/* * spiralinductor.cpp - Spiral inductor class implementation * * Copyright (C) 2016 Andres Martinez-Mera * * This is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2, or (at your option) * any later version. * * This software is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this package; see the file COPYING. If not, write to * the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor, * Boston, MA 02110-1301, USA. * */ #if HAVE_CONFIG_H # include #endif #include "component.h" #include "spiralinductor.h" #include "substrate.h" using namespace qucs; //------------------------------------------------------------------------ // References: // [1] I. Bahl, Lumped Elements for RF and Microwave Circuits, Artech House, Norwood, MA, 2003. // [2] Simple Accurate Expressions for Planar Spiral Inductances. S. S. Mohan. IEEE Journal of Solid State Circuits. // Vol 34, No 10, October 1999 // [3] I. Bahl, Fundamentals of RF and Microwave Transistor Amplifiers, John Wiley and Sons, 2009. //------------------------------------------------------------------------ spiralinductor::spiralinductor () : circuit (2) { type = CIR_SPIRALIND; } //------------------------------------------------------------------ // This function calculates the ABCD matrix of the spiral inductance void spiralinductor::calcABCDparams(nr_double_t frequency) { nr_double_t N = getPropertyDouble ("N");//Number of turns nr_double_t Di = getPropertyDouble ("Di");//Inner diameter nr_double_t W = getPropertyDouble ("W");//Width nr_double_t S = getPropertyDouble ("S");//Spacing between turns substrate * subst = getSubstrate (); nr_double_t Do = Di + 2.*N*W + (2.*N-1)*S; nr_double_t chi = (Do - Di) / (Do + Di);//Fill ratio nr_double_t a = (Di+Do)/4.; nr_double_t Dav = .5*(Do+Di); nr_double_t rho = subst->getPropertyDouble ("rho"); nr_double_t t = subst->getPropertyDouble ("t"); nr_double_t K = 1.+0.333*qucs::pow(1.+S/W, -1.7);// Crowding effect in the corners. The following relies on the assumption that // square, hexagonal and octogonal inductors have the same crowding effect as the spiral inductor nr_double_t c1, c2, c3, c4; if (!strcmp (getPropertyString ("Geometry"), "Circular")) {c1 = 1; c2 = 2.46; c3 = 0; c4 = 0.2;} if (!strcmp (getPropertyString ("Geometry"), "Square")) {c1 = 1.27; c2 = 2.07; c3 = 0.18; c4 = 0.13;} if (!strcmp (getPropertyString ("Geometry"), "Hexagonal")) {c1 = 1.09; c2 = 2.23; c3 = 0; c4 = 0.17;} if (!strcmp (getPropertyString ("Geometry"), "Octogonal")) {c1 = 1.07; c2 = 2.29; c3 = 0; c4 = 0.19;} nr_double_t L = 2.*pi*1e-7*N*N*Dav*c1*(qucs::log(c2/chi) + c3*chi + c4*chi*chi); nr_double_t Rs = rho/t; R = K*pi*a*N*Rs/W;//The resistance is a global variable since it is used in the DC analysis too nr_double_t C = (3.5e-5*Do+0.06)*1e-12; //ABCD matrix ABCD = eye(2); ABCD.set(0,0, nr_complex_t(1-4*pi*pi*frequency*frequency*L*C, 2*pi*R*C*frequency)); ABCD.set(0,1, nr_complex_t(R, 2.*pi*L*frequency)); ABCD.set(1,0, nr_complex_t(-4*pi*pi*C*C*R*frequency*frequency, -8*pi*pi*pi*C*C*L*frequency*frequency*frequency + 4*pi*C*frequency)); ABCD.set(1,1, nr_complex_t(-4.*pi*pi*C*L*frequency*frequency+1., 2.*pi*C*R*frequency)); } void spiralinductor::calcSP (nr_double_t frequency) { calcABCDparams(frequency); matrix Stmp = qucs::atos(ABCD, z0, z0); setMatrixS(Stmp); } void spiralinductor::calcNoiseSP (nr_double_t) { // calculate noise using Bosma's theorem nr_double_t T = getPropertyDouble ("Temp"); matrix s = getMatrixS (); matrix e = eye (getSize ()); setMatrixN (celsius2kelvin (T) / T0 * (e - s * transpose (conj (s)))); } // DC model: The equivalent resistance of the different spiral inductor geometry is assumed to be the same as the series // resistance of the spiral inductor void spiralinductor::initDC (void) { allocMatrixMNA (); if (R != 0.0) { nr_double_t g = 1.0 / R; setVoltageSources (0); allocMatrixMNA (); setY (NODE_1, NODE_1, +g); setY (NODE_2, NODE_2, +g); setY (NODE_1, NODE_2, -g); setY (NODE_2, NODE_1, -g); } // for zero resistances create a zero voltage source else { setVoltageSources (1); setInternalVoltageSource (1); allocMatrixMNA (); voltageSource (VSRC_1, NODE_1, NODE_2); } } void spiralinductor::initAC (void) { setVoltageSources (0); allocMatrixMNA (); } void spiralinductor::initSP(void) { allocMatrixS (); } void spiralinductor::calcAC (nr_double_t frequency) { calcABCDparams(frequency); nr_complex_t y11 = ABCD.get(1,1)/ABCD.get(0,1); nr_complex_t y12 = -det(ABCD)/ABCD.get(0,1); nr_complex_t y21 = -1./ABCD.get(0,1); nr_complex_t y22 = ABCD.get(0,0)/ABCD.get(0,1); setY (NODE_1, NODE_1, y11); setY (NODE_2, NODE_2, y22); setY (NODE_1, NODE_2, y12); setY (NODE_2, NODE_1, y21); } void spiralinductor::calcNoiseAC (nr_double_t) { // calculate noise using Bosma's theorem nr_double_t T = getPropertyDouble ("Temp"); setMatrixN (4 * celsius2kelvin (T) / T0 * real (getMatrixY ())); } // properties PROP_REQ [] = { { "Subst", PROP_STR, { PROP_NO_VAL, "Subst1" }, PROP_NO_RANGE }, { "Geometry", PROP_STR, { PROP_NO_VAL, "Circular" }, PROP_RNG_STR4 ("Circular", "Square", "Hexagonal", "Octogonal") }, { "W", PROP_REAL, { 25e-6, PROP_NO_STR }, PROP_POS_RANGE }, { "Di", PROP_REAL, { 200e-6, PROP_NO_STR }, PROP_POS_RANGE }, { "S", PROP_REAL, { 25e-6, PROP_NO_STR }, PROP_NO_RANGE }, { "N", PROP_REAL, { 3, PROP_NO_STR }, PROP_NO_RANGE }, PROP_NO_PROP }; PROP_OPT [] = { { "Temp", PROP_REAL, { 26.85, PROP_NO_STR }, PROP_MIN_VAL (K) }, PROP_NO_PROP }; struct define_t spiralinductor::cirdef = { "SPIRALIND", 2, PROP_COMPONENT, PROP_NO_SUBSTRATE, PROP_LINEAR, PROP_DEF };