High Powered Ka-band 24.65 to 25.25 GHz tx, 21.40 to 22.00 GHz rx

In 2015, iSat answered a pre-qualification RFI regarding creating transmitting terminals with 75dBW at 25GHz, with options to transmit on both polarisations. After pre-qualification, iSat received the RFP in 2016 and provided a full tender response, fully compliant with statement of works and instructions for bidders. After post-tender qualifications, iSat were down-selected and continued to answer questions of clarification in a competitive and responsive manner. After a nail-biting final negotiation, iSat were awarded the tender, subject to agreement on terms and conditions.

To implement the terms and conditions, iSat provided the customer with a Return Bank Guarantee Bond for the customer deposit, and a Performance Bond for guarantee. iSat’s HSBC bankers provided the bonds, and iSat’s credit record meant that through UKEF Bond Support Scheme, iSat could access the customer deposit to build the project out. Support from financial institutions would not have been possible without iSat’s preferred suppliers also agreeing secure payment and delivery milestones. iSat acted as finance coordinator and facilitator so that all parties were comfortable with the contract.

The contract therefore provided a secure framework within which iSat began to research and develop the new RF modules. These modules had never previously created, and iSat’s RF design team had to match these modules with compatible reflectors to ensure the final solution complied with the ITU interference masks. The application at 75dBW had never previously been contemplated, and required a very low and fixed amount of interference allowed by the ITU specification. A new approach to the shape of the RF modules was taken that enhance the control of the interference pattern. The new shapes would not be manufactured in the normal fashion and drove new production methods never previously used in this market. By marrying the design with this new production process, a technically compliant terminal was achieved. No other supplier has ever addressed these frequencies before, and offered a compliant terminal.

The full turnkey contract required production, test, freight, installation and on-site acceptance, and training. Indoors, the earth station came complete with a bespoke splitter/combiner/inserter shelf that allowed for monitoring all interfaces appropriately at the front and rear of the rack. All power and lightning protection and M&C interfaces were also provided, together with on-going local through life support.

The construction of the 4 port feed was carefully designed to allow for linear polarisation adjustment. The delicate Ka-band waveguides, filters and couplers were supported in a cradled that rocked as the polarisation was adjusted.

High levels of EIRP were maintained by mounting the amplifier close to the feed, and also using rigid waveguide twist for most of the anticipated adjustment required for polarisation, and only a short length of semi-rigid for the final 1 or 2 degrees. Diplexers were specifically designed to keep their insertion loss to a very low figure. And a mechanically adjustable feed holder was used to place the feed at exactly the focal point, allowing a small adjustment for the difference between the focal point for receive frequency, and the optimum for transmit.

A separate external BUC was used before the high powered amp to insert a filter and reduce the noise entering the amplifier

The new frequency terminals will enable expansion of services to be deployed into under-served communications areas under the footprint of the satellite operator.