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

Abstract

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 ([Formula: see text]) and loss tangent ([Formula: see text]) for LDPE was 2.282 and 0.0045, whereas for LDPE-5%BAK the calculated [Formula: see text] and [Formula: see text] 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/10 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 °C screw temperature, 110 rpm, and 11 kg load) while processing with a twin-screw 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.

Three-dimensional printed thermoplastic polyurethane on fabric as wearable smart sensors

“…The ε r and tan δ for substrate (TPU on CLW fiber) were calculated (Table 8) based on the reported literature. 44,45 The controlled variation in ε r of the substrate upon cyclic loading highlights its 4D property, as this results in programable RF output in the ISM band. It may be noted that for ensuring the reliability of the functional prototype, the samples were loaded and unloaded for two consecutive cycles (with 03 repetitions).…”

“…18) ascertains the 4D characteristics of the substrate. The 𝜀 𝑟 and tan 𝛿 for substrate (TPU on CLW fiber) were calculated (Table 8) based on the reported literature [45,46]. The controlled variation in 𝜀 𝑟 of the substrate upon cyclic loading highlights its 4D property, as this results in programable RF output in the ISM band.…”

On PVDF composite as partially absorbable smart implants

“…PVDF composite samples were further explored for their ε r , which was experimentally evaluated using an impedance analyzer (Figure 6). Based upon experimentally observed ε r values, ε eff was calculated using the standard set of equations 21 along with the different parameters of the ring resonator (to be employed as a sensor for smart implant) (Table 6). It may be noted that all dimensions of the ring resonator to be employed as a sensor have been calculated for resonating frequency of 2.45 × 10 9 Hz (i.e.…”

“…In the reported literature, several studies have been reported on non-absorbable implants, prepared with different metals/alloys, and composites [19][20][21] for various orthopedic applications. But yet little has been described on the partially absorbable smart implants of thermoplastic composites for online health monitoring of veterinary patients.…”

On 3D printed intelligent diaphragmatic hernia sensor

“…AM methods are being used in different industries including health and medicine, automotive, electronics, aerospace, food, construction, etc. (Singh et al , 2022a). Figure 1 shows a process flow for AM (Bozkurt and Karayel, 2021).…”