A Low Loss, 6 GHz Large-Signal Bandwidth Analog Pre-Distortion Linearizer for K-Band High Power Amplifiers

This work presents the design, characterization, and validation of an Analog Pre-Distortion (APD) circuit. This circuit is based on a dual-branch configuration with a Schottky diode as a non-linear element and delay line. The Schottky diode is first experimentally characterized and a large signal model is extracted. The manufactured APD circuit provides a 6 GHz bandwidth around a central frequency of 18 GHz. At large-signal, this APD circuit shows to be able to correct up to 3 dB of HPA compression and up to 9° of HPA phase rotation within a 6 GHz large-signal bandwidth, with a low insertion loss of only 7 dB. The complete APD + HPA chain is verified with modulated signals at 19 GHz and results in an improvement of the P 1dB point by 2.6 dB and by 6° in the phase distortion. Finally, the APD is demonstrated with a 750 MHz modulated signal and results in the improvement of the left Adjacent Channel Leakage Ratio (ACLR) by 4.5 dB, of the central Noise-Power Ratio (NPR) by 8.2 dB, and then of the right ACLR by 9.8 dB while maintaining the same maximum output power.