Analysis of 3-D printed meta-structure substrates for microstrip patch antenna design

Recent years have witnessed a shift in antenna design preferences, with polymer-based substrates over conventional PCB substrates. While prior studies have explored Poly-lactic acid (PLA) biocompatible substrates, limited attention has been given to the utilization of 3D printed (PLA) meta-structure substrates for patch antennas. This research examines the effect of infill patterns (triangular and grid) and novel structures (with and without top layers) for obtaining different dielectric constants. It has been observed that the dielectric constant of a single polymer-based material can be altered simply by modifying the internal structure of the substrate. To examine the dielectric constant, six ring-resonator-based sensors with constant infill density (100%) were 3D printed, simulated, and fabricated. S21 values were analyzed to derive dielectric constants and loss tangents. Results indicated distinct characteristics for each substrate, with variations in dielectric constants, such as Sample 1 (Triangle with top layer, εr = 2.47) and Sample 6 (Triangle and grid combination without top layer, εr = 2.41). Notably, substrates without top layers exhibited a decrease in dielectric constant attributed to air gaps and pattern design. Antenna simulations for meta-structure (Sample 5) at a resonant frequency of 2.45 GHz further underscored the significance of infill patterns and top layers in influencing dielectric properties. The idea of analysing substrates with and without a top layer is explored for the first time for antenna design. This study provides valuable insights for optimising antenna designs with different structures to obtain different dielectric constants according to application needs.