Built-in self test systems for silicon-based phased arrays

Phased array silicon chips with built-in-self-test (BIST) have been demonstrated at X-band and W-band using integrated couplers and on-chip receiver circuitry. In the X-band chip (2-element phased array), a dedicated I/Q receiver is built into the chip, while in the W-band case (self-contained 16-element array), the standard I/Q receiver is used for BIST functionality. The BIST is accomplished using a very low loss coupler at the input of each channel which does not introduce additional loss and noise. Measurements on the X-band and W-band chips indicate that BIST results in accurate phase and gain measurements for every phased-array channel on the chip, and allows the measurement of an on-chip array factor, all at microsecond speeds. The BIST can also measure the frequency response of every channel. It is expected that BIST functionality will greatly reduce the cost of phased array testing and allow for on-site calibration and control.