“…The test of high frequency analog circuits is a challenging task, as the presence of a defect or the effects of process-voltage-temperature variations and device aging, does not usually produce a catastrophic circuit failure, but a degradation of circuit performance and specifications [ 21 , 22 , 23 , 24 , 25 ], which compromises yield. A strategy to compensate these performance degradations is to build in monitor circuits with the analog circuit (called hereafter the circuit under test (CUT)) to track variations in their performance [ 26 , 27 , 28 , 29 , 30 ] and, in the eventual case of detecting a circuit degradation, to activate a feedback in the CUT bias to compensate for them. Recently, several studies have proved that by measuring the temperature in a surface point near the CUT, it is feasible to monitor the performances of radio frequency (RF) and millimeter wave (mmW) circuits [ 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 ] or the presence of structural defects [ 38 , 39 ].…”