Hardware Architecture of a Beam Alignment Module for D-band Fronthaul and Backhaul

5G and 6G open the door to millimeter-wave wireless communications, in particular for fronthaul and backhaul applications. Narrow-beam antennas are needed in this context, and a constant adjustment of their beam direction is required. This paper describes the hardware architecture of an antenna alignment system in the D-band, which is intended to be used in the DRAGON European project. The various hardware blocks of this system are discussed, along with their interfaces. In particular, a RISC-V softcore is implemented to execute an alignment algorithm whose task is to choose the beam direction that best follows antenna vibrations. An analysis of the available processing time and the achievable alignment periodicity is provided. Under current assumptions in the project, the beam alignment periodicity is expected to be 540 mu s, which allows 270 mu s of processing time. The FPGA implementation of this architecture uses less than 30 % of a Xilinx Zynq XC7Z045 chip.