Design of CPW-Fed Circularly Polarized Slot Antenna With a Miniature Configuration

This letter proposes the design of a new miniaturized circularly polarized (CP) printed square slot antenna (PSSA) fed by a coplanar waveguide (CPW). The characteristics of the design are that the CP operation and impedance matching can be independently achieved. The 3-dB axial-ratio band can be excited by protruding into the slot a halberd-shaped metal strip from the signal line of the CPW, whereas the VSWR ≤ 2 impedance band can be produced by implanting in the slot a grounded asymmetric inverted-T strip. Design rules established for the proposed antenna can effectively reduce the sizes of the ground plane and the slot.