Antenna on Human Hand with Dielectric (antennaOnHand.sdf)

Keywords:

antennaOnHand, far field, radiation

Problem Description

This problem calculates the far-field radiation pattern of a small wifi antenna. The fields interact with the human hand for which the bone structure was approximated by long thin cylinders. The antenna frequency can be either 2.4 or 5 GHz, the two most common wifi bands.

Opening the Simulation

The Antenna on Human Hand with Dielectric example is accessed from within XSimComposer by the following actions:

  • Select the New → From Example… menu item in the File menu.

  • In the resulting Examples window expand the XSim for Electromagnetics option.

  • Expand the Antennas option.

  • Select “Antenna on Human Hand with Dielectric” and press the Choose button.

  • In the resulting dialog, create a new folder if desired, and press the Save button to create a copy of this example.

The Setup window is now shown with all the implemented physics and geometries. See Fig. 162.

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Fig. 162 Setup Window for the Antenna on Human Hand with Dielectric example, with Grid and farFieldBox History hidden.

Simulation Properties

This file allows the modification of antenna operating frequency, dimensions, orientation, and simulation domain size.

Running the Simulation

  • Proceed to the run window by pressing the Run button in the left column of buttons.

  • Check that you are using these run parameters:

    • Time Step: 3.659083082938294e-12

    • Number of Steps: 3000

    • Dump Periodicity: 300

    • Dump at Time Zero: Checked

  • Click on the Run button in the upper left corner of the right pane.

You will see the output of the run in the right pane. The run has completed when you see the output, “Engine completed successfully”. This result is shown in Fig. 163.

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Fig. 163 The Run Window at the end of execution.

Analyzing the Results

After performing the above actions, continue as follows:

  • Proceed to the Analysis window by pressing the Analyze button in the left column of buttons.

  • Select computeFarFieldFromKirchhoffBox.py from the list and select “Open” (Fig. 164)

  • Input values for the analyzer parameters. The analyzer may be run multiple times, allowing the user to experiment with different values.

    • simulationName: antennaOnHand

    • fieldLabel: E

    • farFieldRadius: 1024.0

    • backgroundEpsRel: 1

    • precision: double

    • numPeriods: 0.25

    • numFarFieldTimes: 2

    • frequency: 5e9

    • numTheta: 45

    • numPhi: 60

    • zeroThetaDirection: (1,0,0)

    • zeroPhiDirection: (0,0,1)

    • incidentWaveAmplitude: blank

    • incidentWaveDirection: (0,0,0)

    • varyingMeshMaxRadius: 0.05

    • principalPlanesOnly: checked

  • Click “Analyze”

  • Depending on the values of numTheta, numPhi, and numFarFieldTimes, the script may need to run for several minutes or longer.

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Fig. 164 The Analyze panel after running computeFarFieldFromKirchhoffBox.py.

Visualizing the Results

  • Proceed to the Visualize Window by pressing the Visualize button in the left column of buttons.

  • Expand Scalar Data

  • Expand farE,

  • Select farE_Magnitude.

  • Expand Geometries

  • Check HandGeomSolidTriangles_surface

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Fig. 165 The Far Field Radiation Pattern.

Further Experiments

The skin can be included as an additional geometry by simply importing the hand geometry a second time within the same set-up, but with a very slightly higher scaling factor (Some “by eye” adjustments of the x-, y-, and z- translation values may be needed).

To add a Skin material:

  • Right click the Materials in the Setup Tree and select Show Material Database

  • Select Custom and then Add to Simulation

  • Double click the Custom material that has now appeared in the Materials section of the setup tree and rename to Skin

  • Finally, change the relative permitivity of the new Skin mateiral to be 40.

One the new Skin material is setup, assign it to the slightly scaled new hand geometry.