The microwave interferometer of the TCABR tokamak is presented in this paper, describing in some detail the phase detection procedure and other technical features. The system has three transceivers and seven waveguide channels coupled to horn antennas. The operating frequency, 140 GHz, allows measuring the electronic density of the TCABR plasmas avoiding cutoff and with relatively small refraction effects. The high intermediate frequency, 18 MHz, together with the large pass-band lter and heterodyne detection system allows measuring fast density changes without loss of signal. Some experimental results and calculations are presented.
