A holistically 3D-printed flexible millimeter-wave Doppler radar: Towards fully printed high-frequency multilayer flexible hybrid electronics systems

TL;DR

This paper presents a fully 3D-printed, flexible, four-layer millimeter-wave Doppler radar system, demonstrating high-frequency multilayer FHE with potential for conformal integration into various applications.

Contribution

It introduces the first fully 3D-printed high-frequency multilayer flexible hybrid electronics system, specifically a millimeter-wave Doppler radar, showcasing its feasibility and performance.

Findings

Successful fabrication of a 3D-printed four-layer millimeter-wave radar

Demonstrated system flexibility through bending tests

Validated sensing performance in field tests

Abstract

Flexible hybrid electronics (FHE) is an emerging technology enabled through the integration of advanced semiconductor devices and 3D printing technology. It unlocks tremendous market potential by realizing low-cost flexible circuits and systems that can be conformally integrated into various applications. However, the operating frequencies of most reported FHE systems are relatively low. It is also worth to note that reported FHE systems have been limited to relatively simple design concept (since complex systems will impose challenges in aspects such as multilayer interconnections, printing materials, and bonding layers). Here, we report a fully 3D-printed flexible four-layer millimeter-wave Doppler radar (i.e., a millimeter-wave FHE system). The sensing performance and flexibility of the 3D-printed radar are characterized and validated by general field tests and bending tests, respectively. Our results demonstrate the feasibility of developing fully 3D-printed high-frequency multilayer FHE, which can be conformally integrated into irregular surfaces (e.g., vehicle bumpers) for applications such as vehicle radars and wearable electronics.