RF Matching Networks Using S-Parameters

The paper presents a design and study of impedance matching for radio frequency (RF) circuit application of common-source amplifier topology. Matching networks for input and output sides of the amplifier were determined from the S-parameters given for the transistor at frequency of 2.6 GHz and ensuring unconditional stability requirement. Impedance matching is necessary in RF circuit design to provide maximum possible power transfer between the source and the load. Two designs were modeled, simulated and analyzed employing L-network input and output matching networks. The design with inductor-capacitor combination in the L-matching networks exhibited a stable and smoother behavior for higher frequencies compared to an all-inductor design. Complex tradeoffs among technology specifications and design parameters are inevitable, therefore should be carefully handled in designing the impedance matching networks, to optimize the performance of the common-source amplifier. Ultimately, the common-source amplifier achieved a gain of 6.569 dB at 2.6 GHz. For future research, physical implementations of the impedance matching networks could be studied in order to improve and optimize the simulated models.