If you read the entire article, you’ll find a mention of an audience member pointing at a drone. Remarkably, the device/weapon was able to precisely bring that drone down without affecting any of the nearby drones. Clearly, they have something working for them. I can only imagine that it would be significantly more challenging than simply throwing a very wide EMP. Controlling an EMP is the seemingly impossible task, and they managed to succeed.
It is just a high-power microwave transmitter, made with gallium nitride field-effect transistors.
Like any microwave transmitter, it can use a directional antenna. If the antenna is big enough, it can have a narrow enough transmitted microwave beacon to intercept only a single drone.
The GaN FETs enable a higher transmitter power at whatever high frequency they are using. At lower frequencies, a 70-kW power was already easily achievable in the past. The higher frequency allows a precise aiming of the microwave beacon with an antenna of reasonable size.
I believe they're using a phased array grid of emitters to electronically steer the microwave, not just a normal directional antenna. This means the antenna doesn't need to physically move to change what is pointing at. (within some bounds)
