Infrared thermal sensor with good SNR

A method of designing an infrared thermal sensor, the method comprising:

• a) defining an infrared thermal sensor comprising a substrate and a cap structure together forming a sealed cavity, a membrane arranged in the cavity for receiving infrared radiation through a window or aperture;
• b) determining a number and geometry of beams to be arranged between the substrate and the membrane for suspending the membrane, and determining a number and geometry of thermocouples to be arranged on said beams for measuring a temperature difference between the membrane and the substrate, in such a way that the ratio of the thermal resistance between the membrane and the substrate through the thermocouples, and the thermal resistance between the membrane and the substrate through the beams and through the gas composition is a value in the range of 0.8 to 1.2, wherein a numerator of the ratio comprises the thermal resistance between the membrane and the substrate through the thermocouples, and a denominator of the ratio comprises the thermal resistance between the membrane and the substrate through the beams and through the gas composition.