| GEMS Simulator |
You can easily use the multiple cores/CPUs inside your PC to speed up the simulation. You can also manually assign the simulation job to each core or CPU to efficiently use the compute resource.
GEMS PC version allows you to use a PC to a moderate size EM problem in a reasonable time (say, from 30 minutes to 2 hours). A dual core processor can speed up the simulation 2 times than a solo core processor. The actual efficiency depends on the CPU type and architecture as well.
Due to the unique memory allocation technique and update procedure in the GEMS software, GEMS can save the 20-40% memory requirement and speed up the simulation 200-300% faster than other FDTD based commercial software.
GEMS PC Version supports Windows XP 32/64 bit system, Windows Vista 32/64 bit system, and Windows 2000. |
| GEMS PC Version Standard Benchmark |
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Antenna type: Helical antenna
Length of helix cross secion: 0.6 mm
Diamter of circular plate: 70 mm
Outputs: Far field pattern
return loss
3-D heat distribution
3-D current distribution
Simulation time: 6 minutes and 30 seconds
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Human body: Kit body
Height: 740 mm
Resolution: 1 mm
Material: 70 layers of tissues
Excitation: Plane wave source
Boundary: 6-layer PML
Outputs: 3-D SAR distribution
3-D heat distribution
1g SAR, 10g SAR Maximum SAR and average SAR
Simulation time: 90 minutes |
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Problem type: Cellphone antenna
Excitation: Coaxial cable
Boundary: 6-layer PML
Outputs: 3-D far field pattern
3-D current distribution
Return loss
Simulation time: 20 seconds |
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Problem type: Signal Integrity
Excitation: Lumped port feed
Boundary: 6-layer PML
Outputs: Transmitted signal
Return loss
Tranmission coefficient
Simulation time: 44 minutes |
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Problem type: GPS antenna
Excitation: Lumped port feed
Boundary: 6-layer PML
Outputs: 3-D far field pattern
3-D current distribution
Return loss
Simulation time: 25 seconds |
A computational domain is discretized into 300x300x300 cells, which is truncated by PEC boundary. We use four different types of PCs to simulate this problem, and the significant advantage of a daul core processor over the solo core processor is edvident from the table below.
CPU type |
Problem size (cells) |
Memory usage |
Simulation time
(1,000 time steps) |
Dual core Intel 2.33 GHz |
300x300x300 |
780 MB |
16 min. 41 sec. |
Dual core Intel 1.83 GHz |
300x300x300 |
780 MB |
24 min. 55 sec. |
Intel Pentium 4 3.0 GHz |
300x300x300 |
780 MB |
25 min. 45 sec. |
Intel Pentium M 2.0 GHz |
300x300x300 |
780 MB |
34 min. 55 sec. |
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Comparison of GEMS PC Version with other FDTD Based Software |
For a helix antenna problem, we compare GEMS with a fast FDTD based commerical software package in terms of memory requirement and simulation time. It is evident that GEMS is much faster then the so-called fast FDTD based software package and uses much less memory than the fast FDTD based commercial software package. The test data for other FDTD based software was carried out by the third party independently based on Intel Pentium D Dual Core 3.4GHz.
If we use a PC including 2 dual core processors with intel Xeon 2.33GHz to simulate the same problem, GEMS only took 24
minutes for 14,500 time steps.GEMS software is a very fast solver and it can further accelerate the simulation using a multiple processor PC. The users do not need to pay extra money for the additional processor if the two processors are installed inside one PC.
If we use 4 PCs (each of them includes 2 dual core processors with intel Xeon 2.33GHz) to simulate the same problem, GEMS only took 6 minutes and 30 seconds for 14,500 time steps. GEMS software can use multiple PCs to accelerate the simulation using a multiple core processor.
Summary of memory requirement and simulation time are plotted in the figures below.
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