This book is a pioneering exploration of a new form of high-frequency attenuation chamber that has the potential to revolutionize antenna measurement techniques. The authors present an innovative concept that leverages the classical principle of changing the polarization of radio waves, eliminating the need for traditional non-reflection chambers. By analyzing experimental results and searching for the optimal shape and composition of a depolarization panel, this monograph provides valuable insights into creating a non-reflective environment for accurately measuring the directional properties of antennas. The book delves into the methodology of frequency analysis, optimization of the depolarization panel, and the creation of a measuring workplace using this panel. It highlights the crucial attenuation phenomenon of suppressing cross-polarization coupling between transmitting and receiving antennas, enabling antenna measurements in any laboratory environment. With its promising results and practical applications in antenna technology, this publication offers a compelling and cutting-edge approach to antenna measurement that will captivate researchers, engineers, and professionals in the field.