Antenna options

Digi devices come in a variety of antenna options. The options that allow you to connect an external antenna are reverse polarity standard subminiature assembly (RPSMA) and U.FL. Typically, you make connections with either a dipole antenna with a U.FL connection, or a U.FL to RPSMA antenna adapter cable.

RPSMA is the more traditional antenna connector, however, if the device is going to be inside of an enclosure, you would need to locate the device near the edge of the enclosure to allow the connector to pass through an available bulkhead. The RPSMA connector uses the same body as a regular SMA connector, but changes the gender of the center conductor. The female RPSMA actually has a male center conductor. We equip the XBee devices with an RPSMA female plug, while the antenna is an RPSMA male jack.

The U.FL connection allows for connectivity to an external antenna. U.FL is a small antenna connection for use with a pigtail connector. A pigtail is a short (typically 4 - 6 in) cable that either terminates into an external antenna port such as an RPSMA, N or TNC connection or an antenna. You would attach the RPSMA connector to a bulkhead. These options allow you to mount the device away from the edge of the enclosure in your product and centrally locate the radio. U.FL is fragile and is not designed for multiple insertions without a specialized tool to separate the pigtail without damaging the connector; for more information, see http://www.digikey.com/product-detail/en/U.FL-LP(V)-N-2/HR5017-ND/513034.

The other available antenna options are printed circuit board (PCB) and wire antennas. We form the PCB antenna directly on the device with conductive traces. A PCB antenna performs about the same as a wire antenna.

An integrated wire antenna consists of a small wire (about 80 mm) sticking up perpendicular to the PCB. It uses a 1/4-wave wire that we solder directly to the PCB of the OEM device.

All Digi devices with antenna connectors have less than 0.1 dB loss; we do not consider one to be "better" than the other in terms of reliability or insertion loss. RF device specifications such as -110 dBm receiver sensitivity, +3 0 dBm TX power, and so forth, already include any insertion loss due to the soldered RF connector.