Ethylenediaminetetraacetic Acid (EDTA) Assisted Single Step Densification of Li₂TiO₃/PTFE Composites at Ultralow Sintering Temperature to Realize a High-Performance Ku-Band Antenna

Abstract

In the last few decades, extensive research has been focused on the ever-increasing demand for energy-efficient materials and technologies in consumer electronics. The low-weight, low-cost, environmentally safe Li-based ceramics are widely investigated as potential materials for Li-ion batteries and low-temperature cofired ceramics (LTCC). In the present work, we combine high volume fractions of Li2TiO3 (LT) ceramic with incredibly versatile polytetrafluoroethylene (PTFE) to synthesize thermally stable, low-loss dielectrics at ultralow temperatures (<150 °C) in a single step without any additional transient liquid phase in a very short time, and the effect of different wt % of ethylenediaminetetraacetic acid (EDTA), which is a chelating agent, on the densification, microstructure, thermal, and broadband dielectric properties of these composites has been studied. X-ray photoelectron and FTIR spectroscopic analyses were used to explain the densification mechanism in these composites. The presence of the OH– ion on the surface of LT and manipulation of the ceramic-polymer interphase by EDTA are significant in the densification of LT-PTFE composites. A cylindrical prototype dielectric resonator antenna (CDRA) was designed, simulated, and fabricated with the 0.7LT-0.3PTFE-5EDTA composite having excellent thermal and dielectric properties, and antenna properties were experimentally verified. The return loss, input impedance, and radiation pattern of the CDRA were examined, and the experimental results match reasonably well with simulated results. This study shows that the 0.7LT-0.3PTFE-5EDTA composite is a potential candidate for the fabrication of an economical, low-loss, lightweight, easy-to-fabricate, wide bandwidth CDRA for telecommunication applications in the Ku-band. Further, it is possible to achieve enhanced bandwidth and gain, by varying the compositions of these composites.

Water and SnF2 Assisted Ultralow-Temperature Sintering of Mechanically Tough Y3Fe5O12 Composites for Magneto-Dielectric Antennas

“…The resonant frequencies of simulated and fabricated MPAs are 5.20 and 5.29 GHz, respectively. Basically, return loss indicates the power reflected from the antenna to the source, and it should be less than −10 dB for the entire acceptable frequency range. , Here, the simulated and fabricated antennas show return loss values of around −20.2 and −17.9 dB, respectively, which are good enough for their practical application. Another parameter that determines the suitability of the antenna for a specific application is its impedance bandwidth, which corresponds to the range of frequencies where the return loss is less than −10 dB.…”

“…35 Also, recently, Santha et al used EDTA as the sintering aid to densify the Li 2 TiO 3 -PTFE composites. 36 In the recent past, on account of the lower polarizability of F − (1.62 Å 3 ) than that of an O 2− ion (2.01 Å 3 ), researchers have more focused on fluoride-based systems to take advantage of CSP for promising microwave dielectric ceramics. Liu et al demonstrated the feasibility of the cold sintering technique followed by the annealing process on the densification of LiF ceramics.…”

“…Funahashi et al applied a chelating complex for the densification of spinel-based ferrites . Also, recently, Santha et al used EDTA as the sintering aid to densify the Li 2 TiO 3 -PTFE composites …”

Investigating the effects of uniaxial pressure on the preparation of MgTiO3–CaTiO3 ceramic capacitors for MRI systems

“…In addition, Li 2 TiO 3 -based materials have shown promise in high-frequency resonant circuits. It has a dielectric constant (ε r ) of around 26 and can be sintered at relatively low temperatures, such as 900 • C [25]. Therefore, they are suitable for lowtemperature processing applications.…”