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{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 12 : Microwave Measurements"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 12.1 Page Number: 649"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#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": 35
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 12.2 Page Number: 650"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from math import log10\n",
"#Given\n",
"vswr=4.0 \n",
"\n",
"modT=(vswr-1)/(vswr+1) \n",
"Lm=-10*log10(1-(modT*modT)) #dB\n",
"print 'Mismatch Loss =',round(Lm,3),'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 = 1.938 dB\n",
"Voltge sensitivity reduces by 64.0 %\n"
]
}
],
"prompt_number": 36
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 12.3 Page Number: 650"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from math import sqrt, pi\n",
"#Given\n",
"f=10E+9 #Hz\n",
"c=3E+10 #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 =',round(vswr,3) \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": 37
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 12.4 Page Number: 651"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Given\n",
"delx=3.5 #cm\n",
"s=0.25 #cm\n",
"\n",
"lmbg=2*delx \n",
"vswr=lmbg/(pi*s) \n",
"print 'VSWR =',round(vswr,3) "
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"VSWR = 8.913\n"
]
}
],
"prompt_number": 38
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 12.5 Page Number: 651"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Given\n",
"vswr=2.0 \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": 39
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 12.6 Page Number: 652"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Given\n",
"from math import tan, sqrt, pi\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 =',round(p,2)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Reflection coefficient = 0.41\n"
]
}
],
"prompt_number": 40
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 12.7 Page Number: 652"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#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 =',round(p,2) \n",
"\n",
"vswrr=(1+p)/(1-p) \n",
"print 'VSWR =', round(vswrr,2) \n",
"\n",
"#Fraction of power delivered\n",
"Pd=1-(p**2) \n",
"Pdp=Pd*100 \n",
"print 'Fraction of power delivered =',Pdp,'%' "
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Reflection coefficient = 0.45\n",
"VSWR = 2.62\n",
"Fraction of power delivered = 80.0 %\n"
]
}
],
"prompt_number": 41
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 12.8 Page Number: 653"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#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 =',round((f/10**9),2), 'GHz' "
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Operating frequency = 17.8 GHz\n"
]
}
],
"prompt_number": 42
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 12.9 Page Number: 653"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"from numpy import array#Given\n",
"p=1.5 \n",
"IsL=1 #dB\n",
"InL=30 #dB\n",
"\n",
"S21=10**(-IsL/20) \n",
"\n",
"#Assuming three 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=array([S11,S12,S13,S21,S22,S23,S31,S32,S33] )\n",
"print 'Matrix is:',S "
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Matrix is: [ 0.2 0.01 0.1 0.1 0.2 0.01 0.01 0.1 0.2 ]\n"
]
}
],
"prompt_number": 43
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 12.10 Page Number: 654"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Given\n",
"R1=10.6 #GHz\n",
"R2=8.30 #GHz\n",
"Q0=8200 \n",
"Q0d=890.0 \n",
"\n",
"Er=(R1/R2)**2 \n",
"print 'Dielectric constant =', round(Er ,2)\n",
"\n",
"Qd=(Q0-Q0d)/(Q0*Q0d) \n",
"print 'Loss tangent of dielectric =',round(Qd ,4)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Dielectric constant = 1.63\n",
"Loss tangent of dielectric = 0.001\n"
]
}
],
"prompt_number": 44
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 12.11 Page Number: 654"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#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 =',round(Er ,3)\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": 45
}
],
"metadata": {}
}
]
}