A dual mode power amplifier configured as a polar amplifier comprising: a linear gain section, comprising: a mode controller arranged to receive amplitude modulating inputs (a(t)), a gain signal, and a mode select signal, and to configure the linear gain section to operate in one of a normal mode and a bypass mode, wherein: in the normal mode, the mode controller is configured to output intermediate amplitude modulating signals (vamp; vamn) based on the amplitude modulating inputs (a(t)); and in the bypass mode, the mode controller is configured to output a constant voltage; and a linear amplifier arranged to receive outputs of the mode controller; and a non-linear gain section arranged to receive frequency modulating inputs (f(t)) and the gain signal, wherein the non-linear gain section comprises a switching amplifier arranged to: receive outputs from the linear amplifier; receive intermediate signals (Lo p; Lo n) of the non-linear gain section based on the frequency modulating inputs (f(t)) and the gain signal; and mix the outputs from the linear amplifier and the intermediate signals (Lo p; Lo n). a linear gain section, comprising: a mode controller arranged to receive amplitude modulating inputs (a(t)), a gain signal, and a mode select signal, and to configure the linear gain section to operate in one of a normal mode and a bypass mode, wherein: in the normal mode, the mode controller is configured to output intermediate amplitude modulating signals (vamp; vamn) based on the amplitude modulating inputs (a(t)); and in the bypass mode, the mode controller is configured to output a constant voltage; and a linear amplifier arranged to receive outputs of the mode controller; and a mode controller arranged to receive amplitude modulating inputs (a(t)), a gain signal, and a mode select signal, and to configure the linear gain section to operate in one of a normal mode and a bypass mode, wherein: in the normal mode, the mode controller is configured to output intermediate amplitude modulating signals (vamp; vamn) based on the amplitude modulating inputs (a(t)); and in the bypass mode, the mode controller is configured to output a constant voltage; and in the normal mode, the mode controller is configured to output intermediate amplitude modulating signals (vamp; vamn) based on the amplitude modulating inputs (a(t)); and in the bypass mode, the mode controller is configured to output a constant voltage; and a linear amplifier arranged to receive outputs of the mode controller; and a non-linear gain section arranged to receive frequency modulating inputs (f(t)) and the gain signal, wherein the non-linear gain section comprises a switching amplifier arranged to: receive outputs from the linear amplifier; receive intermediate signals (Lo p; Lo n) of the non-linear gain section based on the frequency modulating inputs (f(t)) and the gain signal; and mix the outputs from the linear amplifier and the intermediate signals (Lo p; Lo n). receive outputs from the linear amplifier; receive intermediate signals (Lo p; Lo n) of the non-linear gain section based on the frequency modulating inputs (f(t)) and the gain signal; and mix the outputs from the linear amplifier and the intermediate signals (Lo p; Lo n).