New 3D printing techniques have been utilized to make 3D electrical components, such as resistors, capacitors, and inductors, as well as circuits and passive wireless sensors. According to Sung-Yueh Wu and Chen Yang of the Institute of Electronics at the Chinese Academy of Sciences, 3D structures can be created using fused deposition modelling technology and a multiple-nozzle system, with a printing resolution of 30μm.
A 3D printed ‘smart cap’, with an embedded inductor/capacitor tank as the wireless passive sensor, has been demonstrated to monitor the quality of liquid food, such as milk and juice, wirelessly. The result has shown a 4.3% resonance frequency shift from milk stored at room temperature environment for 36 hours.
The technique uses a regular 3D printing equipment to construct 3D microstructures with embedded metallic elements by using fillings of liquid metal paste to produce various basic microelectronics components, such as resistors, capacitors, and inductors. These basic components can be connected to build more complicated circuitries as well as numerous functional systems.
This is an innovative approach to construct arbitrary 3D systems with embedded electrical structures as integrated circuitry for various applications, such as the passive wireless sensors.