The RFE is an integrated transceiver circuit for the 122-GHz ISM band with antennas in QFN 8x8 package. It includes a low-noise amplifier (LNA), quadrature mixers, a poly-phase filter, a voltage controlled oscillator, divide-by-32 outputs and transmit and receive antennas. The RF signal from the oscillator is directed to the RX path via buffer circuits. The RX signal is amplified by the LNA and converted to the baseband by two mixers with quadrature local oscillator (LO). The 120-GHz LO has four analog tuning inputs with different tuning ranges and tuning slopes. The tuning inputs can be combined to obtain a wide frequency tuning range. The analog tuning inputs together with integrated frequency divider and external fractional-N PLL can be used for frequency modulated continuous wave (FMCW) radar operation. With fixed oscillator frequency it can be used in continuous wave (CW) mode. Other modulation schemes are possible as well by utilizing analog tuning inputs. The IC is fabricated in SG13S SiGe BiCMOS technology of IHP GmbH .
The main application field of the 120-GHz transceiver radar frontend is in short range radar systems with a range up to some 10 meters. By using dielectric lenses, the range can be increased considerably. The RFE can be used in FMCW mode as well as in CW mode. Although the chip is intended for use in the ISM band 122 GHz - 123 GHz, it is also possible to extend the bandwidth to the full tuning range of 7 GHz.
What is the covered area / the fild of view?
The area covered by the radar over distance is dependent on the field of view of the sensor. Without lens the sensor has an opening angle of +/-30 degrees (-6dB), with lens this can be narrowed to about +/- 2 degrees.