Dielectric metasurfaces have emerged as low-loss and tunable alternatives to plasmonic antenna systems with potential to form ultrathin optical elements (mirrors, lenses, etc.). Here, we investigate the thermal and geometric dispersion of fundamental Mie resonances in InSb wire and disk resonators on an intrinsic InSb substrate. Resonant properties of these dielectric antennas depend on the size and the refractive index of the wire or disks. Due to its high refractive index (n ~ 4), low electron effective mass (m_e ~ 0.014 m₀) and low band gap (0.17 eV at 300 K), InSb is a suitable candidate for temperature dependent tunable metasurfaces. We fabricate individual InSb antennas of different sizes (0.5μm-5μm) to map geometric shifts of the fundamental scattering resonances in the mid-infrared wavelength region (2-16 μm). We experimentally identify these scattering resonances of InSb wires and disks as dips in the reflection spectra from our FTIR microscope. We track those dips as a function of the resonator size and substrate temperature for both TE and TM polarization states. The generation of thermal free carriers upon heating (300K-600K) gives us a reconfigurable 700nm-shift of the resonant wavelength around 13-14μm. Using FDTD software, we simulate single antenna resonances to plot their geometric dispersion and study their resonant field profiles. Developing the experimental models for the dispersion of the fundamental resonances of dielectric resonators will facilitate the design of large-scale tunable metasurfaces.