I'm wondering why if this continues happening the US consulates have not put in some kind of detection hardware?
Seems like an easy solution
The only situation where it wouldn't make sense to do this is if we already knew the cause, and it was something we had built.
Hard to detect "directed, pulsed radio frequency (RF) energy" when you have no idea what you're actually looking for. If you go looking at the bulk of the electromagnetic spectrum for correlators to a vague symptom list, you'll definitely find them but be no closer to explaining causality (or finding culprits).
Hard to believe, any source for this?
If you don't know where in the frequency band your signal is or what it's shaped like, then if you go hunting, you'll find something. Many things, in fact. You now have the task of taking all those correlations and making a causal story for them causing your sick patients' symptoms.
Depending on how wide the net is you're casting (in frequencies, time, locations of target, and possible attack signal patterns), this is SETI@Home stuff. And if we have no idea what we're looking for, we're going to have to cast a wide net.