Parasitically Loaded CPW-Fed Monopole Antenna for Broadband Operation

The performance of a low-profile coplanar waveguide (CPW)-fed monopole antenna comprising of a straight strip, a parasitic circular-hat patch, and a slotted CPW ground for broadband operation is presented. In this design, use of both the parasitic patch and the embedded ground slots is found an effective skill for intensively exciting dual resonant modes as well as improving the overall impedance bandwidth. The tuning effects of the ground size, the parasitic patch, and the ground slots to the resonance and matching condition were examined, and prototype of the proposed antenna had been constructed and experimentally studied. A measured dual-frequency operation with a broad impedance bandwidth (10 dB return loss) of 77% from 3.4-7.62 GHz, covering the required bandwidths of the lower operating band of the Japan's ultrawideband (UWB), the 3.5/5.5 GHz WiMAX, and the 5.2/5.8 GHz WLAN standards, has finally been explored. Also, a stable monopole-like radiation pattern and an average antenna gain of 4.0 dBi across the operating band have been obtained.