An E-band high speed power detector MMIC using 0.1 μm pHEMT technology has been designed,manufactured and experimentally characterized.By employing a 4-way quadrature structure for phase cancellation,the first,second and third harmonics can be suppressed and the ripple at the output is minimized.Compared to conventional topology with a low pass filter,a short response time and high speed performance of demodulation can be reached.Simulated results indicate that the detector is capable of demodulating an on-off keying signal at a data rate up to 5 Gbps.The fabricated chip occupies 1×1.5 mm~2 and the on-wafer measurement shows a return loss of less than-15 dB,responsivity better than 700 mV/mW and dynamic range of more than 25 dB over 70 to 90 GHz. An E-band high speed power detector MMIC using 0.1 μm pHEMT technology has been designed, manufactured and experimentally characterized. By employing a 4-way quadrature structure for phase cancellation, the first, second and third harmonics can be suppressed and the ripple at the output is minimized. Compared to conventional topology with a low pass filter, a short response time and high speed performance of demodulation can be reached. Simulated results that that the detector is capable of demodulating an on-off keying signal at a data rate up to 5 Gbps. Fabricated chip occupies 1 × 1.5 mm ~ 2 and the on-wafer measurement shows a return loss of less than -15 dB, responsivity better than 700 mV / mW and dynamic range of more than 25 dB over 70 to 90 GHz .