The ADAR1000 is a 4-channel, X and Ku frequency band, beamforming core chip for phased arrays. This device operates in half-duplex between receive and transmit modes. In receive mode, input signals pass through four receive channels and are combined and output at the common RF_IO pin. In transmit mode, the RF_IO input signal is split and passes through the four transmit channels. In both modes, the ADAR1000 provides a ≥31 dB gain adjustment range and a full 360° phase adjustment range in each radio frequency (RF) channel, with 6-bit resolution (less than ≤0.5 dB and 2.8°, respectively).A simple 4-wire serial port interface (SPI) controls all of the on-chip registers. In addition, two address pins allow SPI control of up to four devices on the same serial lines. Dedicated transmit and receive load pins also provide synchronization of all ADAR1000 chips in the same array, and a single pin controls fast switching between the transmit and receive modes.The ADAR1000 is fabricated in a silicon-germanium, bipolar CMOS (BiCMOS) process. The device is available in a compact, 88-terminal, 7 mm × 7 mm, LGA package and is specified from −40°C to +85°C.APPLICATIONSPhased array radarSatellite communications systems