A highly linear mixer design with a schottky diode linearizer for WiMAX applications

摘要

2.6 GHz mixers are designed and implemented in hybrid microwave circuits (HMCs) using the GaAs pseudomorphic high electron mobility transistors (pHEMTs). A crucial goal for the design is to achieve the high linearity required in WiMAX systems. The proposed design is based on a commonly used Gilbert mixer with a Schottky diode linearizer to enhance the linearity. The input 1dB compression point (IP1dB) and the third-order intercept point (IIP3) of the proposed design achieve -3 dBm and 6.8 dBm, respectively. A Schottky diode linearizer has improved the IP1dB by 3 dB and the IIP3 by 3.8 dB without the reduction in conversion gain when compared to the conventional Gilbert mixer. Comparison between simulation and measurement shows good agreement in compensation of gain compression and IIP3 due to a Schottky diode linearizer.