Experimental microwave feedforward linearized amplifiers

Feedforward linearization is an effective technique for improving the linearity of power amplifiers [1][2] especially at microwave frequencies where the output power of currently available devices is limited. Feedforward systems have been designed to improve, microwave power amplifiers´ linearity across the 5.9-6.4 GHz and 7.9-8.4 GHz satellite bands. An optimization method was developed to permit a linear design approach and the practical set up of the experimental feedforward systems [3]. Measured results demonstrated at least 20 dB suppression of the intermodulation distortion across the full operating bands employing auxiliary amplifiers with power rating lower than that of the main amplifier. Comparison of the systems developed with the experimental classical feedforward circuit, which employs two amplifiers with the same power rating, demonstrates that more efficient configurations can be adopted without compromising the performance.