def test_zero_source(self):
"""check no field if zero mag source"""
s = SourcePoint(0, 0, 0, 0, pi)
f = FieldPoint(1, 0, 0)
frequency = 1
wavelength = speed_of_light / frequency
k = 2 * pi / wavelength
propagate_single(s, f, k)
self.assertEqual(round(f.real(), 6), 0)
self.assertEqual(round(f.imag() / 1e-9, 6), 0)
def test_init(self):
"""Position and value match initialisation parameters"""
x = 1.1
y = 2.2
z = 3.3
fp = FieldPoint(x, y, z)
self.assertEqual(fp.x, x)
self.assertEqual(fp.y, y)
self.assertEqual(fp.z, z)
self.assertEqual(fp.v, 0)
def test_phase(self):
"""check phase is 2pi/wavelength"""
s = SourcePoint(0, 0, 0, 1, 0)
frequency = 1
wavelength = speed_of_light / frequency
k = 2 * pi / wavelength
f = FieldPoint(wavelength / 2, 0, 0)
propagate_single(s, f, k)
self.assertEqual(round(f.phase(), 6), 3.141593)
# positive phase expected in negative directions because
# wave travels outward
fnegx = FieldPoint(-wavelength / 2, 0, 0)
propagate_single(s, fnegx, k)
self.assertEqual(round(fnegx.phase(), 6), 3.141593)
f1 = FieldPoint(wavelength, 0, 0)
propagate_single(s, f1, k)
self.assertEqual(round(f1.phase(), 6), 0)
def two_element_az():
"""Two element array, azimuth farfield"""
phis = np.linspace(0, 2 * pi, 100)
fields = []
expected = []
r = 10
for phi in phis:
y = r * cos(phi)
z = r * sin(phi)
fields.append(FieldPoint(0, y, z))
# Expected result from J.D. Kraus Antennas For All Applications
# 3rd Edition (International) pp.90ff
expected.append(1)
sources, frequency = get_sources_two_element()
propagate(sources, fields, frequency)
ff = []
for field in fields:
ff.append(field.abs())
ffa = np.array(ff)
normalised_ffa = ffa / np.max(ffa)
return phis, normalised_ffa, expected
def test_decay_rate(self):
""" check amplitude decays at rate 1/r"""
s = SourcePoint(0, 0, 0, 1, 0)
f = FieldPoint(1, 0, 0)
frequency = 1
wavelength = speed_of_light / frequency
k = 2 * pi / wavelength
propagate_single(s, f, k)
self.assertEqual(round(f.real(), 6), 0.079577)
self.assertEqual(round(f.imag() / 1e-9, 6), 1.66782)
f2 = FieldPoint(2, 0, 0)
propagate_single(s, f2, k)
self.assertEqual(f.abs() / f2.abs(), 2)
f4 = FieldPoint(4, 0, 0)
propagate_single(s, f4, k)
self.assertEqual(round(f.abs() / f4.abs(), 6), 4)
def test_add_value(self):
"""Values are added not replaced"""
fp1 = FieldPoint(0, 0, 0)
fp1.add(1 + 2j)
self.assertEqual(fp1.real(), 1)
self.assertEqual(fp1.imag(), 2)
self.assertEqual(fp1.abs(), (1**2 + 2 * 2)**0.5)
self.assertEqual(fp1.phase(), math.atan(2))
fp1.add(2 + 2j)
self.assertEqual(fp1.real(), 3)
self.assertEqual(fp1.imag(), 4)
self.assertEqual(fp1.abs(), (3**2 + 4**2)**0.5)
self.assertEqual(fp1.phase(), math.atan(4. / 3.))
def test_distance(self):
"""Distance between two points is correct"""
fp1 = FieldPoint(-1, -1, -1)
fp2 = FieldPoint(1, 1, 1)
self.assertEqual(fp1.distance(fp2), 2 * 3**0.5)
self.assertEqual(fp2.distance(fp1), 2 * 3**0.5)