All-digital transmitter based antenna array with reduced hardware Complexity

In this paper, we present a novel architecture for an All-Digital FPGA-based Antenna Array RF Transmitter. The proposed method reduces the complexity inherent to the design of antenna arrays by removing external Digital-to-Analog Converters and external analog upconversion stages. With such a concept, the analog front-end complexity is highly reduced and, consequently, more radiating elements can be integrated. This novel concept has been successfully validated with an FPGA-based transmitter. Normalized radiation patterns as well as Error Vector Magnitude measurements were obtained for different steering angles. A minimum steering resolution of 1° was achieved with a low-complexity baseband phase shifting procedure. In addition to that, an automated calibration procedure is also presented and evaluated.