Technology developed to disarm drones

ARM operates by emitting sonic, ultrasonic, and/or subsonic waves at a drone, thereby inducing vibrations and /or Prandtl layer instability that will lead to flight failure. Propeller blades are especially vulnerable to ARM’s power, either by causing turbulence or transmitting vibrations to the IMU. 

Fractal Antenna Systems’ CEO Nathan Cohen and a colleague invented ARM technology, backed by U.S. patents and pending patents licensed to FRACTAL. Cohen, an astrophysicist with 55 years of experience and 94 U.S. patents, was a professor in the Aerospace and Mechanical Engineering department at Boston University as well as being a subject matter expert in ultrasound and phased RF and acoustic arrays. 

Drawing on decades of multidisciplinary experience, Cohen foresaw the need, over a decade ago, for ARM, as quadcopter drones became both prevalent and a growing issue. 

“The propellor blades become a driven oscillator from ARM, and even isolating the MEMS at the IMU from these oscillations is impractical, especially in smaller drones. The result is flight disruption,” said Cohen.

FRACTAL specialises in RF jamming and antenna systems and has done so for over two decades. However, RF jamming is heavily restricted in the US, creating a legal gap defence from drones.

Cohen explained: “You can’t legally shoot a drone or zap it with microwaves outside military settings. Lasers are costly and affected by humidity. ARM offers an effective alternative for government and enterprise security.”

Therefore, FRACTAl created ARM’s acoustic arrays to target drones, particularly at ultrasonic frequencies - inaudible to humans but disruptive to drones.

“ARM has a patent priority of a decade, but ignoring that, foreign groups have claimed its creation and taken the technology successfully into the ‘prove out’ phase. We are, here in the US, beyond that stage; no surprise since we invented it,” said Cohen, emphasising that the U.S. patents pre-date these efforts and ARM patent licensing is unavailable to foreign firms for U.S. markets. 

“ARM is designed to disable drones. And drones only. This is not a system for crowd or animal control and we are not using inefficient, parametric arrays to achieve our spectrum,” added Cohen.

In the battlefield, ARM can be attached to an attack drone or aerial support to help shut down adversarial drone swarms. Dubbed DRONE BLASTR, the patent pending in situ approach, also licensed to FRACTAL, promises to be an important new method for drone-swarm kills. 

The expectation for ARM is for it to be an important tool in the battlefield for friendly forces. With rising concerns over drone use in illegal surveillance and drug smuggling, Cohen also sees ARM as a vital tool to keep drones out of restricted areas and borders.

“ARM is a major facet of FRACTAL’s journey into drone defense and counter defence. It is a perfect complement to the fractal-based antenna and metamaterial products we are rolling out in these markets in the coming weeks. Government, public safety agencies, and related enterprises should explore partnering with FRACTAL as ARM moves towards product stages,” he concluded.