Flow speed measurement with Doppler effect using ultrasonic receiver for small-sized smart catheter

We measured flow speed in a cylindrical pipe with Doppler effect using an ultrasonic receiver. We proposed a wide frequency range receiver to measure both blood flow speed and blood pressure at the same time in a blood vessel. Our sensor has a piezoresistive cantilever which is put on the boundary between air and liquid in a device. According to this structure, proposed receiver can measure acoustic waves from Hz to MHz order frequency, so that we can obtain blood flow speed (MHz order), and blood pressure change (Hz order) with the same device. We measured flow speed ranging from 6 to 25 mm/s, which was equal to blood flow speed of an arteriole, in a cylindrical pipe, of MHz order Doppler effect.