A Compact Triple Band Receiver System working at K-, Q- and W-band for Medicina, Noto and Sardinia Radio Telescopes

Pietro Bolli (Italian National Institute for Astrophysics), Seog-Tae Han (Korea Astronomy and Space Science Institute), Jihoon Choi (Korea Astronomy and Space Science Institute) and Alessandro Orfei (Italian National Institute for Astrophysics)

A compact triple band receiver system is under development by a mutual collaboration between INAF, Italy and KASI, Korea. Three receivers will be fabricated and installed on the 64 m Sardinia radio telescope, 32 m Noto and Medicina radio telescopes respectively. Each receiver enables simultaneous observations in the three frequency intervals: K-band (18–26 GHz/8 GHz IF bandwidth), Q-band (34–50 GHz/16 GHz IF bandwidth) and W-band (85–116GHz/32 GHz IF bandwidth). An integrated quasi-optical circuit plus a compact triple-band receiver located in a single cryostat is chosen in order to circumvent difficulties in installation and beam alignment. A frequency-independent quasi-optical circuit for each band is adopted to obtain constant aperture efficiency as a function of the observed frequencies. The simulation results show that total aperture efficiency of each recommended frequency band is maintained almost constant within 1%. We present the design details of the compact wideband quasi-optical circuit and the properties of the triple-band receiver optimized for simultaneous multi-frequency observations. It is expected that it will be dedicated to conduct millimeter wave VLBI and Sun observations.