def geometry_monopole_ground(freq_mhz, monopole_length, ground_wire_length,
nr_segments):
wire_radius = 0.0005 # 0.5 mm
nec = context_clean(nec_context())
nec.set_extended_thin_wire_kernel(True)
geo = geometry_clean(nec.get_geometry())
bottom = np.array([0, 0, 0])
top = np.array([0, 0, monopole_length])
wire_tag = 1
geo.wire(tag_id=wire_tag,
nr_segments=nr_segments,
src=bottom,
dst=top,
radius=wire_radius)
add_ground_screen(geo, start_tag=2, length=ground_wire_length)
# Everything is in brass
nec.set_wire_conductivity(brass_conductivity)
nec.geometry_complete(
ground_plane=False) # We added our own 'ground plane'
nec.voltage_excitation(wire_tag=wire_tag, segment_nr=1, voltage=1.0)
return nec
def geometry_logperiodic(l_1, x_1, tau):
"""
x_1 is the distance from the origin to the largest (farthest away) dipole, which has a length of l_1.
The spacing is as follows: l_{i+1}/l_i = tau = x_{i+1}/x_i
"""
wire_radius = 0.00025 # 0.25 mm
# alpha = np.arctan( (l_1/2.0) / x_1 )
nec = context_clean(nec_context())
nec.set_extended_thin_wire_kernel(True)
geo = geometry_clean(nec.get_geometry())
# Dipoles should be oriented in the Z direction; they should be placed on the (positive) X axis
x_i = x_1
l_i = x_1
# As ususal, note that nec tags start at 1, and we typically index from 0!
dipole_center_segs = {} # Maps from NEC wire id!
dipoles_count = 5
for dipole_tag in range(1, dipoles_count + 1):
nr_segments = int(math.ceil(50*l_i/wavelength)) # TODO this might vary when sweeping even!
#print nr_segments
dipole_center_segs[dipole_tag] = nr_segments / 2 + 1
center = np.array([x_i, 0, 0])
half_height = np.array([0 , 0, l_i/2.0])
top = center + half_height
bottom = center - half_height
geo.wire(tag_id=dipole_tag, nr_segments=nr_segments, src=bottom, dst=top, radius=wire_radius)
x_i = tau * x_i
l_i = tau * l_i
# Everything is in brass
nec.set_wire_conductivity(brass_conductivity)
nec.geometry_complete(ground_plane=False)
# The 6th tag is the smallest tag is the source element
for dipole in range(0, dipoles_count - 1):
src_tag = 1 + dipole # NEC indexing
src_seg = dipole_center_segs[src_tag]
dst_tag = src_tag + 1
dst_seg = dipole_center_segs[dst_tag]
nec.transmission_line((src_tag, src_seg), (dst_tag, dst_seg), tl_impedance, crossed_line=True)
smallest_dipole_tag = dipoles_count # Again, start at 1
nec.voltage_excitation(wire_tag=smallest_dipole_tag, segment_nr=dipole_center_segs[smallest_dipole_tag], voltage=1.0)
return nec
def geometry(freq_mhz, length, nr_segments):
wire_radius = 0.01e-3 # 0.01 mm
nec = context_clean(nec_context())
nec.set_extended_thin_wire_kernel(False)
geo = geometry_clean(nec.get_geometry())
center = np.array([0, 0, 0])
half = np.array([length / 2, 0, 0])
pt1 = center - half
pt2 = center + half
wire_tag = 1
geo.wire(tag_id=wire_tag,
nr_segments=nr_segments,
src=pt1,
dst=pt2,
radius=wire_radius)
nec.geometry_complete(ground_plane=False)
nec.set_frequency(freq_mhz)
# Voltage excitation in the center of the antenna
nec.voltage_excitation(wire_tag=wire_tag,
segment_nr=int(nr_segments / 2),
voltage=1.0)
return nec
def geometry(freq_mhz, length, nr_segments):
wire_radius = 0.01e-3 # 0.01 mm
nec = context_clean(nec_context())
nec.set_extended_thin_wire_kernel(False)
geo = geometry_clean(nec.get_geometry())
center = np.array([0, 0, 0])
half = np.array([length / 2, 0, 0])
pt1 = center - half
pt2 = center + half
wire_tag = 1
geo.wire(tag_id=wire_tag, nr_segments=nr_segments, src=pt1, dst=pt2, radius=wire_radius)
nec.geometry_complete(ground_plane=False)
nec.set_frequency(freq_mhz)
# Voltage excitation in the center of the antenna
nec.voltage_excitation(wire_tag=wire_tag, segment_nr=int(nr_segments / 2), voltage=1.0)
return nec
def geometry_logperiodic(l_1, x_1, tau):
"""
x_1 is the distance from the origin to the largest (farthest away) dipole, which has a length of l_1.
The spacing is as follows: l_{i+1}/l_i = tau = x_{i+1}/x_i
"""
wire_radius = 0.00025 # 0.25 mm
# alpha = np.arctan( (l_1/2.0) / x_1 )
nec = context_clean(nec_context())
nec.set_extended_thin_wire_kernel(True)
geo = geometry_clean(nec.get_geometry())
# Dipoles should be oriented in the Z direction; they should be placed on the (positive) X axis
x_i = x_1
l_i = x_1
# As ususal, note that nec tags start at 1, and we typically index from 0!
dipole_center_segs = {} # Maps from NEC wire id!
dipoles_count = 5
for dipole_tag in range(1, dipoles_count + 1):
nr_segments = int(math.ceil(50*l_i/wavelength)) # TODO this might vary when sweeping even!
#print nr_segments
dipole_center_segs[dipole_tag] = nr_segments / 2 + 1
center = np.array([x_i, 0, 0])
half_height = np.array([0 , 0, l_i/2.0])
top = center + half_height
bottom = center - half_height
geo.wire(tag_id=dipole_tag, nr_segments=nr_segments, src=bottom, dst=top, radius=wire_radius)
x_i = tau * x_i
l_i = tau * l_i
# Everything is in brass
nec.set_wire_conductivity(brass_conductivity)
nec.geometry_complete(ground_plane=False)
# The 6th tag is the smallest tag is the source element
for dipole in range(0, dipoles_count - 1):
src_tag = 1 + dipole # NEC indexing
src_seg = dipole_center_segs[src_tag]
dst_tag = src_tag + 1
dst_seg = dipole_center_segs[dst_tag]
nec.transmission_line((src_tag, src_seg), (dst_tag, dst_seg), tl_impedance, crossed_line=True)
smallest_dipole_tag = dipoles_count # Again, start at 1
nec.voltage_excitation(wire_tag=smallest_dipole_tag, segment_nr=dipole_center_segs[smallest_dipole_tag], voltage=1.0)
return nec
def sc_quad_helix(height, diameter, wire_diameter = 0.02):
nec = context_clean(nec_context())
nec.set_extended_thin_wire_kernel(True)
geo = geometry_clean(nec.get_geometry())
wire_r = wire_diameter/2;
helix_r = diameter/2;
#print "Wire Diameter %s" % (wire_r * 2)
helix_turns = 0.5
helix_elevation = 0.1 # elevation of helix above conductive plate
excitation_lenght = 0.1
# helix loop
helix_twist_height = height / helix_turns
geo.wire(tag_id=1, nr_segments=1, src=np.array([helix_r, 0, 0]), dst=np.array([helix_r, 0, -excitation_lenght]), radius=wire_r)
geo.helix(tag_id=1, nr_segments=50, spacing=helix_twist_height, lenght=height, start_radius=np.array([helix_r, helix_r]), end_radius=np.array([helix_r, helix_r]), wire_radius=wire_r)
geo.move(rotate_z=90, move_z=0, copies=3, segment=0, tag_inc=1)
geo.wire(tag_id=10, nr_segments=2, src=np.array([0, 0, height]), dst=np.array([helix_r, 0, height]), radius=wire_r)
geo.wire(tag_id=11, nr_segments=2, src=np.array([0, 0, height]), dst=np.array([0, helix_r, height]), radius=wire_r)
geo.wire(tag_id=12, nr_segments=2, src=np.array([0, 0, height]), dst=np.array([-helix_r, 0, height]), radius=wire_r)
geo.wire(tag_id=13, nr_segments=2, src=np.array([0, 0, height]), dst=np.array([0, -helix_r, height]), radius=wire_r)
## bottom helix connecting wires
geo.wire(tag_id=20, nr_segments=2, src=np.array([0, 0, -excitation_lenght]), dst=np.array([helix_r, 0, -excitation_lenght]), radius=wire_r)
geo.wire(tag_id=21, nr_segments=2, src=np.array([0, 0, -excitation_lenght]), dst=np.array([0, helix_r, -excitation_lenght]), radius=wire_r)
geo.wire(tag_id=22, nr_segments=2, src=np.array([0, 0, -excitation_lenght]), dst=np.array([-helix_r, 0, -excitation_lenght]), radius=wire_r)
geo.wire(tag_id=23, nr_segments=2, src=np.array([0, 0, -excitation_lenght]), dst=np.array([0, -helix_r, -excitation_lenght]), radius=wire_r)
geo.wire(tag_id=1, nr_segments=1, src=np.array([0, 0, -excitation_lenght]), dst=np.array([0, 0, -helix_elevation -excitation_lenght]), radius=wire_r) # vertical wire connecting the patch and helixal antenna
geo.rectangular_patch(a1 = np.array([-1, -1, -helix_elevation - excitation_lenght]), a2 = np.array([1, -1, -helix_elevation - excitation_lenght]), a3= np.array([1, 1, -helix_elevation - excitation_lenght]))
#geo.rectangular_patch(a1 = np.array([-1, -1, 0]), a2 = np.array([1, -1, 0]), a3= np.array([1, 1, 0]))
# Everything is copper
nec.set_wire_conductivity(copper_conductivity)
# finish structure definition
nec.geometry_complete(ground_plane=False)
# Voltage excitation at legs of the antenna
nec.voltage_excitation(wire_tag=1, segment_nr=1, voltage=1.0)
nec.voltage_excitation(wire_tag=2, segment_nr=1, voltage=0.0+1.0j)
nec.voltage_excitation(wire_tag=3, segment_nr=1, voltage=-1.0)
nec.voltage_excitation(wire_tag=4, segment_nr=1, voltage=0.0-1.0j)
#nec.set_frequencies_linear(start_frequency=140, stop_frequency=150, count=100)
#nec.radiation_pattern(thetas=Range(90, 90, count=1), phis=Range(180,180,count=1))
return nec
def sc_quad_helix(height, diameter, wire_diameter = 0.02):
nec = context_clean(nec_context())
nec.set_extended_thin_wire_kernel(True)
geo = geometry_clean(nec.get_geometry())
wire_r = wire_diameter/2;
helix_r = diameter/2;
print "Wire Diameter %s" % (wire_r * 2)
helix_turns = 0.5
# helix loop
helix_twist_height = height / helix_turns
geo.helix(tag_id=1, nr_segments=50, spacing=helix_twist_height, lenght=height, start_radius=np.array([helix_r, 0]), end_radius=np.array([helix_r, 0]), wire_radius=wire_r)
geo.move(rotate_z=90, copies=3, tag_inc=1)
geo.wire(tag_id=10, nr_segments=5, src=np.array([0, 0, height]), dst=np.array([helix_r, 0, height]), radius=wire_r)
geo.wire(tag_id=11, nr_segments=5, src=np.array([0, 0, height]), dst=np.array([0, helix_r, height]), radius=wire_r)
geo.wire(tag_id=12, nr_segments=5, src=np.array([0, 0, height]), dst=np.array([-helix_r, 0, height]), radius=wire_r)
geo.wire(tag_id=13, nr_segments=5, src=np.array([0, 0, height]), dst=np.array([0, -helix_r, height]), radius=wire_r)
# Everything is copper
nec.set_wire_conductivity(copper_conductivity)
# finish structure definition
nec.geometry_complete(ground_plane=False)
# Voltage excitation at legs of the antenna
nec.voltage_excitation(wire_tag=1, segment_nr=1, voltage=1.0 )
nec.voltage_excitation(wire_tag=2, segment_nr=1, voltage=1.0 )
nec.voltage_excitation(wire_tag=3, segment_nr=1, voltage=1.0 )
nec.voltage_excitation(wire_tag=4, segment_nr=1, voltage=1.0 )
#nec.set_frequencies_linear(start_frequency=140, stop_frequency=150, count=100)
#nec.radiation_pattern(thetas=Range(90, 90, count=1), phis=Range(180,180,count=1))
return nec
def geometry(freq, base, length): conductivity = 1.45e6 # Stainless steel ground_conductivity = 0.002 ground_dielectric = 10 wavelength = 3e8/(1e6*freq) n_seg = int(math.ceil(50*length/wavelength)) nec = context_clean(nec_context()) geo = nec.get_geometry() geo.wire(1, n_seg, 0, 0, base, 0, 0, base+length, 0.002, 1.0, 1.0) nec.geometry_complete(1) nec.set_all_wires_conductivity(conductivity) nec.set_finite_ground(ground_dielectric, ground_conductivity) nec.set_frequency(freq) # Voltage excitation one third of the way along the wire nec.voltage_excitation(wire_tag=1, segment_nr=int(n_seg/3), voltage=1.0) return nec
def geometry(freq, base, length):
conductivity = 1.45e6 # Stainless steel
ground_conductivity = 0.002
ground_dielectric = 10
wavelength = 3e8 / (1e6 * freq)
n_seg = int(math.ceil(50 * length / wavelength))
nec = context_clean(nec_context())
geo = nec.get_geometry()
geo.wire(1, n_seg, 0, 0, base, 0, 0, base + length, 0.002, 1.0, 1.0)
nec.geometry_complete(1)
nec.set_all_wires_conductivity(conductivity)
nec.set_finite_ground(ground_dielectric, ground_conductivity)
nec.set_frequency(freq)
# Voltage excitation one third of the way along the wire
nec.voltage_excitation(wire_tag=1, segment_nr=int(n_seg / 3), voltage=1.0)
return nec
def geometry_monopole_ground(freq_mhz, monopole_length, ground_wire_length, nr_segments):
wire_radius = 0.005 # 0.5 mm
nec = context_clean(nec_context())
nec.set_extended_thin_wire_kernel(True)
geo = geometry_clean(nec.get_geometry())
bottom = np.array([0, 0, 0])
top = np.array([0, 0, monopole_length])
wire_tag = 1
geo.wire(tag_id=wire_tag, nr_segments=nr_segments, src=bottom, dst=top, radius=wire_radius)
add_ground_screen(geo, start_tag=2, length=ground_wire_length)
# Everything is in brass
nec.set_wire_conductivity(brass_conductivity)
nec.geometry_complete(ground_plane=False) # We added our own 'ground plane'
nec.voltage_excitation(wire_tag=wire_tag, segment_nr=1, voltage=1.0)
return nec