Additively Manufactured Porous Ceramics as Tunable Dielectrics for Passive Temperature Sensing

ABSTRACT Wireless temperature sensing with passive LC resonators can be significantly enhanced by integrating dielectric materials whose permittivity varies with temperature. In this work, we present a set of 3D‐printed porous ceramic lattices engineered from a multicomponent metal‐oxide ink that serve as tunable dielectrics for temperature‐responsive sensing. The ink, composed of Mn, Ni, Co, Cu, and Zn oxides, is processed through ball milling, 3D printing, debinding, and sintering to produce porous structures with porosities of 54%, 39%, and 24%. Structural and dielectric characterizations confirm that permittivity increases with temperature and decreases with porosity. When positioned on a planar LC sensor and interrogated using a vector network analyzer (VNA), the samples exhibit distinct resonant frequency shifts over the range of 25°C–110°C. Higher dielectric samples show lower resonant frequencies and stronger temperature sensitivity, with Δf/ΔT slopes that are both steep and sample‐specific. Electromagnetic simulations using HFSS closely match experimental S21 data, supporting the observed sensing trends. This work demonstrates a versatile strategy for customizing wireless temperature sensors by tuning the porosity and composition of printed ceramic dielectrics.