High-Voltage RF Switch-Based Antenna Tuning Circuits in CMOS Technologies

Abstract

The main and diversity antennas of modern cellular user equipment are integrated into the chassis of the device. Due to the limited space inside the device and high complexity of front-end electronics, the integrated antennas have small form factor, which leads to low radiation efficiency and high mismatch losses. The performance of the antennas is optimized with aperture tuning techniques. Commercial aperture tuners in modern cellular user equipment are based on high-voltage RF switches in bulk- or SOI-CMOS technologies. The focus of this research is put on the analysis of the second and third order nonlinear products caused by the RF switch, the influence of the substrate capacitance and the hardware characterization of antenna tuning ICs. Additionally, the functionality of the RF switch is extended and novel RF switch-based tuning ICs in CMOS technologies are investigated. All theoretical findings are verified either with measurements of the designed ICs or on the application level using a hardware demonstrator.