Design of a K-band wideband controlled variable attenuator for microwave Built-In-Self-Test applications

This paper presents a new microwave wideband controlled variable attenuator designed in a BiCMOS process. This variable attenuator is implanted as part of a microwave Built-In-Self-Test (BIST) circuit. The proposed BIST cell is dedicated for direct low cost measurement of the gain and the input 1dB compression point (CP1) of a K-band satellite reception chain (18.2 GHz-22 GHz). The simulation of the controlled variable attenuator with RLCk parasitic extraction shows that it can operate up to 100 GHz with a consumption of 4 mA, an area less than 0.009 mm² excluding pads and a gain range of 36 dB when the attenuator is alone and 17 dB when it is concatenated to the other blocks. This result was confirmed with the performed measurement on the BIST device. This BIST circuit gives new perspectives in term of test strategy, cost reduction and measurement accuracy for mm-wave integrated circuits.