Radiofrequency energy includes radio waves and microwaves. RF stands for radio frequency, and its radiation is a "nonionizing electromagnetic energy characterized by relatively long wavelength, low frequency, and low photon energy," according to the division of Environment, Health and Safety at Berkeley Lab. The statement goes on to say "...this weapon is designed to bathe a target's living quarters in microwaves." The committee did not address whether the cause was intentional, who might have been responsible or what the motive might have been. Microwave radiation is considered a subset of RF radiation.
The thing could have been field testing.
( z0 possible :ARG1 ( z1 test :ARG1 ( z2 thing ) :mod ( z3 field ) ) )
(z0 / possible-01
    :ARG1 (z1 / test-01
              :ARG1 (z2 / thing)
              :mod (z3 / field)))
The thing could have been field testing .
z1 :mod z3
z0 :ARG1 z1
z1 :ARG1 z2