Biomedical subjects

W Q Yuan

Publications and source records attributed to W Q Yuan.

2 recordsLinked to original sources

PubMed1988

A concave annular array design, based on phasor summation--Part I: Design methodology.

A detailed method for the design of annular arrays based on phasor summation is developed. The net phase shift across each annulus obtained by phasor summation is a very important factor in the design of an annular array, and determines the strength of the signal received. The method presented in this paper allows the designer to evaluate the trade-offs in parameters such as the strength of the signal from each annulus, the efficiency of each annulus, and the depth of focus that would be achievable. A concave annular array has been fabricated according to this design method. A set of graphs are given for an actual design to illustrate how one may readily evaluate these trade-offs.

Equipment Design↗

PubMed1988

A concave annular array design, based on phasor summation--Part II: Beam profiles and resultant images by B-scan and synthetic focus methods.

A brief review of the synthetic focusing method is given. The theoretical limit of resolution that may be achieved with the synthetic focusing methods is demonstrated using experimental results on a thin thread obtained with an annular array whose design was given in Part I. The advantage of large aperture arrays is illustrated by an in vitro reflection image of a dog artery, made with this array, that has at least four times the spatial resolution of present clinical B-scanners operating in the same frequency range.

Animals↗