Fi bands. The maximum gain is
simulated to be 3.5 dB.Â