# -*- coding: utf-8 -*- """ Space Baron Team nats` Transistor Auto Matcher Take S parameters file input """ import os import sys import math import cmath def print_complex(name, c): print("====") print(name) print("Rect: %f %fj" % (c.real , c.imag)) print("Polar: %f %fj" % (cmath.polar(c)[0] , math.degrees(cmath.polar(c)[1]))) print("====") # needed for test on polar def polar_add(ar, ai, br, bi): a = cmath.rect(ar, math.degrees(ai)) b = cmath.rect(br, math.degrees(bi)) print_complex("polar res", a + b) def pol2rec(ar, ai): a = cmath.rect(ar, math.radians(ai)) return a class TransistorBlock: def __init__(self, file, freq, config): self.freq = freq self.config = config self.spformats = {} self.parse_spar(file,freq) ''' Open S2P Files and extract data ''' def parse_spar(self, file, freq): f = open(file, "r") tmpspars = [] for line in f: if line.startswith("#"): sfor = line.strip().split() self.spformats["UNIT"] = sfor[1] self.spformats["TYPE"] = sfor[2] self.spformats["FORMAT"] = sfor[3] # Apparently the nominal Impedance is splitted: R 50 self.spformats["R"] = sfor[5] elif not line.startswith("!"): tmpline = line.strip().split() if len(tmpline) >= 9: #We skip short line often used for noise parameter tmpspars.append(tmpline) # Parse options: we mainly need to know unit and complex format # http://cp.literature.agilent.com/litweb/pdf/genesys200801/sim/linear_sim/sparams/touchstone_file_format.htms self.spars = {}# 1: Freq 2: S11 3: S21 4: S12 5: S22 for l in tmpspars: if(l[0] != "!" and l[0] != "#"): tmp = [] if self.spformats["FORMAT"] == "RI" : # Real Imaginary tmp.append(complex(float(l[1]), float(l[2]))) # S11 tmp.append(complex(float(l[3]), float(l[4]))) # S21 tmp.append(complex(float(l[5]), float(l[6]))) # S12 tmp.append(complex(float(l[7]), float(l[8]))) # S22 elif self.spformats["FORMAT"] == "MA" : # Magnitude Angle (in degree) tmp.append(cmath.rect(float(l[1]), math.radians(float(l[2])))) # S11 tmp.append(cmath.rect(float(l[3]), math.radians(float(l[4])))) # S21 tmp.append(cmath.rect(float(l[5]), math.radians(float(l[6])))) # S12 tmp.append(cmath.rect(float(l[7]), math.radians(float(l[8])))) # S22 else : print("Unsupported Number Format: %s" % self.spformats["FORMAT"]) exit(-1) # We always set freq to MHz freq = float(l[0]) if self.spformats["UNIT"] == "GHz": freq = freq * 1000 elif self.spformats["UNIT"] == "KHz": freq = freq / 1000 elif self.spformats["UNIT"] == "Hz": freq = freq / 1000000 self.spars[freq] = tmp ''' Calculate John Rollett stability factor ''' def calc_stab(self): S = self.S self.K = (1 + cmath.polar(self.Ds)[0] ** 2 - cmath.polar(S[11])[0] ** 2 - \ cmath.polar(S[22])[0] ** 2) / (2 * cmath.polar(S[21])[0] * cmath.polar(S[12])[0]) ''' Caculate Maximum Available Gain ''' def calc_mag(self): S = self.S self.B1 = 1 + cmath.polar(S[11])[0] ** 2 - cmath.polar(S[22])[0] ** 2 - cmath.polar(self.Ds)[0] ** 2 ksq = 0.0 if self.B1 < 0 : ksq = math.sqrt(self.K**2 - 1) else : ksq = math.sqrt(self.K**2 - 1) * -1 self.MAG = 10 * math.log10(cmath.polar(S[21])[0] / cmath.polar(S[12])[0]) + \ 10 * math.log10(self.K + ksq) ''' Calculate Maximum Unilateral Gain (S12 = 0)''' def calc_gum(self): S = self.S self.GUM = 10 * math.log10(cmath.polar(S[21])[0]**2 / ((1-cmath.polar(S[11])[0]**2)*(1-cmath.polar(S[22])[0]**2))) def set_freq(self, freq): self.freq = freq def calc_stability_mag(self): self.sparam = self.spars[self.freq] self.S = {} self.S[11] = self.sparam[0] self.S[21] = self.sparam[1] self.S[12] = self.sparam[2] self.S[22] = self.sparam[3] S = self.S self.Ds = S[11] * S[22] - S[12] * S[21] self.calc_stab() if self.K < 1 : print("Warning ! K factor %f < 1.0 , amplifier could be unstable" % self.K) print("Undefined Maximum Available Gain") else : print("Stable amplifier design. K factor %f >= 1" % self.K) self.calc_mag() print("Maximum Available Gain: %fdB" % self.MAG) def calc_scm(self): S = self.S if self.K > 1 : self.C1 = S[11] - (self.Ds * complex.conjugate(S[22])) self.C2 = S[22] - (self.Ds * complex.conjugate(S[11])) # B1 is already calculated for MAG self.B2 = 1 + cmath.polar(S[22])[0] ** 2 - cmath.polar(S[11])[0] ** 2 - cmath.polar(self.Ds)[0] ** 2 rad = 0 if self.B2 >= 0: rad = self.B2 - math.sqrt(self.B2**2 - 4 * cmath.polar(self.C2)[0]**2) elif self.B2 < 0: rad = self.B2 + math.sqrt(self.B2**2 - 4 * cmath.polar(self.C2)[0]**2) # Load Reflection magnitude ref_mag = rad / (2 * cmath.polar(self.C2)[0]) self.load_ref = cmath.rect(ref_mag, -cmath.polar(self.C2)[1]) self.source_ref = complex.conjugate(S[11] + ((S[12]*S[21]*self.load_ref) / (1-(self.load_ref * S[22])))) else : print("Can't calculate SCM, K < 1, try lossy match") #Calculate Transducer gain def calc_gt(self): S = self.S a = ((abs(S[21])**2)*(1-abs(self.source_ref)**2)*(1-abs(self.load_ref)**2)) b = abs((1-S[11]*self.source_ref)*(1-S[22]*self.load_ref)-S[12]*S[21]*self.load_ref*self.source_ref)**2 self.GT = 10*math.log10(a/b) if __name__ == '__main__': if(len(sys.argv) < 4): print("Error: usage\nauto_match.py spar_file.s2p frequency configuration\n") exit(-1) fname = sys.argv[1] freq = float(sys.argv[2]) config = sys.argv[3] q1 = TransistorBlock(fname, freq, config) q1.calc_stability_mag() q1.calc_gum() print("GUM: %fdB" % q1.GUM) q1.calc_scm() q1.calc_gt() print("Result") print("Optimum Source Reflection") print_complex("Source Reflection", q1.source_ref) print("Optimum Load Reflection") print_complex("Load Reflection", q1.load_ref) print("Transducer gain: %fdB" % q1.GT) # test book error a = pol2rec(0.4,162) + ((pol2rec(0.04,60)*pol2rec(5.2,63)*pol2rec(0.487,39)) / (1 - pol2rec(0.487,39)*pol2rec(0.35,-39))) print_complex("test", a) print_complex("test", complex.conjugate(a))