A 3D-Printed Microwave Passive Sensor Using Fully Biodegradable and Renewable Materials

This paper presents the feasibility of fully biodegradable and renewable materials in the fabrication of mi-crowave resonator passive sensors using additive manufacturing technology. To demonstrate this application, a microwave ring resonator sensor has been designed and fabricated. The core of sensor is a microwave ring resonator with a resonance at 4.88 GHz which is coupled through the two coupling capacitors at the input and output ports. It is demonstrated that any change in the relative permittivity of the material being sensed above the sensor produces a significant resonant frequency variation in the response of sensor. BioFila silk is used for the substrate part of the sensor. Biofila silk is characterized over an ultra-wide frequency range from 200 MHz to 20 GHZ using Keysight 85070E high performance probe. Annealed copper is used for the conductive parts of the sensor. To the best of our knowledge, this is the first reported passive sensor fabricated with a fully biodegradable and renewable host substrate.