E-band CMOS Built-in Self-Test Circuit Capable of Testing Active Antenna Impedance and Complex Channel Response

A novel built-in self-test (BIST) circuit is presented. The proposed BIST enables the testing of active antenna impedance and the VSWR resilient channel response. The technique is achieved simply by extracting the complex voltages at two nodes on a short-distance transmission line. For efficient implementation, a single-pole double-throw RF switch is used for sharing the signal detector, and the required switch on-off ratio is analyzed mathematically based on detection accuracy. The proposed BIST was experimentally verified with a test chip fabricated with a 40-nm bulk CMOS process. The measured magnitude and phase rms errors for the complex forward waves are less than 1.1dB and 2.5°, respectively, within 82-86GHz. In the impedance estimation test,
$\Gamma$
magnitude and phase rms errors are less than 0.1 and 17°, respectively, within 76-86GHz.