An infrared radiation sensor comprises a substrate, a membrane formed in or at the substrate, a first counter electrode, a second counter electrode, and a composite comprising at least two layers of materials having different coefficients of thermal expansion. At least a portion of the membrane forms a deflectable electrode and the deflectable electrode is electrically floating. A first capacitance is formed between the deflectable electrode and the first counter electrode, and a second capacitance is formed between the deflectable electrode and the second counter electrode. The membrane comprises the composite or is supported at the substrate by the composite. The membrane comprises an absorption region configured to cause deformation of the composite by absorbing infrared radiation, the deformation resulting in a deflection of the deflectable electrode, which causes a change of the first and second capacitances.