What does pattern function do under planeWaveExcitation?

I have a question regarding planeWaveExcitation.

When I create a planeWaveExcitation environment:

p = planeWaveExcitation;
p.Direction     = [0 0 1];
p.Polarization  = [0 1 0];
p.Element       = myArray;

and then I call the pattern() or patternElevation() function:

patternElevation(p, freq);

what is MATLAB actually doing here? Am I actually obtaining a scattering solution for the radiation pattern (i.e. plane wave comes in, excites currents in my element, then re-radiates fields that result in the radiation pattern I am shown), or is something else going on?

I'm also interested in any nuance between using an element vs array as the planeWaveExcitation 'Element.'

Thank you in advance.

Answer 1

[AR]

Hi @Joshua Goglio,

Based on described setup with “planeWaveExcitation” and subsequent calls to “pattern()” or “patternElevation()”, MATLAB is performing scattering analysis and solution. Here it is computing 3 parameters:

1. Incident wave from the specified direction [0 0 1] and polarization [0 1 0] that illuminates the array/antenna.

2. Induced currents excited by the incident wave accounting for mutual coupling.

3. Scattered re-radiated fields from these currents are computed.

The call to “patternElevation(p, freq)” plots the scattered far field pattern. This is not the active transmit pattern. It quantifies how your antenna scatters incident energy.

Using a Single Element vs. an Array in “planeWaveExcitation” differs in the following way:

• Single Element: Scattered field from one antenna.
• Array: Coherent sum of scattered fields from all elements (including mutual coupling and spatial phase effects).

Hope this is helpful!