Patent ID: 6731175
Filing Date: 2004-05-04
Classification: H03F

Abstract:
A high frequency amplifier comprising:a first and second transistor, the first transistor having a drain connected to a source of the second transistor and the second transistor having a gate connected to receive a first voltage; a first, second and third inductor, the first inductor having a first end connected to a gate of the first transistor, the second inductor having a first and second end respectively connected to a source of the first transistor and to receive a second voltage, and the third inductor having a first and second end respectively connected to a drain of the second transistor and to receive the first voltage; a first, second, third, fourth and fifth capacitor, the first capacitor having a first and second end respectively connected to a second end of the first inductor and to receive an input signal, the second capacitor having a first end connected to receive the second voltage, the third capacitor having a first end connected to receive the second voltage, the fourth capacitor having a first and second end respectively connected to the drain of the second transistor and to receive the first voltage, and the fifth capacitor having a first end connected to the drain of the second transistor; a first and second resistor, the first resistor having a first and second end respectively connected to a second end of the second capacitor and to receive the second voltage, and the second resistor having a first and second end respectively connected to a second end of the third capacitor and to receive the second voltage; a first and second variable capacitor, the first variable capacitor having a first and second end respectively connected to a second end of the second capacitor and a second end of the third capacitor, and the second variable capacitor having a first and second end respectively connected to a second end of the fifth capacitor and to output an output signal; a variable resistor having a first and second end respectively connected to the second end of the fifth capacitor and to receive the second voltage; and a received signal strength indicator receiving the output signal and generating an indication signal corresponding to an amplitude of the output signal, by which the first and second variable capacitor, and the variable resistor are tuned.