Power detector chip design and fabrication have experienced significant advancement with the emergence of various technological processes such as BiCMOS and CMOS.With the continuous downscaling of semiconductor devices, chip fabrication has become more complex and less accessible. This paper investigates the design and analysis of RMS power detectors using power MOSFET. A BSIM3 model developed from extracted parameters of the power MOSFET datasheet was employed to design and simulate the RMS power detector. A cascode structure with a current-source load was used to realize high conversion gain and sensitivity. RMS detection is realized by exploiting the square-law principles of MOS transistors in the strong inversion region. The proposed RMS detector targets practical applications in the agricultural sector and educational institutions. The RMS power detector was fabricated using FR4 PCB substrate. The measurement results at 2 GHz suggest that the RMS power detector employed using power MOSFET on FR4 PCB substrate can detect RF power.