Monday, 15 April 2013

Omni antenna options for 4G and 3G/GSM frequencies

For 4G and 3G/GSM access, external antennas can be used to improve signal strength and improve stability/quality of the network connection. Directional antennas typically offer higher gain than omni-directional (omni) antennas, but they have to pointed directly at the local network mast which may be inconvenient for temporary or mobile applications. Omni antennas will offer less gain, but should radiate equally in each direction, making them more flexible for applications such as mobile broadcast or boating as well as security or CCTV applications where the omni antenna may be able to communicate with multiple network masts thereby introducing an element of network redundancy i.e. if one local mast fails, the antenna communicates with another.

There are a number of options when considering omni antennas for 4G, 3G and GSM applications. Here are a selection of omni antennas to think about:

High Gain Multiband Omni - Offering approx. 5 dBi gain across the bands, the high gain omni is especially useful for deployment in weaker signal areas or when the antenna will be located quite some distance from the router/modem and a long low loss cable run is required. Typically, available as wall or pole mount, the high gain omni is mounted outdoors with jumper cable connecting to the router/modem. This antenna should support all bands where possible i.e. 800 MHz, 1800 MHz and 2600 MHz for 4G and 900, 1800 and 2100 Mhz for GSM and 3G connectivity. The FGO antenna from EAD is a good example of a outdoor high gain omni with a robust design and good performance figures. It can be purchased here.

Access Multiband Omni - Where a cost-effective access solution is required, an omni for access can be used where the signal at the antenna is good, but at the router is poor and the cable distances are not too long. Typical examples, a temporary site offices (effectively a metal box!) and basements where the network signal cannot penetrate, but just outside the network is good.  In these cases, a omni antenna with a gain of approx. 2 dBi and a cable run of up to 5M is more than adequate. Multiband support is also advantageous to offer 4G with fall-back to 3G/GSM. This antenna can also be pole or wall-mounted. A good example of that is the OC69721 from Laird which can be purchased as part of a bundle from Connex.

Low Profile High Gain Omni - Another option is to consider a low profile high gain omni antenna which can be used when something more discrete is required. Antennas such as the LTE-HIGAIN-MAG based on the Multiband Phantom antenna from Laird or the BMLPVDB/LTE from PCTEL (contact SAS for more details). The LTE-HIGAIN can be magnetic or permanent mounted, but must be mounted onto a metal surface (or groudnplane) for optimal operation. However these types of antennas can offer execeptional performance in a low-profile package and can be very useful for mobile or height-restricted applications - some examples include library vans, narrowboards and utility cabinets.

Window-Mount Omni - Designed for mobile applications, window-mount antennas can offer a flexible, non-permanent external antenna solution for 4G/3G applications, especially if external/outdoor antennas are not practical or cannot be used in the application. Antennas such as the WA_700/2700 are MIMO ready meaning that they can connect to 2 antenna ports on your 4G router if available otherwise one cable can be connected to a single router antenna connector. The WA_700/2700 datasheet can be downloaded from SAS here. Typical applications for this type of antenna include narrowboats, caravans, vehicles and site offices.

For more information on omni antennas for 4G, LTE, 3G and GSM, please feel free to contact us.