also it could be an idea to provide a docker application?
@better1002 please read the docs, there is plenty of information and examples that show you how to do this - http://docs.gprmax.com/en/latest/output.html#geometry-output
@Alex-VVV diagonal anisotropy is supported - http://docs.gprmax.com/en/latest/features.html#anisotropic-materials
@craig-warren I see that diagonal anisotropy is supported. I guess I wasn’t clear enough, my bad. My material as has a different dielectric constant for the x,y,z direction, so features diagonal anisotropy. My problem is this: those dielectric constants are a function of position. I.e. the value of ε_x at x=0 is not the same as at x=1.
Is this supported?
@Alex-VVV it is possible, but not particularly elegant. You would have to define a new material for each new position. Could be done programmatically using Python in the input file, but really depends on how much variation you have as to the number of materials you would need to create.
@bsesasts Our analytical comparisons with the solution of an infinitesimal dipole are pretty close (http://docs.gprmax.com/en/latest/comparisons_analytical.html) I don't understand why yours are different. Be aware that when you specify the waveform on gprMax for a Hertzian dipole you are specifying the current that runs on this dipole and not a Voltage source gap used to excite that structures of models of real antennas
My input file：
domain: 1.5 1.5 0.0015
dx_dy_dz: 0.0015 0.0015 0.0015
time_window: 35e-9
material: 1.0 0 1.0 0 atmosphere
material: 81.0 0.003 1.0 0 fresh_water
material: 12.0 0.004 1.0 0 L1
waveform: ricker 1 800e6 my_ricker
hertzian_dipole: z 0.15 1.3 0 my_ricker
rx: 0.25 1.3 0
src_steps: 0.02 0 0
rx_steps: 0.02 0 0
box: 0 0 0 1.5 1.5 0.0015 atmosphere
box: 0 0 0 1.5 1.3 0.0015 L1
cylinder: 0.7 0.9 0 0.7 0.9 0.0015 0.25 atmosphere
Definition of reflection coefficient：r=(√(ε_1 )-√(ε_2 ))/(√(ε_1 )+√(ε_2 ))-----------（1）；r：Reflection coefficient，ε_1：Relative permittivity of the first dielectric， ε_2：Relative permittivity of the second dielectric。The phase polarity of reflection wave mainly depends on the dielectric constant of the upper and lower layers，When the relative dielectric constant of the upper medium is larger than that of the lower medium, the reflection number is positive, the phase of the reflected wave is positive, which is consistent with the phase of the initial electromagnetic wave, and vice versa.
A shown in the input file：dielectric constant of the background medium ε_1=12，atmosphere ε_2=1。According to the definition formula of reflection coefficient (1)：The electromagnetic wave is projected from the surface to the top of the cavity, that is, the interface between the background medium and the air. Because of 12>1,,the reflection coefficient is r positive, so the phase of the reflected wave is positive, the phase of the reflected wave is not reversed, and it is consistent with the direct wave。For example，The initial phase of visible radar direct wave is positive (red-blue-red), the phase indicated by the blackest arrow in the A-SCAN is consistent with that of the top black arrow in the B-SCAN and the reflection coefficient formula.
At this point, one part of the electromagnetic wave is reflected at the top of the cavity, and the other part continues to propagate downward through the top of the cavity，To the bottom of the cavity, it can be considered as the interface between air and background media.Now atmosphere ε_2=1, dielectric constant of the background medium ε_1=12，Because of 12>1, According to the definition formula of reflection coefficient (1)，The reflection coefficient is negative, and the phase of the reflected wave at the bottom of the cavity should be opposite to that of the direct wave, which is negative (blue-red-blue). However, the phase is visible from the green arrow in figure A-SCAN, the phase is still positive, and the green arrow in the corresponding B-SCAN indicates that the phase is consistent, positive and the phase is not reverse. This is contrary to the reflection coefficient formula. Why?
A shown in the input file：dielectric constant of the background medium ε_1=12，atmosphere ε_2=1。According to the definition formula of reflection coefficient (1)：The electromagnetic wave is projected from the surface to the top of the cavity, that is, the interface between the background medium and the air. Because of 12>1,,the reflection coefficient is r positive, so the phase of the reflected wave is positive, the phase of the reflected wave is not reversed, and it is consistent with the direct wave。For example，The initial phase of visible radar direct wave is positive (red-blue-red), the phase indicated by the blackest arrow in the A-SCAN is consistent with that of the top black arrow in the B-SCAN and the reflection coefficient formula.
At this point, one part of the electromagnetic wave is reflected at the top of the cavity, and the other part continues to propagate downward through the top of the cavity，To the bottom of the cavity, it can be considered as the interface between air and background media.Now atmosphere ε_2=1, dielectric constant of the background medium ε_1=12，Because of 12>1, According to the definition formula of reflection coefficient (1)，The reflection coefficient is negative, and the phase of the reflected wave at the bottom of the cavity should be opposite to that of the direct wave, which is negative (blue-red-blue). However, the phase is visible from the green arrow in figure A-SCAN, the phase is still positive, and the green arrow in the corresponding B-SCAN indicates that the phase is consistent, positive and the phase is not reverse. This is contrary to the reflection coefficient formula. Why?
@craig-warren can you help me?please
I have come across a paper regarding tree interior imaging to find whether it is hollow or not. I am trying to implement using sfcw waveform since practically it is more realizable. Can I get some support in simulation before I make hardware? sfcw waveform generation, antenna parameters, bistatic system, B scan, and data processing. I work in a research lab and we look forward to developing the hardware.
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