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diff --git a/Antennas_and_Wave_Propagation/chapter17.ipynb b/Antennas_and_Wave_Propagation/chapter17.ipynb new file mode 100644 index 00000000..e9d63ef2 --- /dev/null +++ b/Antennas_and_Wave_Propagation/chapter17.ipynb @@ -0,0 +1,323 @@ +{ + "metadata": { + "name": "" + }, + "nbformat": 3, + "nbformat_minor": 0, + "worksheets": [ + { + "cells": [ + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "<h1>Chapter 17: Antenna Temperature, Remote Sensing and Radar Cross Section<h1>" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "<h3>Example 17-1.1, Page number: 623<h3>" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "from math import pi\n", + "\n", + "#Variable declaration\n", + "Ta = 0.24 #Antenna temperature (K)\n", + "ang = 0.005 #Subtended angle (degrees)\n", + "hpbw = 0.116 #Antenna half power beamwidth (degrees)\n", + "\n", + "#Calculations\n", + "Ts = Ta*(hpbw**2)/(pi*(ang**2/4))\n", + "\n", + "#Result\n", + "print \"The averate temperature of the surface is\", round(Ts), \"K\"" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "The averate temperature of the surface is 164.0 K\n" + ] + } + ], + "prompt_number": 1 + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "<h3>Example 17-1.2, Page number: 625<h3>" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "from math import pi, sqrt\n", + "\n", + "#Variable declaration\n", + "eff_aper = 500 #Antenna effective aperture (m^2)\n", + "wave_lt = 20e-2 #Wavelength (m)\n", + "Tsky = 10.0 #sky temperature (K)\n", + "Tgnd = 300.0 #Ground temperature (K)\n", + "beam_eff = 0.7 #Beam efficiency (unitless)\n", + "aper_eff = 0.5 #Aperture efficiency (unitless)\n", + "\n", + "#Calculations\n", + "phy_aper = aper_eff/eff_aper #Physical aperture (m^2)\n", + "diam = 2*sqrt(phy_aper/pi) #Antenna diameter (m)\n", + "diam_l = diam/wave_lt #Antenna diameter (lambda)\n", + "\n", + "ta_sky = Tsky*beam_eff #Sky contribution to antenna temp. (K)\n", + "ta_side = 0.5*Tsky*(1-beam_eff) #Side-lobe contribution to antenna temp. (K)\n", + "ta_back = 0.5*Tgnd*(1-beam_eff) #Back-lobe contribution to antenna temp. (K)\n", + "\n", + "Ta = ta_sky + ta_side + ta_back\n", + "\n", + "#Result\n", + "print \"The total antenna temperature is\", Ta, \"K\"" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "The total antenna temperature is 53.5 K\n" + ] + } + ], + "prompt_number": 2 + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "<h3>Example 17-2.1, Page number: 629<h3>" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "#Variable declaration\n", + "Tn = 50.0 #Noise temperature (K)\n", + "Tphy = 300.0 #Physical temperature (K)\n", + "Eff = 0.99 #Efficiency (unitless)\n", + "Tn_stg = 80.0 #Noise temperature of first 3 stages (K)\n", + "gain_db = 13.0 #Gain (dB)\n", + "Tphy_tr = 300 #Transmission line physical temperature (K)\n", + "Eff_tr = 0.9 #Transmission line efficiency (unitless)\n", + "\n", + "#Calculations\n", + "gain = 10**(gain_db/10)\n", + "T_r = Tn_stg + Tn_stg/(gain) + Tn_stg/(gain**2)\n", + " #Receiver noise temperature (K)\n", + "Tsys = Tn + Tphy*(1/Eff - 1) + Tphy_tr*(1/Eff_tr - 1) + (1/Eff_tr)*T_r\n", + " #System temperature (K)\n", + "\n", + "#Result\n", + "print \"The system temperature is\", round(Tsys), \"K\"" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "The system temperature is 180.0 K\n" + ] + } + ], + "prompt_number": 3 + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "<h3>Example 17-2.2, Page number: 630<h3>" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "from math import sqrt\n", + "\n", + "#Variable declaration\n", + "phy_aper = 2208 #Physical aperture (m^2)\n", + "f = 1415e6 #Frequency (Hz)\n", + "aper_eff = 0.54 #Aperture efficiency (unitless)\n", + "Tsys = 50 #System temperature (K)\n", + "bw = 100e6 #RF Bandwidth (Hz)\n", + "t_const = 10 #Output time constant (s)\n", + "sys_const = 2.2 #System constant (unitless)\n", + "k = 1.38e-23 #Boltzmann's constant (J/K)\n", + "\n", + "#Calculations\n", + "Tmin = sys_const*Tsys/(sqrt(bw*t_const)) #Minimum detectable temperature(K)\n", + "eff_aper = aper_eff*phy_aper #Effective aperture (m^2)\n", + "Smin = 2*k*Tmin/eff_aper #Minimum detectable flux density (W/m^2/Hz)\n", + "\n", + "#Result\n", + "print \"The minimum detectable flux density is %.1e W/m^2/Hz\" % Smin" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "The minimum detectable flux density is 8.1e-29 W/m^2/Hz\n" + ] + } + ], + "prompt_number": 7 + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "<h3>Example 17-3.1, Page number: 631<h3>" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "from math import pi, log10\n", + "\n", + "#Variable declaration\n", + "k = 1.38e-23 #Boltzmann's constant (J/K)\n", + "trans_pow = 5 #Transponder power (W)\n", + "r = 36000e3 #Distance (m)\n", + "wave_lt = 7.5e-2 #Wavelength (m)\n", + "ant_gain = 30 #Antenna gain (dB)\n", + "earth_ant = 38 #Earth station antenna gain (dB)\n", + "Tsys = 100 #Earth station receiver system temperature (K)\n", + "bw = 30e6 #Bandwidth (Hz)\n", + "\n", + "#Calculations\n", + "s_n = wave_lt**2/(16*(pi**2)*(r**2)*k*Tsys*bw)\n", + "s_n = 10*log10(s_n) #Signal to Noise ratio (dB)\n", + "\n", + "trans_pow_db = 10*log10(trans_pow) #Transponder power (dB)\n", + "erp = ant_gain + trans_pow_db #Effective radiated power (dB)\n", + "\n", + "s_n_downlink = erp + earth_ant + s_n #Signal to Noise ratio downlink(dB)\n", + "\n", + "#Result\n", + "print \"The earth station S/N ratio is\", round(s_n_downlink,1), \"dB\"" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "The earth station S/N ratio is 13.2 dB\n" + ] + } + ], + "prompt_number": 8 + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "<h3>Example 17-4.1, Page number: 634<h3>" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "from math import exp\n", + "\n", + "#Variable declaration\n", + "tf = 0.693 #Absorption co-efficient (unitless)\n", + "Te = 305 #Earth temperature (K)\n", + "Ta = 300 #Satellite antenna temperature (K)\n", + "\n", + "#Calculations\n", + "Tf = (Ta - Te*exp(-tf))/(1-exp(-tf))\n", + "\n", + "#Result\n", + "print \"The forest temperature is\", round(Tf), \"K\"" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "The forest temperature is 295.0 K\n" + ] + } + ], + "prompt_number": 9 + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "<h3>Example 17-5.1, Page number: 639<h3>" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "#Variable declaration\n", + "f = 10e9 #Frequency (Hz)\n", + "wind_speed = 350 #Wind speed (km/h)\n", + "c = 3e8 #Speed of light (m/s)\n", + "vr = 1e3 #Differential velocity (m/h)\n", + "\n", + "#Calculations\n", + "wave_lt = c/f #Wavelength (m)\n", + "freq_shift = 2*(wind_speed*1000/3600)/wave_lt \n", + " #Doppler Frequency shift (Hz)\n", + "T = 1/(2*freq_shift) #Pulse repetition interval (s)\n", + "prf = 1/T #Pulse repetition frequency (Hz)\n", + "\n", + "fmin = 2*(vr/3600)/wave_lt #Frequency resolution (Hz)\n", + "N = 1/(round(fmin,1)*T) #Number of pulses \n", + "\n", + "#Result\n", + "print \"The minimum pulse repetition frequency is\", round(prf,-3), \"Hz\"\n", + "print \"The number of pulses to be sampled is\", round(N)" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "The minimum pulse repetition frequency is 13000.0 Hz\n", + "The number of pulses to be sampled is 699.0\n" + ] + } + ], + "prompt_number": 14 + } + ], + "metadata": {} + } + ] +}
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