{ "metadata": { "name": "", "signature": "sha256:ad12bff96918abc5e35ecb69ed85dad3776e4014893a3bdddb23c1bfeff5820d" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter11:STRIP LINES" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Eg11.1.1:pg-495" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "#calculation of characteristic impedance Z0 of the line\n", "er=5.23 #relative dielectric constant of the board material\n", "h=7 #height from microstrip line to the ground in mils\n", "t=2.8 #thickness of the microstrip line in mils\n", "w=10 #width of the microstrip line in mils\n", "Z0=(87*(math.log((5.98*h)/(t+(0.8*w)))))/sqrt(er+1.41) \n", "print\"The characteristic impedance of the line(in ohms)is =\",round(Z0,2),\"ohms\" #calculation mistake in book" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The characteristic impedance of the line(in ohms)is = 45.74 ohms\n" ] } ], "prompt_number": 13 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Eg11.2.1:pg-505" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "#(a) Calculate the required width w of the conducting strip in order to have a characteristic impedance of 50 ohms \n", "erd=6 #relative dielectric constant of BeO\n", "d=4*(10**-3) #thickness in meter\n", "Z0=50 #characteristic impedance in ohms\n", "w=(377*(d))/((sqrt(erd))*Z0) \n", "print\"The required width of the conducting strip(in metres)is =\",\"{:.3e}\".format(w),\"m\"\n", "\n", "#(b) Calculate the strip line capacitance\n", "ed=8.854*(10**-12)*erd \n", "d=4*(10**-3) #thickness in meter\n", "C=(ed*round(w,5))/d #strip line capacitance\n", "C=C*(10**12) #multiply C by 10**12 for converting it in pF/m\n", "print\"The strip line capacitance(in pF/m)is =\",round(C,1),\"pF/m\"\n", "\n", "#(c) Calculate the strip line inductance\n", "uc=4*math.pi*(10**-7) #permeability of the conductor\n", "d=4*(10**-3) #thickness in meter\n", "L=(uc*d)/w \n", "L=L*(10**6) #converting L in micro H/m\n", "print\"The strip line inductance(in uH/m)is =\",round(L,2),\"micro H/m\" \n", "\n", "#(d)Calculate the phase velocity of the wave in the parallel strip line\n", "c=3*(10**8) #speed of light in meter/second\n", "vp=c/sqrt(erd) \n", "print\"The phase velocity of the wave in the parallel strip line(in m/s)is =\",\"{:.2e}\".format(vp),\"m/s\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The required width of the conducting strip(in metres)is = 1.231e-02 m\n", "The strip line capacitance(in pF/m)is = 163.5 pF/m\n", "The strip line inductance(in uH/m)is = 0.41 micro H/m\n", "The phase velocity of the wave in the parallel strip line(in m/s)is = 1.22e+08 m/s\n" ] } ], "prompt_number": 16 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Eg11.3.1:pg-507" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Determine the characteristic impedance of the coplanar strip line\n", "Pavg=250*(10**-3) #average power flowing in the positive z direction in watt\n", "Io=100*(10**-3) #total peak current in ampere\n", "Z0=(2*Pavg)/(Io**2) \n", "print\"The characteristic impedance of the coplanar strip line(in ohms)is =\",int(round(Z0)),\"ohms\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The characteristic impedance of the coplanar strip line(in ohms)is = 50 ohms\n" ] } ], "prompt_number": 17 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Eg11.4.1:pg-508" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "#(a)Calculate the K factor\n", "er=2.56 #dielectric constant of the insulator(polystyrene)\n", "w=25.0 #strip width in mils\n", "t=14.0 #strip thickness in mils\n", "d=70 #shield depth in mils\n", "K=1.0/(1-(t/d)) \n", "print\"The K factor is =\",K\n", "\n", "#(b)Calculate the fringe capacitance\n", "Cf=round(((8.854*er)*(round((2*K*math.log(K+1)),3)-round(((K-1)*math.log((K**2)-1)),2))),)/round(math.pi,2)\n", "print\"The fringe capacitance(in pF/m)is =\",round(Cf,2),\"pF/m\" \n", "\n", "#(c) Calculate the characteristic impedance of the line\n", "Z0=94.15/((((w/d)*K)+(round(Cf,2)/(8.854*er)))*(sqrt(er))) \n", "print\"The characteristic impedance of the line(in ohms)is =\",round(Z0,3),\"ohms\" #answer is wrong in book" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The K factor is = 1.25\n", "The fringe capacitance(in pF/m)is = 15.61 pF/m\n", "The characteristic impedance of the line(in ohms)is = 51.839 ohms\n" ] } ], "prompt_number": 20 } ], "metadata": {} } ] }