Simulation Advances. Antenna Applications

Transcription

1 Simulation Advances for RF, Microwave and Antenna Applications Presented by Martin Vogel, PhD Application Engineer 1

2 Overview Advanced Integrated Solver Technologies Finite Arrays with Domain Decomposition Hybrid solving: FEBI, IE Regions Physical Optics Solver in HFSS IE Improved Multi Physics flow in Workbench 2

3 Advanced Solvers: Finite Arrays with DDM 3

4 Finite Arrays with Domain Decomposition Efficient solution for repeating geometries (array) with domain decomposition technique (DDM) ANSYS, Inc. October 24, 2011

5 A Review: Domain Decomposition Distributes mesh domains to network of processors Significantly increases simulation capacity Highly scalable to large numbers of processors Automatic generation of domains by mesh partitioning User friendly Load balance Distributes mesh sub-domains to networked processors and memory 5

6 Finite Antenna Arrays Define unit cell and array dimensions Efficient Domain Decomposition solution Leverages repeating nature of array geometries Only mesh unit cell Virtually repeat mesh throughout array Post process full S parameter Couplings included Edge effects included 3D field visualization Far field patterns for full array Memory efficient Enabled with the HFSS HPC product 6

7 Finite Arrays by Domain Decomposition Each element in array treated as solution domain One compute engine can solve multiple elements/domains in series Distributes element sub-domains to networked processors and memory 7

8 Example: Skewed Waveguide Array 16X16 (256 elements and excitations) Skewed Rectangular Waveguide (WR90) Array 1.3M Matrix Size Using 8 cores 3 hrs. solution time 0.4GB Memory total Using 16 cores 2 hrs. solution time 0.8GB Memory total Additional Cores Faster solution time More memory. Unit cell shown with wireframe view of virtual array 8

9 Skewed Waveguide Array Patterns from 8X8 Array Dashed is idealized infinite array analysis Solid from finite array analysis Two simulations use identical mesh Note edge effects due to finite array size 9

10 Running Finite Array Use Master/Slave unit cell design to adapt the mesh Called Unit Cell for Adaptive Meshing in image Copy/Paste Design Called 8X8 Array in image Create a single pass setup in finite array design On Advanced tab use Setup Link to link mesh from unit cell design Doing adaptive meshing in finite array design will be time consuming and not as efficient 10

11 Efficient: 8X8 Array Patch Array Direct solver with 12 cores 5:05: GB RAM Finite Array DDM with 12 cores 00:44: GB 6.8X faster 33.8X less memory 11

12 HPC: Faster with additional cores Linux cluster 16X Dell PowerEdge R610 Dual six core Xeon X5760, 8GB per core Same 8X8 array of probe feed patch antennas 3M+ matrix size, 64 excitations Study performed using 101, 51,26, 11, 6 and 3 engines.* 101 simulation time = 17 min., 20X faster than direct solver *Three engines used as baseline 7 speed factor speed factor Number of cores

13 Hybrid Solving: Finite Element Boundary Integral 13

14 Finite Element Boundary Integral Solving Larger Problems with Rigor Antenna Placement Study: UHF Antenna on Apache UH64 airframe Finite Elements with DDM Boundary Integral (3D Method of Moments) Hybrid Finite Element Boundary Integral (FE BI) 14

15 Hybrid Solving: Finite Element Boundary Integral Apache helicopter UHF antenna placement 900 MHz Solution volume 1,250 m 3 33,750 λ 3 Solution Specs 72 engines Matrix size = 47M 6 adaptive passes 300 GB RAM 5 hr 30 min Finite Elements with DDM 15

16 Hybrid Solving: Finite Element Boundary Integral Apache helicopter UHF antenna placement 900 MHz Solution surface 173 m λ 2 Solution Specs 12 core MP 680k unknowns 9 adaptive passes 83 GB RAM 5 hr 28 min Boundary Integral, 3D MoM with HFSS IE 16

17 Hybrid Solving: Finite Element Boundary Integral Apache helicopter Hybrid Finite Element Boundary Integral UHF antenna placement 900 MHz FEM solution volume 69 m λ 3 IE solution surface 236 m λ 2 Solution Specs 12 cores total using DDM with MP Matrix Size = 2.9M 6 adaptive passes 21 GB RAM 1hr3 min Compared to 72 core FEM solution 14X less memory, 5.5 times faster 17

18 Summary of FEBI performance Type Time, Ratio Memory, Ratio FEM + DDM 5hr 30min, 1 300GB, 1 IE 5hr 28min, 1 83GB, 3.6 FEBI 1hr 3min, GB,

19 FE BI and Distributed Solving Distributes mesh sub domains to network of processors FEM volume can be subdivided into multiple domains IE Domain is distributed to second node in machine list Significantly increases simulation capacity Multi processor nodes can be utilized HPC distributes mesh sub-domains, FEM and IE domains, to networked processors and memory 19 FEM Domain 1 FEM Domain 2 FEM Domain 3 FEM Domain 4 IE Domain

20 Hybrid Solving: IE Regions 20

21 FEBI and Physically Separate Domains Reflector with multiple FE BI domains Conducting reflector and feed horn each surrounded by air with FEBI applied to surface of air volumes But 3D MoM solution from integral equations could be applied directly to reflector s conducting surface only 21

22 HFSS Hybrid Solving IE Regions Parallelized IE regions solved in parallel. Analogous to FEM domains Rigorous Multiple reflections Automated 22

23 HFSS IE Regions Example 23

24 Physical Optics 24

25 HFSS IE PO Asymptotic solver for very large geometries In HFSS IE Currents are approximated in illuminated regions Set to zero in shadow regions No ray tracing or multiple bounces Target applications: Large reflector antennas RCS of large objects such as satellites Option in solution setup for HFSS IE Sourced by incident wave excitations Plane waves or linked HFSS designs as a source 25

26 Physical Optics Solver in HFSS-IE PEC Where: J PO = 2(n x H inc ) For illuminated surfaces J surf 2(n x H inc ) if perfect conductor. For non-illuminated surfaces J surf 0. No need to solve a large matrix equation. 26

27 PO Examples Notice the shadowing of the gun barrel on the tank and of the tank on the ground. 27

28 HFSS IE PO Example Offset reflector 50 λ 0 in diameter fed by a horn HFSS far field link Simulated with 8 cores IE: 48.3min and 11.9GB PO: 23S and 286MB Note > 120x speedup 28

29 ANSYS Workbench Geometry and material transfer 29

30 Ansoft to ANSYS Geometry Transfer Geometry and material assignment transfer from electromagnetic tools to ANSYS Thermal and Mechanical CAD tool 30

31 Highlights New technique for finite phased array antennas IE Regions Physical Optics Solver in HFSS IE Improved Multiphysics flow 31