A sustainable
cold-sintering process was adopted to fabricate
composites of (1–x)SrFe12O19–xLi2MoO4, x = 0.4, 0.5, 0.6, and 0.7 with density up to 91%, and their
broad-band electromagnetic properties were deciphered. X-ray diffraction
(XRD) analysis revealed the coexistence of SrFe12O19 (SFO) and Li2MoO4 (LMO) phases in
the composites, unaccompanied by any additional phases. The evolution
of microstructure facilitating enhanced densification was observed
with an increase in the LMO volume fraction. The real permittivity
(ε′) increased with an increase in the LMO volume fraction,
while the dielectric loss (tan δε) decreased.
Further, the real permeability (μ′) of all of the composites
is greater than unity and the magnetic loss (tan δμ) is of the order of 10–2. The 0.3SFO–0.7LMO
composite with the highest densification possess ε′ =
6.7, tan δε = 2 × 10–3, μ′ = 1.14, and tan δμ = 2 × 10–2 at 900 MHz along with an appreciable
room-temperature saturation magnetization (M
s) of 32.2 emu/g. To demonstrate the application potential
of this magnetodielectric composite toward microwave antenna applications,
a ferrite resonator antenna (FRA) integrated using the SFO–LMO
composite was designed, simulated, and fabricated. The fabricated
FRA resonating at 12.89 GHz exhibited an exceptionally high return
loss of −40 dB and a wide impedance bandwidth of 510 MHz. The
remarkable properties of the fabricated ferrite resonator antenna
suggest that it is a potential candidate for Ku-band applications.
The electromagnetic interference (EMI) shielding market is one of the fast-growing sectors owing to the increasingly complicated electromagnetic environment. Recently, priority has been given to improvise the techniques to fine-tune and predict the shielding properties of structures without exhausting raw materials and reduce the expense as well as the time required for optimization. In this article, we demonstrate an effective and precise method to predict the EMI shielding effectiveness (SE) of materials via simulating the performance of composites having alternate layers of conducting and magnetic materials in a virtual waveguide measurement environment based on the finite element method (FEM). The EMI SE of multilayered heterogeneous arrangements (MHAs) is simulated in the Kband region using ANSYS High Frequency Structure Simulator (HFSS) software, which can be extended to all other bands as well. Various simulations carried out by changing the order of the conducting and magnetic layers and the number of layers revealed that the strategic arrangement of electromagnetic (EM) energy-trapping layers inside the impedance-matching layers in the MHAs significantly contributes toward the enhancement of absorption-dominated EMI shielding. Among the MHAs, the conductingmagnetic-conducting (CMC) systems exhibited the highest shielding effectiveness of above 50 dB. The MHAs are realized for testing using poly(vinylidene fluoride)-based composites of low-cost carbon black and barium hexaferrite, an easily accessible ferrite. Through this study, we propose the idea that materials with high production cost and cumbersome fabrication procedures are not necessary to realize highly efficient shielding materials.
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