Abstract: A new design of infrared thermopiles based on closed membrane with an additional metal-reflective layer is demonstrated. The additional reflective coatings increase the sensor’ s sensitivity and detectivity by reflecting and transferring the heat absorbed in the cold region to the surrounding air. This design largely improves the system reliability. It decreases instability of the sensor’ s parameters resulting from ambient temperature drifting, and thus improves the anti-jamming ability of the whole system.