Updated for input impedance and admittance calculations.

tools/plot_antenna_params.py

@@ -19,16 +19,15 @@
 import os, argparse
 import h5py
 import numpy as np
-np.seterr(divide='ignore', invalid='ignore')
 import matplotlib.pyplot as plt
 import matplotlib.gridspec as gridspec
 
-from gprMax.exceptions import CmdInputError
+from gprMax.constants import complextype
 
-"""Plots antenna parameters (s11 parameter and input impedance) from an output file containing a transmission line source."""
+"""Plots antenna parameters (s11 parameter and input impedance and admittance) from an output file containing a transmission line source."""
 
 # Parse command line arguments
-parser = argparse.ArgumentParser(description='Plots antenna parameters (s11 parameter and input impedance) from an output file containing a transmission line source.', usage='cd gprMax; python -m tools.plot_antenna_params outputfile')
+parser = argparse.ArgumentParser(description='Plots antenna parameters (s11 parameter and input impedance and admittance) from an output file containing a transmission line source.', usage='cd gprMax; python -m tools.plot_antenna_params outputfile')
 parser.add_argument('outputfile', help='name of output file including path')
 parser.add_argument('-tln', default=1, type=int, help='transmission line number')
 args = parser.parse_args()
@@ -41,116 +40,250 @@ iterations = f.attrs['Iterations']
 time = np.arange(0, dt * iterations, dt)
 time = time / 1e-9
 
+# Read/calculate voltages and currents
 path = '/tls/tl' + str(args.tln) + '/'
 Vinc = f[path + 'Vinc'][:]
-Vscat = f[path + 'Vscat'][:]
+Iinc = f[path + 'Iinc'][:]
-Iscat = f[path + 'Iscat'][:]
 Vtotal = f[path +'Vtotal'][:]
+Itotal = f[path +'Itotal'][:]
+Vref = Vtotal - Vinc
+Iref = Itotal - Iinc
 
-# Calculate magnitude of frequency spectra
+# Calculate magnitude of FFTs of voltages and currents
-Vincp = np.abs(np.fft.fft(Vinc))**2
+Vincp = np.abs(np.fft.fft(Vinc))
 freqs = np.fft.fftfreq(Vincp.size, d=dt)
-Vscatp = np.abs(np.fft.fft(Vscat))**2
+delaycorrection = np.zeros(Vincp.size, dtype=complextype)
-s11 = Vscatp / Vincp
+delaycorrection = np.exp(-1j * np.pi * freqs * dt)
-zin = np.zeros(iterations, dtype=np.complex)
+Iincp = np.abs(np.fft.fft(Iinc))
-zin = np.abs(np.fft.fft(Vscat)) / np.abs(np.fft.fft(Iscat))
+Vrefp = np.abs(np.fft.fft(Vref))
+Irefp = np.abs(np.fft.fft(Iref))
+Vtotalp = np.abs(np.fft.fft(Vtotal))
+Itotalp = np.abs(np.fft.fft(Itotal))
+
+# Calculate s11
+s11 = Vrefp / Vincp
+
+# Calculate input impedance
+zin = np.zeros(iterations, dtype=complextype)
+zin = (np.fft.fft(Vtotal) * delaycorrection) / np.fft.fft(Itotal)
+
+# Calculate input admittance
+yin = np.zeros(iterations, dtype=complextype)
+yin = np.fft.fft(Itotal) / (np.fft.fft(Vtotal) * delaycorrection)
 
 # Convert to decibels
-Vincp = 10 * np.log10(Vincp)
+Vincp = 20 * np.log10(Vincp)
-Vscatp = 10 * np.log10(Vscatp)
+Iincp = 20 * np.log10(Iincp)
-s11 = 10 * np.log10(s11)
+Vrefp = 20 * np.log10(Vrefp)
+Irefp = 20 * np.log10(Irefp)
+Vtotalp = 20 * np.log10(Vtotalp)
+Itotalp = 20 * np.log10(Itotalp)
+s11 = 20 * np.log10(s11)
 
-# Set plotting range to -60dB from maximum power
+# Set plotting range
-pltrange = np.where((np.amax(Vincp) - Vincp) > 60)[0][0] + 1
+# To a certain drop from maximum power
-pltrange = np.s_[0:pltrange]
+#pltrange = np.where((np.amax(Vincp) - Vincp) > 30)[0][0] + 1
+# To a maximum frequency
+pltrange = np.where(freqs > 2e9)[0][0]
+pltrange = np.s_[1:pltrange]
 
+# Figure 1
 # Plot incident voltage
-fig1, ax = plt.subplots(num='Transmission line parameters', figsize=(20, 10), facecolor='w', edgecolor='w')
+fig1, ax = plt.subplots(num='Transmission line parameters', figsize=(20, 12), facecolor='w', edgecolor='w')
-gs1 = gridspec.GridSpec(2, 2, hspace=0.3)
+gs1 = gridspec.GridSpec(4, 2, hspace=0.7)
-ax1 = plt.subplot(gs1[0, 0])
+ax = plt.subplot(gs1[0, 0])
-ax1.plot(time, Vinc, 'r', lw=2, label='Vinc')
+ax.plot(time, Vinc, 'r', lw=2, label='Vinc')
-ax1.set_title('Incident voltage')
+ax.set_title('Incident voltage')
-ax1.set_xlabel('Time [ns]')
+ax.set_xlabel('Time [ns]')
-ax1.set_ylabel('Voltage [V]')
+ax.set_ylabel('Voltage [V]')
-ax1.set_xlim([0, np.amax(time)])
+ax.set_xlim([0, np.amax(time)])
-ax1.grid()
+ax.grid()
 
 # Plot frequency spectra of incident voltage
-ax2 = plt.subplot(gs1[0, 1])
+ax = plt.subplot(gs1[0, 1])
-markerline, stemlines, baseline = ax2.stem(freqs[pltrange]/1e9, Vincp[pltrange], '-.')
+markerline, stemlines, baseline = ax.stem(freqs[pltrange]/1e9, Vincp[pltrange], '-.')
 plt.setp(baseline, 'linewidth', 0)
 plt.setp(stemlines, 'color', 'r')
 plt.setp(markerline, 'markerfacecolor', 'r', 'markeredgecolor', 'r')
-ax2.plot(freqs[pltrange]/1e9, Vincp[pltrange], 'r', lw=2)
+ax.plot(freqs[pltrange]/1e9, Vincp[pltrange], 'r', lw=2)
-ax2.set_title('Incident voltage')
+ax.set_title('Incident voltage')
-ax2.set_xlabel('Frequency [GHz]')
+ax.set_xlabel('Frequency [GHz]')
-ax2.set_ylabel('Power [dB]')
+ax.set_ylabel('Power [dB]')
-ax2.grid()
+ax.grid()
 
-# Plot scattered (field) voltage
+# Plot incident current
-ax3 = plt.subplot(gs1[1, 0])
+ax = plt.subplot(gs1[1, 0])
-ax3.plot(time, Vscat, 'r', lw=2, label='Vscat')
+ax.plot(time, Iinc, 'b', lw=2, label='Vinc')
-ax3.set_title('Reflected voltage')
+ax.set_title('Incident current')
-ax3.set_xlabel('Time [ns]')
+ax.set_xlabel('Time [ns]')
-ax3.set_ylabel('Voltage [V]')
+ax.set_ylabel('Current [A]')
-ax3.set_xlim([0, np.amax(time)])
+ax.set_xlim([0, np.amax(time)])
-ax3.grid()
+ax.grid()
 
-# Plot frequency spectra of scattered voltage
+# Plot frequency spectra of incident current
-ax4 = plt.subplot(gs1[1, 1])
+ax = plt.subplot(gs1[1, 1])
-markerline, stemlines, baseline = ax4.stem(freqs[pltrange]/1e9, Vscatp[pltrange], '-.')
+markerline, stemlines, baseline = ax.stem(freqs[pltrange]/1e9, Iincp[pltrange], '-.')
+plt.setp(baseline, 'linewidth', 0)
+plt.setp(stemlines, 'color', 'b')
+plt.setp(markerline, 'markerfacecolor', 'b', 'markeredgecolor', 'b')
+ax.plot(freqs[pltrange]/1e9, Iincp[pltrange], 'b', lw=2)
+ax.set_title('Incident current')
+ax.set_xlabel('Frequency [GHz]')
+ax.set_ylabel('Power [dB]')
+ax.grid()
+
+# Plot total voltage
+ax = plt.subplot(gs1[2, 0])
+ax.plot(time, Vtotal, 'r', lw=2, label='Vinc')
+ax.set_title('Total (incident + reflected) voltage')
+ax.set_xlabel('Time [ns]')
+ax.set_ylabel('Voltage [V]')
+ax.set_xlim([0, np.amax(time)])
+ax.grid()
+
+# Plot frequency spectra of total voltage
+ax = plt.subplot(gs1[2, 1])
+markerline, stemlines, baseline = ax.stem(freqs[pltrange]/1e9, Vtotalp[pltrange], '-.')
 plt.setp(baseline, 'linewidth', 0)
 plt.setp(stemlines, 'color', 'r')
 plt.setp(markerline, 'markerfacecolor', 'r', 'markeredgecolor', 'r')
-ax4.plot(freqs[pltrange]/1e9, Vscatp[pltrange], 'r', lw=2)
+ax.plot(freqs[pltrange]/1e9, Vtotalp[pltrange], 'r', lw=2)
-ax4.set_title('Reflected voltage')
+ax.set_title('Total (incident + reflected) voltage')
-ax4.set_xlabel('Frequency [GHz]')
+ax.set_xlabel('Frequency [GHz]')
-ax4.set_ylabel('Power [dB]')
+ax.set_ylabel('Power [dB]')
-ax4.grid()
+ax.grid()
 
+# Plot total current
+ax = plt.subplot(gs1[3, 0])
+ax.plot(time, Itotal, 'b', lw=2, label='Vinc')
+ax.set_title('Total (incident + reflected) current')
+ax.set_xlabel('Time [ns]')
+ax.set_ylabel('Current [A]')
+ax.set_xlim([0, np.amax(time)])
+ax.grid()
+
+# Plot frequency spectra of reflected current
+ax = plt.subplot(gs1[3, 1])
+markerline, stemlines, baseline = ax.stem(freqs[pltrange]/1e9, Itotalp[pltrange], '-.')
+plt.setp(baseline, 'linewidth', 0)
+plt.setp(stemlines, 'color', 'b')
+plt.setp(markerline, 'markerfacecolor', 'b', 'markeredgecolor', 'b')
+ax.plot(freqs[pltrange]/1e9, Itotalp[pltrange], 'b', lw=2)
+ax.set_title('Total (incident + reflected) current')
+ax.set_xlabel('Frequency [GHz]')
+ax.set_ylabel('Power [dB]')
+ax.grid()
+
+## Plot reflected (reflected) voltage
+#ax = plt.subplot(gs1[4, 0])
+#ax.plot(time, Vref, 'r', lw=2, label='Vref')
+#ax.set_title('Reflected voltage')
+#ax.set_xlabel('Time [ns]')
+#ax.set_ylabel('Voltage [V]')
+#ax.set_xlim([0, np.amax(time)])
+#ax.grid()
+#
+## Plot frequency spectra of reflected voltage
+#ax = plt.subplot(gs1[4, 1])
+#markerline, stemlines, baseline = ax.stem(freqs[pltrange]/1e9, Vrefp[pltrange], '-.')
+#plt.setp(baseline, 'linewidth', 0)
+#plt.setp(stemlines, 'color', 'r')
+#plt.setp(markerline, 'markerfacecolor', 'r', 'markeredgecolor', 'r')
+#ax.plot(freqs[pltrange]/1e9, Vrefp[pltrange], 'r', lw=2)
+#ax.set_title('Reflected voltage')
+#ax.set_xlabel('Frequency [GHz]')
+#ax.set_ylabel('Power [dB]')
+#ax.grid()
+#
+## Plot reflected (reflected) current
+#ax = plt.subplot(gs1[5, 0])
+#ax.plot(time, Iref, 'b', lw=2, label='Iref')
+#ax.set_title('Reflected current')
+#ax.set_xlabel('Time [ns]')
+#ax.set_ylabel('Current [A]')
+#ax.set_xlim([0, np.amax(time)])
+#ax.grid()
+#
+## Plot frequency spectra of reflected current
+#ax = plt.subplot(gs1[5, 1])
+#markerline, stemlines, baseline = ax.stem(freqs[pltrange]/1e9, Irefp[pltrange], '-.')
+#plt.setp(baseline, 'linewidth', 0)
+#plt.setp(stemlines, 'color', 'b')
+#plt.setp(markerline, 'markerfacecolor', 'b', 'markeredgecolor', 'b')
+#ax.plot(freqs[pltrange]/1e9, Irefp[pltrange], 'b', lw=2)
+#ax.set_title('Reflected current')
+#ax.set_xlabel('Frequency [GHz]')
+#ax.set_ylabel('Power [dB]')
+#ax.grid()
+
+# Figure 2
 # Plot frequency spectra of s11
-fig2, ax = plt.subplots(num='Antenna parameters', figsize=(20, 10), facecolor='w', edgecolor='w')
+fig2, ax = plt.subplots(num='Antenna parameters', figsize=(20, 12), facecolor='w', edgecolor='w')
-gs2 = gridspec.GridSpec(2, 2, hspace=0.3)
+gs2 = gridspec.GridSpec(3, 2, hspace=0.5)
-ax5 = plt.subplot(gs2[0, 0])
+ax = plt.subplot(gs2[0, 0])
-markerline, stemlines, baseline = ax5.stem(freqs[pltrange]/1e9, s11[pltrange], '-.')
+markerline, stemlines, baseline = ax.stem(freqs[pltrange]/1e9, s11[pltrange], '-.')
 plt.setp(baseline, 'linewidth', 0)
-plt.setp(stemlines, 'color', 'r')
+plt.setp(stemlines, 'color', 'g')
-plt.setp(markerline, 'markerfacecolor', 'r', 'markeredgecolor', 'r')
+plt.setp(markerline, 'markerfacecolor', 'g', 'markeredgecolor', 'g')
-ax5.plot(freqs[pltrange]/1e9, s11[pltrange], 'r', lw=2)
+ax.plot(freqs[pltrange]/1e9, s11[pltrange], 'g', lw=2)
-ax5.set_title('s11 parameter')
+ax.set_title('s11')
-ax5.set_xlabel('Frequency [GHz]')
+ax.set_xlabel('Frequency [GHz]')
-ax5.set_ylabel('Power [dB]')
+ax.set_ylabel('Power [dB]')
-ax5.grid()
+ax.grid()
 
 # Plot input resistance (real part of impedance)
-ax6 = plt.subplot(gs2[1, 0])
+ax = plt.subplot(gs2[1, 0])
-markerline, stemlines, baseline = ax6.stem(freqs[pltrange]/1e9, zin[pltrange].real, '-.')
+markerline, stemlines, baseline = ax.stem(freqs[pltrange]/1e9, np.abs(zin[pltrange]), '-.')
 plt.setp(baseline, 'linewidth', 0)
-plt.setp(stemlines, 'color', 'r')
+plt.setp(stemlines, 'color', 'g')
-plt.setp(markerline, 'markerfacecolor', 'r', 'markeredgecolor', 'r')
+plt.setp(markerline, 'markerfacecolor', 'g', 'markeredgecolor', 'g')
-ax6.plot(freqs[pltrange]/1e9, zin[pltrange].real, 'r', lw=2)
+ax.plot(freqs[pltrange]/1e9, np.abs(zin[pltrange]), 'g', lw=2)
-ax6.set_title('Input impedance')
+ax.set_title('Input impedance (resistive)')
-ax6.set_xlabel('Frequency [GHz]')
+ax.set_xlabel('Frequency [GHz]')
-ax6.set_ylabel('Resistance [Ohms]')
+ax.set_ylabel('Resistance [Ohms]')
-ax6.set_ylim(bottom=0)
+ax.set_ylim([0, 2000])
-ax6.grid()
+ax.grid()
 
 # Plot input reactance (imaginery part of impedance)
-ax7 = plt.subplot(gs2[1, 1])
+ax = plt.subplot(gs2[1, 1])
-markerline, stemlines, baseline = ax7.stem(freqs[pltrange]/1e9, zin[pltrange].imag, '-.')
+markerline, stemlines, baseline = ax.stem(freqs[pltrange]/1e9, zin[pltrange].imag, '-.')
 plt.setp(baseline, 'linewidth', 0)
-plt.setp(stemlines, 'color', 'r')
+plt.setp(stemlines, 'color', 'g')
-plt.setp(markerline, 'markerfacecolor', 'r', 'markeredgecolor', 'r')
+plt.setp(markerline, 'markerfacecolor', 'g', 'markeredgecolor', 'g')
-ax7.plot(freqs[pltrange]/1e9, zin[pltrange].imag, 'r', lw=2)
+ax.plot(freqs[pltrange]/1e9, zin[pltrange].imag, 'g', lw=2)
-ax7.set_title('Input impedance')
+ax.set_title('Input impedance (reactive)')
-ax7.set_xlabel('Frequency [GHz]')
+ax.set_xlabel('Frequency [GHz]')
-ax7.set_ylabel('Reactance [Ohms]')
+ax.set_ylabel('Reactance [Ohms]')
-ax7.set_ylim(bottom=0)
+ax.set_ylim(-2000, 2000)
-ax7.grid()
+ax.grid()
+
+# Plot input admittance (magnitude)
+ax = plt.subplot(gs2[2, 0])
+markerline, stemlines, baseline = ax.stem(freqs[pltrange]/1e9, np.abs(yin[pltrange]), '-.')
+plt.setp(baseline, 'linewidth', 0)
+plt.setp(stemlines, 'color', 'g')
+plt.setp(markerline, 'markerfacecolor', 'g', 'markeredgecolor', 'g')
+ax.plot(freqs[pltrange]/1e9, np.abs(yin[pltrange]), 'g', lw=2)
+ax.set_title('Input admittance (magnitude)')
+ax.set_xlabel('Frequency [GHz]')
+ax.set_ylabel('Admittance [Siemens]')
+ax.grid()
+
+# Plot input admittance (phase)
+ax = plt.subplot(gs2[2, 1])
+markerline, stemlines, baseline = ax.stem(freqs[pltrange]/1e9, np.angle(yin[pltrange], deg=True), '-.')
+plt.setp(baseline, 'linewidth', 0)
+plt.setp(stemlines, 'color', 'g')
+plt.setp(markerline, 'markerfacecolor', 'g', 'markeredgecolor', 'g')
+ax.plot(freqs[pltrange]/1e9, np.angle(yin[pltrange], deg=True), 'g', lw=2)
+ax.set_title('Input admittance (phase)')
+ax.set_xlabel('Frequency [GHz]')
+ax.set_ylabel('Phase [degrees]')
+ax.grid()
 
 plt.show()
-fig1.savefig(os.path.splitext(os.path.abspath(file))[0] + '_tl_params.png', dpi=150, format='png', bbox_inches='tight', pad_inches=0.1)
+#fig1.savefig(os.path.splitext(os.path.abspath(file))[0] + '_tl_params.png', dpi=150, format='png', bbox_inches='tight', pad_inches=0.1)
-fig2.savefig(os.path.splitext(os.path.abspath(file))[0] + '_ant_params.png', dpi=150, format='png', bbox_inches='tight', pad_inches=0.1)
+#fig2.savefig(os.path.splitext(os.path.abspath(file))[0] + '_ant_params.png', dpi=150, format='png', bbox_inches='tight', pad_inches=0.1)
 #fig1.savefig(os.path.splitext(os.path.abspath(file))[0] + '_tl_params.pdf', dpi=None, format='pdf', bbox_inches='tight', pad_inches=0.1)
 #fig2.savefig(os.path.splitext(os.path.abspath(file))[0] + '_ant_params.pdf', dpi=None, format='pdf', bbox_inches='tight', pad_inches=0.1)
 f.close()