Capacitively coupled electrical substitution for bolometers

A new method for electrical substitution was designed, implemented and evaluated with a 120 mum thick glass membrane gold layer resistive microbolometer. The method which allows space savings and time constant reduction is based on the usage of electrical substitution directly onto the sensing element thanks to capacitive coupling. Time constant and signal to noise ratio (SNR) were evaluated through measurements and compared for three configurations : open-loop, classical electrical substitution (ES) closed-loop and proposed capacitively coupled electrical substitution (CCES). Unlike classical ES, this new method can be applied to all existing resistive bolometers without material changes (extra heater).