filter.cc Source File

00001 // filter.cc:
00002 //
00003 // The following code builds a 2 GHz maximally flat low-pass filter.
00004 // See Pozar, page 489.
00005 
00006 #include "supermix.h"
00007 
00008 int main()
00009 {
00010   device::T = 295. * Kelvin;
00011   device::Z0 = 50. * Ohm;
00012 
00013   capacitor c1;
00014   c1.parallel();
00015   c1.C = 0.984 * pFarad;
00016 
00017   inductor l2(6.438*nHenry);
00018   l2.series();
00019 
00020   capacitor c3;
00021   c3.parallel();
00022   c3.C = 3.183 * pFarad;
00023 
00024   inductor l4 = l2;
00025   capacitor c5(c1);
00026 
00027   circuit filter;
00028   int input = filter.add_port(c1, 1);
00029   int output = filter.add_port(c5, 2);
00030   filter.connect(c1, 2, l2, 1);
00031   filter.connect(l2, 2, c3, 1);
00032   filter.connect(c3, 2, l4, 1);
00033   filter.connect(l4, 2, c5, 1);
00034 
00035   cout << fixed << setprecision(3);
00036   cout << "2 GHz low-pass filter" << endl << endl;
00037   cout << "F(GHz)" << "\t" << "S21" << "\t" << "Phase" << endl;
00038 
00039   complex::out_degree();
00040   complex::out_separator("\t");
00041   
00042   for(double f=0.25; f<5.0; f+=0.25)  {
00043     device::f = f*GHz;
00044     sdata response = filter.get_data();
00045     complex S21 = response.S[output][input];
00046     cout << device::f/GHz << "\t" << S21 << endl;
00047   }
00048 
00049 }