Energy measurement error caused by finite directivity of the reflectometer

The importance of accurate energy measurement during a microwave heating process as well as operation of a simplified measurement system for scientific research of the heating process are briefly recalled in the paper. A detailed description of the error components caused by the finite directivity of the couplers creating a reflectometer is given. A dependence of energy measurement error on the finite directivity as a function of reflection coefficient is different from such dependence when reflection coefficient only is measured.