This project aims at the development of a on-board tunable channel filter in Ku-Band, which is the first step for the development of such reconfigurable IMUX devices.
Reconfigurable hardware platforms for modern communication systems are highly desired since by allowing for real-time system adaptation to different parameters (users varying demands and distribution, environmental conditions etc.) tends to maximize the return of investment.
One of the major bottlenecks in the development of reconfigurable payloads is the input and output filtering section, where for the moment filters of fixed centre frequency and bandwidth are employed. The utilization of reconfigurable IMUX and OMUX would allow substantial reduction of both mass and costs wrt today's switched multiplexer solution. Ideally one reconfigurable IMUX and OMUX design could apply to all payloads operating in a certain band. Thus, the necessity to design a new filtering section everytime a new payload is developed would be eliminated, while the reconfigurability would also eliminate many risks regarding last-minute changes in the development of a payload/system.
The key issues for the in-orbit reconfigurable channel filter are:
To handle these issues, a RF and mechanical (tuning mechanism) co-design approach will be implemented.
The main benefit of this project will be the demonstration of a possible attractive design for space qualified reconfigurable channel filters in Ku-Band. Such a demonstration will enable the design of reliable channel filters for future reconfigurable IMUX devices in Ku-Band.
The current baseline channel filter design consist in the cascading of 2 asymmetric response BPFs (BPF-1 + BPF-2, pseudo LPF + pseudo HPF configuration), with centre frequency fc tuning screws. With this configuration no direct BW tuning is required, since BW selection is achieved by shifting fc1 and fc2.
Each individual BPF is based in waveguide 3D cavity resonators, to benefit from the high Q and relatively low modelling and realization complexity. The cavities accommodation is such as to present compact profile. Tuning will be implemented by means of tuning screws penetrating inside the resonators. Screws movement is achieved by means of a single motor for each type of tuning, e.g., one motor moves all BPF-1 fc tuning screws and another motor moves all BPF-2 fc tuning screws.
The main features of the proposed solution are:
The study is divided in two phases of overall duration equal to 24 months. The first phase (10 months) is dedicated to:
The second phase (14 months), which will take place only upon positive decision of the Agency, foresees:
The filter will be tested according to the agreed plan. The obtained results will be evaluated with respect to the expected performances and will also be used as a basis for proposing further improvements and applications for IMUX.
In the first stage of the project the following activities have been performed:
Once the preferred solutions are identified with ESA, the refinement of the trade-offs and preliminary analyses will be performed. The trade-offs will be supported by experimental results obtained by means of bread-boarding activities on selected test-items.