Background With the development of high-power microwave technology, dielectric materials in terahertz (THz) communication, detection, and other systems, especially semiconductor materials, will face a more severe microwave strong field environment, which poses new requirements for obtaining the terahertz dielectric properties of materials under a microwave strong field.
Purpose This paper proposes a method and system for measuring the complex dielectric constant of THz materials under microwave electric fields, based on the free-space method, which addresses the technical challenge of the complex dielectric constant of THz materials under microwave electric fields loading.
Methods A compressed rectangular resonant cavity was designed in typical L, S, and X bands in industrial and radar systems to provide a stable and controllable microwave electric field loading environment. At the same time, a free-space complex permittivity testing system was built in the range of 0.11-0.5 THz to achieve non-contact characterization of the THz dielectric properties of materials.
Results Based on the above-described measurement method and system, the reliability of the system was validated by testing fused silica and comparing the results with reference data from the existing literature. Subsequently, the THz dielectric properties of a typical semiconductor material, GaAs, were measured under different microwave electric fields, and the power-dependent response behavior of its dielectric properties was obtained.
Conclusions This study can provide testing technology support for in-depth analysis of the THz dielectric nonlinear behavior of materials under microwave electric fields, and provide important basic data for the iterative development of THz material research and applications in complex electromagnetic environments.
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