In this letter, the validity of lumped element class-F amplifier circuit design approaches, which were previously proposed by the same authors, has been demonstrated experimentally using microwave InGaP/GaAs HBT. By means of the proposed class-F amplifier design method, more than 4th order higher harmonic frequencies can be taken into account in class-F microwave amplifier design using only lumped element components. In this approach, miniaturization of class-F amplifier circuit has also been realized. A collector efficiency of 71.2% and a power-added efficiency of 69.2% have been measured at an operating fundamental frequency of 1 GHz considering up to the 4th order higher harmonic frequency.