A DDS-PLL beam steering polar transmitter for narrowband IoT communications

This work presents the design and implementation of a low-complexity beam steering polar transceiver based on a revised DDS-PLL phase shifter architecture. The proposed modulator-less topology targets narrowband communications for enhanced Internet-of-Things systems, and has been prototyped using an FPGA evaluation board and a custom PCB with four PLLs centered at 2.453-GHz. Measured system performance are discussed for an experimental data rate of 32-kbps achieved through the implementation of a 16-PSK modulation. Being a frequency independent architecture, the proposed solution represents a very effective choice in multi-band devices and it has the potential for being integrated as an RF System-on-Chip.