S band is a frequency range from approximately 2 to 4 GHz.

S band is used for Digital Audio Radio Satellite (DARS) satellite radio systems such as Sirius XM Satellite Radio.  Sirius XM uses frequencies between 2,320.00 and 2,332.50 MHz, and also between 2,332.50 and 2,345.00 MHz.

S band is also used by many weather, communications, and intelligence satellites.  Most of these satellites transmit using CW, usually with sidebands.  PSK with a sub-carrier is a less popular option.

A portion of the S band from 2.4 to 2.4835 Ghz is used by 802.11b/g/n wireless network devices and some cordless telephones.

Bluetooth operates on a portion of the S band from 2.402 GHz to 2.480 GHz.

The S band will also be used for Mobile Satellite Service. The FCC has approved frequencies from 2.0 to 2.2 Ghz for use in MSS and the European Commission has approved frequences from 1.98 to 2.01 GHz and from 2.17 to 2.2 GHz for MSS.

Many WiMAX implementations utilize a portion of S band spectrum, although the ranges differ widely between countries.