{ "metadata": { "name": "" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "

Chapter 4: Radiation

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

Example 4-4.1, Page number: 75

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#Variable declaration\n", "theta = 30 #Angle of radiation (degrees)\n", "epsilon_0 = 8.854e-12 #Permittivity of free space (F/m)\n", "I_dl = 10 #Current in length dl (A-m)\n", "r = 100e3 #Distance of point from origin (m)\n", "\n", "#Calculation\n", "E_mag = (I_dl*math.sin(theta*math.pi/180))/(4*math.pi*epsilon_0)\n", " #Magnitude of Electric field vector (V/m)\n", "H_mag = (I_dl*math.sin(theta*math.pi/180))/(4)\n", " #Magnitude of Magnetic field vector (T)\n", "\n", "#Result\n", "print \"The magnitude of E vector is \", round(E_mag,-9), \"V/m\"\n", "print \"The magnitude of H vector is\", round(H_mag, 3), \"/pi T\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The magnitude of E vector is 45000000000.0 V/m\n", "The magnitude of H vector is 1.25 /pi T\n" ] } ], "prompt_number": 6 }, { "cell_type": "markdown", "metadata": {}, "source": [ "

Example 4-4.2, Page number: 76

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#Variable declaration\n", "v = 3e8 #Speed of light(m/s)\n", "f = 10e6 #Frequency (Hz)\n", "\n", "#Calculation\n", "w = 2*math.pi*f #Angular frequency(rad/s)\n", "r = v/w #Distance (m)\n", "\n", "#Result\n", "print \"The distance for the specified condition is\", round(r, 2), \"m\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The distance for the specified condition is 4.77 m\n" ] } ], "prompt_number": 3 }, { "cell_type": "markdown", "metadata": {}, "source": [ "

Example 4-4.3, Page number: 76

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#Variable declaration\n", "c = 3e8 #Speed of light (m/s)\n", "f = 3e9 #Frequency (Hz)\n", "\n", "#Calculation\n", "v = 0.6*c #60% of velocity of light (m/s)\n", "w = 2*math.pi*f #Angular frequency (rad/s)\n", "r = v/w #Distance (m)\n", "\n", "#Result\n", "print \"The distance for the specified condition is\", round(r,6), \"m\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The distance for the specified condition is 0.009549 m\n" ] } ], "prompt_number": 4 }, { "cell_type": "markdown", "metadata": {}, "source": [ "

Example 4-5.1, Page number: 80

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#Variable declaration\n", "dl = 1e-2 #Length of radiating element (m)\n", "I_eff = 0.5 #Effective current (A)\n", "f = 3e9 #Frequency (Hz)\n", "c = 3e8 #Velocity of light (m/s)\n", "\n", "#Calculation\n", "w = 2*math.pi*f #Angular Frequency (rad/s)\n", "P = 20*(w**2)*(I_eff**2)*(dl**2)/(c**2) #Radiated power (W)\n", "\n", "#Result\n", "print \"The radiated power is\", round(P, 2), \"W\"\n", "\n", "#The final result is incorrect in the book because of the calculation mistake" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The radiated power is 1.97 W\n" ] } ], "prompt_number": 5 }, { "cell_type": "markdown", "metadata": {}, "source": [ "

Example 4-5.2, Page number: 80

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Variable declaration\n", "L = 5 #Length of radiating element (m)\n", "f1 = 30e3 #Frequency (Hz) \n", "f2 = 30e6 #Frequency (Hz) \n", "f3 = 15e6 #Frequency (Hz)\n", "c = 3e8 #Velocity of light (m/s) \n", "\n", "#Calculation\n", "wave_lt1 = c/f1 #Wavelength (m)\n", "wave_lt1 /= 10\n", "R_r1 = 800*(L/wave_lt1)**2 #Radiation resistance (ohm)\n", "\n", "wave_lt2 = c/f2 #Wavelength (m)\n", "L = wave_lt2/2 #Effective length (m)\n", "R_r2 = 200*(L/wave_lt2)**2 #Radiation resistance (ohm)\n", "\n", "wave_lt3 = c/f3 #Wavelength (m)\n", "L = wave_lt3/4 #Effective length (m)\n", "R_r3 = 400*(L/wave_lt3)**2 #Radiation resistance (ohm)\n", "\n", "#Result\n", "print \"The radiation resistance for f1 is\", R_r1, \"ohms\"\n", "print \"The radiation resistance for f2 is\", round(R_r2), \"ohms\"\n", "print \"The radiation resistance for f3 is\", round(R_r3), \"ohms\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The radiation resistance for f1 is 0.02 ohms\n", "The radiation resistance for f2 is 50.0 ohms\n", "The radiation resistance for f3 is 25.0 ohms\n" ] } ], "prompt_number": 6 }, { "cell_type": "markdown", "metadata": {}, "source": [ "

Example 4-6.1, Page number: 82

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#Variable declaration\n", "Im = 5 #Maximum current (A)\n", "r = 1e3 #Distance (km)\n", "eta = 120*math.pi #Intrinsic impedence (ohm)\n", "theta = 60*math.pi/180 #Angle of radiation (radians)\n", "\n", "#Calculation\n", "sin2 = math.sin(theta)**2 #Sine squared theta (unitless)\n", "P_av = (eta*(Im**2))/(8*(math.pi**2)*(r**2))\n", "P_av = P_av*(math.cos(math.pi/2*math.cos(theta))**2)/(sin2)\n", " #Average power (W)\n", " \n", "#Result\n", "print \"The average power available at 1km distance is\", round(P_av,9), \"W\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The average power available at 1km distance is 7.9577e-05 W\n" ] } ], "prompt_number": 8 } ], "metadata": {} } ] }