That's an article about a mobile Russian radar unit. This drone appears to be a stealth drone, so it's less likely that radar would have been the key to downing it.
Cyber attacks, stealth-penetrating radar, etc. seem unlikely.
Until there are real facts, maybe Occam's razor is the best course. The simpler explanation is that the drone just malfunctioned.
I doubt they would disclose how exactly they did it, but Iran receiving an electronic warfare equipment not 6 weeks ago and then this drone miraculously falling into their hands undamaged - it is reasonable to assume there is correlation. Or perhaps they shot it down, made a replica and tried convincing the US that they could land their drones at will. However, I think it is highly unlikely that the drone just "malfunctioned", and in a way that allowed it to be captured in perfect condition.
You might want to look up an incident in Serbia where the stealth jet was in fact downed that way (a bit more complicated that just a radar, but it was still tracked along the sky from the ground through electronic means).
Zoltan [the Serbian battery commander, whose missiles downed an American F-16, and, most impressively, an F-117] used the human spotters and brief use of radar, with short range shots at American bombers. The SA-3 was guided from the ground, so you had to use surprise to get an accurate shot in before the target used jamming and evasive maneuvers to make the missile miss. The F-117 he shot down was only 13 kilometers away.
Zoltan got some help from his enemies. The NATO commanders often sent their bombers in along the same routes, and didn't make a big effort to find out if hotshots like Zoltan were down there, and do something about it. Never underestimate your enemy.
