This paper presents the design, simulation and measurement of a broadband back-end module (BEM) for radio-astronomy applications in the Ka-band. It is a direct conversion receiver based on low noise amplification, band pass filtering and Schottky diode detection. System simulations are based on individual linear-subsystems S-parameters measurements together with non-linear detector model. Measurements show more than 30 dB of RF gain over the 26 to 36 GHz band with a noise figure below 3.9 dB. Detected voltage is in the range 1-10 mV which meets the application specifications.