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{
"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": {}
}
]
}
|
