Real time measurement of VSWR with directional couplers

In this paper a method of measuring VSWR is introduced and discussed. In this method, first, the power of incident wave and reflected wave is measured separately with relevant directional coupler and detector. Then the magnitude of voltage reflection coefficient and VSWR are calculated by MCU. The theoretic analysis of this method and fixed error induced by nonideal directivity of the directional coupler are discussed in the paper. Additionally, the ways for diminishing the error are given out. Some experiment results are shown.