Optimizing ultra-wideband balanced power amplifiers through the selection of different output impedance transformation based on SiP techniques

Abstract

In this paper, two improved ultra-wideband (UWB) balanced power amplifiers based on the flip-chip system-in-package technique and electronic design automation (EDA) are proposed. The conventional approach to system-on-chip (SoC) involves integrating all sub-circuit designs into a single manufacturing process. However, in radio frequency circuits, adopting the SoC approach necessitates intricate matching designs, leading to an increase in development costs. In this study, two types of SiGe unit power amplifiers attempted to achieve a flat S21 response using simpler matching for input/output. The cascode architecture was adopted as the main structure for the first type of unit power amplifier (type I). Subsequently, the design of the second type unit power amplifier was built upon the foundation of the first type, with the only difference being the implementation of two parallel cascode structures (type II), and the primary goal is to enhance both gain and output power compared to the first type. In addition, for this second type unit power amplifier, in conjunction with a quadrature hybrid coupler, the optimal impedance matching value was selected to maintain the flatness of gain across the entire UWB range. Furthermore, the poor performance of S11,22 of these two types of unit power amplifiers was improved by using quadrature hybrid couplers using the WIPD process combined with EDA simulation. Therefore, using flip-chip packaging technology can effectively reduce the increased wafer fabrication costs caused by complex matching designs in active circuits. This improved system has the potential to offer a new practical application for UWB power amplifier design.