Fully passive dual-chain X-Band upconverter with two 5–7 GHz SMA RF inputs, a single external LO SMA passively split to two mixer chains, and dual on-board 8–10 GHz 50 Ω PCB outputs with PI-match networks, no DC-powered components, BOM <$300 #PassiveUpconverter #DualChain #XBand #NoDCPower #BOMUnder300