Progress in the design of the front-end of the C-Band PAF prototype for the SRT Primary Focus

We present the progress in the design of the front end of the room-temperature C-Band (4.75-6.00 GHz) Phased Array Feed (PAF) prototype for the Sardinia Radio Telescope (SRT). The front end consists of two stages: the first one is composed of an 8x8 array of dual-polarization Vivaldi antenna elements integrated with MMIC (Monolithic Microwave Integrated Circuit); the second one is a signal acquisition chain consisting of a conditioning circuit that adapts the signal levels to the backend. In the currently planned configuration, only a subset of 32 elements are connected to the LNAs, while the rest of them are terminated into $50 \Omega -$matched loads. We provide an overview of all the frontend components and briefly describe the backend, which is based on a Radio Frequency System-on-Chip (RF-SoC) architecture.