Temperature Stable Cold Sintered (Bi0.95Li0.05)(V0.9Mo0.1)O4-Na2Mo2O7 Microwave Dielectric Composites

Abstract

Dense (Bi0.95Li0.05)(V0.9Mo0.1)O4-Na2Mo2O7 (100−x) wt.% (Bi0.95Li0.05)(V0.9Mo0.1)O4 (BLVMO)-x wt.% Na2Mo2O7 (NMO) composite ceramics were successfully fabricated through cold sintering at 150 °C under at 200 MPa for 30 min. X-ray diffraction, back-scattered scanning electron microscopy, and Raman spectroscopy not only corroborated the coexistence of BLVMO and NMO phases in all samples, but also the absence of parasitic phases and interdiffusion. With increasing NMO concentration, the relative pemittivity (εr) and the Temperature Coefficient of resonant Frequency (TCF) decreased, whereas the Microwave Quality Factor (Qf) increased. Near-zero TCF was measured for BLVMO-20wt.%NMO composites which exhibited εr ~ 40 and Qf ~ 4000 GHz. Finally, a dielectric Graded Radial INdex (GRIN) lens was simulated using the range of εr in the BLVMO-NMO system, which predicted a 70% aperture efficiency at 26 GHz, ideal for 5G applications.

Cold sintered CaTiO3-K2MoO4 microwave dielectric ceramics for integrated microstrip patch antennas

“…Therefore, antennas, resonators, filters, substrates and microstrip lines in 5G communication devices will require low dielectric loss, low εr (<15) materials, such as alumina, silicates, molybdates, borates and tungstates. [6][7][8][9][10][11][12][13][14] However, ceramics are manufactured using conventional sintering technology (>1000 o C) and thus cannot be directly integrated into polymer circuit boards (PCBs 34 and K2MoO4 (KMO, εr = 6.37, TCF = -70 ppm/°C) 32 , were selected to prepare a series of ceramic composites with the prospect for producing a low εr (<15), near-zero TCF and high Q×f material suitable for 5G antenna substrates.…”

Microwave Dielectric Properties of (1-x) Li2MoO4–xMg2SiO4 Composite Ceramics Fabricated by Cold Sintering Process

“…The relative density and microwave dielectric properties of the cold-sintered sample was the same as that of a sample sintered at 540 • C (Saraiva et al, 2017). Similarly, other molybdate ceramics such as K 2 Mo 2 O 7 (Guo et al, 2017), (Bi 0.95 Li 0.05 )(V 0.9 Mo 0.1 )O 4 -Na 2 Mo 2 O 7 (Wang et al, 2019a), (LiBi) 0.5 MoO 4 (Guo et al, 2017) etc. have been prepared by CSP with acceptable MW dielectric properties and a dense microstructure.…”

Microwave Sintering and Microwave Dielectric Properties of (1–x)Ca0.61La0.26TiO3-xNd(Mg0.5Ti0.5)O3 Ceramics

“…With the advent of the 5G era, microwave dielectric ceramics attract more and more attention [ 1 ]. Microwave dielectric ceramics can not only be used as insulating substrates material in microwave circuits, also as the key basic material to fabricate dielectric resonators, dielectric filters, dielectric oscillators, phase shifters, microwave capacitors, etc., for microwave communication technology [ 2 ]. Therefore, microwave components play an increasingly important role in miniaturization, integration, and cost reduction of modern communication tools [ 3 ].…”