This work presents a gate-driven fully-differential inverter-based Operational Transconductance Amplifier (OTA) with a proper body bias using both rectangular transistor arrays (RTA) and improved composite transistors (ICT). Two versions of the same OTA were designed and compared with post-layout simulations referring to a 180 nm CMOS process. Simulation results show that the RTA OTA version has a 38 dB voltage gain, achieves a 1.1 kHz GBW for a 10 pF load, and consumes 970 pW total power for a 0.3 V supply voltage. The ICT OTA version shows better performance resulting in 48 dB voltage gain, 0.91 kHz GBW for a 10 pF load, and 810 pW total power consumption for a 0.3 V supply voltage.