# K/Ka-Band Very High Data-Rate Receivers: A Viable Solution for Future Moon Exploration Missions
## 7 Conclusions  
In the next years, the cislunar space will be the target for a variety of projects, such as the Lunar Orbital Platform-Gateway and the Lunar Relay Satellites. This calls for new technologies to be developed and, among them, for the set-up of a suitable telecommunications infrastructure. Such infrastructure should have the capability of carrying out the simultaneous multi-band communications between Earth, the Moon, including visiting (rovers) and descent/ascent (landers, terminals) vehicles, and other elements in cislunar orbit. Since this kind of missions employs many information-intensive (high resolution, high coverage, high duty cycle) sensors, high speed data links will be required. The above scenario is investigated in the present paper and, specifically, the feasibility study of a high data rate receiver operating in the K/Ka band is carried out. Starting from a careful mission and system analysis, the main specifications of such a receiver are outlined. Particularly relevant are some new features that need to be considered in this applications, such as: Autonomous Doppler shift compensation, autonomous determination of the uplink signal characteristics and autonomous handover between base stations. The foreseen receiver uses a low noise down-converter from K/Ka-band to a first IF at 3.7 GHz, a software defined radio for the second frequency conversion and the I/Q demodulation (including ADCs) and a FPGA-based decoder and data interface. A preliminary front-end breadboard operating between 27.5 and 30 GHz has been implemented. The breadboard is based on COTS and commercial EVBs and features a 46 dB gain, a 3.4 dB noise figure and a \(-\)37 dBm input-referred 1 dB compression point. A final demodulation test, carried on a QPSK signal at 40 Msym/s, show the feasibility of the proposed receiver, even on the basis of the low cost, off the shelf integrated circuits. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Ref.** & **Mission Scenario** & \(f_{0}\) & **FE Gain** & \(F_{RX}\) & \(P_{\mathbf{1}dB}\) & **Data Rate** & **DC Power** & **Mass** \\  & **(GHz)** & **(dB)** & **(dB)** & **(dBm)** & **(Mb/s)** & **(W)** & **(kg)** \\ \hline
[34] & GEO satellites & 27.50–31.00 & 55 & 2.3 & \(-\)42 & n.a. & 5 (+) & 0.2 (+) \\
[35] & International Space Station & 22.52–23.12 & n.a. & 2.3 & n.a. & 12.5 & n.a. & 19.2 (*) \\ this & Moon \& cislunar space & 27.50–30.00 & 1.9 (\(\dagger\)) & \(-\)37 & 100 & 8 & 0.6 (\(\ddagger\)) \\ \hline \hline \end{tabular} (*) only Ka-band receiver front-end; (*) includes a 40 W transmitter unit; (\(\dagger\)) noise figure equal to 3.4 dB with end-launcher and input CPW line; (\(\ddagger\)) estimated value.  
\end{table} 
Table 7: State-of-the-Art for K/Ka-Band Receivers for Space Applications. While the receiver design may seem a conventional one, it is worth mentioning once again that the aim of this work is to assess and validate the receiver concept according to those aspects that are critical for the success of a space mission. Indeed it can be considered as remarkable the fact that a receiver design (which can be assumed common practice for consumer applications) is proven to withstand all the challenges of the space environment, as stated in the discussion. This demonstrates that new approaches can be as reliable as traditional ones, and also more cost effective. F.A., P.M., L.R., V.P., S.B., R.V.G., L.R., G.B., F.F., P.B. (UniPG) and F.P., M.F., [PERSON], [PERSON], [PERSON] and [PERSON]. (PicoSaTs) conceived the study; [PERSON] and [PERSON]. (GMSpazio) simulated the mission scenario; [PERSON] and [PERSON] proposed an antenna solution; [PERSON], [PERSON], (UniPG) and [PERSON], [PERSON], A.C., E.D.F., F.D. and [PERSON]. (PicoSaTs) designed the breadboard, performed the experiments and analyzed the data; [PERSON]. (Silicon Infusion) designed and developed the DVB-S2 modem; [PERSON] and [PERSON]. (PoliTO and ESA-ESTEC) critically revised the architectural and the breadboard design; [PERSON].