A 28-GHz MMID Frontend in 90-nm CMOS for Miniature Wireless Sensors

In this work, a 28-GHz millimeter-wave identification (MMID) frontend implemented in 90-nm CMOS for wireless sensors is presented. The MMID frontend consists of a rectifier and a modulator. The feature of the proposed MMID frontend is that the functions of modulation and impedance matching are combined in one circuit. In dormant mode, the measured input return loss (IRL) of the MMID frontend is greater than 10 dB from 26.5 to 34.1 GHz. At 28 GHz, the measured IRL is 1.8 dB and 13.3 dB for the modulated transistors being on and off, respectively, corresponding to an on-off ratio of 11.5 dB for the backscattered power. With −2-dBm input power at 28 GHz, the measured DC output voltage reaches 1.2 V, which is high enough for 90-nm CMOS circuits to function.