Micrometer-Accuracy Distance Measurement using 122 GHz LTCC Radar System-in-Package

In this paper, a 122 GHz Low Temperature Co-fired Ceramic (LTCC) technology based radar system-in-package (SiP) is used to measure short distances with an accuracy of a few micrometers. At the core of the radar SiP, lies a silicon-germanium transceiver chip with 6.5 GHz bandwidth. The off-chip antennas required for transmitting and receiving a 122 GHz signal as well as the package, which serves as an interface between the millimeter-wave and baseband circuitry are realized in LTCC technology. The radar SiP is surface-mounted on a baseband module, which drives the radar in a frequency modulated continuous wave mode. The radar is used to measure distances of the order of a few meters and a micrometer accuracy is achieved by combining the principles of frequency and phase evaluation.