LoRa USB Dongle PCB Design

I need a compact USB dongle that can both send and receive LoRa data on the European 868 MHz band, all while relying on a built-in PCB antenna—no external connectors. The job covers the full hardware cycle: schematic capture, PCB layout, antenna tuning, a clean Bill of Materials, and ready-for-manufacture Gerbers. USB should enumerate as a standard serial or CDC device so any computer can treat the dongle as a simple COM port; feel free to choose a proven bridge such as an STM32 with native USB or a CP2102-style UART bridge as long as drivers are readily available for Windows, macOS, and Linux. The RF front end must use a Semtech-compatible transceiver (e.g., SX1262/SX1276 family) and meet ETSI limits on 868 MHz transmissions. Deliverables • Schematic (PDF + native CAD) • PCB files (Gerber, drill, pick-and-place, assembly drawings) • Tuned antenna layout with simulation or test report proving VSWR < 2:1 at 868 MHz • Complete BOM with ordering links and alternates in case of shortages • Two assembled prototypes that pass a basic range test (open field, 500 m line-of-sight Tx/Rx using 125 kHz bandwidth, SF12) • Brief firmware example proving bidirectional LoRa packets over USB serial, plus README describing build environment Acceptance criteria 1. Dongle enumerates over USB and echoes payloads in both directions using simple AT-style commands. 2. Conducted RF output power and harmonic suppression comply with ETSI EN 300 220. 3. PCB antenna performance confirmed by antenna analyzer and on-air test. I will handle final mass production once prototypes meet the above checks, but please remain available for minor revisions and DFM feedback from the assembler. Looking forward to collaborating on a neat, driver-free LoRa USB stick that “just works” out of the box.