Inductively coupled transformer with tunable impedance match network

Abstract

The invention relates to a packaged RF power transistor. The packaged RF power transistor includes an RF input lead, a DC gate bias lead, an RF power transistor comprising gate, source and drain terminals, and an input match network. The input match network includes a primary inductor electrically connected to the RF input lead, a secondary inductor electrically connected to the gate terminal and to the DC gate bias lead, and a tuning capacitor electrically connected to the RF input lead and physically disconnected from the gate terminal. The input match network is configured to block DC voltages between the RF input lead and the gate terminal and to propagate AC voltages in a defined frequency range from the RF input lead to the gate terminal. The tuning capacitor is configured to adjust a capacitance of the input match network based upon a variation in DC voltage applied to the RF input lead.

Description

technical field [0001] This instant application relates to radio frequency power transistors, and more specifically to input matching of radio frequency power transistors. Background technique [0002] High power RF transistors such as LDMOS (Laterally Diffused Metal Oxide Semiconductor) transistors have input and output impedances significantly lower than 50 ohms (high quality factor impedance), however functional RF circuits must be matched to 50 ohms. To facilitate impedance matching to 50 ohms, RF transistors are usually designed with matching circuits on the input and output of the transistor, which are integrated into the packaged transistor. The matching network helps reduce the figure of merit of the packaged transistor to make it easier to match 50 ohms. Typically, impedance improvement can only be achieved in a small frequency range. In addition, matching networks help shape the frequency response of transistors and amplifiers to have high gain at the desired fre...

AI Technical Summary

Problems solved by technology

However, these techniques introduce additional cost and complexity, and cannot compensate for all possible effects from the rated

Images