Compact Multifrequency Slot Antenna Design Incorporating Embedded Arc-Strip

A compact coplanar waveguide (CPW)-fed multifrequency circular slot antenna design loaded with arc-shaped metallic strips is investigated and verified in this letter. The proposed design implemented on a 0.8-mm FR-4 substrate shows that the arc-shaped metallic strips yield the multiple resonant modes for multiband vision. Unlike other multifrequency antennas whose sizes are determined by the lower resonant frequency, the compact size of the proposed slot is determined by the upper resonant frequency. Other operating frequencies are obtained by inserting arc-shaped metallic strips without increasing the overall antenna area. The prototype for different applications examined by modifying the angles of the arc-shaped metallic strips reveals that the input impedance bandwidths of the operating frequencies range from 5.0% to 64.7%. Moreover, these operating resonant bands exhibit the broadside radiation patterns with efficiency better than 45%.