Low Noise Amplifier for Use with Submillimeter Electric-Field Probes

摘要

In the past several years, there has been increasing concern over the effects on human beings of low level electromagnetic radiation. Submillimeter Electric Field probes were developed to directly measure E fields in biological media. These probes are also very useful for measuring E fields in cavities where solving the mathematical equations, because of the geometries of the cavities, is very difficult or impossible. An amplification system for these probes is investigated. This system is designed, built, and laboratory tested. A theoretical gain equation is developed relating the output voltage of the system to the impinging E field on the probe. Additionally, a complete noise analysis is accomplished. Theoretical noise work is verified in the laboratory, along with the gain equation. Finally, modulation of the probe amplifier system is shown to feasible and is demonstrated in the laboratory. This will allow the measurement of the relative phase shift between two points in a cavity. Keywords: Low noise amplifier; Theses; Noise analysis; Electric field probes.