Abstract | A novel linearisation technique for reduction in the third-order intermodulation distortion products, with injection of second harmonics through a feedback loop of a power amplifier, was applied in this paper. The power amplifier including the feedback loop components (bandpass filter, phase shifter, attenuator) was designed as a hybrid microwave integrated circuit by using the program Libra. The adjustable parameters are the phase and amplitude of the loop signals. Therefore, a voltage that controls a phase shift of the phase shifter and a control current of a PIN diode in the attenuator circuit were optimised to obtain a reduction in the third-order intermodulation distortion. The achievable improvement was found to be 21 dB for the case of two fundamental signals at the power amplifier input |
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Keywords | Circuit CAD, circuit optimisation, feedback amplifiers hybrid integrated circuits, intermodulation distortion linearisation techniques, microstrip circuits, microwave integrated circuits, microwave power amplifiers, 2.49 GHz 2.52 GHz, 5 to 5.4 GHz, Libra program, PIN diode control current, RF wireless systems, attenuator, bandpass filter, feedback loop, hybrid microwave integrated circuit, linearisation technique, loop signal amplitude loop signal phase, low intermodulation amplifiers, microstrip technique, microwave wireless systems, phase shifter, power amplifier, second harmonics injection, third-order intermodulation distortion products |
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