@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?
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
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?
1 reply
My name is Rohan Gupta and I am a 3rd-year Computer Science undergraduate student at Shri Mata Vaishno Devi University. I have been working with Python for a couple of years now and have in-depth knowledge of it. I look forward to contributing to gprMax as part of this year's GSoC.
My Linkedin Profile:- https://www.linkedin.com/in/rohang4837b4124/
Hello @agianno, @IraGia, and other contributors! My name is Sai and I am currently in my final year in a Materials Science and Engineering(MSE) Bachelors degree from IIT Indore and I am going to join a masters from September. I am interested in working on photonic materials simulation and project #8: "Modelling complex materials" suits my background and I can get a fundamental understanding of FDTD software in a materials context. I have a good understanding of Electromagnetism from my Astronomy minor and I have also received a job offer in a leading software firm as a software engineering associate. I declined this job offer because I wanted a career in research and this project will act as the right platform for me to enter the field of FDTD and photonic materials simulations. I had sent an email to @agianno and @IraGia with more details about my background and suitability to this project.
Could you please guide me as to how to get started and in framing my proposal? Thanks in advance!
2 replies
C:\Users\lwb\gprMax>conda activate gprMax
(gprMax) C:\Users\lwb\gprMax>python -m gprMax user_models/cylinder_Ascan_2D.in
Traceback (most recent call last):
File "C:\Users\lwb\miniconda3\envs\gprMax\lib\runpy.py", line 188, in _run_module_as_main
mod_name, mod_spec, code = _get_module_details(mod_name, _Error)
File "C:\Users\lwb\miniconda3\envs\gprMax\lib\runpy.py", line 147, in _get_module_details
return _get_module_details(pkg_main_name, error)
File "C:\Users\lwb\miniconda3\envs\gprMax\lib\runpy.py", line 111, in _get_module_details
import(pkg_name)
File "C:\Users\lwb\gprMax\gprMax__init__.py", line 11, in <module>
from .gprMax import api as run
File "C:\Users\lwb\gprMax\gprMax\gprMax.py", line 39, in <module>
from gprMax.model_build_run import run_model
File "C:\Users\lwb\gprMax\gprMax\model_build_run.py", line 44, in <module>
from gprMax.fields_updates_ext import update_electric
ModuleNotFoundError: No module named 'gprMax.fields_updates_ext'
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