The earliest electromagnetic wave used for radar
exploration had a length of 23 cm, but this band was defined as the L band (English Long prefix), and the center wavelength of this band later became 22 cm. When using electromagnetic waves with a wavelength of 10 cm, the band is defined as the S-band (the English abbreviation prefix, meaning electromagnetic waves shorter than the original wavelength).
After the advent of fire-fighting radars that mainly use 3 cm electromagnetic waves, 3 cm wavelength electromagnetic waves are called the X band because X represents a point on the coordinates.
To combine the benefits of the X and S bands, radars with a central wavelength of 5 cm have gradually emerged, but this band is called the C band (C or Compromise, the English word for "combination"). ..
After the British, the Germans also started to develop their own radar and chose 1.5 cm as the center wavelength of the radar. Electromagnetic waves of this wavelength are called the K band (K = Kurz, the prefix for "short" in German).
"Unfortunately" the German-selected wavelength with Germanic "precision" is strongly absorbed by water vapor. As a result, radars in this band cannot be used in wet or foggy weather. To avoid this absorption peak, radars designed after the war usually use the Ka band (Ka is the abbreviation for K-above in English, meaning above the K band) and a little lower frequency (Ku, English). )Use the. Abbreviation for K-under. Means the band below the K band.
Lastly, this band is called the P band because the earliest radars used meter waves (P is an abbreviation for Previous, meaning "past" in English).