Cobalt–Polymer Nanocomposite Dielectrics for Miniaturized Antennas

Abstract

Cobalt-polymer magnetic nanocomposites have been synthesized and characterized for their microstructure and properties such as permeability, permittivity, dielectric and magnetic losses from 100 MHz to 2 GHz to study their suitability as antenna dielectrics. Oxide-passivated cobalt nanoparticles were dispersed in epoxies to form nanocomposite toroids and thin-film resonator structures on organic substrates. Permeabilities of 2.10 and 2.65 were measured up to 500 MHz, respectively, with 25-nm to 50-nm and 5-nm nanoparticles in the nanocomposites. The loss tangent ranged from 0.02 to 0.04 at these frequencies. A combination of stable permeability of $2 at 1 GHz to 2 GHz and permittivity of $7 was achieved with nanocomposites having 5-nm nanoparticles. The magnetic nanomaterials described in this paper can overcome the limitations from domain-wall and eddy-current losses in microscale metal-polymer composites, leading to enhanced frequency stability. The paper also demonstrates integration of metal-polymer nanocomposites as thin-film build-up layers with two-metal-layer structures on organic substrates.

A Review on Nanocomposites. Part 1: Mechanical Properties

“…Moreover, this miniaturization trend could cover not only microelectronics but also micromechanical devices. Nanocomposites might be considered as alternatives to composites and alloys in manufacturing micro-products [16]. For example, manufacturing airframe [17] or wings [18] of micro-air vehicles (MAVs) using conventional composites [19] such as carbon fiber, glass fiber or Kevlar reinforced plastics could be replaced by CNTs or carbon nanofiber (CNF) nanocomposites that have higher strength-to-weight ratio and flexibility.…”

Non-conductive ferromagnets based on core double-shell nanoparticles for radio-electric applications

“…(Castel et al 2007 ), printable Co nanoparticles materials (Nelo et al 2010 ) and Co epoxy-based nanocomposites (Raj et al 2014 ). It proves that eddy currents are canceled and ferromagnetic losses are shifted until unconventional frequencies.…”

“…In RF, polymer–metal nanocomposites are aimed to overcome the main obstacle of high-moment transition metals that are conductive. Recent works on nanocomposites of cobalt were reported but magnetization degradation was observed indicating that stable nanoparticles are needed (Nelo et al 2010 ; Raj et al 2014 ). They can be protected with a shell that must be a protection against surface oxidation and spin-quenching especially with cobalt (van Leeuwen et al 1994 ).…”

Self-Healing of Core–Shell Magnetic Polystyrene Nanocomposites

“…Magnetic nanoparticle polymer nanocomposites are an important class of polymeric materials with applications such as bioseparation, 1 magnetic sensors, 2 optoelectronic storage, 3 miniaturized antenna, 4 shape memory polymers and polymer actuators, 5,6 and EMI shielding. 7−9 Magnetic nanoparticles have extraordinary properties depending on their chemical composition, size, shape, and aspect ratio.…”

“…Magnetic nanoparticle polymer nanocomposites are an important class of polymeric materials with applications such as bioseparation, magnetic sensors, optoelectronic storage, miniaturized antenna, shape memory polymers and polymer actuators, , and EMI shielding. − Magnetic nanoparticles have extraordinary properties depending on their chemical composition, size, shape, and aspect ratio . Surface functionalization of magnetic nanoparticles is essential for targeted design performance in many applications such as hyperthermia, drug delivery, magnetic resonance imaging (MRI), biocompatible cell labeling, and more. − Functionalization could be tailored using biocompatible ligands targeted for cell internalized and in vivo monitoring, or chemical functionality for dispersion in a polymeric system. Magnetic nanoparticles have been used for recording media, magnetic resonance imaging, targeted drug delivery, and hyperthermia. − Magnetic nanoparticles can be tailored for specific target tumor location and to generate heat for cancer treatments …”