Which system operates in the highest frequency range?

The infrared system operates in the highest frequency range compared to the other options. Infrared radiation occupies the electromagnetic spectrum just beyond the visible light spectrum, generally ranging from about 300 GHz to 400 THz, which translates to wavelengths from about 1 mm to 750 nm. This range is significantly higher than that of microwave systems, which operate in the range of about 300 MHz to 300 GHz, and radio systems, which typically operate in lower frequency bands from around 3 kHz to 300 GHz.

Satellite systems, while they may utilize frequencies that overlap with microwaves and even infrared (especially in the case of certain satellite communications), primarily function within the microwave range. Thus, although satellite systems utilize a variety of frequencies, they do not reach the high frequencies that characterize infrared systems.

Understanding these frequency ranges is crucial in wireless communication to ensure the correct technology is employed for a given application, as different applications benefit from different frequency properties, such as penetration, range, and bandwidth availability.