A new analytic expression for the impulse response of concave radiators is used to compute the transient pressure distributions of phased annular arrays with spherical geometry. The process of phasing the array to achieve variable focusing is treated by summing the delayed impulse responses of the individual annuli. The example of pressure distributions of a five element annular array is treated in detail, and some recommendations are given for practical computer studies.
GruetzmacherJ., Piezoelektrischer Kristall mit Ultraschallkonvergenz, Zeits. f. Physik96, 342–349 (1935).
2.
LabawL. W., Curved quartz crystals as supersonic generators, J. Acoust. Soc. Amer. 16, 237–245 (1945).
3.
O'NeilH. T., Theory of focusing radiators, J. Acoust. Soc. Amer. 21, 516–526 (1949).
4.
OberhettingerF., On transient solutions of the “baffled piston” problem, J. Res. NBS, 65B, 1–6 (1961).
5.
StepanishenP. R., Transient radiation from pistons in an infinite planar baffle, J. Acoust. Soc. Amer. 49, 1629–1638 (1971).
6.
StepanishenP. R., The time dependent force and radiation impedance on a piston in a rigid infinite planar baffle, J. Acoust. Soc. Amer. 49, 941–849 (1971).
7.
LockwoodJ. C.WilletteJ. G., High-speed method for computing the exact solution for the pressure variations in the nearfield of a baffled piston, J. Acoust. Soc. Amer. 53, 735–741 (1973).
8.
RobinsonD. E.LeesS.BessL., Near field transient radiation patterns for circular pistons, IEEE Trans. Acoustics, Speech and Signal Processing ASSP-22, 395–403 (1974).
9.
FarnC. L. S.HuangH., Transient acoustic fields generated by a body of arbitrary shape, J. Acoust. Soc. Amer. 43, 252–257 (1968).
10.
FreedmanA., Sound field of plane or gently curved pulsed radiators, J. Acoust. Soc. Amer. 48, 221–227 (1970).
11.
KossoffG., Design of narrow-beanwidth transducers, J. Acoust. Soc. Amer. 35, 905–912 (1963).
12.
PenttinenA.LuukkalaM., The impulse response and pressure nearfield of a curved ultrasonic radiator, J. Phys. D, 9, 1547–1557 (1976).
13.
ReidJ. M.WildJ. J., Current developments in ultrasonic equipment for mechanical diagnosis, Proc. Nat. Electronics Council12, 44–58 (1956).
14.
HubelbankM.TretiakO. J., Focused Ultrasonic Transducer Design, in Research Laboratory of Electronics, MIT, QPR98, 169–177 (1970).
15.
UedaM.SatoT.MaedaY., Dynamic focusing ultrasonic transducer by using analog gate delay circuits, Bulletin of the Tokyo Institute of Technology119, 55–63 (1973).
16.
HaverlR. A.StollerM., Ultrasonic Body Scanner and Method, United States Patent #4,137,777, Mediscan Inc., Feb 6, 1979.
17.
GreenP. S.HavliceJ. F.HolzemerJ. F.RamseyS. D.Jr.TaenzerJ. C.MoessnerH. Z., Design and construction of a dynamically focused annular array, IEEE Trans. Sonics and Ultrasonics, SU-25, 259 (1978).
FosterF. S.PattersonM. S.ArditiM.HuntJ. W., The conical scanner: A two transducer ultrasound scatter imaging technique, Ultrasonic Imaging3, 62–82 (1981).
