# Excitation

Excitation data consist of voltage sources, plane waves, waveguide sources, equivalent sources and Hertzian dipoles.

## Voltage Sources on Segments

A voltage source on a segment generates the following data block:
                    EXCITATION BY VOLTAGE SOURCE AT A SEGMENT

Name:
Excitation index:              1
Frequency in Hz:               FREQ =    7.49481E+07
Wavelength in m:               LAMBDA =  4.00000E+00
Open circuit voltage in V:     |U0| =    1.00000E+00
Phase in degrees:              ARG(U0) =        0.00
Attached to port:              Segment port
Port at segment with label:    1
Absolute number of segment:    11
Radius of segment in m:        2.00000E-03
Location of the port in m:     x =  0.00000E+00, y =  0.00000E+00, z =  0.00000E+00
Positive direction:            x =  0.00000E+00, y =  0.00000E+00, z =  1.00000E+00

Similar information is provided for other voltage sources (such as a voltage source on an edge port and on a microstrip port and a voltage source connected to a general network).

## Waveguide Ports and Waveguide Sources

Data for the port and the source are split into three blocks. The geometrical data for the port is given first:
                         DATA FOR WAVEGUIDE PORTS

Waveguide port label: Port
Port type: Rectangular
Port dimensions
Width:         1.29600E-01 m
Height:        6.48000E-02 m
Port reference points in m:
Point S1:               x = -2.37927E-01, y = -6.48000E-02, z = -3.24000E-02
Point S2:               x = -2.37927E-01, y =  6.48000E-02, z = -3.24000E-02
Direction of propagation: x =  1.00000E+00, y =  0.00000E+00, z =  0.00000E+00

Subsequently follows the data for the modes.
                         MODE EXPANSION DATA OF A WAVEGUIDE PORT

Waveguide port label: Port
Frequency:        1.64500E+09 Hz

Mode indices  Cutoff freq.  Transverse wave impedance  Propagation factor  Description
m   n    in Hz      real part   imag. part   real part  imag. part
TE    0   1   2.3132E+09  0.0000E+00  3.8105E+02  3.4085E+01  0.0000E+00   Evanescent
TE    0   2   4.6264E+09  0.0000E+00  1.4331E+02  9.0626E+01  0.0000E+00   Evanescent
TE    1   0   1.1566E+09  5.2979E+02  0.0000E+00  0.0000E+00  2.4515E+01   Propagating
TE    1   1   2.5862E+09  0.0000E+00  3.1053E+02  4.1826E+01  0.0000E+00   Evanescent
TE    1   2   4.7688E+09  0.0000E+00  1.3845E+02  9.3812E+01  0.0000E+00   Evanescent
TE    2   0   2.3132E+09  0.0000E+00  3.8105E+02  3.4085E+01  0.0000E+00   Evanescent
TE    2   1   3.2713E+09  0.0000E+00  2.1916E+02  5.9264E+01  0.0000E+00   Evanescent
TE    2   2   5.1725E+09  0.0000E+00  1.2637E+02  1.0277E+02  0.0000E+00   Evanescent
TM    1   1   2.5862E+09  0.0000E+00  4.5703E+02  4.1826E+01  0.0000E+00   Evanescent
TM    1   2   4.7688E+09  0.0000E+00  1.0251E+03  9.3812E+01  0.0000E+00   Evanescent
TM    2   1   3.2713E+09  0.0000E+00  6.4758E+02  5.9264E+01  0.0000E+00   Evanescent
TM    2   2   5.1725E+09  0.0000E+00  1.1230E+03  1.0277E+02  0.0000E+00   Evanescent
Lastly the data for the impressed waveguide mode is provided:
                    EXCITATION BY IMPRESSED WAVEGUIDE MODE

Name:
Excitation index:              1
Frequency in Hz:               FREQ =    1.64500E+09
Wavelength in m:               LAMBDA =  1.82245E-01
Impressed mode:                TE 1 0
Amplitude in A/m:               1.00000E+00 * PWFAKTOR (see below)
Phase in degrees:                      0.00
Transmitted power in W:         1.13772E+00 * PWFAKTOR^2 (see below)
Attached to port label:        Port

## FEM Current Source

For a FEM excitation (impressed current source) the following information is provided:
                    EXCITATION BY IMPRESSED CURRENT ELEMENT (FEM)

Name:                          CurrentSource1
Excitation index:              1
Frequency in Hz:               FREQ =    3.00000E+09
Wavelength in m:               LAMBDA =  6.54669E-02
Amplitude in A:                |I| =     1.00000E+00
Phase in degrees:              ARG(I) =     0.00
Attached to port:              FEM line port
Start point of the port in m:  x =  0.00000E+00, y =  6.50000E-03, z = -1.00000E-03
End point of the port in m:    x =  0.00000E+00, y =  6.50000E-03, z =  0.00000E+00
Port length in m:              1.00000E-03

## FEM Modal Source

The data for this source is split into two blocks of data. The mode expansion for the port is given first:
                         MODE EXPANSION DATA OF A MODAL PORT

FEM modal port: Port1
Frequency:        3.00000E+09 Hz

Eigenvalues computed with ARPACK [Z]

Mode            Propagation factor       Description
counter      real part   imaginary part

1       0.00000E+00      9.59751E+01   Propagating (fundamental mode)
Next follows the data for the source:
                         EXCITATION BY IMPRESSED MODAL PORT MODE

Name:                          FEMModalSource1
Excitation index:              1
Frequency in Hz:               FREQ =    3.00000E+09
Impressed mode:                Fundamental
Amplitude in V/m:               1.00000E+00
Phase in degrees:                      0.00
Transmitted power in W:         5.00000E-01
Attached to port:              Port1

## Plane Wave Source

If an incident plane wave is used then the output file has the following format:
               EXCITATION BY INCIDENT PLANE ELECTROMAGNETIC WAVE

Name:
Excitation index:              1
Frequency in Hz:               FREQ =    1.49896E+07
Wavelength in m:               LAMBDA =  2.00000E+01
Direction of incidence:        THETA = -180.00  PHI =    0.00
Polarisation:                  LINEAR
Axial ratio:                   V =      0.0000
Polarisation angle:            ETA =    0.00
Direction of propag.:          BETA0X =  0.00000E+00
(unit vector)                BETA0Y =  0.00000E+00
BETA0Z =  1.00000E+00
Wave number:                   BETA0  = ( 3.14159E-01 +j 0.00000E+00)
Phase reference point in m:    x =  0.00000E+00, y =  0.00000E+00, z =  0.00000E+00
Field strength in V/m:         |E0X| =  1.00000E+00   ARG(E0X) =     0.00
(Phase in degrees)           |E0Y| =  0.00000E+00   ARG(E0Y) =     0.00
|E0Z| =  0.00000E+00   ARG(E0Z) =     0.00

The vector $\beta$ , whose components are given, is the vector which points in the direction of propagation. The vector ${E}_{0}$ represents the direction of the electric field.

## Near Field Source

For an impressed near field (aperture) source, the following information is given:
                         EXCITATION BY NEAR FIELD SOURCE

Name:                          NearFieldSource1
Aperture number:               1
Frequency in Hz:               FREQ =    1.64500E+09
Wavelength in m:               LAMBDA =  1.82245E-01
Number of electric dipoles:    90 (of which 20 suppressed)
Number of magnetic dipoles:    90 (of which 32 suppressed)
Extent of the source:          X = -5.83200E-02 ...  5.83200E-02 m
Y = -2.59200E-02 ...  2.59200E-02 m
Z = -2.56439E-01 ... -2.56439E-01 m
Note: No specific information regarding the magnitude and phase of the dipole elements that make up the excitation is given in the output.

## Impressed Radiation Pattern

Excitation by an impressed radiation pattern point source is shown in the output as follows:
                    EXCITATION BY A FAR FIELD POINT SOURCE

Excitation index:              1
Frequency in Hz:               FREQ =    1.60000E+09
Wavelength in m:               LAMBDA =  1.87370E-01
Max. field strength * dist. in V:   5.91419E+01 * PWFAKTOR (see below)
Radiated power in W:                1.12755E+00 * PWFAKTOR^2 (see below)
Directivity of the antenna in dB:      17.138
Distance for far field cond. in m:  1.96442E+00
Source position in m:          x =  0.00000E+00, y =  0.00000E+00, z =  0.00000E+00
Number of grid points  NTHETA = 37
NPHI   = 73
Angular range THETA in degrees:    0.00 ... 180.00
PHI   in degrees:    0.00 ... 360.00
Note: No specific information regarding the magnitude and phase of the impressed pattern that make up the excitation is given in the output.

## Spherical Mode Source

For an impressed spherical mode source, the following information is written to the output:

                   EXCITATION BY AN IMPRESSED SPHERICAL MODE

Name:                          SphericalModesSource1
Excitation index:              1
Frequency in Hz:               FREQ =    6.25000E+09
Wavelength in m:               LAMBDA =  4.79668E-02
Source position in m:          x =  0.00000E+00, y =  0.00000E+00, z =  2.54000E-01
Rotation about the axes:       X = -180.00
Y =   48.46
Z =    0.00
Number of modes:                 880 (of which 38 suppressed)
Propagation direction:       C = 4 (outwards)
mode indices          coefficient in sqrt(Watt)   rad. power(Watt)
J      S      M      N         magn.        phase         power
1      1     -1      1      2.54050E-05    -25.23      3.22706E-10
2      2     -1      1      4.50632E-05      1.04      1.01535E-09
3      1      0      1      5.41621E-07     40.48      1.46677E-13

## Hertzian Dipoles

Point source type (Hertzian dipole) excitations result in the following information output:
                         EXCITATION BY ELECTRIC DIPOLE

Name:                          ElectricPointSource1
Excitation index:              1
Frequency in Hz:               FREQ =    3.00000E+08
Wavelength in m:               LAMBDA =  9.99308E-01
Amplitude in Am:               |IL| =    1.00000E+00
Phase in degrees:              ARG(IL) =        0.00
Dipole position in m:          x =  0.00000E+00, y =  0.00000E+00, z =  0.00000E+00
Orientation of dipole:         THETA =    0.00
PHI   =    0.00

The above output is for an electric dipole. The magnetic dipole will have similar output.