How to make a wideband ultrasonic transducer?

Hi,

I've been trying to image ultrasonic reflections at 40 kHz with the Velleman piezo ultrasonic transmitters and receivers--they work well, but what I need is something with a wider bandwidth, say 30 to 60 kHz, in order to minimize standing waves and speckling (like you get with lasers). The circuits to generate frequency-shifting chirps aren't too hard to figure out, but I can't find any information on broadening the response of the transducers, if that is possible. I have read that a capacitor and coil can be used, but I'm not sure how, or if it works with piezo elements. Any suggestions?

Thanks
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Uh, I just found a post at https://www.electro-tech-online.com/threads/looking-for-ultrasonic-transducer.87722/ that recommends the SensComp 600 electrostatic transducer, that has a good frequency range, but needs 200V or more. Do you know of others that work at a lower voltage?

Most piezo ultrasonic transducers resonate and have a fairly narrow bandwidth.
Murata make many of them and maybe you will find a wideband one they make.