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"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# Chapter 6: Electric Dipoles, Thin Linear Antennas \n",
" and Arrays of Dipoles and Apertures

# "
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"

### Example 6-8.1, Page number: 174"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"\n",
"#Variable declaration\n",
"z = 333.0 #Driving point impedence (ohm)\n",
"r = 300.0 #twin-line impedence (ohm)\n",
"z1 = 73.0 #Self impedence of lambda/2 dipole (ohm)\n",
"z2 = 13.0 #Mutual impedence with lambda/2 spacing (ohm)\n",
"\n",
"#Calculation\n",
"pv = (z-r)/(z+r) #Reflection coefficient (unitless)\n",
"vswr = (1+pv)/(1-pv) #Voltage Standing Wave Ratio (unitless)\n",
"gain_l2 =math.sqrt((2*z1)/(z1-z2)) #Field gain over lambda/2 dipole (unitless)\n",
"gain_l2_db = 20*math.log10(gain_l2) #Field gain (in dB)\n",
"gain_iso = (gain_l2**2)*1.64 #Gain over isotropic source (unitless)\n",
"gain_iso_db = 10*math.log10(gain_iso) #Gain over isotropic source (in dB)\n",
"\n",
"#Result\n",
"print \"The VSWR is\", vswr\n",
"print \"The field gain over lambda/2 dipole is\", round(gain_l2,2), \"or\", round(gain_l2_db,1), \"dB\"\n",
"print \"\"\"The gain over isotropic source is %.1f or %.1f dB\n",
" \"\"\" % (round(gain_iso),gain_iso_db)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The VSWR is 1.11\n",
"The field gain over lambda/2 dipole is 1.56 or 3.9 dB\n",
"The gain over isotropic source is 4.0 or 6.0 dB\n",
" \n"
]
}
],
"prompt_number": 6
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"

### Example 6-8.2, Page number:175

### "
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"\n",
"#Variable declaration\n",
"z = 73.0 #Self impedence of lambda/2 dipole (ohm)\n",
"zm = 64.4 #Mutual impedence with lambda/8 spacing (ohm)\n",
"\n",
"#Calculation\n",
"D = math.sqrt((2*z)/(z-zm))*math.sin(math.pi/8) #Field gain over lambda/2 dipole (unitless)\n",
"D_db = 20*math.log10(D) #Field gain over lambda/2 dipole (in dB)\n",
"\n",
"gain_iso = (D**2)*1.64 #gain over isotropic source (unitless)\n",
"gain_iso_db = 10*math.log10(gain_iso) #gain over isotropic source (in dB)\n",
"\n",
"#Result\n",
"print \"The field gain over lambda/2 dipole is\", round(D,2), \"or\", round(D_db,2), \"dB\"\n",
"print \"The gain over isotropic source is\", round(gain_iso,2), \"or\", round(gain_iso_db,1), \"dB\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The field gain over lambda/2 dipole is 1.58 or 3.96 dB\n",
"The gain over isotropic source is 4.08 or 6.1 dB\n"
]
}
],
"prompt_number": 5
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"

### Example 6-12.1, Page number: 196

### "
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from math import sqrt, log10\n",
"\n",
"#Variable declaration\n",
"s1 = 0.4 #Spacing 1(lambda)\n",
"s2 = 0.5 #Spacing 2(lambda)\n",
"s3 = 0.6 #Spacing 3(lambda)\n",
"R_21_1 = 6.3 #Mutual resistance for s1 (ohm)\n",
"R_21_2 = -12.691 #Murual resistance for s2 (ohm)\n",
"R_21_3 = -23.381 #Mutual resistance for s3 (ohm) \n",
"Z = 73.13 #Self impedence of lambda/2 dipole (ohm)\n",
"\n",
"#Calculation\n",
"gain_1 = sqrt(2*(Z/(Z+R_21_1))) #Gain in fieldfor s1 (unitless)\n",
"gain_iso1 = 1.64*(gain_1**2) #Power gain over isotropic (unitless)\n",
"gain_iso_db1 = 10*log10(gain_iso1) #Power gain (in dBi)\n",
"\n",
"gain_2 = sqrt(2*(Z/(Z+R_21_2))) #Gain in fieldfor s2 (unitless)\n",
"gain_iso2 = 1.64*(gain_2**2) #Power gain over isotropic (unitless)\n",
"gain_iso_db2 = 10*log10(gain_iso2) #Power gain (in dBi)\n",
"\n",
"gain_3 = sqrt(2*(Z/(Z+R_21_3))) #Gain in fieldfor s3 (unitless)\n",
"gain_iso3 = 1.64*(gain_3**2) #Power gain over isotropic (unitless)\n",
"gain_iso_db3 = 10*log10(gain_iso3) #Power gain (in dBi)\n",
"\n",
"#Result\n",
"print \"The gain in field over half wave antenna for s1 is\", round(gain_1,2)\n",
"print \"\"\"The power gain over isotropic for s1 is %.2f or %.1f dBi\n",
" \"\"\" % (gain_iso1,gain_iso_db1)\n",
" \n",
"print \"The gain in field over half wave antenna for s2 is\", round(gain_2,2)\n",
"print \"\"\"The power gain over isotropic for s2 is %.2f or %.2f dBi\n",
" \"\"\" % (gain_iso2,gain_iso_db2)\n",
" \n",
"print \"The gain in field over half wave antenna for s3 is\", round(gain_3,2)\n",
"print \"\"\"The power gain over isotropic for s3 is %.2f or %.2f dBi\n",
" \"\"\" % (gain_iso3,gain_iso_db3)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The gain in field over half wave antenna for s1 is 1.36\n",
"The power gain over isotropic for s1 is 3.02 or 4.8 dBi\n",
" \n",
"The gain in field over half wave antenna for s2 is 1.56\n",
"The power gain over isotropic for s2 is 3.97 or 5.99 dBi\n",
" \n",
"The gain in field over half wave antenna for s3 is 1.71\n",
"The power gain over isotropic for s3 is 4.82 or 6.83 dBi\n",
" \n"
]
}
],
"prompt_number": 7
}
],
"metadata": {}
}
]
}