[ Overview |
lucernhammer MT |
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[ Benchmark Data |
FAQ |
Ordering Information ]
[ Overview |
lucernhammer MT |
Serenity |
Galaxy |
Orion |
Lyra |
Emerald ]
[ Benchmark Data |
FAQ |
Ordering Information ]
UT Austin Thin Plate Benchmarks
On this page are presented simulated RCS for several thin plate targets from the Austin Benchmark Suites for Computational Electromagnetics, a publicly available benchmark suite for RCS simulations. The suite is available on github via the following link:
http://github.com/UTAustinCEMGroup/AustinCEMBenchmarks.
The construction and measurement of these plate targets is covered in considerable detail in a powerpoint presentation within the benchmark suite, so we will not repeat that information here. It is worth noting that the dimensions and aspect ratio of the plates in this benchmark were chosen to effect a revisit of the "business card" thin plate target considered previously by the EMCC, but with significantly more frequency and material diversity.
The thin plate targets considered below are: PEC plate, dielectric plate, MAGRAM plate, MAGRAM loaded PEC plate, and MAGRAM loaded dielectric plate.
The dimensions and measurement setup for the thin plate targets is shown below. The plates have a width of W, length of 7W/4, and a thickness t. The plates were mounted on a foam column in the range and rotated in the xy plane, so our simulations follow this setup with observations at an elevation angle of 0 degrees and azimuths between 0 and 90 (or 180) degrees.
All calculations below were performed on a Dell Precision T7900 workstation running Ubuntu Linux, with dual twelve-core Intel Xeon CPUs (E5-2690 v3) at 2.6 GHz with 256 GB of RAM, and dual NVIDIA GTX 1080Ti GPUs, each with 12GB of onboard RAM. Serenity utilizes both GPUs, and the Adaptive Cross Approximation (ACA) was used for all test cases.
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Thin plate dimensions and scattering coordinate system (from benchmark). |
The five target configurations are illustrated in more detail in the graphic from the benchmark below.
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Thin plates problem description (from benchmark) |
PEC Plate
Per the benchmark, the PEC plate comprised a 6 x 10.5 inch piece of 6061-T6 aluminum, with a thickness of 64 mil (0.064 inches). For Serenity, this is modeled in Rhinoceros 3D as a three-dimensional thin slab of the same dimensions, and a surface mesh was generated to achieve approximately 12 unknowns per wavelength at 10.24 GHz (highest frequency in the benchmark). These are illustrated in the graphic below.
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| Slab surface model | Slab surface mesh |
As this object is very thin, we will apply only the EFIE in the MoM solution. This yielded results more closely aligned with the measurements than when using the CFIE with an alpha = 0.5.
Dielectric Plate
A low-loss dielectric plate was 3D-printed using Polymax polylactic acid (PLA) filament. This plate has the same width and thickness as the PEC plate, but its thickness was slightly less at 1.5 mm. For input into Serenity, the facet model for the PEC plate was reused, but scaled down slightly to yield a total thickness of 1.5mm.
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| PLA Filament Material Properties |
The material properties of the PLA filament are summarized in the table above, taken from the benchmark. These were entered as-is into the Serenity material summary file.
MAGRAM Plate
The MAGRAM plate comprises a piece of ARC Technologies DD-13490 Magnetic Absorber, having the same overall dimensions as the dielectric plate. The facet model for the dielectric plate was reused, but with the different material properties summarized in the table below (per the benchmark). In Serenity, this problem is treated in exactly the same way as the dielectric plate, but with these different material properties.
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| MAGRAM Material Properties |
MAGRAM-Coated PEC Plate
This problem consists of a 64 mil thick PEC plate coated with 1.5 mm of MAGRAM. It was not stated explicitly in the benchmark how this target was assembled, though a reasonable assumption is that the PEC and MAGRAM plates considered previously were simply stacked together. It is shown in several of the slides that a piece of foam was used to support the PEC and dielectric plates, so it is reasonable to assume that the piece of MAGRAM was simply slid into the foam in front of the PEC plate, without the need for adhesive between the plates.
To construct a facet model for this object, the facet models for the PEC plate and dielectric plate were joined together with a septum dividing the halves. This yields separate boundaries between the free space and PEC region, free space and dielectric region, and the PEC and MAGRAM region, respectively.
MAGRAM-Coated Dielectric Plate
This problem consists of the 1.5 mm thick dielectric plate coated with 1.5 mm of MAGRAM. It is assumed that this target was put together following the same process used to assemble the MAGRAM-Coated PEC Plate.
For this object, the facet model for the MAGRAM-Coated PEC Plate was reused, with the PEC rear portion scaled slightly so as to yield a thickness of 1.5 mm.
CAD Models
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| Thin PEC Plate VV RCS, 2.56 GHz | Thin PEC Plate HH RCS, 2.56 GHz |
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| Thin PEC Plate VV RCS, 5.12 GHz | Thin PEC Plate HH RCS, 5.12 GHz |
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| Thin PEC Plate VV RCS, 7.0 GHz | Thin PEC Plate HH RCS, 7.0 GHz |
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| Thin PEC Plate VV RCS, 10.24 GHz | Thin PEC Plate HH RCS, 10.24 GHz |
Compared here is the RCS of the Thin PEC Plate at 2.56, 5.12, 7.0 and 10.24 GHz. For this test case, we have also included results obtained by Serenity for a plate with zero thickness, to illustrate the difference. To obtain a facet model for the zero thickness plate, the front face of the thin plate model was extracted and the rest of the model simply deleted. The differences in the RCS are readily apparent, particularly at angles above 45 degrees. Clearly, a model with finite thickness is needed to accurately model the scattered field of the thin plate. A similar observation was made in the benchmark with their own simulated results.
2.56 GHz Data:
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| Thin Dielectric Plate VV RCS, 2.56 GHz | Thin Dielectric Plate HH RCS, 2.56 GHz |
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| Thin Dielectric Plate VV RCS, 5.12 GHz | Thin Dielectric Plate HH RCS, 5.12 GHz |
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| Thin Dielectric Plate VV RCS, 7.0 GHz | Thin Dielectric Plate HH RCS, 7.0 GHz |
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| Thin Dielectric Plate VV RCS, 10.24 GHz | Thin Dielectric Plate HH RCS, 10.24 GHz |
Compared here is the RCS of the Thin Dielectric Plate at 2.56, 5.12, 7.0 and 10.24 GHz. We note that the measurement differs from the simulation quite significantly for incident angles greater than 60 degrees. In the benchmark, it was stated that this was due to backscattering from the foam support column in the measurement range, and further compounded by the low RCS of the dielectric plate. This caused their coherent background subtraction to be insufficient in characterizing the target's RCS.
Materials Files:
2.56 GHz Data:
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| Thin MAGRAM Plate VV RCS, 2.56 GHz | Thin MAGRAM Plate HH RCS, 2.56 GHz |
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| Thin MAGRAM Plate VV RCS, 5.12 GHz | Thin MAGRAM Plate HH RCS, 5.12 GHz |
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| Thin MAGRAM Plate VV RCS, 7.0 GHz | Thin MAGRAM Plate HH RCS, 7.0 GHz |
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| Thin MAGRAM Plate VV RCS, 10.24 GHz | Thin MAGRAM Plate HH RCS, 10.24 GHz |
Compared here is the RCS of the Thin MAGRAM Plate at 2.56, 5.12, 7.0 and 10.24 GHz. The comparison is fairly good.
Materials Files:
2.56 GHz Data:
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| MAGRAM Coated PEC Plate VV RCS, 2.56 GHz | MAGRAM Coated PEC Plate HH RCS, 2.56 GHz |
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| MAGRAM Coated PEC Plate VV RCS, 5.12 GHz | MAGRAM Coated PEC Plate HH RCS, 5.12 GHz |
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| MAGRAM Coated PEC Plate VV RCS, 7.0 GHz | MAGRAM Coated PEC Plate HH RCS, 7.0 GHz |
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| MAGRAM Coated PEC Plate VV RCS, 10.24 GHz | MAGRAM Coated PEC Plate HH RCS, 10.24 GHz |
Compared here is the RCS of the Thin MAGRAM Coated PEC Plate at 2.56, 5.12, 7.0 and 10.24 GHz. The effects of the RAM are readily apparent versus increasing frequency, and the overall comparison with the measurements is very good, particularly at higher frequencies.
Materials Files:
2.56 GHz Data:
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| MAGRAM Coated Dielectric Plate VV RCS, 2.56 GHz | MAGRAM Coated Dielectric Plate HH RCS, 2.56 GHz |
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| MAGRAM Coated Dielectric Plate VV RCS, 5.12 GHz | MAGRAM Coated Dielectric Plate HH RCS, 5.12 GHz |
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| MAGRAM Coated Dielectric Plate VV RCS, 7.0 GHz | MAGRAM Coated Dielectric Plate HH RCS, 7.0 GHz |
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| MAGRAM Coated Dielectric Plate VV RCS, 10.24 GHz | MAGRAM Coated Dielectric Plate HH RCS, 10.24 GHz |
Compared here is the RCS of the Thin MAGRAM Coated Dielectric Plate at 2.56, 5.12, 7.0 and 10.24 GHz. The RCS is fairly symmetric about 90 degrees, suggesting that the overall backscatter from this object is due mostly to the MAGRAM, with the dielectric portion having little influence on the overall RCS. The comparison is fairly good, though the simulated RCS is slightly lower than the measurements across a wide range of observation angles. The reason for this is not known.
Materials Files:
2.56 GHz Data: