Radiation by Transducer of Waveguide Type into Conical Half-Spaces Coaxial With It

Introduction. The present stage of development of hydroacoustic equipment is characterized by a constant improvement of an element base and by an increase in computing power. However, in solving of applied problems one is increasingly faced with a restriction on the realized bandwidth of electroacoustic transducers and antennas. The most of well-known methods of bandwidth expansion do not provide a linear character of the phase-frequency characteristic (PFC) of radiation in the working frequency band, which is of primary importance for the effective formation of relatively short, frequency-tunable, and complex acoustic signals. From this position, the use of a transducer of waveguide type (TWT) is preferential. Its construction and electrical excitation method provides a close to linear phase response of radiation.

Aim. The development of a generalized computational model. It has to include particular cases of TWT radiation into cylindrical waveguides coaxial with it and into half-spaces, and also to take into account the influence of waves reflected from the boundaries of the TWT on its field characteristics.

Materials and methods. The TWT was presented by a coaxial set of identical water filled piezocylinders with amplitude-phase excitation, provided a mode of broadband radiation in the form of traveling waves. The usage of the method of partial regions allowed one to obtain a solution of the problem of TWT radiation through water filled apertures into the conical adjacent half-spaces, variable in angle.

Results. Frequency characteristics of TWT sound pressure results calculated in accordance with the solution of the synthesis problem in the frontal and rear directions for different angles of cone opening were presented and analyzed. Using the proposed computational model of TWT, the possibility of obtaining a bandwidth of the order of 3 octaves was demonstrated. An influence of the thickness of the passive flanges, which are used to link the TWT in the antennas was estimated. The possibility of radiation in the working frequency band of TWT of ultrashort ultra-short single-period pulses for different angles of cone opening was considered. A comparative assessment of the result of calculation with other particular solutions (the radiation by TWT in coaxial water-filled waveguides and also – in half-spaces) was presented

Conclusion. An expedient to use a generalized computational model for a more accurate description of the acoustic fields of real antenna models made up of TWT was concluded.

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