Comparative study of equivalent circuit models for photoconductive antennas

Area of Science:

• Terahertz (THz) Photonics
• Antenna Engineering
• Computational Electromagnetics

Background:

• Photoconductive antennas (PCAs) are crucial for THz generation.
• Accurate modeling of PCAs using equivalent circuit models (ECMs) is complex due to multiphysics.
• A standardized validation methodology for PCA ECMs is lacking.

Purpose of the Study:

• To compare existing equivalent circuit models (ECMs) for photoconductive antennas (PCAs).
• To introduce a novel validation methodology for PCA ECMs.
• To present and validate an improved two-element ECM for PCA modeling.

Main Methods:

• Comparison of reported ECMs using consistent simulation parameters and validation metrics (THz waveform, optical power saturation, voltage consistency).
• Simulation of ECMs contrasted with experimental THz pulse measurements from an H-shaped PCA.
• Development and validation of an alternative two-element ECM incorporating space-charge and radiation screening effects.

Main Results:

• Established a unique set of parameters and indicators for comparing PCA ECMs.
• Demonstrated accurate reproduction of measured THz pulses using the proposed two-element ECM.
• The new ECM accurately models THz pulse generation with fewer circuit elements.

Conclusions:

• The proposed validation methodology enables effective comparison of PCA ECMs.
• The novel two-element ECM accurately captures PCA behavior, including screening effects.
• This simplified ECM offers an advantage for efficient and accurate PCA modeling.