Which military band corresponds to a sensor operating at 3.5 x 10^8 Hz?

The correct answer is the B-Band, which corresponds to a frequency range of 1.0 to 2.0 GHz (or 10^9 to 2 x 10^9 Hz). The frequency mentioned in the question is 3.5 x 10^8 Hz, which is equivalent to 350 MHz (or 0.35 GHz). This places the frequency in a different category entirely, as this value falls within the UHF (Ultra High Frequency) range but is not characteristic of any of the specified bands in the context given.

While the B-Band includes frequencies from 1 to 2 GHz, the frequency in the question, being lower at 350 MHz, does not match to it. Typically, 350 MHz is designated to be in the C-band, which spans from 4.0 to 8.0 GHz, aligning better with lower frequency operations.

It’s clear that while the designated bands have their own specific frequency ranges, the band corresponding to lower frequencies around 350 MHz would not match the operational characteristics of the B-band but rather places a focus on frequencies more accurately identified within the A-Band or specific sub-bands unless detailed differently for specialized applications.