def target(x):
global freq, target_impedance
base_height = np.exp(x[0]) # Make it positive
length = np.exp(x[1]) # Make it positive
if (length > 10.0):
return 100
try:
z = monopole.impedance(freq, base_height, length)
return reflection_coefficient(z, z0=target_impedance)
except RuntimeError as re:
return 100
def target(x):
global freq
base_height = np.exp(x[0]) # Make it positive
length = np.exp(x[1]) # Make it positive
z = monopole.impedance(freq, base_height, length)
return reflection_coefficient(z, z0=50.0)
#
# Plot of reflection coefficient vs antenna length for a fixed base height.
#
import monopole
import numpy as np
import pylab as plt
from antenna_util import reflection_coefficient
lengths = np.linspace(0.2, 5.0, 270)
reflections = []
z0 = 50
for l in lengths:
freq = 134.5
z = monopole.impedance(freq, base=0.5, length=l)
reflections.append(reflection_coefficient(z, z0))
plt.plot(lengths, reflections)
plt.xlabel("Antenna length (m)")
plt.ylabel("Reflection coefficient")
plt.title("Reflection coefficient vs length (base_height=0.5m)")
plt.grid(True)
plt.show()
plt.savefig("reflection_coefficient.png")
# Plot stuff
import matplotlib.pyplot as plt
from antenna_util import reflection_coefficient
l_best = 0.01
r_best = -9999.9
z0 = 50.0
droop = to_radians(40.0)
for l in np.linspace(0.03, 0.19, 70):
z, gains_db, thetas, phis = inverted_v(freq=1545.42, base=0.1, length=l, angle=droop, phi_start=60, phi_stop=90)
gmean = np.mean(np.mean(from_db(gains_db)))
gmax = np.max(np.max(from_db(gains_db)))
gmin = np.min(np.min(from_db(gains_db)))
r = (gmean) * (1.0 - reflection_coefficient(z, z0)) / (1.5 + gmax - gmin)
if (r > r_best):
r_best = r
l_best = l
print r_best
print l_best
z, gains_db, thetas, phis = inverted_v(freq=1545.42, base=0.1, length=l_best, angle=droop, phi_start=10, phi_stop=90)
print z
print reflection_coefficient(z,50)
ax = plt.subplot(111, polar=True)
for j in range(0,10):
l_best = 0.01
r_best = -9999.9
z0 = 50.0
droop = to_radians(40.0)
for l in np.linspace(0.03, 0.19, 70):
z, gains_db, thetas, phis = inverted_v(freq=1545.42,
base=0.1,
length=l,
angle=droop,
phi_start=60,
phi_stop=90)
gmean = np.mean(np.mean(from_db(gains_db)))
gmax = np.max(np.max(from_db(gains_db)))
gmin = np.min(np.min(from_db(gains_db)))
r = (gmean) * (1.0 - reflection_coefficient(z, z0)) / (1.5 + gmax - gmin)
if (r > r_best):
r_best = r
l_best = l
print r_best
print l_best
z, gains_db, thetas, phis = inverted_v(freq=1545.42,
base=0.1,
length=l_best,
angle=droop,
phi_start=10,
phi_stop=90)
#
# Plot of reflection coefficient vs antenna length for a fixed base height.
#
import monopole
import numpy as np
import pylab as plt
from antenna_util import reflection_coefficient
lengths = np.linspace(0.2, 5.0, 270)
reflections = []
z0 = 50
for l in lengths:
freq = 134.5
z = monopole.impedance(freq, base=0.5, length=l)
reflections.append(reflection_coefficient(z, z0))
plt.plot(lengths, reflections)
plt.xlabel("Antenna length (m)")
plt.ylabel("Reflection coefficient")
plt.title("Reflection coefficient vs length (base_height=0.5m)")
plt.grid(True)
plt.show()
plt.savefig("reflection_coefficient.png")
def target(x): global freq base_height = np.exp(x[0]) # Make it positive length = np.exp(x[1]) # Make it positive z = monopole.impedance(freq, base_height, length) return reflection_coefficient(z, z0=50.0)
#if (r > r_best):
#r_best = r
#l_best = l
#print r_best
#print l_best
z, gains_db, thetas, phis = quad_helix(freq=1545.42,
base=0.1,
length=l_best,
angle=droop,
phi_start=5,
phi_stop=90)
print z
print reflection_coefficient(z, 50)
ax = plt.subplot(111, polar=True)
for j in range(0, 10):
ax.plot(thetas,
gains_db[:, j] + 20,
linewidth=3,
label=("%s" % (phis[j] * 180.0 / 3.1415)))
ax.grid(True)
ax.set_title("Gain at an elevation of 45 degrees", va='bottom')
plt.savefig('RadiationPattern.png')
plt.legend()
plt.show()
#import matplotlib.pyplot as plt