**3.2. Basic plotting of data**

22 MATLAB – A Fundamental Tool for Scientific Computing and Engineering Applications – Volume 1

chapter 3.

information).

**Figure 2.** Extraction of Axes (in our example)

**3.1. Basic transformation of rough data** 

this on some practical examples of EM field applications.

row vector (x-component, apmlitude) has 8 elements. See Table 2.

**3. Viewing the results** 

Note: It may be necessary to convert data to suitable matrix form (e.g. rough data are in the form of a row vector with axial information for each element). We will look into it in the

Now that we know what our data source looks like we can simply process it to view the results and highlight some of their aspects according to our needs (see Table 2. for axial

In this section we are going to show some examples of how obtained data can be viewed, how to interpret those results, what type of projection should we use etc. We shall illustrate

As mentioned above we might obtain rough data in the form of a row vector. Let us illustrate this in this simple example. Our computational domain is 2 by 2 by 2 thus obtained First of all, we need to bear in mind that we have time-dependent data. The most basic process is to plot actual situation (distribution of intensity of electric or magnetic) at a given time, or amplitude of vector. (In some applications we may need to plot just one component of this vector. This is even simpler because then we can disregard following method.)

Phasor of intensity of electric or magnetic field can be represented by modulus and phase or real and imaginary part. We need to merge all the components of the vector and obtain real and imaginary part. This can be simply done (i.e. vector adding component matrices together). Then we have one matrix of complex numbers. We can choose specific time in which we need EM field to be plotted simply by adding <0,2π> to the phase of each vector and then we can plot real and imaginary modulus of the vector in specified time. Or we take just the amplitude of vectors and plot them.

It is very usual to plot RMS (i.e. Root Mean Square) value of vectors which is defined as follows.

$$\left|RMS\right|E\left|\right| = \frac{\left|E\right|}{\sqrt{2}}\tag{3}$$

This can be again obtained very simply from amplitude of intensity of electric field. (Note that this same procedure can be used also in the case of intensity of magnetic field *H*, usually in applications involving heating and/or drying we deal only with intensity of electric field *E*, because it is the source of heat generation in exposed samples.)

Now that we have three dimensional matrix of values of *RMS|E|* we can plot it to see what our results look like. In the following section there is an example we prepared to illustrate how the results can be viewed and interpreted.
