Chemically Sensitized Thin-Film Bulk Acoustic Wave Resonators as Humidity Sensors G. M. Ashley, P. B. Kirby, T. P. Butler, R. Whatmore, and J. K. Luo Centre for Material Research and Innovation, University of Bolton, Bolton BL3 5AB, United Kingdom Microsystems and Nanotechnology Centre, University of Cranfield, Bedfordshire MK43 0AL, United Kingdom Centre for Advanced Photonics and Electronics,...