Design and optimization of single-ended CMOS T/R switch for IoT applications at 2.4 GHz

Abstract

The rapid development of Internet of Things (IoT) and wireless communication technologies places increasing demands on the performance and integration of Radio Frequency (RF) front-end modules. The increasing complexity and multifunctionality of RF systems impose stringent requirements on the design of RF switches. In this dissertation, a single-ended complementary metal-oxide-semiconductor (CMOS) transmit/receive (T/R) switch operating at 2.4 GHz frequency band is designed and optimized to improve insertion loss (IL), isolation, and linearity, while ensuring stable performance under varying input power conditions. Specifically, an optimized schematic is developed by incorporating gate resistors and configuring the Width-to- Length (W/L) ratio to facilitate transmission efficiency and reduce signal degradation. Furthermore, in the layout design the ground plane area is expanded to mitigate the impact of parasitic components, thereby reducing discrepancies between simulation phases and the practical physical verification. The pre-simulation results achieve a high isolation of 28.184315 dB and an IL of only -1.458635 dB, which surpass the predefined performance targets by a considerable margin. Moreover, the overall post-simulation performance remains highly satisfactory, with only negligible degradation. These simulation results demonstrate that the proposed optimized CMOS switch can effectively sustain low IL and high isolation performance, making it highly suitable for low-power wireless IoT systems.