Development of Anisotropic Magnetic Nanocomposites for Miniaturized RF Device Applications

The miniaturization of radio frequency (RF) components has become increasingly in-demand due to the popularity of mobile devices, such as smartphones, tablets, and other ad-hoc networking products. Many state-of-the-art RF components are bulky and lack high power handling capability due to the typical use of ferrite materials and a permanent magnet that magnetizes the ferrites. Anisotropic magnetic nanocomposites (AMNs), on the other hand, are capable of working as the magnetic layer within passive RF components, due to enhanced magnetic properties in a preferred direction, a relatively large remanent magnetization, and a self-biased microwave response. Here we present a new class of AMNs based on high aspect ratio (>1000) magnetic nanowires and functional matrices for nonreciprocal device applications. These AMNs show large remanent magnetization and tunable ferromagnetic resonant frequency, and have demonstrated excellent performance in a miniaturized passive circulator.