Design of h-shaped fractal antenna for microbolometer and its thermal performance estimation

The design results of an H-shaped fractal antenna for application in multi-band microbolometers and the thermal performance estimation result of the microbolometer are reported. The H-shaped fractal antenna has been designed for wavelengths of 25 and 150 μm based on a dipole antenna formula and finite element method (FEM) simulation. Simulation results show that the absorption peaks exist at 27 and 150 μm. To verify the absorption characteristics of the designed antenna, the antenna was fabricated and the absorption characteristics for the x-polarised incident wave radiated from the + z-direction were measured. The measured transmittance dips at 27 and 146 μm almost agreed with the absorption peaks of the simulation results. The thermal performance estimation of an H-shaped fractal antenna-coupled VO₂ microbolometer and obtained voltage sensitivities of 0.63 and 4.81 mV/(W/m²) at 27 and 150 μm absorption peaks, respectively, are also presented.