A radio frequency (RF) amplifier and a bias circuit are provided. The RF amplifier includes an amplifier, a first inductive-capacitive resonance circuit, and a first bias circuit. The amplifier includes an input terminal configured to receive an incoming RF signal through a first RF path. The first inductive-capacitive resonance circuit includes a first terminal coupled to a first reference voltage. A second terminal of the first inductive-capacitive resonance circuit is coupled to the first RF path. In response to the first reference voltage being at a first reference level, the RF amplifier is enabled; in response to the first reference voltage being at a second reference level, the RF amplifier is disabled. The first bias circuit includes a first terminal configured to be coupled to the first reference voltage and a second terminal coupled to the input terminal of the amplifier to provide a first direct current (DC) component.