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diff --git a/Antennas_and_Wave_Propagation/chapter19.ipynb b/Antennas_and_Wave_Propagation/chapter19.ipynb new file mode 100644 index 00000000..e7875d72 --- /dev/null +++ b/Antennas_and_Wave_Propagation/chapter19.ipynb @@ -0,0 +1,136 @@ +{ + "metadata": { + "name": "" + }, + "nbformat": 3, + "nbformat_minor": 0, + "worksheets": [ + { + "cells": [ + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "<h1>Chapter 19: The Fourier Transform Relation between Aperture Distribution and Far-field Pattern<h1>" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "<h3>Example 19-8.1, Page number: 690<h3>" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "from math import sin, pi\n", + "\n", + "#Variable declaration\n", + "gal_ext = 400000 #Extent of galaxy (light-years)\n", + "alpha = 0.032 #Extent of galaxy (degrees)\n", + "f = 5e9 #Frequency (Hz)\n", + "a = 36e3 #Maximum VLA Spacing (m)\n", + "c = 3e8 #Speed of light (m/s)\n", + "wid = 0.03 #Width of image (degrees)\n", + "hei = 0.008 #Height of image (degrees)\n", + "flux_den = 2.5e-23 #Average flux density (W/m^2)\n", + "bw = 1e9 #Bandwidth (Hz)\n", + "\n", + "#Calculations\n", + "dist = gal_ext/sin(alpha*pi/180) #Distance to the galaxy (light-years)\n", + "dist_m = dist*(365*24*3600*c)\n", + "\n", + "wave_lt = c/f #Wavelength (m)\n", + "a_lambda = a/wave_lt #Spacing in wavelength (unitless)\n", + "pix_size = 51/a_lambda #Resolution or Pixel size (degrees)\n", + "pix_size_arc = pix_size*3600 #Pixel size (arc seconds)\n", + "\n", + "area = wid*hei #Area of image (square degrees)\n", + "area_arc = area*(3600**2) #Area of image (arc seconds)\n", + "num_pix = area_arc/pix_size_arc**2 #Number of pixels\n", + "\n", + "rad_pow = flux_den*4*pi*(dist_m**2)*bw\n", + "\n", + "#Result\n", + "print \"The distance to the galaxy is\", round(dist,-8), \"light years\"\n", + "print \"The resolution or pixel size is\", round(pix_size_arc,2), \"arc seconds\"\n", + "print \"The number of pixels is\", round(num_pix)\n", + "print \"The radio power of the galaxy is %.1e W\" % rad_pow" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "The distance to the galaxy is 700000000.0 light years\n", + "The resolution or pixel size is 0.31 arc seconds\n", + "The number of pixels is 33218.0\n", + "The radio power of the galaxy is 1.4e+37 W\n" + ] + } + ], + "prompt_number": 17 + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "<h3>Example 19-8.2, Page number:691<h3>" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "from math import pi, log10\n", + "\n", + "#Variable declaration\n", + "f = 10e9 #Frequency (Hz)\n", + "c = 3e8 #Speed of light (m/s)\n", + "dia = 100 #Dish diameter (m)\n", + "aper_eff = 0.725 #Aperture efficiency (unitless)\n", + "\n", + "#Calculation\n", + "wave_lt = c/f #Wavelength (m)\n", + "hpbw = 66/(dia/wave_lt) #Half power beam width (degrees)\n", + "\n", + "gain = 41000/(hpbw**2) #Gain from beamwidth (unitless)\n", + "gain_db = 10*log10(gain) #Gain from beamwidth (dBi)\n", + "\n", + "gain_ap = 4*(pi**2)*(dia/2)**2*(aper_eff)/(wave_lt**2) \n", + " #Gain from effective aperture(unitless)\n", + "gain_ap_db = 10*log10(gain_ap) #Gain from effective aperture (dBi)\n", + "\n", + "side_lobe = -23 #First side lobe level from table (dB)\n", + "\n", + "#Result\n", + "print \"The Half Power Beamwidth is\", round(hpbw,3), \"degrees\"\n", + "print \"The gain from beamwidth is\", round(gain_db), \"dBi\"\n", + "print \"The gain from effective aperture is\", round(gain_ap_db), \"dBi\"\n", + "print \"The first side-lobe level is\", side_lobe,\"dB\"" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "The Half Power Beamwidth is 0.02 degrees\n", + "The gain from beamwidth is 80.0 dBi\n", + "The gain from effective aperture is 79.0 dBi\n", + "The first side-lobe level is -23 dB\n" + ] + } + ], + "prompt_number": 19 + } + ], + "metadata": {} + } + ] +}
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