Our daily electromagnetic environment is becoming increasingly complex with the rapid development of consumer electronics and wireless communication technologies, which in turn necessitates the development of electromagnetic interference (EMI) shielding, especially for transparent components. We engineered a transparent EMI shielding film with crack-template based metallic mesh (CT-MM) that shows highly homogeneous light transmission and strong microwave shielding efficacy. The CT-MM film is fabricated using a cost-effective lift-off method based on a crackle template. It achieves a shielding effectiveness of ~26 dB, optical transmittance of ~91% and negligible impact on optical imaging performance. Moreover, high–quality CT-MM film is demonstrated on a large–calibre spherical surface. These excellent properties of CT-MM film, together with its advantages of facile large-area fabrication and scalability in processing on multi-shaped substrates, make CT-MM a powerful technology for transparent EMI shielding in practical applications.
Reducing electromagnetic
interference (EMI) across a broad radio
frequency band is crucial to eliminate adverse effects of increasingly
complex electromagnetic environment. Current shielding materials or
methods suffer from trade-offs between optical transmittance and EMI
shielding capability. Moreover, poor mechanical flexibility and fabrication
complexity significantly limit their further applications in flexible
electronics. In this work, an ultrathin (8 nm) and continuous doped
silver (Ag) film was obtained by introducing a small amount of copper
during the sputtering deposition of Ag and investigated as transparent
EMI shielding components. The electromagnetic Ag shielding (EMAGS)
film was realized in the form of conductive dielectric–metal–dielectric
design to relieve the electro-optical trade-offs, which transmits
96.5% visible light relative to the substrate and shows an excellent
average EMI shielding effectiveness (SE) of ∼26 dB, over a
broad bandwidth of 32 GHz, covering the entire X, Ku, Ka, and K bands.
EMI SE >30 dB was obtained by simply stacking two layers of EMAGS
films together and can be further improved up to 50 dB by separating
two layers with a quarter-wavelength space. The flexible EMAGS film
shows a stable EMI shielding performance under repeated mechanical
bending. In addition, large-area EMAGS films were demonstrated by
a roll-to-roll sputtering system, proving the feasibility for mass
production. The high-performance EMAGS film holds great potential
for various applications in wearable electronics, healthcare devices,
and electronic safety areas.
Vortex beam carrying orbital angular momentum (OAM) has been widely explored in optical and microwave regions attributed to its potential characteristics in communication systems. For circular polarization incidence, Pancharatnam–Berry (PB) phase is a direct resource to generate phase gradient along the azimuthal direction required by specific OAM mode. The main drawback of PB phase is that it only affects cross‐polarized fields and keeps the copolarized part unmodulated. Here, a paradigm‐shift perspective of noninterleaved metasurfaces is proposed, which can simultaneously generate separate multiple integer and fractional OAM modes occupying both copolarized and cross‐polarized output channels. The scheme is validated by a series of experimental demonstrations in the microwave regime. By adjusting the polarization states of both input and receiving ends, different integer and fractional OAM modes are demonstrated in the full transmission channels. The results offer a unique recipe to enhance information capacity of metasurfaces and trigger versatile electromagnetic (EM) wave function integrations for advanced compact systems. A variety of applications can be readily expected in spin‐selective optics, spin‐Hall metadevices, and multitask metasurfaces operating in both reflection and transmission modes.
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