NawfalMotii79
318 lines
11 KiB
Python
318 lines
11 KiB
Python
# openems_quartz_slotted_wg_10p5GHz.py
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# Slotted rectangular waveguide (quartz-filled, εr=3.8) tuned to 10.5 GHz.
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# Builds geometry, meshes (no GetLine calls), sweeps S-params/impedance over 9.5–11.5 GHz,
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# computes 3D far-field, and reports estimated max realized gain.
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import os
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import tempfile
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import numpy as np
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import matplotlib.pyplot as plt
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import time
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# --- openEMS / CSXCAD bindings ---
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from openEMS import openEMS
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from openEMS.physical_constants import C0
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try:
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from CSXCAD import ContinuousStructure, AppCSXCAD_BIN
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HAVE_APP = True
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except Exception:
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from CSXCAD import ContinuousStructure
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AppCSXCAD_BIN = None
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HAVE_APP = False
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#Set PROFILE to "sanity" first; run and check [mesh] cells: stays reasonable.
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#If it’s small, move to "balanced"; once happy, go "full".
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#Toggle VIEW_GEOM=True if you want the 3D viewer (requires AppCSXCAD_BIN available).
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# =========================
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# USER SETTINGS / PROFILES
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# =========================
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PROFILE = "sanity" # choose: "sanity" | "balanced" | "full"
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VIEW_GEOM = False # True => launch AppCSXCAD viewer (if available)
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SIMULATE = True # False => skip FDTD (for quick post-proc dev)
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THREADS = 0 # 0 => all cores
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# --- profiles tuned for i5-1135G7 + 16 GB ---
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profiles = {
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"sanity": {
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"Nslots": 12, "mesh_res": 0.8,
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"air_x": 6.0, "air_y": 20.0, "air_z": 10.0,
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"n_theta": 61, "n_phi": 121, "freq_pts": 201, "pml": 6
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},
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"balanced": {
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"Nslots": 24, "mesh_res": 0.6,
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"air_x": 8.0, "air_y": 30.0, "air_z": 12.0,
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"n_theta": 91, "n_phi": 181, "freq_pts": 301, "pml": 8
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},
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"full": {
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"Nslots": 32, "mesh_res": 0.5,
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"air_x": 10.0, "air_y": 40.0, "air_z": 15.0,
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"n_theta": 91, "n_phi": 181, "freq_pts": 401, "pml": 8
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}
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}
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cfg = profiles[PROFILE]
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# =====================
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# BAND & WAVEGUIDE SPEC
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# =====================
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f0 = 10.5e9
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f_span = 2.0e9
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f_start, f_stop = f0 - f_span/2, f0 + f_span/2
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er_quartz = 3.8 # fused silica/quartz
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# Array constraint (λ0/2 pitch, 1 mm septum) => internal a ~ 13.28 mm
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lambda0_mm = (C0/f0) * 1e3
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a = 13.28 # mm (broad wall, internal)
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b = 6.50 # mm (narrow wall, internal) <-- comfortable machining
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# Slot starters (tune later for taper)
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slot_w = 0.60 # mm across x
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# --- guide wavelength at 10.5 GHz (TE10) ---
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fc10 = (C0/(2.0*np.sqrt(er_quartz))) * (1.0/(a*1e-3)) # Hz
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lambda_d = (C0/f0) / np.sqrt(er_quartz) # m
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lambda_g = lambda_d / np.sqrt(1.0 - (fc10/f0)**2) # m
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lambda_g_mm = lambda_g * 1e3
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# --- slots geometry (from λg) ---
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slot_s = 0.5*lambda_g_mm
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slot_L = 0.47*lambda_g_mm
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margin = 0.25*lambda_g_mm
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# ===================================
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# FDTD / CSX / MESH (explicit lines)
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# ===================================
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unit_mm = 1e-3
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Sim_Path = os.path.join(tempfile.gettempdir(), f'openems_quartz_slotted_wg_{PROFILE}')
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FDTD = openEMS(NrTS=int(6e5), EndCriteria=1e-5)
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FDTD.SetGaussExcite(0.5*(f_start+f_stop), 0.5*(f_stop-f_start))
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FDTD.SetBoundaryCond([f'PML_{cfg["pml"]}']*6)
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FDTD.SetOverSampling(4)
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FDTD.SetTimeStepFactor(0.95)
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CSX = ContinuousStructure()
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FDTD.SetCSX(CSX)
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mesh = CSX.GetGrid()
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mesh.SetDeltaUnit(unit_mm)
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# Pads & extent
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t_metal = 0.8 # mm metal wall thickness
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air_x = cfg["air_x"]
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air_y = cfg["air_y"]
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air_z = cfg["air_z"]
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mesh_res = cfg["mesh_res"]
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# Length from Nslots
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Nslots = cfg["Nslots"]
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guide_length_mm = margin + (Nslots-1)*slot_s + margin
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# Simulation extents (mm)
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x_min, x_max = -air_x, a + air_x
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y_min, y_max = -5.0, b + t_metal + air_y
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z_min, z_max = -air_z, guide_length_mm + air_z
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# Slot centers and edges (mm)
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z_centers = margin + np.arange(Nslots)*slot_s
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delta0 = 0.90 # mm offset from centerline (± alternated)
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x_centers = (a/2.0) + np.array([+delta0 if i%2==0 else -delta0 for i in range(Nslots)])
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x_edges = np.concatenate([x_centers - slot_w/2.0, x_centers + slot_w/2.0])
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z_edges = np.concatenate([z_centers - slot_L/2.0, z_centers + slot_L/2.0])
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# Mesh lines: explicit (NO GetLine calls)
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x_lines = sorted(set([x_min, -t_metal, 0.0, a, a+t_metal, x_max] + list(x_edges)))
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y_lines = [y_min, 0.0, b, b+t_metal, y_max]
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z_lines = sorted(set([z_min, 0.0, guide_length_mm, z_max] + list(z_edges)))
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mesh.AddLine('x', x_lines)
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mesh.AddLine('y', y_lines)
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mesh.AddLine('z', z_lines)
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# Print complexity and rough memory (to help stay inside 16 GB)
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Nx, Ny, Nz = len(x_lines)-1, len(y_lines)-1, len(z_lines)-1
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Ncells = Nx*Ny*Nz
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print(f"[mesh] cells: {Nx} × {Ny} × {Nz} = {Ncells:,}")
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mem_fields_bytes = Ncells * 6 * 8 # rough ~ (Ex,Ey,Ez,Hx,Hy,Hz) doubles
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print(f"[mesh] rough field memory: ~{mem_fields_bytes/1e9:.2f} GB (solver overhead extra)")
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dx_min = min(np.diff(x_lines)); dy_min = min(np.diff(y_lines)); dz_min = min(np.diff(z_lines))
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print(f"[mesh] min steps (mm): dx={dx_min:.3f}, dy={dy_min:.3f}, dz={dz_min:.3f}")
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# Optional smoothing to limit max cell size
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mesh.SmoothMeshLines('all', mesh_res, ratio=1.4)
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# =================
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# MATERIALS & SOLIDS
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# =================
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pec = CSX.AddMetal('PEC')
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quartzM = CSX.AddMaterial('QUARTZ'); quartzM.SetMaterialProperty(epsilon=er_quartz)
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airM = CSX.AddMaterial('AIR')
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# Quartz full block
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quartzM.AddBox([0, 0, 0], [a, b, guide_length_mm])
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# PEC tube walls
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pec.AddBox([-t_metal, 0, 0], [0, b, guide_length_mm]) # left
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pec.AddBox([a, 0, 0], [a+t_metal,b, guide_length_mm]) # right
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pec.AddBox([-t_metal,-t_metal,0],[a+t_metal,0, guide_length_mm]) # bottom
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pec.AddBox([-t_metal, b, 0], [a+t_metal,b+t_metal,guide_length_mm]) # top (slots will pierce)
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# Slots (AIR) overriding top metal
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for zc, xc in zip(z_centers, x_centers):
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x1, x2 = xc - slot_w/2.0, xc + slot_w/2.0
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z1, z2 = zc - slot_L/2.0, zc + slot_L/2.0
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prim = airM.AddBox([x1, b, z1], [x2, b+t_metal, z2])
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prim.SetPriority(10) # ensure cut
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# =========
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# WG PORTS
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# =========
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port_thick = max(4*mesh_res, 2.0) # mm
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p1_start = [0, 0, max(0.5, 10*mesh_res)]
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p1_stop = [a, b, p1_start[2] + port_thick]
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FDTD.AddRectWaveGuidePort(port_nr=1, start=p1_start, stop=p1_stop,
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p_dir='z', a=a*unit_mm, b=b*unit_mm, mode_name='TE10', excite=1)
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p2_stop = [a, b, guide_length_mm - max(0.5, 10*mesh_res)]
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p2_start = [0, 0, p2_stop[2] - port_thick]
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FDTD.AddRectWaveGuidePort(port_nr=2, start=p2_start, stop=p2_stop,
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p_dir='z', a=a*unit_mm, b=b*unit_mm, mode_name='TE10', excite=0)
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# =========
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# NF2FF BOX
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# =========
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def create_nf2ff(FDTD_obj, name, start, stop, frequency):
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try:
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return FDTD_obj.CreateNF2FFBox(name=name, start=start, stop=stop, frequency=frequency)
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except AttributeError:
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return FDTD_obj.AddNF2FFBox(name=name, start=start, stop=stop, frequency=frequency)
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nf2ff = create_nf2ff(
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FDTD,
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name='nf2ff',
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start=[x_min+1.0, y_min+1.0, z_min+1.0],
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stop =[x_max-1.0, y_max-1.0, z_max-1.0],
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frequency=[f0]
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)
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# ==========
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# VIEW GEOM
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# ==========
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if VIEW_GEOM and HAVE_APP and AppCSXCAD_BIN:
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os.makedirs(Sim_Path, exist_ok=True)
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csx_xml = os.path.join(Sim_Path, f'quartz_slotted_wg_{PROFILE}.xml')
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CSX.Write2XML(csx_xml)
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os.system(f'"{AppCSXCAD_BIN}" "{csx_xml}"')
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# ... right before the FDTD run:
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t0 = time.time()
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FDTD.Run(Sim_Path, cleanup=True, verbose=2, numThreads=THREADS)
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t1 = time.time()
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print(f"[timing] FDTD solve elapsed: {t1 - t0:.2f} s")
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# ... right before NF2FF (far-field):
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t2 = time.time()
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try:
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res = nf2ff.CalcNF2FF(Sim_Path, [f0], theta, phi)
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except AttributeError:
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res = FDTD.CalcNF2FF(nf2ff, Sim_Path, [f0], theta, phi)
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t3 = time.time()
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print(f"[timing] NF2FF (far-field) elapsed: {t3 - t2:.2f} s")
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# ... S-parameters postproc timing (optional):
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t4 = time.time()
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for p in ports:
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p.CalcPort(Sim_Path, freq)
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t5 = time.time()
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print(f"[timing] Port/S-params postproc elapsed: {t5 - t4:.2f} s")
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# =======
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# RUN FDTD
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# =======
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if SIMULATE:
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FDTD.Run(Sim_Path, cleanup=True, verbose=2, numThreads=THREADS)
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# ==========================
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# POST: S-PARAMS / IMPEDANCE
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# ==========================
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freq = np.linspace(f_start, f_stop, profiles[PROFILE]["freq_pts"])
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ports = [p for p in FDTD.ports] # Port 1 & 2 in creation order
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for p in ports:
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p.CalcPort(Sim_Path, freq)
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S11 = ports[0].uf_ref / ports[0].uf_inc
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S21 = ports[1].uf_ref / ports[0].uf_inc
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Zin = ports[0].uf_tot / ports[0].if_tot
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plt.figure(figsize=(7.6,4.6))
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plt.plot(freq*1e-9, 20*np.log10(np.abs(S11)), lw=2, label='|S11|')
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plt.plot(freq*1e-9, 20*np.log10(np.abs(S21)), lw=2, ls='--', label='|S21|')
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plt.grid(True); plt.legend(); plt.xlabel('Frequency (GHz)'); plt.ylabel('Magnitude (dB)')
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plt.title(f'S-Parameters (profile: {PROFILE})')
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plt.figure(figsize=(7.6,4.6))
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plt.plot(freq*1e-9, np.real(Zin), lw=2, label='Re{Zin}')
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plt.plot(freq*1e-9, np.imag(Zin), lw=2, ls='--', label='Im{Zin}')
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plt.grid(True); plt.legend(); plt.xlabel('Frequency (GHz)'); plt.ylabel('Ohms')
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plt.title('Input Impedance (Port 1)')
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# ==========================
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# POST: 3D FAR-FIELD / GAIN
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# ==========================
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n_theta, n_phi = cfg["n_theta"], cfg["n_phi"]
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theta = np.linspace(0, np.pi, n_theta)
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phi = np.linspace(0, 2*np.pi, n_phi)
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try:
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res = nf2ff.CalcNF2FF(Sim_Path, [f0], theta, phi)
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except AttributeError:
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res = FDTD.CalcNF2FF(nf2ff, Sim_Path, [f0], theta, phi)
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idx_f0 = np.argmin(np.abs(freq - f0))
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Dmax_lin = float(res.Dmax[0])
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mismatch = 1.0 - np.abs(S11[idx_f0])**2
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Gmax_lin = Dmax_lin * float(mismatch)
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Gmax_dBi = 10*np.log10(Gmax_lin)
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print(f"[far-field] Dmax @ {f0/1e9:.3f} GHz: {10*np.log10(Dmax_lin):.2f} dBi")
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print(f"[far-field] mismatch (1-|S11|^2): {float(mismatch):.3f}")
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print(f"[far-field] est. max realized gain: {Gmax_dBi:.2f} dBi")
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# Normalized 3D pattern
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E = np.squeeze(res.E_norm) # [th, ph]
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E = E / np.max(E)
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TH, PH = np.meshgrid(theta, phi, indexing='ij')
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R = E
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X = R * np.sin(TH) * np.cos(PH)
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Y = R * np.sin(TH) * np.sin(PH)
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Z = R * np.cos(TH)
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fig = plt.figure(figsize=(7.2,6.2))
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ax = fig.add_subplot(111, projection='3d')
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ax.plot_surface(X, Y, Z, rstride=2, cstride=2, linewidth=0, antialiased=True, alpha=0.92)
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ax.set_title(f'Normalized 3D Pattern @ {f0/1e9:.2f} GHz\n(peak ≈ {Gmax_dBi:.1f} dBi)')
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ax.set_box_aspect((1,1,1))
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ax.set_xlabel('x'); ax.set_ylabel('y'); ax.set_zlabel('z')
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plt.tight_layout()
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# ==========================
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# QUICK 2D GEOMETRY PREVIEW
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# ==========================
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plt.figure(figsize=(8.4,2.8))
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plt.fill_between([0,a], [0,0], [guide_length_mm, guide_length_mm], color='#dddddd', alpha=0.5, step='pre', label='WG top aperture')
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for zc, xc in zip(z_centers, x_centers):
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plt.gca().add_patch(plt.Rectangle((xc - slot_w/2.0, zc - slot_L/2.0),
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slot_w, slot_L, fc='#3355ff', ec='k'))
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plt.xlim(-2, a+2); plt.ylim(-5, guide_length_mm+5)
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plt.gca().invert_yaxis()
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plt.xlabel('x (mm)'); plt.ylabel('z (mm)')
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plt.title(f'Top-view slot layout (N={Nslots}, profile={PROFILE})')
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plt.grid(True); plt.legend()
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plt.show()
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