Transducer Arrays Of Acoustic Orbital Angular Momentum

The topological charges of orbital angular momentum provide intrinsically orthogonal channels,and theoretically the topological charge of acoustic orbital angular momentum is infinite,so it can greatly improve the information transmission rate of underwater acoustic communication as a new multiplexing dimension.However,lack of research on underwater acoustic orbital angular momentum transmission technology makes the application of acoustic orbital angular momentum in the field of underwater acoustic communication extremely limited.This paper takes underwater orbital angular momentum multiplexing technology to realize underwater high-speed acoustic communication as the background,and uses underwater acoustic orbit angular momentum transmission technology as the research direction.It focuses on the following aspects:Firstly,the theory of acoustic momentum orbital momentum emission with different topological charges based on the phased principle was studied,and the Cymbal transducer was developed based on the finite element method.The ring-shaped phased array prototype constructed by the Cymbal transducer was acoustically orbited.Angular momentum test experiments,by measuring the sound pressure amplitude and phase information of the acoustic orbital angular momentum of different topological charges,verified the theory of acoustic orbital angular momentum emission of different topological charges based on the phase control principle,and proved that the energy conversion based on Cymbal The ring-shaped phased array can realize the emission of angular orbital angular momentum of different orders by controlling the excitation signals of the array elements.In order to overcome the shortcomings of multi-channel excitation of phased arrays when transmitting acoustic orbital angular momentum,an equally spaced spatial spiral array that realizes acoustic orbital angular momentum transmission by physical spiral is proposed,and different topological charges are launched based on spatial spiral arrays.Based on the theory of acoustic orbital angular momentum,a spatial spiral array prototype based on the Cymbal transducer was developed,and the underwater acoustic performance of the spiral array was measured.By measuring the sound pressure amplitude and phase information of the acoustic orbital angular momentum with different topological loads It is verified that the spatial spiral array can realize the emission of angular momentum of the acoustic orbit through the phase difference formed by the spatial position difference of the primitives.The decoupling technology of acoustic orbital angular momentum in different coupling modes is studied.First,a single radius phased array is used to realize the coupling and decoupling of underwater acoustic orbital angular momentum with different topological loads.Disadvantages caused by coupling are developed.A combined radius form emission array is developed,which greatly simplifies the decoupling process of the angular momentum of the acoustic orbit while ensuring the decoupling accuracy.Combining the acoustic orbit angular momentum coupling and decoupling process with the multiplexing and demodulation process in the information transmission process,the underwater acoustic communication experiments based on the acoustic orbit angular momentum multiplexing technology have verified the acoustic orbits of different topological charges The orthogonality between the angular momentums proves that the acoustic orbital angular momentum multiplexing technology can be used to realize the function of underwater data transmission.