<Motivation and Innovation>
Antenna miniaturization has been one of the fundamental challenges for decades. Conventional small antennas use electric current for radiation which relies on electromagnetic wave resonance that leads to antenna sizes comparable to the electromagnetic wavelength. Here we demonstrated a new antenna miniaturization mechanism, acoustically actuated nanomechanical magnetoelectric (ME) antennas, that could successfully miniaturize the magnitude of 1-2 orders using magnetic current for radiation. The ME Antennas open up a variety of opportunities due to their unique and particular properties. With the advantages of high magnetic field sensitivity, highest antenna gain within all nano-scale antennas at the similar frequency, the integrated capability to CMOS technology, and the ground plane immunity from the metallic surface or the human body, the nano-antennas have bright future for bio-medical applications, wearable antennas, internet of things, etc.
<Interest and Media>
The first successful demonstration of ME antennas published in Nature Communications led to strong funding interests from different funding agencies, different companies and was widely cited in different news media, including Nature, Science, news in different websites and newspapers in different languages, TV interview, etc.
NATURE NEWS: Ultra-small antennas point way to miniature brain implants
SCIENCE NEWS: Mini-antennas could power brain-computer interfaces, medical devices
<New Antenna Mechanism>
The antennas are designed by using COMSOL Multiphysics (Best Poster Award - COMSOL Conference 2017 Boston) based on the bulk acoustic wave (BAW) resonator to transfer the dynamic strain across the piezoelectric layer and magnetostrictive layer. Two proposed antennas nano-plate resonators (NPR) and thin-film bulk acoustic wave resonators (FBAR) have the same excitation but with different resonance modes providing a variety of frequency coverages. From the transmitting aspect, RF electric field will induce alternating strain wave/acoustic wave that can induce a dynamic change of the magnetization due to the converse ME coupling and generate magnetic current for radiation; Reciprocally, from the receiving aspect, the RF magnetic field component of the electromagnetic wave can be detected and induce an dynamic voltage/charge due to the direct ME coupling. The acoustic wave length is about 5 orders shorter than the electromagnetic wavelength at the same frequency. Therefore, since the ME antennas are operating at the acoustic resonant frequency instead of EM wave resonant frequency, the antennas can dramatically shrink into hundreds to thousands of times smaller.
All devices are fabricated with the same fabrication processes on one small chip which includes thousands of antennas. The frequency of the antenna is simply defined by the resonator geometry. This indicates that by simple device geometry design, we can achieve a very wide frequency band from tens of MHz to tens of GHz on only one chip. A bank of multi-frequency MEMS resonators can be connected to a CMOS oscillator circuit for the realization of reconfigurable ME antenna arrays.