{ "metadata": { "name": "", "signature": "sha256:4900eeee12d5add487271b429c0cbafd110530ef7f850ea37e0c5905f6da1030" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Ch-12 : Microwave Measurements" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Page Number: 649 Example 12.1" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from __future__ import division\n", "#Given\n", "Is=0.1*(10**-6) #A\n", "Pi=0 #dBm\n", "Cs=0.1*(10**-12) #F\n", "Ls=2*(10**-9) \n", "Cj=0.15*(10**-12) #F\n", "Rs=10 #ohm\n", "T=293 #K\n", "nktbye=25*(10**-3) #V\n", "\n", "#Rj\n", "Rj=(nktbye/Is) \n", "print 'Rj:' ,Rj/1000,'Kohm'\n", "\n", "#Bi\n", "Bi=nktbye/2 \n", "Bii=Bi*1000 \n", "print 'Bi:' ,Bii,'A/W'\n", "\n", "#Bv\n", "Bv=Rj*Bii \n", "print 'Bv:',Bv, 'V/W'" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Rj: 250.0 Kohm\n", "Bi: 12.5 A/W\n", "Bv: 3125000.0 V/W\n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Page Number: 650 Example 12.2" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from math import log10 \n", "#Given\n", "vswr=4 \n", "\n", "modT=(vswr-1)/(vswr+1) \n", "Lm=-10*log10(1-(modT*modT)) #dB\n", "print 'Mismatch Loss:' ,Lm,'dB'\n", "\n", "#Sensitivity reduces by a factor\n", "Bvd=(1-(modT*modT)) \n", "Bvdp=Bvd*100 \n", "print 'Voltge sensitivity reduces by:' ,Bvdp,'%'" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Mismatch Loss: -0.0 dB\n", "Voltge sensitivity reduces by: 100 %\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Page Number: 650 Example 12.3" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from math import sqrt , pi\n", "#Given\n", "f=10e9 #Hz\n", "c=3e10 #cm/s\n", "a=4 #cm\n", "s=0.1 #cm\n", "lmb=c/f #cm\n", "lmbg=lmb/(sqrt(1-((lmb/(2*a))**2))) \n", "vswr=lmbg/(pi*s) \n", "print 'VSWR: %0.3f'%vswr\n", "\n", "#Answer in book for lmbg is given as 3.49 but it should be 3.23 and hence the answer will be 10.3" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "VSWR: 10.301\n" ] } ], "prompt_number": 4 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Page Number: 651 Example 12.4" ] }, { "cell_type": "code", "collapsed": false, "input": [ " \n", "#Given\n", "delx=3.5 #cm\n", "s=0.25 #cm\n", "\n", "lmbg=2*delx \n", "vswr=lmbg/(pi*s) \n", "print 'VSWR: %0.3f'%vswr" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "VSWR: 8.913\n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Page Number: 651 Example 12.5" ] }, { "cell_type": "code", "collapsed": false, "input": [ " \n", "#Given\n", "vswr=2 \n", "Pin=4.5e-3 #W\n", "\n", "modT=(vswr-1)/(vswr+1) \n", "#Power reflected,\n", "Pr=(modT**2)*Pin \n", "#As coupler samples only 1/1000th power\n", "Prr=Pr*1000 \n", "print 'Reflected Power:' ,Prr,'W'" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Reflected Power: 0.5 W\n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Page Number: 652 Example 12.6" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from math import tan\n", "#Given\n", "Z0=50 #ohm\n", "p=2.4 \n", "L=0.313 \n", "x=2*pi*L \n", "y=tan(x) \n", "\n", "Zl=(Z0*(1+(p*p*1J)))/(p+(p*1J)) \n", "T=(Zl-Z0)/(Zl+Z0) \n", "p=sqrt(((T.real))**2+((T.imag))**2) \n", "print 'Reflection coefficient: %0.3f'%p" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Reflection coefficient: 0.412\n" ] } ], "prompt_number": 6 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Page Number: 652 Example 12.7" ] }, { "cell_type": "code", "collapsed": false, "input": [ " \n", "#Given\n", "Zl=25+25*1J #ohm\n", "Z0=50 #ohm\n", "\n", "T=(Zl-Z0)/(Zl+Z0) \n", "p=sqrt(((T.real))**2+((T.imag))**2) \n", "print 'Reflection coefficient: %0.3f'%p\n", "\n", "vswrr=(1+p)/(1-p) \n", "print 'VSWR: %0.3f'%vswrr\n", "\n", "#Fraction of power delivered\n", "Pd=1-(p**2) \n", "Pdp=Pd*100 \n", "\n", "print 'Fraction of power delivered:',Pdp, '%'" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Reflection coefficient: 0.447\n", "VSWR: 2.618\n", "Fraction of power delivered: 80.0 %\n" ] } ], "prompt_number": 8 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Page Number: 653 Example 12.8" ] }, { "cell_type": "code", "collapsed": false, "input": [ " \n", "#Given\n", "d=2.4 #cm\n", "lmbc=1.8 \n", "c=3*10**10 #cm/s\n", "\n", "lmbg=2*d \n", "lmb=(lmbg*lmbc)/(sqrt(lmbg**2+lmbc**2)) \n", "#Operating frequency\n", "f=c/lmb \n", "print 'Operating frequency: %0.3f'%(f/10**9),'GHz'" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Operating frequency: 17.800 GHz\n" ] } ], "prompt_number": 9 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Page Number: 653 Example 12.9" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from numpy import mat\n", "#Given\n", "p=1.5 \n", "IsL=1 #dB\n", "InL=30 #dB\n", "\n", "S21=10**(-IsL/20) \n", "\n", "#Assuming tgree ports to be identical\n", "S32=S21 \n", "S13=S21 \n", "\n", "#Isolations are also the same\n", "S31=10**(-InL/20) \n", "S23=S31 \n", "S12=S31 \n", "\n", "#Refelction coefficients are also the same\n", "T=(p-1)/(p+1) \n", "S11=T \n", "S22=T \n", "S33=T \n", "\n", "S=mat([[S11, S12, S13], [S21, S22, S23], [S31, S32, S33] ])\n", "print 'Matrix is:\\n' ,S" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Matrix is:\n", "[[ 0.2 0.03162278 0.89125094]\n", " [ 0.89125094 0.2 0.03162278]\n", " [ 0.03162278 0.89125094 0.2 ]]\n" ] } ], "prompt_number": 10 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Page Number: 654 Example 12.10" ] }, { "cell_type": "code", "collapsed": false, "input": [ " \n", "#Given\n", "R1=10.6 #GHz\n", "R2=8.30 #GHz\n", "Q0=8200 \n", "Q0d=890 \n", "\n", "Er=(R1/R2)**2 \n", "print 'Dielectric constant %0.3f'%Er\n", "\n", "Qd=(Q0-Q0d)/(Q0*Q0d) \n", "print 'Loss tangent of dielectric' ,Qd" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Dielectric constant 1.631\n", "Loss tangent of dielectric 0\n" ] } ], "prompt_number": 13 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Page Number: 654 Example 12.11" ] }, { "cell_type": "code", "collapsed": false, "input": [ " \n", "#Given\n", "l0=0.15 #cm\n", "lmbg=2*2.24 #cm\n", "le=1.14 #cm\n", "a=2.286 #cm\n", "d=2 \n", "\n", "B0=(2*pi)/lmbg \n", "x=tan(B0*l0)/(B0*l0) \n", "#Also\n", "x1=(l0*x)/le \n", "#Correct value seems to be\n", "Bele=2.786 \n", "e1=((((a/pi)**2)*(Bele/le)**2)+1) \n", "e2=(((2*a)/lmbg)**2)+1 \n", "Er=e1/e2 \n", "print 'Er: %0.3f'%Er\n", "\n", "\n", "#Answer in book for Er is given as 2.062 but it should be 2.038" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Er: 2.039\n" ] } ], "prompt_number": 14 } ], "metadata": {} } ] }