A Direct Solving Approach for High-Order Power Amplifier Matching Network Design

In this article, a direct solving method for power amplifier (PA) matching network design is explored from a theoretical perspective. Commonly, the input impedance function of a multivariable matching network is a transcendental equation and it is unsolvable. In the proposed new method, this problem can be solved to some extent by transforming the transcendental equations into solvable linear equations, where the unknown coefficients can be calculated easily. A family of impedance functions is obtained if the order of matching network is higher than the number of functions, and the best one can be selected according to the practical demand in PA design. As a design example, a triband PA with arbitrary frequency points (0.9/2.3/3.5 GHz) is implemented to validate the proposed approach. The calculation results show that the proposed method can solve the matching problem of high-order circuits. And the simulation and experiment results agree with the calculation results very well, which verified the validity of the proposed method.