A 79-GHz LTCC RF-frontend for short-range applications

An RF-frontend based on low temperature co-fired ceramic (LTCC) technology is presented in this paper. The frontend is designed for the 76 - 81 GHz frequency band, using high-permittivity material (ε_r = 7.4) and a 4-channel transceiver chip based on SiGe technology. A bond matching structure was designed with two-stage quarter-wavelength transformer, and a laminated waveguide (LWG) was chosen as transmission line in LTCC. A transition transfers energy from the differential microstrip lines into the LWG. An LWG-fed patch array antenna acts as transmit and receive antenna. A frequency-modulated continuous-wave radar sensor was built with the frontend in combination with a baseband board. The functionally of the RF-frontend was verified by distance measurements. This compact, low-cost LTCC frontend is suitable for short-range applications.