The InDiThera project, carried out by Infineon Technologies AG from 1 November 2019 to 31 May 2023, focused on developing a radar‑based microwave imaging system for early breast‑cancer detection. The core objective was to design, fabricate and characterize a K‑band transceiver chip operating at 24 GHz with a 7 GHz bandwidth, and to integrate it into a demonstrator that could be used for clinical evaluation.
The chip, named INDTX‑C11, was fabricated in a 65 nm CMOS process and measures 2.15 mm × 1.45 mm. It incorporates a transmitter and receiver front‑end, a low‑noise amplifier, a mixer, and a reconfigurable analog baseband that can be tuned for different imaging modes. A phase‑locked loop supplies a stable local oscillator, while a direct‑digital synthesizer generates the chirp waveform required for frequency‑modulated continuous‑wave (FMCW) operation. The design also includes a programmable gain amplifier and a low‑noise RF front‑end that can be directly driven by the antenna array.
Measured performance shows a flat output power across the 7 GHz bandwidth, with a maximum of roughly 0 dBm at the centre frequency of 24 GHz. The receiver conversion gain remains above 15 dB throughout the band, and the noise figure stays below 5 dB, ensuring high sensitivity for detecting subtle dielectric contrasts in breast tissue. The transceiver can be interfaced with a 2‑D or 3‑D antenna array, allowing flexible deployment in either a monostatic or multistatic configuration. Compatibility with electrical impedance tomography (EIT) measurements was also achieved, reducing cross‑talk and improving image quality.
A dedicated hardware‑software interface was defined to stream raw radar data over a serial peripheral interface (SPI) in real time. The software stack, written in C++, handles data acquisition, calibration, and preliminary image reconstruction. A graphical user interface provides live visualization of the received signals and the reconstructed dielectric maps. The demonstrator board, built around the INDTX‑C11, includes a 4‑channel RF front‑end, a high‑speed ADC, and a field‑programmable gate array (FPGA) that orchestrates the data flow.
The project also explored the use of flexible antenna arrays on polymer substrates, enabling conformal coupling to the breast surface. In a pilot study, the system was able to resolve simulated tumour phantoms with diameters as small as 5 mm, demonstrating the potential for early detection. The integration of the radar system with a millimetre‑wave imaging pipeline paves the way for a non‑ionising, cost‑effective screening tool that could complement existing modalities such as mammography, ultrasound, and MRI.
Collaboration within InDiThera brought together Infineon Technologies AG, academic researchers, and clinical partners. Infineon led the chip design, fabrication, and system integration, while university collaborators contributed to algorithm development, phantom design, and clinical validation. The project was funded under the German federal InDiThera programme, which supports early‑stage research in diagnostic technologies. The partnership model allowed the sharing of expertise and resources, accelerating the transition from laboratory prototype to a clinically relevant demonstrator. The project’s outcomes provide a solid foundation for future development of a commercial microwave imaging system for breast‑cancer screening.