RF Power Amplifier Circuit With Transformer-Based Phase Shifting

The patent changes the fundamental parameter of phase shifting from using a quarter-wavelength transmission line (which requires large physical length) to using a transformer-based impedance conversion circuit. This parameter change allows achieving the same 90-degree phase shift function with a much smaller circuit footprint by utilizing electromagnetic transformation rather than physical wave propagation length.

The patent replaces the mechanical/electromagnetic wave propagation-based phase shifting mechanism (transmission line) with an electrical circuit-based mechanism (transformer and impedance conversion circuit). This substitution enables phase shifting through impedance transformation ratios rather than physical length, dramatically reducing the required circuit area.

The patent designs the transformer-based circuit to perform multiple functions simultaneously: impedance conversion and phase shifting. The same transformer and impedance conversion circuit that reduce circuit size also provide the necessary 90-degree phase shift, eliminating the need for separate phase shifting components and maintaining functional accuracy while minimizing area.

The patent carefully controls and adjusts circuit parameters (transformer turns ratio, impedance values of main and auxiliary lines) to achieve both size reduction and phase shifting accuracy. By optimizing these parameters, the circuit maintains precise phase control despite the compact design.