The brief
A client preparing a proposal needed the complete communications and power architecture for an unmanned platform operating at very low Earth orbit altitudes: one receive link, two transmit links, and a power system to run them. The design had to survive the radiation environment at that altitude without the cost of an all-space-grade bill of materials.
What was delivered
- Receive chain (L-band). Preselection filtering, a low-noise amplifier, digital step attenuation for gain control, and a balun into a high-speed ADC feeding a radiation-tolerant FPGA over JESD204B, with a low-jitter clocking tree. The cascade was built stage by stage, and the link budget was closed against free-space loss at the 100 km mission range.
- Two transmit chains (S-band). From a DAC through upconversion with a synthesized LO to a power amplifier in the several-watt class, with EIRP budgets for each link.
- Power architecture. Every rail defined and budgeted, using radiation-hardened point-of-load regulators and isolated converters from the platform bus.
- Radiation-tolerance strategy. Inherently tolerant technologies first (GaN and GaAs RF parts), then enhanced and space-grade silicon only where the environment demanded it, which kept cost and lead time down without leaving single-event risk unaddressed.
Why it mattered
Architecture decisions made at the proposal stage set the cost, schedule and risk of everything after. A worked cascade, closed link budgets and a defensible part strategy gave the client a technically credible bid, and a design that could go straight into detailed schematic work if they won it.