The CSA-218-A is a compact, cavity-backed spiral antenna designed to transmit and receive in the frequency band of 2.0 GHz to 18.0 GHz. The antenna exhibits an excellent impedance match and radiation pattern. It is available in either right hand circular polarization (CSA-218-AR) or left hand circular polarization (CSA-218-AL). It is capable of receiving both linearly polarized signals and a circularly polarized signal. The linear gain (dBil) is about 3 dB lower than the circular gain (dBic). These advantages render the antenna a very good candidate for electronic-warfare, direction-finding, telemetry and surveillance systems, as well as flush-mounted airborne applications. The antenna can be used as a broadband feed for reflector antennas. The RF output of the antenna is a type SMA female connector, located at the bottom of the antenna. The antenna is rated for 1 Watt of input power.