An aluminium nitride (AlN) passive resonance circuit intended for thermallymatched high temperature wireless sensor nodes (WSN) was manufactured using thick-lmtechnology. Characterization was done for temperatures up to 900C in both a hot-chuck forfrequencies below 5 MHz, and using wireless readings of resonating circuits at 15 MHz, 59 MHz,and 116 MHz. The substrate for the circuits was sintered polycrystalline AlN. Using a simpliedmodel for the resonators where the main contribution of the frequency-shift was considered tocome from a shift of the dielectric constant for these frequencies, the temperature dependency ofthe dielectric constant for AlN was found to decrease with increasing frequency up to 15 MHz.With an observed frequency shift of 0.04% at 15 MHz, and up to 0.56% at 59 MHz over atemperature range of 900C, AlN looks as a promising material for integration of resonancecircuits directly on the substrate.