Antennas and track formation (DI term)
Introduction to passive underwater detection

A passive antenna is made up of a set of piezoelectric sensors which convert pressure variations in the water into an electric current transmitted to a receiver responsible for processing, the main one being the formation of panoramic channels (FV). In practice, this general definition conceals a very wide variety of equipment.

First of all, many materials are piezoelectric, such as bone. Hydrophones can be made from sections of chicken bone, which is certainly economical, but the sensitivity may not be there. It's better to use more expensive ceramics or appropriate polymers. Remember that the sensitivity of a hydrophone (Sh) is $20\text{log}V\text{/}p$...