Aperture coupled microstrip antenna for circular polarization and maximum coupling

This paper presents design and simulation of aperture coupled microstrip antenna for circular polarization and maximum coupling. The glass epoxy (ε
_r
= 4.3) is selected as the dielectric substrate for the patch as well as the quadrature hybrid coupler feed. The antenna is designed for a center frequency of 915 MHz with a bandwidth of 26 MHz in the unlicensed ISM band of (902-928) MHz for RFID applications. The antenna is modeled using ADS 2002C from Agilent Technologies. Antenna performance characteristics like VSWR, return loss, impedance bandwidth, gain, 3 dB beam width and radiated power are determined.