Suspended Structure Tunable Impedance Matching Network Based on Polyimide Membrane Capacitance

This article presents a tunable impedance matching network using polyimide membrane capacitance. The paper shows a matching network designed to transform a 10 Ω output impedance to a 50 Ω load working at 10 GHz. The polyimide membrane is used as an effective capacitance in matching circuit designs, which results in a change of the matching configuration. So, this matching network can also transform a 20 Ω output impedance to a 50 Ω load at 16 GHz. The matching network uses a suspension structure to reduce losses based on an electrochemical deep etching technology for silicon. The impedance level is typical of power amplifiers at microwave frequencies. This matcher can be used in new highly integrated microwave/millimeter wave circuits, such as high‐output power amplifiers, multipliers, and ultra‐wideband antenna arrays. It is expected that these circuits will be applied in low‐cost, low‐power intelligent RF front‐end microsystems and on‐chip systems in future. In addition, multiple matching points can be obtained by means of changing the thickness of the polyimide film to adjust the capacitance value. Additionally, multiple units can be cascaded to expand multiple matching points.