Low-cost monostatic radio-acoustic sounding system for indoor temperature profiling

This paper presents a novel solution to the problems of clutter in the application of indoor radio-acoustic-sounding systems (RASS). A low-cost monostatic configuration comprising a horn-lens surrounded by an annular array of 40kHz acoustic transducers is constructed. A combination of the high acoustic frequency, and hence, high attenuation, and the narrow beam reduce the possibility of interference and allow for an extremely small spatial sample of temperature. Measured results confirm the acoustic antenna characteristics, and simulations indicate that the RASS should be capable of operation out to a range of 7m. Experimental results using the 17.6GHz radar do not yet show the sensitivity to detect the acoustic pulse.