Co-Design of Wideband High Efficient Power Amplifier Using Suspended Substrate Stripline Filter as the Output Matching Network

Abstract

A wideband high efficient power amplifier(PA) with an integrated suspended substrate stripline (SSS) filter as its output matching network (OMN) is presented in this paper. Compared with classical PAs, the suspended substrate stripline filter replace the output match network, and the input impedance of the filter in this design is no longer $\mathbf{50 \Omega}$ , but a complex impedance. So that it can match the optimal output impedance of the PA directly. And then high efficient power amplifier can be obtained. Besides, a conventional OMN of the PA is eliminated entirely, which leads to a small size and low insertion loss. The filter is made up of microstrip half-wavelength stepped-impedance resonators and wrapped in a metal cavity. Thus, increasing bandwith and reducing the insertion loss. two controlled transmission zero is generated at the right side of the passband, resulting in high selectivity. Both theoretical analysis and measured results are presented for validation. The bandwith of the PA for more than 65% PAE is 340MHz at 2.45GHz, the maximum PAE is 76.6% at 2.28GHz.