FieldDecay

The field decay monitor displays how the electromagnetic field intensity decays over time during an FDTD simulation. Monitoring field decay is essential for ensuring accurate and reliable frequency-domain results.

Setup

A field decay monitor is automatically included in all FDTD simulations.

Visualization

After opening the simulation results, you will find the field decay datasets under "Monitor Datasets". Field decay values are recorded at each time step, showing how the electromagnetic field intensity decreases over the simulation duration.

Why Field Decay Matters

The frequency-domain response obtained in FDTD simulations only accurately represents the continuous-wave response of the system if the electromagnetic fields at the beginning and end of the time stepping are very close to zero.

When fields have not fully decayed by the end of the simulation:

• Frequency-domain results may not be accurate
• Spectral responses can show artificial oscillations or smoothed features
• High-Q resonant features may not be properly captured