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<HTML><HEAD><TITLE>radarFDTD - a full 3D simulation of electromagnetic waves with efficient absorbing boundary conditions</TITLE><LINK REV="made" HREF="mailto:feedback@suse.de"></HEAD><BODY><!-- INDEX BEGIN --><UL> <LI><A HREF="#NAME">NAME</A> <LI><A HREF="#SYNOPSIS">SYNOPSIS</A> <LI><A HREF="#DESCRIPTION">DESCRIPTION</A> <LI><A HREF="#CONFIGURATION_FILE">CONFIGURATION FILE</A> <UL> <LI><A HREF="#VERSION_NUMBER">VERSION NUMBER</A> <LI><A HREF="#MEMORY">MEMORY</A> <LI><A HREF="#MAXIMUM_PML_CONDUCTIVITY">MAXIMUM PML CONDUCTIVITY</A> <LI><A HREF="#MAXIMUM_STRETCHING">MAXIMUM STRETCHING</A> <LI><A HREF="#STEEPNESS">STEEPNESS</A> <LI><A HREF="#SIMULATION_LENGTH">SIMULATION LENGTH</A> <LI><A HREF="#SIZE_OF_SIMULATION_SPACE">SIZE OF SIMULATION SPACE</A> <LI><A HREF="#CELL_SIZES">CELL SIZES</A> <LI><A HREF="#TIME_STEP_SIZE">TIME STEP SIZE</A> <LI><A HREF="#DATA_STORAGE_I">DATA STORAGE I</A> <LI><A HREF="#DATA_STORAGE_II">DATA STORAGE II</A> <LI><A HREF="#NUMBER_OF_PERFECTLY_MATCHED_LAYE">NUMBER OF PERFECTLY MATCHED LAYERS</A> <LI><A HREF="#NUMBER_OF_MATERIALS">NUMBER OF MATERIALS</A> <LI><A HREF="#MATERIAL_PARAMETERS">MATERIAL PARAMETERS</A> <LI><A HREF="#NUMBER_OF_MATERIAL_BOXES">NUMBER OF MATERIAL BOXES</A> <LI><A HREF="#POSITIONS_OF_MATERIAL_BOXES">POSITIONS OF MATERIAL BOXES</A> <LI><A HREF="#NUMBER_OF_TRANSMITTER_BOXES">NUMBER OF TRANSMITTER BOXES</A> <LI><A HREF="#POSITION_OF_TRANSMITTER_BOXES">POSITION OF TRANSMITTER BOXES</A> <LI><A HREF="#CHOOSING_TRANSMITTER_MODE">CHOOSING TRANSMITTER MODE</A> <LI><A HREF="#NUMBER_OF_RECEIVER_BOXES">NUMBER OF RECEIVER BOXES</A> <LI><A HREF="#RECEIVER_SPECIFICATION">RECEIVER SPECIFICATION</A> <LI><A HREF="#END_OF_CONFIG_FILE">END OF CONFIG FILE</A> </UL> <LI><A HREF="#CONTACT">CONTACT</A></UL><!-- INDEX END --><HR><P><H1><A NAME="NAME">NAME</A></H1><P>radarFDTD - a full 3D simulation of electromagnetic waves with efficientabsorbing boundary conditions<P><HR><H1><A NAME="SYNOPSIS">SYNOPSIS</A></H1><P>radarFDTD directory [configuration file]<P><HR><H1><A NAME="DESCRIPTION">DESCRIPTION</A></H1><P>When started the program needs a directory as a command line parameter. Ifthere is no second parameter defined it assumes the file is named sim.cfg.After starting it will output quite a few informations about the simulationit is going to start. The most important part is the section about memory,do not try to run the program in the swap area, since this will surely slowit down and may risk your hard disk which may start to smoke after a fewweeks of hard work :-(.<P><HR><H1><A NAME="CONFIGURATION_FILE">CONFIGURATION FILE</A></H1><P>In this section there will be a short description of all sections withinthe file sim.cfg. Feel free to experiment with those settings, but do notblame me, if something goes entirely wrong... ;-)<P>Since I am not a native English speaker, I hope you are not offended if Ileft some mistakes in here.<P>Last thing, before we start: all lines which are empty or have a leadingpound sign '#' are ignored (BTW, can someone explain to me why this doublecross is called pound sign?).<P><HR><H2><A NAME="VERSION_NUMBER">VERSION NUMBER</A></H2><P><PRE> # version number is... 3</PRE><P>This just states the version number this configuration file was writtenfor. This is checked by the program and if it does not match the internallayout, it will not use it.<P><HR><H2><A NAME="MEMORY">MEMORY</A></H2><P><PRE> # maximum number of bytes the program may allocate 100000000</PRE><P>This is the number of bytes the program is allowed to allocate. Pleasechange this according to your own need (or the memory limits of yourcomputer; remember: this limit should be less than the physical amount ofmemory installed)<P><HR><H2><A NAME="MAXIMUM_PML_CONDUCTIVITY">MAXIMUM PML CONDUCTIVITY</A></H2><P><PRE> # insert maximum pml conductivity here [S/m] 0.025</PRE><P>There is a fixed equation which rules the rise of conductivity. If you areinterested in a more detailed explanation, have a look at the paper of Fangand Wu from 1996 (citation can be found in the README file). As a goodfirst guess try something between 10 and 50 mS/m, which should bereasonable good.<P><HR><H2><A NAME="MAXIMUM_STRETCHING">MAXIMUM STRETCHING</A></H2><P><PRE> # insert maximum pml-stretching here [1] 4.0</PRE><P>Stretching should prevent evanescent waves to keep on moving within theperfectly matched layers, do not use too high values here, 2 to 4 seems tobe quite reasonable.<P><HR><H2><A NAME="STEEPNESS">STEEPNESS</A></H2><P><PRE> # insert steepness here 2.0</PRE><P>The higher the value for steepness is, the less reflection will occur atthe boundary between the simulation space and the absorbing layer which isgenerally a good thing. But unfortunately a high value here means thatthere will be a high reflection before a wave manages to reach the layer,which is a PEC (perfectly conducting layer)<P><HR><H2><A NAME="SIMULATION_LENGTH">SIMULATION LENGTH</A></H2><P><PRE> # Length of Simulation [s] 30.0e-9</PRE><P>This just states the overall time duration of the simulation in seconds. Donot try to run a simulation too long, i.e. for a few seconds if yoursimulation space is only a few meters wide... it will take ages<P><HR><H2><A NAME="SIZE_OF_SIMULATION_SPACE">SIZE OF SIMULATION SPACE</A></H2><P><PRE> # size of simulation space (number of boxes in x-, y- and z-direction, respectively 41 41 41</PRE><P>These three numbers specify how man cells are used in each direction (letus call them x,y and z for the time being). I usually use odd numbers, so Ican place the transmitter in the very middle of the simulation box, buthandle this as you like to<P><HR><H2><A NAME="CELL_SIZES">CELL SIZES</A></H2><P><PRE> # real size of a box [m] (x,y,z) 0.025 0.025 0.025</PRE><P>Here you specify how big (or small) a single Yee-cell should be, in thisexample this is about 2.5 cm (which is roughly an inch ;-)). Be carefulwith this selection, since you should have at least 10 boxes per mainwavelength you want to simulate, otherwise you might get strange wavythings out of the simulation.<P><HR><H2><A NAME="TIME_STEP_SIZE">TIME STEP SIZE</A></H2><P><PRE> # this number is a bit special: if positive it is the size of a time steps in seconds, # if negative, a matching time step is computed via the Courant-criterion # and finally divided by this number, i.e. ⌨️ 快捷键说明
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