The present disclosure provides systems and methods associated with mode conversion for ultrasound and acoustic radiation devices. A method is disclosed for manufacturing a mode converting structure comprising a holographic metamaterial that, when positioned relative to an acoustic radiation device (AR), modifies an acoustic field profile of the AR device from an input mode to an output mode, the method including identifying a volumetric distribution of acoustic material properties within the mode converting structure to transform an input pressure field distribution of acoustic radiation in the input mode to an output field distribution of acoustic radiation that approximates the target radiation pattern in the output mode and manufacturing the mode converting structure using the identified volumetric distribution of acoustic material properties.

In an embodiment an acoustic transmission system includes a primary side having a transmitting unit configured to provide a transmit signal, a receiving unit configured to receive a received signal in response to the transmitted signal and an electroacoustic transducer configured to convert the transmit signal into an acoustic signal and an acoustic signal into the receive signal and a secondary side having a transponder configured to receive a receive signal and transmit a transmit signal and an electroacoustic transducer located between the primary side and the secondary side, the electroacoustic transducer having a medium permeable to acoustic signals.

In an embodiment an acoustic transmission system includes a primary side having a transmitting unit configured to provide a transmit signal, a receiving unit configured to receive a received signal in response to the transmitted signal and an electroacoustic transducer configured to convert the transmit signal into an acoustic signal and an acoustic signal into the receive signal and a secondary side having a transponder configured to receive a receive signal and transmit a transmit signal and an electroacoustic transducer located between the primary side and the secondary side, the electroacoustic transducer having a medium permeable to acoustic signals.

An acoustic apparatus includes: a three-dimensional network structural body that is an aggregate of filaments that are made of a resilient resin, each randomly looped or curled, fused to each other, and intertwined with each other; an at least one speaker that generates acoustic waves; and a board-like resonance board. The three-dimensional network structural body has a front surface that is held in direct or indirect contact with a human body, and an inner surface that faces the front surface. The at least one speaker includes a vibrating portion that faces the inner surface of the three-dimensional network structural body, and a frame portion that holds the vibrating portion while allowing the vibrating portion to vibrate. The frame portion is mounted to one side surface of the board-like resonance board through intermediation of a resilient mounting material.

A conversation assisting method of the present invention is performed in a first space in order to transmit an acoustic signal between the first space and a second space, separated by an isolation object, by using the isolation object. In the conversation assisting method of the present invention, a sound to be transmitted to the second space is emitted from the first space side to the isolation object at a predetermined intensity. Further, in the conversation assisting method of the present invention, a sound transmitted through the isolation object is picked up, and from the picked-up sound, a sound except for the emitted sound is emphasized and output.

An active mechanical waveguide including an ultrasonically-transmissive material and a plurality of reflection points defined along a length of the waveguide may be driven at multiple resonant frequencies to sense environmental conditions, e.g., using tracking of a phase derivative. In addition, frequency-dependent reflectors may be incorporated into an active mechanical waveguide, and a drive frequency may be selected to render the frequency-dependent reflectors substantially transparent.

An active mechanical waveguide including an ultrasonically-transmissive material and a plurality of reflection points defined along a length of the waveguide may be driven at multiple resonant frequencies to sense environmental conditions, e.g., using tracking of a phase derivative. In addition, frequency-dependent reflectors may be incorporated into an active mechanical waveguide, and a drive frequency may be selected to render the frequency-dependent reflectors substantially transparent.

A MEMS based device includes a phononic crystal body formed from unit cells and having a defect line extending through the phononic crystal body. Unit cells inside of the defect line lack a same phononic bandgap as the unit cells outside of the defect line. An input MEMS resonator is mechanically coupled to a first end of the defect line, and an output MEMS resonator is mechanically coupled to a second end of the defect line. Each of the unit cells outside of the defect line has an identical geometry. The input MEMS resonator and output MEMS resonator each have a natural frequency within the same phononic bandgap possessed by the unit cells outside of the defect line. There may be more than one defect line, and in such cases, the MEMS device may include more than one input MEMS resonator and/or more than one output MEMS resonator.

The ultrasonic tubular transducer is activated at the centre thereof by two symmetrical electromechanical converters. The vibration generated by the two electromechanical converters is converted and then transmitted to the tube via a coupler. The ultrasonic transducer can be vibrationally isolated from the interfaces thereof by caps equally suitable for connecting the transducer to a stationary frame, a free end or another similar ultrasonic transducer. A device for pre-stressing electromechanical converters has a hole bored at the centre thereof in order to allow cables from the transducer as well as from adjacent transducers to pass therethrough.

The ultrasonic tubular transducer is activated at the centre thereof by two symmetrical electromechanical converters. The vibration generated by the two electromechanical converters is converted and then transmitted to the tube via a coupler. The ultrasonic transducer can be vibrationally isolated from the interfaces thereof by caps equally suitable for connecting the transducer to a stationary frame, a free end or another similar ultrasonic transducer. A device for pre-stressing electromechanical converters has a hole bored at the centre thereof in order to allow cables from the transducer as well as from adjacent transducers to pass therethrough.