A method for measuring the velocity of a multiphase fluid flowing in a pipe. The receiver includes a coiled wire that couples the energy field, the wire having an air or ferrite core. The control unit further includes a second controlling arrangement, which in turn includes an FV arithmetic unit 24 and integrator 25; and a switcher unit 27. Then, the sidewall spacers and the insulating films are etched back, so that the sidewall spacers are formed of the insulating film over the sidewalls of the first, second, and third gate electrodes.