# 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.

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.