Abstract: An ultrasonic transducer utilizes a unique forward acoustic transmission line comprised of a composite structure partially consisting of a portion of a continuous smooth sheet of material, such as an automobile bumper, from which the acoustic beam is emitted. This makes it invisible to sight, thus allowing for an improved object detection system in which the sensors cannot be seen, so that they do not interfere with the smooth lines that were designed into the surface of the object or vehicle onto which they are mounted. This is a significant improvement for applications where the look and style of the surface of the platform is important, such as in automotive park assist systems.

Abstract: An ultrasonic transducer utilizes an acoustic transmission line to increase the sensitivity of both the transmitting response and the receiving response. The resonant element of the transducer could employ a ceramic disc operating in the radial resonance mode for its transduction means, or it could be a half wavelength resonator utilizing a forward transmission line, a rear transmission line, and a non-resonant ceramic for transduction. The shape of the forward transmission line is designed to generate the desired acoustic radiation pattern at the frequency of resonance, which could be a broad or narrow conical beam or a fan shaped beam. A sealed housing structure is disclosed that contains the forward transmission line that is acoustically disconnected from the rest of the housing. This housing provides improved environmental protection and allows for easy mounting of the transducer without effecting its electroacoustic response characteristics.

Abstract: The bearing accuracy and long-range sonar target detection capability of a multi-cardioid directional receiving hydrophone array is improved by electronically producing mirror images of the cardioid directional patterns of each directional hydrophone in the array whereby the number of receiving channels are effectively doubled by this invention which in turn results in higher signal-to-noise ratios especially when receiving distant relatively weaker sonar signals. As a result, the accuracy of measurement of target range and bearing by the improved directional hydrophone array will be significantly increased.