D band
There are two nomenclatures for frequency bands: that of the IEEE and that of Nato.
Since the Nato nomenclature uses alphabetically consecutive designations, the D band follows the C band with a frequency range of 1 GHz to 2 GHz and thus corresponds approximately to the L band in the IEEE nomenclature.
In the aforementioned frequency range, radio services are only slightly disturbed, so this frequency band is used for broadband radio services with a long range and for air reconnaissance radar systems. However, ranges are limited to line-of-sight links due to wave propagation.
In the IEEE nomenclature, the D-band occupies the frequency range between 110 GHz and 170 GHz and thus belongs to the millimeter waves. This frequency band is thus adjacent to the W band.