A Two-Channel 8–20-GHz SiGe BiCMOS Receiver With Selectable IFs for Multibeam Phased-Array Digital Beamforming Applications

An 8-20-GHz two-channel SiGe BiCMOS receiver is presented for digital beam-forming applications. The receiver is based on a dual-down-conversion architecture with selectable IF for interference mitigation and results in a channel gain (in-phase and quadrature paths) of 46-47 dB at 11-15 GHz and >;36 dB at 8-20 GHz with an instantaneous bandwidth of 150 MHz. A 2-bit gain control (0-16 dB) is also provided at baseband. The mea sured noise figure (NF) is <;4.1 dB (3.1 dB at 15-16 GHz) and is independent of the gain state. The measured OPldB is -10 dBm and the input PldB is -56 to -40 dBm at 15 GHz depending on the gain, which is sufficient for satellite applications. The on-chip channel-to-channel coupling is <; -48 dB. The measured evanescent mode is <;3% for a 1-Ms/s quadrature phase-shift keying (QPSK) modulation at 8-20 GHz, and <;1.8% for a 0.1-, 1-, and 10-Ms/s QPSK, 16 quadrature amplitude modulation (QAM), and 64-QAM modulations at 15 GHz. The chip is fabricated using a 0.18-μm SiGe BiCMOS process, has electrostatic discharge protection on the RF and dc pads, consumes 70 mA per channel from a 3.0-V power supply, and is 2.6 × 2.2 mm
²
, including all pads. A 15-GHz eight-element phased array with an NF <;3.8 dB is also demonstrated with multiple simultaneous beam performance. To our knowledge, this is the first two-channel 8-20-GHz beam-forming chip in SiGe BiCMOS technology.