coplanar.cpp

Go to the documentation of this file.

/*
 * coplanar.cpp - coplanar class implementation
 *
 * Copyright (C) 2008 Michael Margraf <[email protected]>
 * Copyright (C) 2005, 2006 Stefan Jahn <[email protected]>
 * Modified for Kicad: 2011 jean-pierre.charras
 *
 * This program 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 of the License, or (at
 * your option) any later version.
 *
 * This program 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.
 *
 */
 
 
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
 
#include "coplanar.h"
#include "units.h"
 
COPLANAR::COPLANAR() : TRANSLINE()
{
 m_Name = "CoPlanar";
 backMetal = false;
 Init();
}
 
 
GROUNDEDCOPLANAR::GROUNDEDCOPLANAR() : COPLANAR()
{
 m_Name = "GrCoPlanar";
 backMetal = true;
}
 
 
// -------------------------------------------------------------------
void COPLANAR::calcAnalyze()
{
 m_parameters[SKIN_DEPTH_PRM] = skin_depth();
 
 // other local variables (quasi-static constants)
 double k1, kk1, kpk1, k2, k3, q1, q2, q3 = 0, qz, er0 = 0;
 double zl_factor;
 
 // compute the necessary quasi-static approx. (K1, K3, er(0) and Z(0))
 k1 = m_parameters[PHYS_WIDTH_PRM]
 / ( m_parameters[PHYS_WIDTH_PRM] + m_parameters[PHYS_S_PRM] + m_parameters[PHYS_S_PRM] );
 kk1 = ellipk( k1 );
 kpk1 = ellipk( sqrt( 1 - k1 * k1 ) );
 q1 = kk1 / kpk1;
 
 
 // backside is metal
 if( backMetal )
 {
 k3 = tanh( ( M_PI / 4 ) * ( m_parameters[PHYS_WIDTH_PRM] / m_parameters[H_PRM] ) )
 / tanh( ( M_PI / 4 )
 * ( m_parameters[PHYS_WIDTH_PRM] + m_parameters[PHYS_S_PRM]
 + m_parameters[PHYS_S_PRM] )
 / m_parameters[H_PRM] );
 q3 = ellipk( k3 ) / ellipk( sqrt( 1 - k3 * k3 ) );
 qz = 1 / ( q1 + q3 );
 er0 = 1 + q3 * qz * ( m_parameters[EPSILONR_PRM] - 1 );
 zl_factor = ZF0 / 2 * qz;
 }
 // backside is air
 else
 {
 k2 = sinh( ( M_PI / 4 ) * ( m_parameters[PHYS_WIDTH_PRM] / m_parameters[H_PRM] ) )
 / sinh( ( M_PI / 4 )
 * ( m_parameters[PHYS_WIDTH_PRM] + m_parameters[PHYS_S_PRM]
 + m_parameters[PHYS_S_PRM] )
 / m_parameters[H_PRM] );
 q2 = ellipk( k2 ) / ellipk( sqrt( 1 - k2 * k2 ) );
 er0 = 1 + ( m_parameters[EPSILONR_PRM] - 1 ) / 2 * q2 / q1;
 zl_factor = ZF0 / 4 / q1;
 }
 
 
 // adds effect of strip thickness
 if( m_parameters[T_PRM] > 0 )
 {
 double d, se, We, ke, qe;
 d = ( m_parameters[T_PRM] * 1.25 / M_PI )
 * ( 1 + log( 4 * M_PI * m_parameters[PHYS_WIDTH_PRM] / m_parameters[T_PRM] ) );
 se = m_parameters[PHYS_S_PRM] - d;
 We = m_parameters[PHYS_WIDTH_PRM] + d;
 
 // modifies k1 accordingly (k1 = ke)
 ke = We / ( We + se + se ); // ke = k1 + (1 - k1 * k1) * d / 2 / s;
 qe = ellipk( ke ) / ellipk( sqrt( 1 - ke * ke ) );
 
 // backside is metal
 if( backMetal )
 {
 qz = 1 / ( qe + q3 );
 er0 = 1 + q3 * qz * ( m_parameters[EPSILONR_PRM] - 1 );
 zl_factor = ZF0 / 2 * qz;
 }
 // backside is air
 else
 {
 zl_factor = ZF0 / 4 / qe;
 }
 
 // modifies er0 as well
 er0 = er0
 - ( 0.7 * ( er0 - 1 ) * m_parameters[T_PRM] / m_parameters[PHYS_S_PRM] )
 / ( q1 + ( 0.7 * m_parameters[T_PRM] / m_parameters[PHYS_S_PRM] ) );
 }
 
 // pre-compute square roots
 double sr_er = sqrt( m_parameters[EPSILONR_PRM] );
 double sr_er0 = sqrt( er0 );
 
 // cut-off frequency of the TE0 mode
 double fte = ( C0 / 4 ) / ( m_parameters[H_PRM] * sqrt( m_parameters[EPSILONR_PRM] - 1 ) );
 
 // dispersion factor G
 double p = log( m_parameters[PHYS_WIDTH_PRM] / m_parameters[H_PRM] );
 double u = 0.54 - ( 0.64 - 0.015 * p ) * p;
 double v = 0.43 - ( 0.86 - 0.54 * p ) * p;
 double G = exp( u * log( m_parameters[PHYS_WIDTH_PRM] / m_parameters[PHYS_S_PRM] ) + v );
 
 // loss constant factors (computed only once for efficiency's sake)
 double ac = 0;
 
 if( m_parameters[T_PRM] > 0 )
 {
 // equations by GHIONE
 double n = ( 1 - k1 ) * 8 * M_PI / ( m_parameters[T_PRM] * ( 1 + k1 ) );
 double a = m_parameters[PHYS_WIDTH_PRM] / 2;
 double b = a + m_parameters[PHYS_S_PRM];
 ac = ( M_PI + log( n * a ) ) / a + ( M_PI + log( n * b ) ) / b;
 }
 
 double ac_factor = ac / ( 4 * ZF0 * kk1 * kpk1 * ( 1 - k1 * k1 ) );
 double ad_factor = ( m_parameters[EPSILONR_PRM] / ( m_parameters[EPSILONR_PRM] - 1 ) )
 * m_parameters[TAND_PRM] * M_PI / C0;
 
 
 // ....................................................
 double sr_er_f = sr_er0;
 
 // add the dispersive effects to er0
 sr_er_f += ( sr_er - sr_er0 ) / ( 1 + G * pow( m_parameters[FREQUENCY_PRM] / fte, -1.8 ) );
 
 // for now, the loss are limited to strip losses (no radiation
 // losses yet) losses in neper/length
 m_parameters[LOSS_CONDUCTOR_PRM] =
 20.0 / log( 10.0 ) * m_parameters[PHYS_LEN_PRM] * ac_factor * sr_er0
 * sqrt( M_PI * MU0 * m_parameters[FREQUENCY_PRM] / m_parameters[SIGMA_PRM] );
 m_parameters[LOSS_DIELECTRIC_PRM] = 20.0 / log( 10.0 ) * m_parameters[PHYS_LEN_PRM] * ad_factor
 * m_parameters[FREQUENCY_PRM] * ( sr_er_f * sr_er_f - 1 )
 / sr_er_f;
 
 m_parameters[ANG_L_PRM] = 2.0 * M_PI * m_parameters[PHYS_LEN_PRM] * sr_er_f
 * m_parameters[FREQUENCY_PRM] / C0; /* in radians */
 
 m_parameters[EPSILON_EFF_PRM] = sr_er_f * sr_er_f;
 m_parameters[Z0_PRM] = zl_factor / sr_er_f;
}
 
 
// -------------------------------------------------------------------
void COPLANAR::show_results()
{
 
 setResult( 0, m_parameters[EPSILON_EFF_PRM], "" );
 setResult( 1, m_parameters[LOSS_CONDUCTOR_PRM], "dB" );
 setResult( 2, m_parameters[LOSS_DIELECTRIC_PRM], "dB" );
 
 setResult( 3, m_parameters[SKIN_DEPTH_PRM] / UNIT_MICRON, "µm" );
}
 
 
#define MAX_ERROR 0.000001
 
// -------------------------------------------------------------------
/* @function calcSynthesize
 *
 * @TODO Add a warning in case the synthetizin algorithm did not converge.
 * Add it for all transmission lines that uses @ref minimizeZ0Error1D .
 */
void COPLANAR::calcSynthesize()
{
 if( isSelected( PHYS_WIDTH_PRM ) )
 minimizeZ0Error1D( &( m_parameters[PHYS_WIDTH_PRM] ) );
 else
 minimizeZ0Error1D( &( m_parameters[PHYS_S_PRM] ) );
}
 
// -------------------------------------------------------------------
void COPLANAR::showSynthesize()
{
 if( isSelected( PHYS_WIDTH_PRM ) )
 setProperty( PHYS_WIDTH_PRM, m_parameters[PHYS_WIDTH_PRM] );
 
 if( isSelected( PHYS_S_PRM ) )
 setProperty( PHYS_S_PRM, m_parameters[PHYS_S_PRM] );
 
 setProperty( PHYS_LEN_PRM, m_parameters[PHYS_LEN_PRM] );
 
 if( !std::isfinite( m_parameters[PHYS_S_PRM] ) || m_parameters[PHYS_S_PRM] <= 0 )
 {
 if( isSelected( PHYS_S_PRM ) )
 setErrorLevel( PHYS_S_PRM, TRANSLINE_ERROR );
 else
 setErrorLevel( PHYS_S_PRM, TRANSLINE_WARNING );
 }
 
 if( !std::isfinite( m_parameters[PHYS_WIDTH_PRM] ) || m_parameters[PHYS_WIDTH_PRM] <= 0 )
 {
 if( isSelected( PHYS_WIDTH_PRM ) )
 setErrorLevel( PHYS_WIDTH_PRM, TRANSLINE_ERROR );
 else
 setErrorLevel( PHYS_WIDTH_PRM, TRANSLINE_WARNING );
 }
 
 if( !std::isfinite( m_parameters[PHYS_LEN_PRM] ) || m_parameters[PHYS_LEN_PRM] < 0 )
 setErrorLevel( PHYS_LEN_PRM, TRANSLINE_ERROR );
 
 if( !std::isfinite( m_parameters[Z0_PRM] ) || m_parameters[Z0_PRM] < 0 )
 setErrorLevel( Z0_PRM, TRANSLINE_WARNING );
 
 if( !std::isfinite( m_parameters[ANG_L_PRM] ) || m_parameters[ANG_L_PRM] < 0 )
 setErrorLevel( ANG_L_PRM, TRANSLINE_WARNING );
}
 
 
void COPLANAR::showAnalyze()
{
 setProperty( Z0_PRM, m_parameters[Z0_PRM] );
 setProperty( ANG_L_PRM, m_parameters[ANG_L_PRM] );
 
 if( !std::isfinite( m_parameters[PHYS_S_PRM] ) || m_parameters[PHYS_S_PRM] <= 0 )
 setErrorLevel( PHYS_S_PRM, TRANSLINE_WARNING );
 
 if( !std::isfinite( m_parameters[PHYS_WIDTH_PRM] ) || m_parameters[PHYS_WIDTH_PRM] <= 0 )
 setErrorLevel( PHYS_WIDTH_PRM, TRANSLINE_WARNING );
 
 if( !std::isfinite( m_parameters[PHYS_LEN_PRM] ) || m_parameters[PHYS_LEN_PRM] < 0 )
 setErrorLevel( PHYS_LEN_PRM, TRANSLINE_WARNING );
 
 if( !std::isfinite( m_parameters[Z0_PRM] ) || m_parameters[Z0_PRM] < 0 )
 setErrorLevel( Z0_PRM, TRANSLINE_ERROR );
 
 if( !std::isfinite( m_parameters[ANG_L_PRM] ) || m_parameters[ANG_L_PRM] < 0 )
 setErrorLevel( ANG_L_PRM, TRANSLINE_ERROR );
}