A multi-stage amplifier is provided that uses tunable transmission lines, as well as a calibration method for the multi-stage amplifiers. A multi-stage amplifier, comprises a plurality of tunable amplification stages, wherein each of the tunable amplification stages comprises a tunable resonator based on a transmission line having a tunable element. The tunable elements may vary a capacitance or an inductance to tune a frequency of an applied signal. A calibration method is provided for a multi-stage amplifier having a plurality of transmission lines, an input stage and an output stage. The multi-stage amplifier is calibrated by generating a signal to determine a frequency for a substantially maximum power; generating an error signal by comparing the frequency for the substantially maximum power with a desired frequency; varying a digital control code applied to each of the tunable transmission lines, input stage and output stage until the error signal satisfies predefined criteria.