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Functions of an Antenna

An antenna is a device that acts as a transformer to provide a good match between the feeding line as a local source of power and free space. If the antenna is not matched to free space, power will be reflected back toward the transmitter, resulting in a loss in radiated power. The antenna is one of the most critical parts of the radar system. It performs the following essential functions:

The antenna structure must maintain the operating characteristics under all environmental conditions. Radomes are generally used where relatively severe environmental conditions are experienced.

The basic performance of radar can be shown to be proportional to the product of the antenna area or aperture and the mean transmitted power. Investment in the antenna, therefore, brings direct results in the system's performance.

Taking into account these functions and the required efficiency of the radar antenna, two arrangements are generally applied: