Bidirectional 5–7 GHz ↔ 8–10 GHz high‑power frequency‑shifter PCBA using 3.0 GHz, 0 dBm external LO with shared 50 Ω CPWG RF port on 80 × 60 mm RO4350B, delivering TX ≥ +32 dBm and RX NF < 1.5 dB