GEMS Output

GEMS software is based on Parallel Finite Difference Time Domain metrhod (PFDTD).However, GEMS has both the time domain and frequency domain outputs for the most basic parameters such as port information (return loss, impedance, transmission coefficient), far field (including directivity, gain, axial ratio), SAR and heat. To have a good extension, GEMS also output the time domain information so that hte users can dirve more results from the time domain parameters whenever it is necessary.

Port Output

GEMS provides two types of ports: (1) lumped port and wave port. Lumped port includes excitaation source, matched load, port output parameters such as s-parameters (magnitude in linear and dB scales) and phase, impedance (real and imaginary part), time domain voltage and current outputs.

      The implementation of lumped port in GEMS is relatively simple, you only need to draw a line between the signal line and ground plane and then assiugn it to be a port.

Far Field Output

GEMS can output far field for radiation problems and RCS for scattering problems. You can generate a far field and RCS variations with the spatial angle (phi, theta or both), or variations with the frequencies at the specified directions.

        Far field outputs in GEMS include 2-D and 3-D far field pattern, directivity, gain, axial ratio, polarization, efficiency, monostatic RCS,bistatic RCS.

       You can directly plot these results in the display window, or you can use GEMS data-post processing module to generate more specific results for your applications.

Mode Port Output

GEMS allows you to excite an arbitrary shape of waveguide with any modes, and extract s-parameter of the waveguide port for any modes supported by this waveguide.

       The outputs of a mode port include port s-parameter (magnitude and phase), port impedance (real and imaginary parts), port time domain mode votlage, current, voltage and current differences, which can be used to calculate the port attenuation factor and propagation constant..

FSS Output

You can use GEMS to simulate general periodic structure such as infinite FSS (frequency selective surface), finite FSS (take the edge effect of FSS array), curved FSS (actual application). The FSS screen can be PEC or lossy material, and GEMS can efficiently simulate the multpole layer FSS structure.

SAR Output

GEMS can output 1g SAR, 10g SAR, SAR distribution on a selected surface and in a 3-D region or entire human body. GEMS is a unique software which can simulate entire human body with 1 mm resolution and output and visualize 3-D SAR distribution in entire human body. GEMS allows you to import the voxel data directly and provides a human tissue material library.

      In addition, GEMS allows you to place an antenna inside the human body. GEMS can also calculate the thermal distribution inside the specific region of human body.

Thermal Energy Output

If the material is lossy or conductor and you require the thermal energy distribution in a specific region for the SI, EMC, or EMI probelms, GEMS will generate the thermal energy distribution at the pre-specified frequencies. Like the SAR output, GEMS calculate the heat absorbed by a certain material in the specified volumn.

       Only GEMS can simulate and visualize 3-D thermal distribution in the entire computational domain.

Voltage Output

As an extended option, GEMS allows you to add a voltage excitation or output in anywhere inside the computational domain whenever it is necessary.

      The voltage output is time domain signals and you can use them calculate any other frequency parameters through data-post processing module.

Current Output

As an extended option, GEMS allows you to add a current excitation or output in anywhere inside the computational domain whenever it is necessary.

      The current output is time domain signals and you can use them calculate any other frequency parameters through data-post processing module.

RCS Output

Besides far field pattern, GEMS allows you to calculate the RCS (radar cross section) of a complex structure when a plane wave is incident. When you need to calculate RCS, you need to set the Huygens' box be outside of the plane wave box. GEMS will take care of this for you if you tell GEMS you need the scattered field or total field.

      You can calculate both the monostatic and bistatic RCS for both 2-D and 3-D structures.

1-D Field Output

GEMS allows to generate field output along a streight line in both the time and freuqency domains.

2-D Field Output

GEMS can generate the field or current distributions on a specified plane in both the time domain and frequency domain. The outputs include the differnet components or tangential component.

        GEMS allows you to animiate the field variation on the specified planes at the selected time steps. you can also pick up a curve from the distribution to see the field or current variation along a specific line.

3-D Current Output

GEMS can generate 3-D surface current distribution on the surface of conductor. For the thin PEC plate, GEMS will generate the surface current on both surfaces.

Cartesian and Polar Sysytems

Default coordinate system is Cartesian system, namely, if you double-click on an option in the result tree, the result will be plotted in the Cartesian system.

     You can plot them in the polar system if you like, however, for the dB scale, you need to specify a reference. For the linear scale, you can directly select one option and then click on the Polar button in the toolbar.

1-D Cureve Operations

A 1-D curve may be plotted in the Cartessian or Polar coordinate system or in Smith Chart.

       The basic operations on a 1-D curve include: (1) change its curve color and style; (2) adjust its display range; (3) add its title and axis label; (4) change its legends; (5) plot more than one curves in one figure.

      GEMS allows you to export the data into a data file and export it as a BMP file, a vector format file or a vector curve only. You can copy and paste the curves into Microsoft PowerPoint or Words and then edit it there.

3-D Surface Operations

A 3-D surface data may be plotted in the Cartessian or Polar coordinate system. 3-D surface plots include time domain field and current distributions, frequency domain field and current distributions, and 3-D far field pattern.

       The basic operations on a 3-D surface include: (1) change display scale; (2) view a cut plane; (3) change the figure title.

      GEMS allows you to export the data into a data file. Yo can copy and paste the curves into other figure editor software.

Data Export and Import

Select the output option in the result tree and then the export option in the File menu, you can export the data of the option into a data file. Forethermore, you can export a group of options into a data file if you understand the file format used in GEMS software.

     You can also import a data file to the result tree if you know its format is required by GEMS. After you import a data file, it will appear in the Customize entrance. You can handle it as a regular output option.

Formula Library

GEMS provides you a standard formula library which allows you to generate the results you are interested in from the GEMS direct time domain or frequency domain results. You can define your own hot buttons to conveniently place the formula in the formula box. You can also add your own formulas to the formula library.

Customized Library

GEMS provides some frequently used formulas in the GEMS display module. Whenever it is necessary, you can build your formula library for the special data processing in GEMS data post-processing module. You can also define hot keys for your own formulas and share your library with you colleagues if you are desired to do so.