Are there ultrasonic transducers which are able to produce a "chirp" sound wave?
Piezoelectric speakers, the kind commonly found in ultrasonic transducers generally operate in a narrow frequency range when operating at ultrasonic range (a resonate frequency of the metallic diaphragm). This is very true once you get above about ~60 kHz. However if the ultrasonic "chirp" you are looking for can be in the range of say 20-60 kHz you could be in luck, i.e., http://www.conrad-electronic.co.uk/ce/en/product/710991/KEPO-piezo-element-25-60-kHz-515-mm

You could use the Tone function (which goes up to 65535 Hz) to produce the frequency sweep you desire. However if you want to go up to frequencies in the 100+ kHz range you will be delving into research territory and hence extremely expensive equipment.

Having said that, technologies change very quickly and I my knowledge may already be out of date. Hope this helps.