On comparison of recycled LDPE and LDPE-bakelite composite based 3D printed patch antenna

In the past two decades number of studies have been reported on the use of thermoplastics as a substrate for 3D printed patch antennas. However, no work has been reported on the thermoplastic-thermosetting composite-based substrate for 3D printed patch antennas and their mechanical, morphological, rheological, and radiofrequency (RF) characterization for sensing applications. In this study low-density polyethylene (LDPE) and LDPE-5% bakelite (BAK) composite-based patch antenna (resonating frequency 2.45 GHz) were printed (for secondary recycling) on fused deposition modeling (FDM) setup. The RF characteristics were measured using a vector network analyzer (VNA). Ring resonator test was used for measuring the dielectric properties of substrates (which suggests that the dielectric constant (epsilon(r)) and loss tangent (tan delta) for LDPE was 2.282 and 0.0045, whereas for LDPE-5%BAK the calculated epsilon(r) and tan delta was 2.0663, 0.0051 respectively). This study highlights that for the LDPE-5%BAK composite there was a marginal increase in the size of the patch antenna; but this resulted in improved transmittance, gain, and return loss for typical sensor applications. As regards to printability of substrate, 5% BAK resulted in a melt flow index (MFI) of 9.96 g/10 min in contrast to 12.208 g/ 1 0 min for a neat LDPE sample. The selected LDPE-5%BAK composite resulted in peak strength (PS) and break strength (BS) of 16.08 MPa and 14.47 MPa (at 180 degrees C screw temperature, 110 rpm, and II kg load) while processing with a twinscrew extruder (TSE), which was observed better than the neat LDPE (PS 11.98 MPa, BS 10.79 MPa). The results were supported with porosity (%), surface roughness (Ra) analysis based upon scanning electron microscopy (SEM) and bond strength using attenuated total reflection (ATR) based Fourier transformed infrared (FTIR) analysis.

Automated summary

This study printed 3D patch antennas using LDPE and LDPE-5%BAK composite materials, demonstrating that the LDPE-5%BAK composite material can provide better mechanical and RF characteristics compared to pure LDPE, making it suitable for sensor applications.