Abstract: The present invention discloses a harmonic reflective tuner system consisting of a radio-frequency (RF) or microwave transmission line having a longitudinal axis, containing two harmonic resonators sliding on the central conductor, where the harmonic resonators are comprising a pair of identical RF slugs, mechanically attached together. The two harmonic resonators will reflect two harmonic frequencies of a base frequency F0. The harmonic reflective tuner of this invention has an input and output, said input being connected to the DUT trough a diplexer in parallel with the fundamental tuner.