Architecture of C-band Phased Array Feed with RFSoC digital beamformer

We describe the architecture of a room-temperature C-band Phased Array Feed (PAF) demonstrator based on Radio Frequency System-on-Chip (RFSoC) for radio astronomy application. The instrument operates across the 4.75-6.00 GHz RF band (C-band). The RF section includes a compact module based on an 8×8 array of dual-polarization antennas integrated with MMIC (Monolithic Microwave Integrated Circuit) Low Noise Amplifiers (LNAs). A subset of 32 elements of one of the two polarization channels of the 128 antennas are connected to the LNAs, while the rest are terminated into internal loads. Following two stages of filtering and signal conditioning, the 32 RF signals are injected in two commercial RFSoC digital boards, each accepting 16 inputs with 1.25 GHz bandwidth, that will perform the frequency channelization, the partial and final beamforming of four independent beams with 1.25 GHz instantaneous bandwidth.