A Compact Triple-Band and Dual-Sense Circularly Polarized Truncated Patch Antenna

A triple-band dual-sense circularly polarized truncated patch antenna is proposed. The truncated patch is fed by the aperture etched on the ground plane. Firstly, a $y$ -axis directional rectangular slot is introduced in the truncated patch to excite two orthogonal modes for left hand circular polarization(LHCP). Then an $x$ -axis directional rectangular slot is employed to obtain right hand circular polarization (RHCP) performance. After that, one parasitic stub is loaded in the central of the $x$ -axis directional rectangular slot, thus, an extra RHCP can be realized. Finally, the other parasitic stub is loaded beneath the truncated patch to improve the impedance and axial ratio performances. The etched slots and loaded stubs technologies are used in a single radiating patch to realize different senses at three different operating bands. And the senses and operating bands can be controlled by tuning according slots and stubs. Consequently, a compact triple-band dual-sense circularly polarized antenna is successfully designed. The 3-dB axial-ratio bandwidths of the proposed antenna are 2.6% (3.55-3.64 GHz), 0.24% (4.175-4.185 GHz), and 0.47% (4.26-4.28 GHz), respectively.