Abstract: This paper describes the design and packaged measurement results of a W-band high sensitivity power de tector . The proposed detector is developed in a standard 0. 1μm GaAs pHEMT technology. The measured results of packaged module indicate that when the input power of RF signal is -15 dBm, the voltage sensitivity is better than 6000mV/ mW from 90GHz to 95GHz. The module achieves a good wide-band performance, and the span of the operation frequency covers from 86GH to 100GHz which are extensively used in common W band applications. In addition, this chip has a compact structure which occupies 2×1mm² , making it an ideal candidate for high density RF front-end integration.