Biomedical imaging Ultrasound L2

What is hyugen's principle?
- Each point on the aperture generates a spherical wave
- Their combination creates different net pressures at points in the observation field
When are we in Fraunhoffer diffraction?
- z>>A²
- λ
What is directivity

How beam amplitude varies with angle
What is the formula for the beam spread of a rectangular aperture?
- if α = λ
- 2H
What is formula for beam spread in a circular aperture? Say for example the diameter
What is the condition for fresnel diffraction
- z< A²
- λ
What ways can you focus a beam?

With a lens or a bowl

Author

keesukim

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Biomedical imaging Ultrasound L2

Description

Ultrasound lecture 2 about diffraction

Updated

2018-04-18T16:01:42Z

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