Integrated power measurement circuit for RF power amplifiers

A RF power measurement circuit, which operates on the same chip with an integrated RF power amplifier, is presented. The circuit is capable of measuring load variation dependent output power changes. Full integration saves the PCB area needed for the line coupler used in conventional power detection methods. The circuit was realised using GaAs MMIC technology and tested on a standard FR4 test board at 900 MHz. The circuit detects RF power in a range of 35 dB with a sensitivity of 0.8 V/W showing good agreement with the simulations.