PK��I�����-Antennas and Wave Propagation/chapter25.ipynb{ "metadata": { "name": "" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "

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### Example 15-21.1, Page number: 574

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from math import pi\n", "\n", "dia = 1000 #diameter of asteroid (m)\n", "prc = 0.4 #Power reflection coefficient of asteroid (unitless)\n", "f = 4e9 #Frequency (Hz)\n", "P = 1e9 #Power (W)\n", "s = 20e3 #Asteroid speed (m/s)\n", "ast_dis = 0.4 #Distance of asteroid (AU)\n", "au = 1.5e11 #Astronomical Unit (m)\n", "c = 3e8 #Speed of light (m/s)\n", "k = 1.38e-23 #Boltzmann's constant (m^2 kg s^-2 K^-1)\n", "Tsys = 10 #System temperature (K)\n", "B = 1e6 #Bandwidth (Hz)\n", "snr = 10 #Signal to noise ratio (dB)\n", "eap = 0.75 #Aperture efficiency (unitless)\n", "\n", "sigma = prc*pi*s**2 #Radar cross section (m^2)\n", "ast_dm = au*ast_dis #Astroid distance (m)\n", "lmda = c/f #Wavelength(m)\n", "\n", "d4 = (64*(lmda**2)*(ast_dm**4)*k*Tsys*B*snr)/((eap**2)*pi*(sigma)*P)\n", "d = d4**(0.25) #Diameter of dish (m)\n", "\n", "delf = 2*s/lmda #Doppler shift (Hz)\n", "delt = 2*(ast_dm)/c #Time delay (s)\n", "\n", "timp = ast_dm/s #Time before impact (s) \n", "\n", "\n", "#Result\n", "print \"The diameter of the dish is\", round(d), \"m\"\n", "print \"The doppler shift is %.1f Hz\" % delf\n", "print \"The time delay for the radar signal is\", delt, \"s\"\n", "print \"The time before impact is\", timp, \"s\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The diameter of the dish is 292.0 m\n", "The doppler shift is 533333.3 Hz\n", "The time delay for the radar signal is 400.0 s\n", "The time before impact is 3000000.0 s\n" ] } ], "prompt_number": 153 }, { "cell_type": "markdown", "metadata": {}, "source": [ "

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### Example 7-11.2, Page number: 264

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from math import pi,sqrt\n", "\n", "#Variable declaration\n", "n = 10 #Number of turns (unitless)\n", "dia = 1e-3 #Diameter of copper wire (m)\n", "dia_rod = 1e-2 #Diameter of ferrite rod (m)\n", "len_rod = 10e-2 #Length of ferrite rod (m)\n", "mu_r = 250 - 2.5j #Relative permeability (unitless)\n", "mu_er = 50 #Efeective relative permeability (unitless)\n", "f = 1e6 #Frequency (Hz)\n", "c = 3e8 #Speed of light (m/s)\n", "mu_0 = pi*4e-7 #Absolute permeability (H/m)\n", "\n", "#Calculations\n", "wave_lt = c/f #Wavelength (m)\n", "radius = dia_rod/2\n", "C_l = (2*pi*radius)/(wave_lt) #Circumference of loop (m)\n", "Rr = 197*(mu_er**2)*(n**2)*(C_l**4) #Radiation resistance (ohm)\n", "Rf = 2*pi*f*mu_er*(mu_r.imag/mu_r.real)*mu_0*(n**2)*(pi*radius**2)/len_rod #Loss resistance(ohm)\n", "cond = 1/((7e-5**2)*f*pi*mu_er) #Conductivity (S/m)\n", "delta = 1/(sqrt(f*pi*mu_er*cond)) #Depth of penetration(m)\n", "\n", "RL = n*(C_l/dia)*sqrt((f*mu_0)/(pi*cond)) #Ohmic resistance (ohm)\n", "k = Rr/(RL+abs(Rf)) #Radiation efficiency (unitless)\n", "\n", "L = mu_er*(n**2)*(radius**2)*mu_0/len_rod #Inductance (H)\n", "Q = 2*pi*f*L/(abs(Rf) + Rr + RL) #Ratio of energy stored to energy lost per cycle (unitless)\n", "\n", "fHP = f/Q #Bandwidth at half power (Hz)\n", "\n", "\n", "#Results\n", "print \"The radiation efficiency is \", round(k,11)\n", "print \"The value of Q is \", round(Q,3)\n", "print \"The half-power bandwidth is\", round(fHP), \"Hz\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The radiation efficiency is 6.65e-09\n", "The value of Q is 11.076\n", "The half-power bandwidth is 90289.0 Hz\n" ] } ], "prompt_number": 6 }, { "cell_type": "markdown", "metadata": {}, "source": [ "