Microwave phased array digital beamforming system design challenges for SKA

There are many challenges in the design of broadband microwave phased array digital beamformers for SKA-Phase 1. The list is not simply limited to funding or time, but rather many technology challenges of bandwidth, RFI, cooling, coherency, and complexity. However, there have been Commercial Off The Shelf (COTS) technological advancements in recent times for RF, ADC and digital technologies that will ease the system design challenges ahead. This paper describes an experimental system being developed by the SKA Dish Consortium for the SKA1-survey instrument. Phased arrays typically contain a very large number of receive chains and produce huge data rates. Cost is typically driven by performance and hence careful component selection and system design is critical to meet budget expectations. This paper describes the beamforming system as a whole and covers all aspects of the design rather than one specific component. The application is radio astronomy, but it could be applied to defence, medical and telecommunication systems that use electronically steered arrays.