Antennas are the quintessential communication devices used to transmit and receive information encoded in electromagnetic waves. Their debilitating shortcoming is that they are resistant to miniaturization because their gain and efficiency plummet when they are shrunk to dimensions much smaller than the wavelength of the electromagnetic wave. The radiation efficiency, for instance, is limited to ~, A (radiating area)/ (lambda)E2 where A is the radiating area of the antenna and l is the wavelength that is radiated. This is known as the Harrington limit.
We have recently invented and demonstrated a new genre of antennas that leverages magnetization precession or spin waves, induced in periodic arrays of nanomagnets by various types of external stimuli, to radiate electromagnetic waves in space. These unconventional antennas sport gain and intrinsic radiation efficiencies which can exceed the Harrington limit by as much as five orders of magnitude. We have investigated and demonstrated a large family of such antennas employing different systems such as multiferroic magnonic crystals, the spin Hall effect and topological insulators. These antennas have dimensions 3-4 orders of magnitude smaller than the wavelength, making antenna miniaturization possible. They can have embedded applications such as in medically implanted devices for acute care, stealth devices for defense and crime-fighting, and on-chip communication.
There are additional unusual features that these antennas exhibit. Despite being “point sources” that are much smaller than the wavelength, these antennas do not radiate isotropically like a point source, but instead exhibit an anisotropic radiation pattern because of the inherent anisotropy of the spin waves that are the source of the electromagnetic radiation. One can steer the principal lobe of the radiated beam by manipulating the external stimuli, which enables active electronic scanning (AESA) without requiring a phased array. This talk will describe this new genre of nano-antennas.
Co-sponsored by: Electron Devices Society (ED15) – Northern Va Chapter
Speaker(s): Prof.Supriyo Bandyopadhyay,
Agenda:
Introduction of speaker – 6:30 pm
Presentation – 6:35 pm
Q&A – 7:30 pm
Virtual: https://events.vtools.ieee.org/m/484353