[eme / examples] add EME examples
This commit is contained in:
Forgejo Actions
parent
9a0c693848
commit
f8ad0250d1
5 changed files with 537 additions and 0 deletions
310
examples/eme_bend.py
Normal file
310
examples/eme_bend.py
Normal file
|
|
@ -0,0 +1,310 @@
|
|||
"""
|
||||
Mode-matching / EME example for a straight-to-bent waveguide interface.
|
||||
|
||||
This example demonstrates a cylindrical-waveguide EME workflow:
|
||||
|
||||
1. build a rib-waveguide cross-section,
|
||||
2. solve straight port modes with `waveguide_2d`,
|
||||
3. solve bend modes with `waveguide_cyl`,
|
||||
4. assemble the straight-to-bend interface scattering matrix with
|
||||
`meanas.fdfd.eme.get_s(...)`,
|
||||
5. optionally cascade a straight section, bend section, and interface pair into
|
||||
a compact multiport network using `scikit-rf`.
|
||||
"""
|
||||
|
||||
from __future__ import annotations
|
||||
|
||||
import importlib
|
||||
|
||||
import numpy
|
||||
from numpy import pi
|
||||
from scipy import sparse
|
||||
|
||||
import gridlock
|
||||
from gridlock import Extent
|
||||
|
||||
from meanas.fdfd import eme, waveguide_2d, waveguide_cyl
|
||||
from meanas.fdmath import unvec
|
||||
|
||||
|
||||
WL = 1310.0
|
||||
DX = 40.0
|
||||
RADIUS = 6e3
|
||||
WIDTH = 400.0
|
||||
THF = 161.0
|
||||
THP = 77.0
|
||||
EPS_SI = 3.51 ** 2
|
||||
EPS_OX = 1.453 ** 2
|
||||
MODE_NUMBERS = numpy.array([0])
|
||||
STRAIGHT_SECTION_LENGTH = 12e3
|
||||
BEND_ANGLE = pi / 2
|
||||
|
||||
|
||||
def require_optional(name: str, package_name: str | None = None):
|
||||
package_name = package_name or name
|
||||
try:
|
||||
return importlib.import_module(name)
|
||||
except ImportError as exc: # pragma: no cover - user environment guard
|
||||
raise SystemExit(
|
||||
f"This example requires the optional package '{package_name}'. "
|
||||
"Install example dependencies with `pip install -e './meanas[examples]'`.",
|
||||
) from exc
|
||||
|
||||
|
||||
def build_geometry(
|
||||
*,
|
||||
dx: float = DX,
|
||||
width: float = WIDTH,
|
||||
thf: float = THF,
|
||||
thp: float = THP,
|
||||
eps_si: float = EPS_SI,
|
||||
eps_ox: float = EPS_OX,
|
||||
) -> tuple[gridlock.Grid, numpy.ndarray, list[list[numpy.ndarray]], float]:
|
||||
x0 = (width / 2) % dx
|
||||
omega = 2 * pi / WL
|
||||
|
||||
grid = gridlock.Grid(
|
||||
[
|
||||
numpy.arange(-800, 800 + dx, dx),
|
||||
numpy.arange(-400, 400 + dx, dx),
|
||||
numpy.arange(-2 * dx, 2 * dx + dx, dx),
|
||||
],
|
||||
periodic=True,
|
||||
)
|
||||
epsilon = grid.allocate(eps_ox)
|
||||
|
||||
grid.draw_cuboid(
|
||||
epsilon,
|
||||
foreground=eps_si,
|
||||
x=Extent(center=x0, span=width + 1200),
|
||||
y=Extent(min=0, max=thf),
|
||||
z=Extent(min=-1e6, max=0),
|
||||
)
|
||||
grid.draw_cuboid(
|
||||
epsilon,
|
||||
foreground=eps_ox,
|
||||
x=Extent(max=-width / 2, span=300),
|
||||
y=Extent(min=thp, max=1e6),
|
||||
z=Extent(min=-1e6, center=0),
|
||||
)
|
||||
grid.draw_cuboid(
|
||||
epsilon,
|
||||
foreground=eps_ox,
|
||||
x=Extent(min=width / 2, span=300),
|
||||
y=Extent(min=thp, max=1e6),
|
||||
z=Extent(min=-1e6, center=0),
|
||||
)
|
||||
|
||||
dxes = [grid.dxyz, grid.autoshifted_dxyz()]
|
||||
dxes_2d = [[d[0], d[1]] for d in dxes]
|
||||
return grid, epsilon, dxes_2d, omega
|
||||
|
||||
|
||||
def solve_straight_modes(
|
||||
epsilon_slice: numpy.ndarray,
|
||||
*,
|
||||
omega: float,
|
||||
dxes_2d: list[list[numpy.ndarray]],
|
||||
mode_numbers: numpy.ndarray = MODE_NUMBERS,
|
||||
) -> tuple[list[tuple[numpy.ndarray, numpy.ndarray]], numpy.ndarray]:
|
||||
e_xys, wavenumbers = waveguide_2d.solve_modes(
|
||||
epsilon=epsilon_slice.ravel(),
|
||||
omega=omega,
|
||||
dxes=dxes_2d,
|
||||
mode_numbers=mode_numbers,
|
||||
)
|
||||
eh_fields = [
|
||||
waveguide_2d.normalized_fields_e(
|
||||
e_xy,
|
||||
wavenumber=wavenumber,
|
||||
dxes=dxes_2d,
|
||||
omega=omega,
|
||||
epsilon=epsilon_slice.ravel(),
|
||||
)
|
||||
for e_xy, wavenumber in zip(e_xys, wavenumbers, strict=True)
|
||||
]
|
||||
return eh_fields, wavenumbers
|
||||
|
||||
|
||||
def solve_bend_modes(
|
||||
epsilon_slice: numpy.ndarray,
|
||||
*,
|
||||
omega: float,
|
||||
dxes_2d: list[list[numpy.ndarray]],
|
||||
rmin: float,
|
||||
mode_numbers: numpy.ndarray = MODE_NUMBERS,
|
||||
) -> tuple[list[tuple[numpy.ndarray, numpy.ndarray]], numpy.ndarray, numpy.ndarray]:
|
||||
e_xys, angular_wavenumbers = waveguide_cyl.solve_modes(
|
||||
epsilon=epsilon_slice.ravel(),
|
||||
omega=omega,
|
||||
dxes=dxes_2d,
|
||||
mode_numbers=mode_numbers,
|
||||
rmin=rmin,
|
||||
)
|
||||
linear_wavenumbers = waveguide_cyl.linear_wavenumbers(
|
||||
e_xys=e_xys,
|
||||
angular_wavenumbers=angular_wavenumbers,
|
||||
rmin=rmin,
|
||||
epsilon=epsilon_slice.ravel(),
|
||||
dxes=dxes_2d,
|
||||
)
|
||||
eh_fields = [
|
||||
waveguide_cyl.normalized_fields_e(
|
||||
e_xy,
|
||||
angular_wavenumber=angular_wavenumber,
|
||||
dxes=dxes_2d,
|
||||
omega=omega,
|
||||
epsilon=epsilon_slice.ravel(),
|
||||
rmin=rmin,
|
||||
)
|
||||
for e_xy, angular_wavenumber in zip(e_xys, angular_wavenumbers, strict=True)
|
||||
]
|
||||
return eh_fields, linear_wavenumbers, angular_wavenumbers
|
||||
|
||||
|
||||
def build_cascaded_network(
|
||||
skrf,
|
||||
*,
|
||||
interface_s: numpy.ndarray,
|
||||
straight_wavenumbers: numpy.ndarray,
|
||||
bend_angular_wavenumbers: numpy.ndarray,
|
||||
n_modes: int,
|
||||
) -> object:
|
||||
net_sb = skrf.Network(f=[1 / WL], s=interface_s[numpy.newaxis, ...])
|
||||
net_bs = net_sb.copy()
|
||||
net_bs.renumber(numpy.arange(2 * n_modes), numpy.roll(numpy.arange(2 * n_modes), n_modes))
|
||||
|
||||
straight_phase = sparse.diags_array(numpy.exp(-1j * straight_wavenumbers[:n_modes] * STRAIGHT_SECTION_LENGTH))
|
||||
bend_phase = sparse.diags_array(numpy.exp(-1j * bend_angular_wavenumbers[:n_modes] * BEND_ANGLE))
|
||||
zero = numpy.zeros((n_modes, n_modes), dtype=complex)
|
||||
|
||||
straight_s = numpy.block([[zero, straight_phase.toarray()], [straight_phase.toarray(), zero]])
|
||||
bend_s = numpy.block([[zero, bend_phase.toarray()], [bend_phase.toarray(), zero]])
|
||||
net_straight = skrf.Network(f=[1 / WL], s=straight_s[numpy.newaxis, ...])
|
||||
net_bend = skrf.Network(f=[1 / WL], s=bend_s[numpy.newaxis, ...])
|
||||
|
||||
return skrf.network.cascade_list([net_straight, net_sb, net_bend, net_bs, net_straight])
|
||||
|
||||
|
||||
def print_summary(
|
||||
interface_s: numpy.ndarray,
|
||||
cascaded_s: numpy.ndarray,
|
||||
straight_wavenumbers: numpy.ndarray,
|
||||
bend_linear_wavenumbers: numpy.ndarray,
|
||||
bend_angular_wavenumbers: numpy.ndarray,
|
||||
omega: float,
|
||||
n_modes: int,
|
||||
) -> None:
|
||||
straight_neff = numpy.real(straight_wavenumbers / omega)
|
||||
bend_neff = numpy.real(bend_linear_wavenumbers / omega)
|
||||
print('straight effective indices:', ', '.join(f'{value:.5f}' for value in straight_neff[:4]))
|
||||
print('bend effective indices :', ', '.join(f'{value:.5f}' for value in bend_neff[:4]))
|
||||
print('bend angular wavenumbers :', ', '.join(f'{value:.5e}' for value in bend_angular_wavenumbers[:4]))
|
||||
|
||||
interface_transmission = abs(interface_s[n_modes, 0]) ** 2
|
||||
interface_reflection = abs(interface_s[0, 0]) ** 2
|
||||
print(f'interface fundamental transmission |S_{n_modes},0|^2 = {interface_transmission:.6f}')
|
||||
print(f'interface fundamental reflection |S_00|^2 = {interface_reflection:.6f}')
|
||||
|
||||
total_cascaded_output = numpy.sum(abs(cascaded_s[:, 0]) ** 2)
|
||||
bend_through = abs(cascaded_s[n_modes, 0]) ** 2
|
||||
bend_reflection = abs(cascaded_s[0, 0]) ** 2
|
||||
print(f'cascaded bend through power |S_{n_modes},0|^2 = {bend_through:.6f}')
|
||||
print(f'cascaded bend reflection |S_00|^2 = {bend_reflection:.6f}')
|
||||
print(f'cascaded left-incident total output power = {total_cascaded_output:.6f}')
|
||||
|
||||
|
||||
def plot_results(
|
||||
*,
|
||||
pyplot,
|
||||
interface_s: numpy.ndarray,
|
||||
cascaded_s: numpy.ndarray,
|
||||
straight_mode: tuple[numpy.ndarray, numpy.ndarray],
|
||||
bend_mode: tuple[numpy.ndarray, numpy.ndarray],
|
||||
shape_2d: tuple[int, int],
|
||||
) -> None:
|
||||
fig_s, axes = pyplot.subplots(1, 2, figsize=(12, 4))
|
||||
interface_plot = axes[0].imshow(abs(interface_s) ** 2, origin='lower', cmap='magma')
|
||||
fig_s.colorbar(interface_plot, ax=axes[0])
|
||||
axes[0].set_title('Straight-to-bend interface |S|^2')
|
||||
axes[0].set_xlabel('Incident mode index')
|
||||
axes[0].set_ylabel('Outgoing mode index')
|
||||
|
||||
cascaded_plot = axes[1].imshow(abs(cascaded_s) ** 2, origin='lower', cmap='magma')
|
||||
fig_s.colorbar(cascaded_plot, ax=axes[1])
|
||||
axes[1].set_title('Cascaded bend network |S|^2')
|
||||
axes[1].set_xlabel('Incident mode index')
|
||||
axes[1].set_ylabel('Outgoing mode index')
|
||||
|
||||
straight_e = unvec(straight_mode[0], shape_2d)
|
||||
bend_e = unvec(bend_mode[0], shape_2d)
|
||||
straight_intensity = numpy.sum(abs(straight_e) ** 2, axis=0).T
|
||||
bend_intensity = numpy.sum(abs(bend_e) ** 2, axis=0).T
|
||||
|
||||
fig_modes, axes_modes = pyplot.subplots(1, 2, figsize=(10, 4))
|
||||
straight_plot = axes_modes[0].imshow(straight_intensity, origin='lower', cmap='viridis')
|
||||
fig_modes.colorbar(straight_plot, ax=axes_modes[0])
|
||||
axes_modes[0].set_title('Straight fundamental mode |E|^2')
|
||||
bend_plot = axes_modes[1].imshow(bend_intensity, origin='lower', cmap='viridis')
|
||||
fig_modes.colorbar(bend_plot, ax=axes_modes[1])
|
||||
axes_modes[1].set_title('Bent fundamental mode |E|^2')
|
||||
if pyplot.get_backend().lower().endswith('agg'):
|
||||
pyplot.close(fig_s)
|
||||
pyplot.close(fig_modes)
|
||||
else:
|
||||
pyplot.show()
|
||||
|
||||
|
||||
def main() -> None:
|
||||
pyplot = require_optional('matplotlib.pyplot', package_name='matplotlib')
|
||||
skrf = require_optional('skrf', package_name='scikit-rf')
|
||||
|
||||
grid, epsilon, dxes_2d, omega = build_geometry()
|
||||
epsilon_slice = epsilon[:, :, :, 2]
|
||||
rmin = RADIUS + grid.xyz[0].min()
|
||||
|
||||
straight_modes, straight_wavenumbers = solve_straight_modes(epsilon_slice, omega=omega, dxes_2d=dxes_2d)
|
||||
bend_modes, bend_linear_wavenumbers, bend_angular_wavenumbers = solve_bend_modes(
|
||||
epsilon_slice,
|
||||
omega=omega,
|
||||
dxes_2d=dxes_2d,
|
||||
rmin=rmin,
|
||||
)
|
||||
|
||||
interface_s = eme.get_s(
|
||||
straight_modes,
|
||||
straight_wavenumbers,
|
||||
bend_modes,
|
||||
bend_linear_wavenumbers,
|
||||
dxes=dxes_2d,
|
||||
)
|
||||
cascaded = build_cascaded_network(
|
||||
skrf,
|
||||
interface_s=interface_s,
|
||||
straight_wavenumbers=straight_wavenumbers,
|
||||
bend_angular_wavenumbers=bend_angular_wavenumbers,
|
||||
n_modes=len(MODE_NUMBERS),
|
||||
)
|
||||
cascaded_s = cascaded.s[0]
|
||||
|
||||
print_summary(
|
||||
interface_s,
|
||||
cascaded_s,
|
||||
straight_wavenumbers,
|
||||
bend_linear_wavenumbers,
|
||||
bend_angular_wavenumbers,
|
||||
omega,
|
||||
len(MODE_NUMBERS),
|
||||
)
|
||||
plot_results(
|
||||
pyplot=pyplot,
|
||||
interface_s=interface_s,
|
||||
cascaded_s=cascaded_s,
|
||||
straight_mode=straight_modes[0],
|
||||
bend_mode=bend_modes[0],
|
||||
shape_2d=grid.shape[:2],
|
||||
)
|
||||
|
||||
|
||||
if __name__ == '__main__':
|
||||
main()
|
||||
Loading…
Add table
Add a link
Reference in a new issue