An amplification device includes a signal input terminal, a signal output terminal, an amplification unit, a coupler, an inductive element and a capacitive element. The amplification unit includes an input terminal and an output terminal, where the input terminal is coupled to the signal input terminal. The coupler includes an input terminal, an output terminal and a coupling terminal, where the input terminal is coupled to the output terminal of the amplification unit, and the output terminal is coupled to the signal output terminal. The inductive element is coupled to the coupler in parallel and includes a first terminal and a second terminal, where the first terminal is coupled to the output terminal of the amplification unit, and the second terminal is coupled to the output terminal of the coupler. The capacitive element is coupled between the output terminal of the coupler and a reference voltage terminal.

An amplifier device may include an amplifier transistor and having harmonic termination circuitry and an output impedance network, such as an output T network, coupled to the output of the amplifier transistor. The amplifier device may be configured as an inverted F class amplifier having an operational frequency range with a center frequency of less than or equal to around 2.6 GHz. The harmonic termination circuitry and output impedance network may be configured to create a short circuit or near short circuit at the amplifier transistor output for third harmonic frequencies of the center frequency of the amplifier transistor and to create an open circuit or near open circuit at the amplifier transistor output for second harmonic frequencies of the center frequency. The output impedance network may be configured to increase the output impedance at the center frequency and reduce signal loss for the amplifier device.

An aspect of the disclosure relates to a method of reducing a third-order intermodulation component at a first terminal of a transistor, including: receiving an input radio frequency (RF) signal cycling with a first frequency at a control terminal of the transistor; generating a feedback RF signal cycling at a second frequency at a second terminal of the transistor, wherein the second frequency is substantially twice the first frequency; and generating a third-order intermodulation cancellation component at the first terminal including combining the input RF signal with the feedback RF signal, wherein the third-order intermodulation cancellation component has a magnitude and phase substantially equal to and opposite a magnitude and phase of the third-order intermodulation component at the first terminal of the transistor, respectively.

The present disclosure provides a receiving circuit for adaptive impedance matching and an operating method thereof. The receiving circuit includes: a first amplification module configured to amplify an input signal input from an input end of the first amplification module to generate a first amplified signal; a frequency mixing module, an input end of which is connected to an output end of the first amplification module, and configured to down-convert the first amplified signal to generate a down-converted signal; and a second amplification module, an input end of which is connected to an output end of the frequency mixing module, and configured to amplify the down-converted signal to generate an output signal, wherein the first amplification module includes an active negative feedback structure for providing adaptive impedance matching in a first bandwidth range.

A gain equalizer and a method for controlling a tunable gain of the gain equalizer are provided. The gain equalizer includes a common source stage and a switch array. The common source stage is configured to apply the tunable gain to an input signal, in order to generate an amplified signal. The common source stage includes input transistors and cascode transistors, wherein the cascode transistors are respectively coupled to the input transistors. The input transistors are configured to receive the input signal via gate terminals of the input transistors, respectively, and the cascode transistors are configured to output the amplified signal via drain terminals of the cascode transistors, respectively. In addition, the switch array is coupled between respective source terminals of the cascode transistors, wherein the tunable gain is controlled according to an equivalent impedance of the switch array.