Gas analyzer utilizing cancellation of parallel microwave beams

摘要

A method for analyzing a gaseous mixture by means of microwave absorption including the steps of: generating microwave energy of at least one frequency known to be absorbed by the component of interest of the gaseous mixture for the presence of one specific gas component; transmitting two beams of the microwave energy simultaneously to a measuring cell and to a reference cell, both cells containing none of the specific gas component of interest; recombining the microwave energy through the matching arms of a waveguide "magic" tee with an "H" arm and an "E" arm; adjusting the phase and amplitude of the reference or measuring beam signals of microwave energy until a null is detected at the "E" arm of the waveguide "magic" tee and all microwave energy is detected at the "H" arm of the microwave tee; allowing the measuring cell to fill with the gaseous mixture to be analyzed; correlating the energy detected at the "H" arm to the concentration of the gaseous component of interest, according to Beer's law. Also provided is an apparatus which may be used in conjunction with this method.