Tunable inductor circuit, phase tuning circuit and applications thereof

An amplifier, comprising:

• an apparatus for adjusting the phase difference of a signal having first and second signal components, comprising:
• a variable phasing network having first and second inputs and an output, the first input of the variable phasing network being coupled to the second signal component;
• and
• a phase detector having two inputs and one output, wherein one input of the phase detector is coupled to the first signal component and the other input is coupled to the output of the variable phasing network, wherein the phase detector detects a phase difference between the first signal component and a signal at the output of the variable phasing network and generating a control voltage based on the phase difference at the output of the phase detector that is coupled to the second input of the variable phasing network, wherein the variable phasing network receives the control voltage from the output of the phase detector and changes the phase of the second signal component;
• a signal splitter having an input and first and second outputs, the signal splitter being adapted to receive as input a radio frequency (RF) signal and generate first and second signal components at the first and second outputs respectively, the input of the variable phasing network being coupled to the second output of the signal splitter;
• a first amplifier connected to the first output of the signal splitter, the first amplifier amplifying the first signal component and generating an output signal at an output;
• and
• a second amplifier coupled to the output of the variable phasing network, the second amplifier amplifying an output signal of the variable phasing network and generating an output signal;
• wherein the phase detector is coupled to the outputs of the first and second amplifiers and detects a phase difference therebetween and generates a control voltage based thereon that is coupled to the input of the variable phasing network.