{
"metadata": {
"name": "",
"signature": "sha256:54ccd26f8e7172369b740037968be286180ddfff5f2fc10ebe6be83fc34647f9"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"HF,VHF AND UHF ANTENNAS (CHAPTER 6)"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"EXAMPLE 6.1,PAGE NUMBER 278 "
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from math import pi,sin\n",
"\n",
"# Variable Declaration\n",
"\n",
"f = 30 # frequency in MHz\n",
"f = 30*10**6 # frequency in Hz\n",
"c = 3*10**8 # speed of light in m/s\n",
"lamda = c/f # wavelength in meter\n",
"Delta = 30 # angle of elevation in Degrees\n",
"\n",
"#calculation\n",
"\n",
"H = lamda/(4 * sin(Delta*pi/180)) # Rhombic height in m\n",
"l = lamda/(2 * sin(Delta*pi/180) **2) # wire length in m\n",
"phi = 90-Delta # tilt angle in Degrees\n",
"\n",
"#Results\n",
"\n",
"print \"Rhombic height is:\",round(H,2),\"meter\"\n",
"print \"Tilt angle is:\",round(phi,2),\"degrees\"\n",
"print \"length of wire is:\",round(l,2),\"meter\"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Rhombic height is: 5.0 meter\n",
"Tilt angle is: 60.0 degrees\n",
"length of wire is: 20.0 meter\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"EXAMPLE 6.2,PAGE NUMBER 278"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from math import pi,sin\n",
"\n",
"\n",
"# Variable Declaration\n",
"\n",
"f = 20 # frequency in MHz\n",
"f = 20*10**6 # frequency in Hz\n",
"c = 3*10**8 # speed of light in m/s\n",
"lamda = c/f # wavelength in meter\n",
"\n",
"#calculation\n",
"\n",
"Delta = 10 # angle of elevation in Degrees\n",
"H = lamda/(4 * sin(Delta*pi/180)) # Rhombic height in m\n",
"l = lamda/(2 * sin(Delta*pi/180) **2) # wire length in m\n",
"phi = 90-Delta # tilt angle in Degrees\n",
"\n",
"#Results\n",
"\n",
"print \"Rhombic height is:\",round(H,3),\"meter\"\n",
"print \"Tilt angle is:\",round(phi,2),\"degrees\"\n",
"print \"length of wire is:\",round(l,3),\"meter\"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Rhombic height is: 21.595 meter\n",
"Tilt angle is: 80.0 degrees\n",
"length of wire is: 248.726 meter\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"EXAMPLE 6.3,PAGE NUMBER 279-281"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from math import pi,sin,cos\n",
"\n",
"\n",
"\n",
"# Variable Declaration\n",
"\n",
"f = 30 # frequency in MHz\n",
"f = 30*10**6 # frequency in Hz\n",
"c = 3*10**8 # speed of light in m/s\n",
"lamda = c/f # wavelength in meter\n",
"\n",
"#calculation and results:\n",
"\n",
"\n",
"\n",
"print \"for Delta = 10 degrees\"\n",
"\n",
"\n",
"Delta1 = 10 # angle of elevation in Degrees\n",
"H1 = lamda/(4 * sin(Delta1*pi/180)) # Rhombic height in m\n",
"l1 = lamda/(2 * sin(Delta1*pi/180) **2) # wire length in m\n",
"phi1 = 90-Delta1 # tilt angle in Degrees\n",
"print \"Rhombic height is:\",round(H1,3),\"meter\"\n",
"print \"Tilt angle is:\",round(phi1,2),\"degrees\"\n",
"print \"length of wire is:\",round(l1,2),\"meter\"\n",
"\n",
"\n",
"\n",
"\n",
"print \"for Delta = 15 degrees\"\n",
"\n",
"\n",
"Delta2 = 15 # angle of elevation in Degrees\n",
"H2 = lamda/(4 * sin(Delta2*pi/180)) # Rhombic height in m\n",
"l2 = lamda/(2 * sin(Delta2*pi/180) **2) # wire length in m\n",
"phi2 = 90-Delta2 # tilt angle in Degrees\n",
"print \"Rhombic height is:\",round(H2,3),\"meter\"\n",
"print \"Tilt angle is:\",round(phi2,2),\"degrees\"\n",
"print \"length of wire is:\",round(l2,2),\"meter\"\n",
"\n",
"\n",
"\n",
"print \"for Delta = 20 degrees\"\n",
"\n",
"\n",
"Delta3 = 20 # angle of elevation in Degrees\n",
"H3 = lamda/(4 * sin(Delta3*pi/180)) # Rhombic height in m\n",
"l3 = lamda/(2 * sin(Delta3*pi/180) **2) # wire length in m\n",
"phi3 = 90-Delta3 # tilt angle in Degrees\n",
"print \"Rhombic height is:\",round(H3,3),\"meter\"\n",
"print \"Tilt angle is:\",round(phi3,2),\"degrees\"\n",
"print \"length of wire is:\",round(l3,2),\"meter\"\n",
"\n",
"\n",
"\n",
"\n",
"print \"for Delta = 25 degrees\"\n",
"\n",
"\n",
"Delta4 = 25 # angle of elevation in Degrees\n",
"H4 = lamda/(4 * sin(Delta4*pi/180)) # Rhombic height in m\n",
"l4 = lamda/(2 * sin(Delta4*pi/180) **2) # wire length in m\n",
"phi4 = 90-Delta4 # tilt angle in Degrees\n",
"print \"Rhombic height is:\",round(H4,3),\"meter\"\n",
"print \"Tilt angle is:\",round(phi4,2),\"degrees\"\n",
"print \"length of wire is:\",round(l4,2),\"meter\"\n",
"\n",
"\n",
"\n",
"\n",
"print \"for Delta = 30 degrees\"\n",
"\n",
"\n",
"Delta5 = 30 # angle of elevation in Degrees\n",
"H5 = lamda/(4 * sin(Delta5*pi/180)) # Rhombic height in m\n",
"l5 = lamda/(2 * sin(Delta5*pi/180) **2) # wire length in m\n",
"phi5 = 90-Delta5 # tilt angle in Degrees\n",
"print \"Rhombic height is:\",round(H5,3),\"meter\"\n",
"print \"Tilt angle is:\",round(phi5,2),\"degrees\"\n",
"print \"length of wire is:\",round(l5,2),\"meter\"\n",
"\n",
"\n",
"\n",
"\n",
"print \"for Delta = 35 degrees\"\n",
"\n",
"\n",
"Delta6 = 35 # angle of elevation in Degrees\n",
"H6 = lamda/(4 * sin(Delta6*pi/180)) # Rhombic height in m\n",
"l6 = lamda/(2 * sin(Delta6*pi/180) **2) # wire length in m\n",
"phi6 = 90-Delta6 # tilt angle in Degrees\n",
"print \"Rhombic height is:\",round(H6,3),\"meter\"\n",
"print \"Tilt angle is:\",round(phi6,2),\"degrees\"\n",
"print \"length of wire is:\",round(l6,2),\"meter\"\n",
"\n",
"\n",
"\n",
"\n",
"print \"for Delta = 40 degrees\"\n",
"\n",
"\n",
"Delta7 = 40 # angle of elevation in Degrees\n",
"H7 = lamda/(4 * sin(Delta7*pi/180)) # Rhombic height in m\n",
"l7 = lamda/(2 * sin(Delta7*pi/180) **2) # wire length in m\n",
"phi7 = 90-Delta7 # tilt angle in Degrees\n",
"print \"Rhombic height is:\",round(H7,3),\"meter\"\n",
"print \"Tilt angle is:\",round(phi7,2),\"degrees\"\n",
"print \"length of wire is:\",round(l7,2),\"meter\"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"for Delta = 10 degrees\n",
"Rhombic height is: 14.397 meter\n",
"Tilt angle is: 80.0 degrees\n",
"length of wire is: 165.82 meter\n",
"for Delta = 15 degrees\n",
"Rhombic height is: 9.659 meter\n",
"Tilt angle is: 75.0 degrees\n",
"length of wire is: 74.64 meter\n",
"for Delta = 20 degrees\n",
"Rhombic height is: 7.31 meter\n",
"Tilt angle is: 70.0 degrees\n",
"length of wire is: 42.74 meter\n",
"for Delta = 25 degrees\n",
"Rhombic height is: 5.916 meter\n",
"Tilt angle is: 65.0 degrees\n",
"length of wire is: 27.99 meter\n",
"for Delta = 30 degrees\n",
"Rhombic height is: 5.0 meter\n",
"Tilt angle is: 60.0 degrees\n",
"length of wire is: 20.0 meter\n",
"for Delta = 35 degrees\n",
"Rhombic height is: 4.359 meter\n",
"Tilt angle is: 55.0 degrees\n",
"length of wire is: 15.2 meter\n",
"for Delta = 40 degrees\n",
"Rhombic height is: 3.889 meter\n",
"Tilt angle is: 50.0 degrees\n",
"length of wire is: 12.1 meter\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"EXAMPLE 6.4,PAGE NUMBER 281"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from math import pi,sin,cos\n",
"\n",
"\n",
"\n",
"# Variable Declaration\n",
"\n",
"f = 30 # frequency in MHz\n",
"f = 30*10**6 # frequency in Hz\n",
"c = 3*10**8 # speed of light in m/s\n",
"lamda = c/f # wavelength in meter\n",
"Delta = 30 # angle of elevation in Degrees\n",
"\n",
"#calculation\n",
"\n",
"k = 0.74 # constant\n",
"H = lamda/(4 * sin(Delta*pi/180)) # Rhombic height in m\n",
"l = lamda/(2 * sin(Delta*pi/180) **2)*k # wire length in m\n",
"phi = 90-Delta # tilt angle in Degrees\n",
"\n",
"#Results\n",
"\n",
"print \"Rhombic height is:\",round(H,2),\"meter\"\n",
"print \"Tilt angle is:\",round(phi,2),\"degrees\"\n",
"print \"length of wire is:\",round(l,2),\"meter\"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Rhombic height is: 5.0 meter\n",
"Tilt angle is: 60.0 degrees\n",
"length of wire is: 14.8 meter\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"EXAMPLE 6.5,PAGE NUMBER 282"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from math import pi,sin\n",
"\n",
"\n",
"# Variable Declaration\n",
"\n",
"f = 20 # frequency in MHz\n",
"f = 20*10**6 # frequency in Hz\n",
"c = 3*10**8 # speed of light in m/s\n",
"lamda = c/f # wavelength in meter\n",
"Delta = 20 # angle of elevation in Degrees\n",
"k = 0.74 # constant\n",
"\n",
"#calculation\n",
"\n",
"H = lamda/(4 * sin(Delta*pi/180)) # Rhombic height in m\n",
"l = lamda/(2 * sin(Delta*pi/180) **2)*k # wire length in m\n",
"phi = 90-Delta # tilt angle in Degrees\n",
"\n",
"\n",
"#Results\n",
"\n",
"\n",
"print \"Rhombic height is:\",round(H,2),\"meter\"\n",
"print \"Tilt angle is:\",round(phi,2),\"degrees\"\n",
"print \"length of wire is:\",round(l,2),\"meter\"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Rhombic height is: 10.96 meter\n",
"Tilt angle is: 70.0 degrees\n",
"length of wire is: 47.44 meter\n"
]
}
],
"prompt_number": 5
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"EXAMPLE 6.6,PAGE NUMBER 282"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from __future__ import division\n",
"\n",
"\n",
"\n",
"# Variable Declaration\n",
"\n",
"\n",
"f_MHz = 172 # frequency in MHz\n",
"c = 3*10**8 # speed of light in m/s\n",
"\n",
"#calculation\n",
"\n",
"lamda = c/f_MHz # wavelength in m\n",
"La = 478/f_MHz # length of driven element in feet\n",
"Lr = 492/f_MHz # length of reflector in feet\n",
"Ld = 461.5/f_MHz # length of director in feet\n",
"S = 142/f_MHz # element spacing in feet\n",
"\n",
"\n",
"#Results\n",
"\n",
"\n",
"print \"length of driven element is:\", round(La,2),\"feet\"\n",
"print \"length of reflector is:\", round(Lr,2),\"feet\"\n",
"print \"length of director is:\", round(Ld,3),\"feet\"\n",
"print \"element spacing is:\",round(S,3),\"feet\"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"length of driven element is: 2.78 feet\n",
"length of reflector is: 2.86 feet\n",
"length of director is: 2.683 feet\n",
"element spacing is: 0.826 feet\n"
]
}
],
"prompt_number": 6
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"EXAMPLE 6.7,PAGE NUMBER 283"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from __future__ import division\n",
"\n",
"# Variable Declaration\n",
"\n",
"\n",
"G = 12 # required gain in dB\n",
"f = 200 # frequency in MHz \n",
"f = 200*10**6 # frequency in Hz\n",
"c = 3*10**8 # speed of light in m/s\n",
"\n",
"#calculations\n",
"\n",
"\n",
"lamda = c/f # wavelength in m\n",
"La = 0.46*lamda # length of driven element in m (note: in book La is given 0.416*lamda misprint)\n",
"Lr = 0.475*lamda # length of reflector in m\n",
"Ld1 = 0.44*lamda # length of director1 in m\n",
"Ld2 = 0.44*lamda # length of director2 in m\n",
"Ld3 = 0.43*lamda # length of director3 in m\n",
"Ld4 = 0.40*lamda # length of director4 in m\n",
"SL = 0.25*lamda # spacing between reflector and driver in m\n",
"Sd = 0.31*lamda # spacing director and driving element in m\n",
"d = 0.01*lamda # diameter of elements in m\n",
"l = 1.5*lamda # length of array in m\n",
"\n",
"\n",
"#Results\n",
"\n",
"\n",
"print \"length of driven element is:\" ,round(La,2),\"m\"\n",
"print \"length of reflector is:\",round(Lr,4),\"m\"\n",
"print \"length of director1 is:\",round(Ld1,2),\"m\"\n",
"print \"length of director2 is:\",round(Ld2,2),\"m\"\n",
"print \"length of director3 is:\",round(Ld3,3),\"m\"\n",
"print \"length of director4 is:\",round(Ld4,2),\"m\"\n",
"print \"spacing between reflector and driver is:\",round(SL,3),\"m\"\n",
"print \"spacing director and driving element is:\",round(Sd,3),\"m\"\n",
"print \"diameter of elements is:\",round(d,3),\"m\"\n",
"print \"length of array is:\",round(l,2),\"m\"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"length of driven element is: 0.69 m\n",
"length of reflector is: 0.7125 m\n",
"length of director1 is: 0.66 m\n",
"length of director2 is: 0.66 m\n",
"length of director3 is: 0.645 m\n",
"length of director4 is: 0.6 m\n",
"spacing between reflector and driver is: 0.375 m\n",
"spacing director and driving element is: 0.465 m\n",
"diameter of elements is: 0.015 m\n",
"length of array is: 2.25 m\n"
]
}
],
"prompt_number": 7
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"EXAMPLE 6.8,PAGE NUMBER 283"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from __future__ import division\n",
"from math import atan\n",
"\n",
"\n",
"# Variable Declaration\n",
"\n",
"\n",
"G = 9 # required gain in dB\n",
"f_l = 125 # lowest frequency in MHz\n",
"f_l = 125*10**6 # lowest frequency in Hz\n",
"f_h = 500 # highest frequency in MHz\n",
"f_h = 500*10**6 # lowest frequency in Hz\n",
"c = 3*10**8 # speed of light in m/s\n",
"tau = 0.861 # scaling factor\n",
"sigma = 0.162 # spacing factor\n",
"\n",
"\n",
"#calculation\n",
"\n",
"\n",
"lamda_l = c/f_l # longest wavelength in m\n",
"lamda_s = c/f_h # shortest wavelength in m\n",
"alpha = 2*atan((1-tau)/(4*sigma)) # wedge angle in Degrees\n",
"L1 = lamda_l/2 # in m\n",
"L2 = tau*L1 # in m\n",
"L3 = tau*L2 # in m\n",
"L4 = tau*L3 # in m\n",
"L5 = tau*L4 # in m\n",
"L6 = tau*L5 # in m\n",
"L7 = tau*L6 # in m\n",
"L8 = tau*L7 # in m\n",
"L9 = tau*L8 # in m\n",
"L10 = tau*L9 # in m\n",
"L11 = tau*L10 # in m\n",
"\n",
"# element spacing relation\n",
"#formula : sn = 2*sigma*Ln\n",
"\n",
"\n",
"S1 = 2*sigma*L1 # in m\n",
"S2 = 2*sigma*L2 # in m\n",
"S3 = 2*sigma*L3 # in m\n",
"S4 = 2*sigma*L4 # in m\n",
"S5 = 2*sigma*L5 # in m\n",
"S6 = 2*sigma*L6 # in m\n",
"S7 = 2*sigma*L7 # in m\n",
"S8 = 2*sigma*L8 # in m\n",
"S9 = 2*sigma*L9 # in m\n",
"S10 = 2*sigma*L10 # in m\n",
"S11 = 2*sigma*L11 # in m\n",
"\n",
"\n",
"\n",
"#results\n",
"\n",
"\n",
"print(\"designing of log-periodic antenna:\")\n",
"\n",
"print \"L1 is:\",round(L1,4),\"m\"\n",
"print \"L2 is:\",round(L2,4),\"m\"\n",
"print \"L3 is:\",round(L3,4),\"m\"\n",
"print \"L4 is:\",round(L4,4),\"m\"\n",
"print \"L5 is:\",round(L5,4),\"m\"\n",
"print \"L6 is:\",round(L6,4),\"m\"\n",
"print \"L7 is:\",round(L7,4),\"m\"\n",
"print \"L8 is:\",round(L8,4),\"m\"\n",
"print \"L9 is:\",round(L9,4),\"m\"\n",
"print \"L10 is:\",round(L10,4),\"m\"\n",
"print \"L11 is:\",round(L11,4),\"m\"\n",
"\n",
"print \"elements spacing relation:\"\n",
"\n",
"print \"S1 is:\",round(S1,4),\"m\"\n",
"print \"S2 is:\",round(S2,4),\"m\"\n",
"print \"S3 is:\",round(S3,4),\"m\"\n",
"print \"S4 is:\",round(S4,4),\"m\"\n",
"print \"S5 is:\",round(S5,4),\"m\"\n",
"print \"S6 is:\",round(S6,4),\"m\"\n",
"print \"S7 is:\",round(S7,4),\"m\"\n",
"print \"S8 is:\",round(S8,4),\"m\"\n",
"print \"S9 is:\",round(S9,4),\"m\"\n",
"print \"S10 is:\",round(S10,4),\"m\"\n",
"print \"S11 is:\",round(S11,4),\"m\"\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"designing of log-periodic antenna:\n",
"L1 is: 1.2 m\n",
"L2 is: 1.0332 m\n",
"L3 is: 0.8896 m\n",
"L4 is: 0.7659 m\n",
"L5 is: 0.6595 m\n",
"L6 is: 0.5678 m\n",
"L7 is: 0.4889 m\n",
"L8 is: 0.4209 m\n",
"L9 is: 0.3624 m\n",
"L10 is: 0.312 m\n",
"L11 is: 0.2687 m\n",
"elements spacing relation:\n",
"S1 is: 0.3888 m\n",
"S2 is: 0.3348 m\n",
"S3 is: 0.2882 m\n",
"S4 is: 0.2482 m\n",
"S5 is: 0.2137 m\n",
"S6 is: 0.184 m\n",
"S7 is: 0.1584 m\n",
"S8 is: 0.1364 m\n",
"S9 is: 0.1174 m\n",
"S10 is: 0.1011 m\n",
"S11 is: 0.087 m\n"
]
}
],
"prompt_number": 8
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"EXAMPLE 6.9,PAGE NUMBER 285"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from math import pi,cos,sqrt\n",
"\n",
"\n",
"# Variable Declaration\n",
"\n",
"E_rms = 10 # electric field in mV/m\n",
"E_rms = 10*10 **-3 # electric field in V/m\n",
"f = 2 # frequency in MHz\n",
"f = 2*10 **6 # frequency in Hz\n",
"N = 10 # number of turns\n",
"phi = 0 # angle between the plane of loop and direction of incident wave in Degrees\n",
"S = 1.4 # area of loop antenna in m **2\n",
"c = 3*10 **8 # speed of light in m/s\n",
"\n",
"#calculation\n",
"\n",
"lamda = c/f # wavelength in m\n",
"E_max = sqrt(2)*E_rms # electric field in V/m\n",
"V_rms = (2*pi*E_max*S*N/lamda)*cos(phi) # induced voltage\n",
"\n",
"#Result\n",
"\n",
"print \"induced voltage is:\",round(V_rms*1000,2),\"mV\"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"induced voltage is: 8.29 mV\n"
]
}
],
"prompt_number": 9
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"EXAMPLE 6.10,PAGE NUMBER 285"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"# Variable Declaration\n",
"\n",
"\n",
"D = 0.5 # diameter of loop antenna in m\n",
"a = D/2 # radius of loop antenna in m\n",
"f = 1 # frequency in MHz\n",
"f = 1*10**6 # frequency in Hz\n",
"c = 3*10**8 # speed of light in m/s\n",
"\n",
"#calculation\n",
"\n",
"lamda = c/f # wavelength in m\n",
"Rr = 3720*(a/lamda) # radiation resistance of loop antenna in ohm\n",
"\n",
"\n",
"#Results\n",
"\n",
"print \"radiation resistance of loop antenna is:\",Rr,\"ohm\"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"radiation resistance of loop antenna is: 3.1 ohm\n"
]
}
],
"prompt_number": 10
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"EXAMPLE 6.11,PAGE NUMBER 285-286"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from __future__ import division\n",
"from math import pi\n",
"\n",
"# Variable Declaration\n",
"\n",
"a = 0.5 # radius of loop antenna in m\n",
"f = 0.9 # frequency in MHz\n",
"f = 0.9*10**6 # frequency in Hz\n",
"c = 3*10**8 # speed of light in m/s\n",
"\n",
"#calculation\n",
"\n",
"lamda = c/f # wavelength in m\n",
"k = (2*pi*a)/lamda # constant\n",
"\n",
"#Results\n",
"\n",
"print \"the value of k is:\",round(k,2)\n",
"print \"since,k<1/3\"\n",
"print \"So Directivity of loop antenna is D = 1.5\"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"the value of k is: 0.01\n",
"since,k<1/3\n",
"So Directivity of loop antenna is D = 1.5\n"
]
}
],
"prompt_number": 11
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"EXAMPLE 6.13,PAGE NUMBER 286"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from sympy import Symbol\n",
"\n",
"#variable declaration and calculation\n",
"\n",
"Lm = Symbol('Lm') # defining Lm as lambda\n",
"d = 1.5*Lm # diameter of antenna in m\n",
"a = d/2 # radius of antenna in m\n",
"Rr = 3720*(a/Lm) # radiation resistance of loop antenna in ohm\n",
"D = 4.25*(a/Lm) # Directivity of the loop antenna\n",
"\n",
"#results\n",
"\n",
"print \"radiation resistance of the loop antenna is:\",round(Rr,0),\"ohm\"\n",
"print \"Directivity of the loop antenna is:\",round(D,4)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"radiation resistance of the loop antenna is: 2790.0 ohm\n",
"Directivity of the loop antenna is: 3.1875\n"
]
}
],
"prompt_number": 12
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"EXAMPLE 6.14,PAGE NUMBER 287"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from math import sqrt,pi\n",
"from sympy import Symbol\n",
"\n",
"#Variable declaration\n",
"\n",
"Gp = 28 # power gain\n",
"\n",
"#calculations\n",
"\n",
"Lm = Symbol('Lm') # defining Lm as lamda\n",
"d = Lm/2 # length of dipole\n",
"\n",
"#formula : Gp = 4*(L/lamda)\n",
"\n",
"L = Gp*Lm/4 # array length\n",
"N = 7*2 # Number of elements in the array when spaced at lamda/2\n",
"\n",
"# formula : B.W = 2*sqrt((2*/N)*(lamda/d))\n",
"\n",
"BW = 2*sqrt(2*Lm/(N*d)) # null-to-null beam width in radians\n",
"BW_d = BW*180/pi # null-to-null beam width in degrees\n",
"\n",
"#Results\n",
"\n",
"print \"Number of elements in the array when spaced at lamda/2 are:\",N\n",
"print \"array length(where Lm is wavelength in m) is:\",L,\"m\"\n",
"print \"null-to-null beam width is:\",round(BW_d,1),\"degrees\"\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Number of elements in the array when spaced at lamda/2 are: 14\n",
"array length(where Lm is wavelength in m) is: 7*Lm m\n",
"null-to-null beam width is: 61.3 degrees\n"
]
}
],
"prompt_number": 13
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"EXAMPLE 6.15,PAGE NUMBER 287"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from __future__ import division\n",
"from math import pi,sqrt\n",
"\n",
"\n",
"# Variable Declaration\n",
"\n",
"S = 0.05 # spacing in m\n",
"Dh = 0.1 # diameter of helical antenna in m\n",
"N = 20 # number of turns\n",
"f = 1000 # frequency in MHz\n",
"f = 1000*10**6 # frequency in MHz\n",
"c = 3*10**8 # speed of light in m/s\n",
"\n",
"\n",
"#calculation\n",
"\n",
"\n",
"lamda = c/f # wavelength in m\n",
"C = pi*Dh # circumfrence of helix in m\n",
"La = N*S # axial legth in m\n",
"phi_not = (115*(lamda**(3/2))/(C*sqrt(La))) # B.W.F.N., null-to-null beamwidth of main beam in Degreess\n",
"phi = (52*lamda**(3/2)/(C*sqrt(La))) # H.P.B.W, half power beamwidth in Degreess\n",
"D = (15*N*C**2*S/(lamda)**3) # Directivity\n",
"\n",
"#Results\n",
"\n",
"print \"B.W.F.N., null-to-null beamwidth of main beam is:\",round(phi_not,1),\"degrees\"\n",
"print \"H.P.B.W, half power beamwidth is:\",round(phi,1),\"degrees\"\n",
"print \"Directivity is:\",round(D,2)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"B.W.F.N., null-to-null beamwidth of main beam is: 60.1 degrees\n",
"H.P.B.W, half power beamwidth is: 27.2 degrees\n",
"Directivity is: 54.83\n"
]
}
],
"prompt_number": 14
}
],
"metadata": {}
}
]
}