In this article, we present an open testing and measurement bench allowing one to characterize the performance of any UHF RFID tag. The architecture is based on a vectorial generator and a real-time spectrum analyzer. Both instruments are controlled by a single script on a remote controller. The bench is able to extract the power on tag forward and power on tag reverse, the delta RCS and the read range of a UHF tag. This bench can offer similar functionalities as the industrial solution such as the Voyantic Tagformance Pro reader. All relevant design files will be released as open source to the community.