An Inverse Class-F Circularly Polarized Active Integrated Antenna

In this paper, an inverse Class-F circularly polarized (CP) active integrated antenna is proposed. In the design, a Lshaped slot is etched in the radiating patch, which achieves circular polarization for the antenna. Subsequently, a defected ground structure (DGS) and two T-shaped slits are introduced in the CP antenna to suppress the second and third harmonics, which make the antenna an inverse Class-F load. Finally, the proposed CP antenna is directly integrated with the power amplifier (PA), which allows the PA to operate in the inverse Class-F mode, thus improving the power-added efficiency (PAE) of the PA. The inverse Class-F AIA can obtain a PAE of 73.01% and an output power of 41 dBm at 2.45 GHz.