Millimeter-Wave Wafer-Scale Silicon BiCMOS Power Amplifiers Using Free-Space Power Combining

This paper presents the first millimeter-wave wafer-scale power-amplifier array implemented in a 0.13-m BiCMOS technology. The power combining is done in the free-space using high efficiency on-chip antennas. A 3 x 3 power-amplifier array is demonstrated with an equivalent isotropic radiated power of 33-35 dBm at 90-98 GHz. This results in a total on-chip power of 21-23 dBm and a total radiated power of 17.5-19.5 dBm. The measured patterns of the array show single-mode operation and similar to 100% free-space power-combining efficiency with a 3-dB beamwidth of 28 and a directivity of 15.5 dB (gain of 12 dB). The total power-combining efficiency including the antenna losses is 45+/-10%. The application areas are in millimeter-wave transmitters and wafer-scale phased arrays.