Active reflector tag for millimeter wave harmonic radar at 61/122 GHz ISM Band Based on 130 nm-BiCMOS SiGe:C Technology

This paper presents a nonlinear reflector suitable for operation in a harmonic radar at 61/122 GHz ISM band. The challenges for high dynamic range measurements are pointed out to undermine the advantages of active tags at this frequency range. The active tag is based on a MMIC fabricated in a modern 130 nm SiGe:C BiCMOS technology. On the MMIC gain stages and a frequency doubler for the frequency translation are implemented. Measurements are presented to characterize the conversion gain of the MMIC itself and the entire tag respectively. The impulse response of the tag is measured by emulating the FMCW transceiver with a VNA. For a sweep of 2 GHz the tag shows a spatial resolution of 9.8 cm. The MMIC has a power conversion gain of 31 dB for -41 dBm input power at 61 GHz. It consumes 40 mA at a 3.3 V supply. With these characteristics the tag enables high accuracy harmonic radar applications in the millimeter wave range.