This guide provides a brief reference to the Graphical User Interface (GUI) that implements the propagation of a TE (Transverse
Electric)/TM (Transverse Magnetic) wave through a multilayered structure of media (also double-negative materials are supported) with different electromagnetic characteristics.
The incident wave is a TE/TM plane wave in the the zy plane (sinusoidal regime with temporal convention
ejωt ), traveling
from +z to -z.
The GUI has four main output windows displaying the x (orthogonal) component of the field, specifically the electric field or the magnetic
field when a TE or a TM wave is considered, respectively. The top left-hand figure shows the total field, superposition of
the progressive and of the regressive waves, which, on turn, are depicted in the top right-hand and in the bottom left-hand
figures. Finally, the bottom right-hand figure shows the field values corresponding to a vertical cut of the plane, specifically
for y = 0 m. The GUI also allows to plot, in separate windows, the parallel field associated to the main orthogonal field (both
y and z components are calculated).
All the figures can be zoomed in and out and the values of those reporting the 2D field distribution can be inspected
pixel by pixel (the position of the pixel and the associated field value will be shown in the bottom-left corner of the GUI). Finally, the power
reflected by the whole multilayered structure (in terms of percentage of the power incident on the first interface) is plotted in the title of the
"Total field" figure (both for orthogonal and parallel fields).
Contents
- Installing the GUI
- Running the GUI
- GUI input parameters and buttons
- Frequency
- Electric permittivity
- Conductivity
- Magnetic permeability
- z-coordinate of the interfaces
- Incident field
- Angle of incidence
- Axes range
- Number of samples of each axis
- TE/TM wave selection
- Real/Absolute values
- Animate fields
- TL model
- Parallel field
- Save results
- Calculate
- Stop animation
- Help
- Close all figures
Installing the GUI
To install the GUI, copy the files "PlaneWaveGUI.m" and "Help.html" to the same folder.
Running the GUI
To launch the GUI, open Matlab®, change the "Current Directory" to the folder where files have been copied. Afterwards, to start the GUI, type "PlaneWaveGUI" at Matlab® prompt.
GUI input parameters and buttons
A brief description of the GUI elements (fields, buttons, options, etc.) is provided here:
Frequency
This field allows to specify the frequency of the plane wave, expressed in Hz. Obviously, only positive values are accepted. If this field is filled in with multiple values (in vector format such as [1e9:1e9:9e9]), the GUI will iteratively calculate results for each of the frequencies.
Electric permittivity
This field allows to specify the values of the relative electric permittivity associated to the materials defined. Each entry of the vector refers to a medium, starting from the one defined in the semispace z > 0 m. In fact, at least two materials should be defined, whose interface is set in z = 0 m. Complex values of the electric permittivity (indicating power losses associated to the material) are allowed (the imaginary part has to be negative, according to the temporal convention ejωt ). Both positive (dielectric) and negative (plasmas/double negative materials) values are accepted.
Conductivity
This field allows to specify the values of the electric conductivity associated to the materials defined (imperfect dielectric or good conductor). Each entry of the vector refers to a medium, starting from the one defined in the semispace z > 0 m. In fact, at least two materials should be defined, whose interface is set in z = 0 m. Only real positive values are accepted.
Magnetic permeability
This field allows to specify the values of the relative magnetic permeability associated to the materials defined. Each entry of the vector refers to a medium, starting from the one defined in the semispace z > 0 m. In fact, at least two materials should be defined, whose interface is set in z = 0 m. Complex values of the magnetic permeability (indicating power losses associated to the material) are allowed (the imaginary part has to be negative, according to the temporal convention ejωt ). Finally, both positive (magnetic media) and negative (ferrites/double negative materials) values are accepted.
z-coordinate of the interfaces
This field allows to specify the z position (in meters) of the discontinuities between the defined materials. At least one discontinuity in z = 0 m should be defined. As the plane wave travels from +z to -z, the position of the interfaces has to be incrementally negative.
Incident field
This field allows to specify the oscillation amplitude of the incident field. The value must be expressed V/m or in A/m if a TE or a TM wave is considered, respectively. Only positive values are accepted.
Angle of incidence
This field allows to specify the angle of incidence of the plane wave impinging on the first discontinuity. The angle is defined by the normal to the wave fronts and the y axis and it increases in the counter clockwise direction starting from the y axis. Therefore, 0° means normal incidence, 90° a wave traveling from -y to +y and -90° a wave traveling from +y to -y. The angle must be expressed in degrees and only values comprised between -90° and 90° are accepted. If this field is filled in with multiple values (in vector format such as [-30:10:30]), the GUI will iteratively calculate results for each of the incidence angles.
Axes range
This field allows to specify the ranges of the z and y axes (in meters), thus causing both axes to have the same dimensions. As the GUI defines at least two materials whose discontinuity is set in z = 0 m, such value must be included in the axes ranges.
Number of samples of each axis
This field allows to specify the spatial discretization of the plane by entering the number of samples of each axis. Obviously only values greater than 0 are accepted.
TE/TM wave selection
This pop-up menu allows to choose between a TE or a TM wave. Results show the x component of the electric field or of the magnetic field if a TE or a TM wave is selected, respectively.
Real/Absolute values
This pop-up menu allows to choose if real or absolute values of the field should be displayed in the output windows.
Animate fields
If this option is selected, the bottom right-hand window shows the variation of the fields with time. The effect of such an options can be appreciated only if real values of the fields are calculated.
TL model
If this option is selected, a figure is opened providing details of the calculations preformed by the GUI. Specifically, each material is represented through its equivalent transmission line (TL) model and several quantities are shown/calculated:
- the electromagnetic characteristics of the media (relative electric permittivity and magnetic permeability, electric conductivity);
- intrinsic impedance associated to the TE/TM wave;
- the wavelength, the phase constant and the absorption coefficient (relative to the z direction);
- the reflection coefficients at each interface (considering the effect of all the media beyond the interface).
A maximum number of 12 materials can be defined as long as this option is selected.
Parallel field
If this option is selected, the GUI will also calculate and show, in separate windows, the parallel field associated to the main orthogonal field (both y and z components).
Save results
If this option is selected, the GUI will save the produced results to disk. The workspace will be saved into
a 'mat' file in the same folder containing the GUI script. If multiple frequency and/or incidence angle values are provided as
input, the GUI will save a file for each of such values. Files are saved with the following name:
GUIresults_dd-mmm-yyyy_numXXXXXX.mat
where 'dd' is the day, 'mmmm' is the month (characters) and 'yyyy' is the year. Finally, 'XXXXXX' is the file counter that is
automatically increased by the GUI according to the files already saved in the script folder. The maximum number of files that can
be saved is 999999, after which the GUI will ask the user to delete some files before saving a new one.
Specifically, each file includes the following structured variables:
- IN consisting of the following fields:
- IncField = amplitude of the incident field [V/m or A/m]
- Frequency = frequency of the EM wave [Hz]
- IncAngle = angle of incidence [degrees]
- RelElPerm = relative electric permittivity of the media
- RelMagPerm = relative magnetic permeability of the media
- Conduct = conductivity of the media [S/m]
- Zinterfaces = z-coordinate of the discontinuities [m]
- axesRange = axes range [m]
- AxisNumSamples = number of samples of each axis
- TE_TMwave = 1 --> TE wave, 2 --> TM wave
- OUT consisting of the following fields (example for TE waves below):
- AttConst = absorption coefficient of the media (relative to the z direction) [Np/m]
- PhaseConst = phase constant of the media (relative to the z direction) [rad/m]
- WaveLength = the wavelength of the media (relative to the z direction) [m]
- zTE = intrinsic impedance associated to the TE wave [&Omega]
- ReflCoeffTE_right = reflection coefficients defined with respect to the intrinsic impedance of the media. This is the coefficient at the interface between the medium and the following one (on the right).
- ReflCoeffTE_left = reflection coefficients defined with respect to the intrinsic impedance of the media. This is the coefficient at the interface between the medium and the previous one (on the left).
- Ex_T = 2D total x-component of the electric field (complex values) [V/m]
- Ex_P = 2D progressive-only x-component of the electric field (complex values) [V/m]
- Ex_R = 2D regressive-only x-component of the electric field (complex values) [V/m]
- Hy_T = 2D total y-component of the magnetic field (complex values) [A/m]
- Hy_P = 2D progressive-only y-component of the magnetic field (complex values) [A/m]
- Hy_R = 2D regressive-only y-component of the magnetic field (complex values) [A/m]
- Hz_T = 2D total z-component of the magnetic field (complex values) [A/m]
- Hz_P = 2D progressive-only z-component of the magnetic field (complex values) [A/m]
- Hz_R = 2D regressive-only z-component of the magnetic field (complex values) [A/m]
Calculate
This button starts a new calculation of the wave propagation. When a new input parameter is provided to the GUI, the change will apply only after the request for a new calculation.
Stop animation
This button stops the calculation of the field variation with time.
Help
This button opens this brief guide.
Close all figures
This button closes all the figures generated by the GUI.