split a vector into normal and tangential component

i have E field vectors(x,y,z) of two ports.i want to find out the tangential magnitude of the E field vectors. to calculate th tangential magnitude i need to split the normal and tangential components of the total efield vector. i have tried some formulas. but that did not work out.

can somebody just me the way to split the tangential and normal components of a vector in MATLAB?

[Torsten]

Normal and tangential to what ?

Best wishes

Torsten.

[Guillaume]

A vector does not have intrisic tangential and normal components. The tangential and normal components are always relative to a surface and at a point on that surface.

So, to answer your question, you need to have an equation for the surface (or a list of point) and the location of the point on that surface at which you want to decompose that vector.

See wikipedia as well.

[Sasi umaiyal]

thanks for the reply. yes i do have list of points and the location of all the points on the surface. now i want to calculate 'tangential magnitude'. there is where i got stuck.

[Torsten]

So the points that make up the surface and the points where you are given the vector field E do not necessarily coincide ?

Best wishes

Torsten.

[David Sziroczak]

Here are the steps you need to do:

1) You need to generate a unit vector which is normal to your surface.

2) Then generate the scalar product of that vector and your E field vector.

3) Multiply the unit vector with the scalar value: this will give you the normal to surface component.

4) To get the tangential, substract the normal component from the E vector.

Hope this helps,

Best regards,

David