Circularly Polarized Defected Ground Broadband Antennas for Wireless Communication Applications

In this chapter a broadband antenna with defected ground is proposed for mobile (1.9–2.1 GHz), Wireless LAN (2.4 GHz) and Bluetooth (2.4–2.45 GHz) applications. The proposed antenna exhibits circular polarization in the range of 2.2–2.45 GHz with axial ratio less than 3 dB. A modified ground structure antenna is also proposed in this work for notching the band between (2.2–2.45 GHz). Antenna model 1 with circular polarization is providing impedance bandwidth of 32% and Antenna model 2 with linear polarization is providing impedance bandwidth of 25% (1.7–2.2 GHz) at fundamental resonant frequency and 16% (2.5–2.9 GHz) at second resonant frequency. The axial ratio bandwidth for circularly polarized antenna is around 38%. The designed antennas are providing peak realized gain of more than 5 dB in the operating bands and showing excellent monopole like radiation patterns with good impedance matching.