Dual Band Resonance in Tetragonal BaTiO₃/NBR Composites for Microwave Absorption Applications

Abstract

Tetragonal BaTiO 3 bulk samples are prepared using the solidstate route in conjunction with intermediate high-temperature annealing steps. The (002) and (200) X-ray diffraction peaks near 2Ɵ~45°and 310, 520, and 720 cm -1 characteristic vibrational modes in Raman spectroscopic measurements confirm the tetragonal crystallographic structure of BaTIO 3 bulk samples. The 1100°C annealed BaTiO 3 sample showed optimal tetragonality~1.016 and the same is used for BaTiO 3 -acrylonitrile butadiene rubber (NBR) composites at different BaTiO 3 loading fractions in parts per hundred (PHR). These BaTiO 3 /NBR composite systems exhibit dual band microwave resonance, widening the operating window for microwave absorption applications. Eighty PHR BaTiO 3 /NBR composite exhibits microwave reflection losses (RL) at 9.5 and 16.5 GHz with~-9 and~-18 dB reflection losses, respectively. The onset of dual band is attributed to the ferroelectric-induced dipolar relaxation at 9.5 GHz and its second-order resonance at 16.5 GHz in such composite systems.

Formation of BaFe12−xNbxO19 and its high electromagnetic wave absorption properties in millimeter wave frequency range

“…As is shown in Figure 1A, for the sample without doping, a-Fe 2 O 3 , c-Fe 2 O 3 , BaCO 3 phases emerge at 500°C-650°C. It is known that the raw chemicals Ba(NO 3 ) 2…”

“…Microwave absorbing materials are of great importance to attenuate electromagnetic pollution arising from explosive development of information technology and defend against radar detection for military stealth. [1][2][3][4][5][6] Recently, millimeter waves with frequency range of 30-300 GHz are proposed for radar detection due to the advantages of high resolution and all-weather characteristic, in which atmospheric windows of 35 GHz, 94 GHz, 140 GHz, 220 GHz are the most attractive frequencies. 7,8 Hence, there is an urgent need to develop high-efficiency absorbing materials aiming at the corresponding bands.…”

Recent advancements in the electromagnetic interference shielding performance of nanostructured materials and their nanocomposites: a review

“…429 BaTiO 3 /PANI composite prepared by adding PANI (50 wt%) to BaTiO 3 (BaTiO 3 /PANI wt ratio ¼ 1 : 1) showed the minimum reection loss of À20 dB (23 Hz) and À27 dB (33 GHz). 430 PANI-tetragonal BaTiO 3 , 431 CNT (2 wt%)/BaTiO 3 (34.5 wt%)/ epoxy, 432 BaTiO 3 -CoFe 2 O 4 lled LDPE, 433 graphite nanoplatelets (6 wt%)/BaTiO 3 (30 wt%)/epoxy, 434 NiO@SiO 2 (15 wt%)/PVDF, 435 EPDM/BaTiO 3 (20 phr)/MWCNT (10 phr), 436 tetragonal BaTiO 3 (80 phr)/NBR, 437 CNT/BaTiO 3 /polyaniline, 438 445 and PANI/TiO 2 /g-Fe 2 O 3 , 446 have also been studied for their EMI shielding efficiencies.…”

Scattering and Coupling Reduction of Dipole Antenna Using Gradient Index Metamaterial Based Cloak

“…For instance, by mixing Barium Titanate with Polydimethylsiloxane (PDMS), a flexible dielectric composite material can be prepared. It has an additional advantage that the permittivity can be controlled by varying the concentration of Barium Titanate in the composite [21][22][23][24]. Also, using similar chemical approaches, a composite can be prepared wherein permittivity and permeability of the material can be varied simultaneously, as demonstrated by various research groups [25][26][27][28].…”