A Ku-Band 8-Element Phased-Array Transmitter with Built-in-Self-Test Capability

An 8-elements Ku-band phased-array transmitter with built-in-self-test (BIST) capability is presented. A fully symmetrical coupler feed line is used to improve the accuracy of the BIST and calibration procedure. 5-bit phase shifters and 4-bit attenuators with less phase and amplitude errors are designed to control the beam direction and side lobes. The RMS phase and amplitude errors of the phase shifters are less than 3.6° and 0.8 dB, respectively. The RMS amplitude and phase errors of the attenuators are less than 0.94 dB and 3.2°. The measured single path power gain including the power divider is 11.9 dB. The output referred P1dB is 13 dBm for each channel. ESD protection and temperature sensors are integrated. The chip is fabricated in 180 nm bulk CMOS technology. Compact design is adopted to minimize the size of each channel, which is suitable for the large-scale phased-array system. The size of the whole chip is 8.5×3 mm², and that of each channel is 3.8×0.5 mm².