Пример #1
0
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
Пример #2
0
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)
Пример #3
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")
Пример #4
0
# 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):
Пример #5
0
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)
Пример #6
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")

Пример #7
0
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)
Пример #8
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