A 2.3-8.2 GHz room temperature multi-channel receiver for phased array feed application

We describe the design, fabrication and test results of a multi-channel heterodyne receiver operating at room temperature across the 2.3-8.2 GHz Radio Frequency (RF) band. Such a “Warm Section” (WS) receiver is part of a Phased Array Feed (PAF) demonstrator that is being built for radio astronomy application. The WS receiver is cascaded to the PAF cryogenic section that incorporates an antenna array with low noise pre-amplification stages. The WS receiver consists of four rack-mountable modules, each of which can process eight RF inputs. Four modules are arranged in a standard 19” rack to allow handling a total of 32 RF signals. The modules perform filtering (through four-way switch filter bank) and down-conversion (to the 375-650 MHz IF band). The IF signals are converted to optical through analogue Wavelength Division Multiplexing IFoF (IF over fiber) transmitters incorporated into the WS receiver. The signals are sent through optical fibers to a backend, where they are converted back to IF before digitization by an Analog-to-Digital Unit