Design of a Millimeter-Wave Broadband Linearizer Based on an Extended Design Space

Abstract

In this study, a broadband linearizer design method based on an extended design space is proposed to optimize the design complexity and linearization performance of conventional linearizers for broadband operation. The gain characteristics of the power amplifier (PA) and linearizer are fitted to simplify the analyses and to quickly derive the ideal objective function of the linearizer design. Then, the 1 dB compression point of a nonlinear system is redefined and used to further extend the design space of the linearizer. To verify the proposed design method, a millimeter-wave linearizer prototype based on the extended design space was designed and fabricated. The linearizer was tested with continuous-wave and 100 MHz two-tone signals from 40 GHz to 43 GHz. The measurement results of the linearized PA showed that the output 1 dB power point (OP1dB) was improved by more than 1.7 dB, the phase error was reduced by more than 15°, and the third-order intermodulation distortion (IMD3) was suppressed by 8.6 dB–13.1 dB over the working frequencies. The proposed linearizer achieved good linearization performance, low power consumption, and simple design implementation, and it was not necessary to tune the bias during broadband operation, making it applicable in complex communication scenarios.