The project, carried out from October 2019 to September 2022 under the German Federal Ministry of Education and Research’s TELGA programme, set out to provide a fully electronic traceability system for sterilised surgical instruments. The goal was to embed a miniature, energy‑autonomous RFID transponder directly into the metal body of instruments such as forceps, thereby preserving the instruments’ appearance and handling characteristics while enabling automated identification throughout the hospital supply chain.

Technically, the core achievement was the design and fabrication of a 5.6 GHz ISM‑band transponder ASIC with an integrated ceramic antenna. The choice of 5.6 GHz was driven by the need for a read range of 10–20 cm, sufficient for inline process control in autoclaves, while keeping the antenna size small enough for integration into a machined cavity. The ASIC was fabricated in a commercial CMOS process and incorporates a simple SPI interface for future sensor integration. In laboratory tests the transponder achieved a read success rate exceeding 99 % under a variety of orientations and in the presence of surrounding metal, a performance that surpasses conventional low‑frequency (LF) and high‑frequency (HF) RFID systems which suffer from induced eddy currents in metallic environments.

The antenna design utilised a ceramic carrier with multiple metal layers to form a resonant structure that fits within a shallow cavity in the instrument’s handle. Simulation and measurement of the antenna’s input impedance guided the optimisation of the cavity geometry, resulting in a compact resonator that maintained the required bandwidth for ISO 18000‑6C compliance. The integration process involved a specialised adhesive and filler material that bonded the transponder to the instrument without compromising the sterilisation cycle. Over 500 autoclave cycles were performed on instrument prototypes, and no failures of the adhesive, filler, or transponder were observed, confirming the robustness of the integration method.

Parallel to the transponder development, a custom read device was realised. The front‑end of the reader was built from discrete SHF components—rat‑race couplers and Wilkinson power dividers—allowing rapid optimisation and replacement of antenna modules. The reader implements the ISO 18000‑6C protocol stack using off‑the‑shelf baseband and protocol processors, and communicates with a middleware layer via a USB interface. Characterisation in a radio‑frequency shielded chamber demonstrated full functionality and a stable read range consistent with the transponder’s specifications. The middleware, written in Java, connects the reader to a hospital inventory management system, enabling real‑time tracking of instrument status.

Collaboration across the project was structured around the distinct technical domains. Fraunhofer Institute for Medical and Biological Engineering (IMS) led the reader development and system integration, while Fraunhofer Institute for Photonic Microsystems (IPMS) and the University of Paderborn jointly designed the transponder ASIC and antenna. Alltec GmbH contributed industrial expertise on instrument manufacturing and sterilisation processes, ensuring that the integration method met regulatory requirements such as the EU Medical Device Regulation (2017/745). The project’s deliverables included a fully characterised prototype, a detailed integration protocol, and a demonstration of the system’s performance on a set of forceps subjected to routine sterilisation cycles.

In summary, the project delivered a miniature, high‑frequency RFID transponder that can be embedded into metal surgical instruments, achieving a read range of 10–20 cm, a >99 % read success rate, and durability over 500 autoclave cycles. The system’s modular design, compliance with ISO 18000‑6C, and proven integration method position it as a viable solution for hospitals seeking automated, reliable traceability of sterilised instruments.