As the number of wireless applications increases and with the continuous need for more speed and efficiency, the upgrading to the Long Term Evolution (LTE) technology is becoming the only choice for mobile operators to keep up with customer needs. LTE is a 4G wireless communications standard developed to provide up to 10 times the speed of 3G networks for mobile devices such as smart phones, tablets, notebooks and wireless hotspots. Therefore, operators around the world are making plans to enhance their networks by integrating LTE technology and many operators are already building out their networks and transforming them to take advantage of all the benefits of LTE. According to the global LTE deployment map, global 4G/LTE subscriptions will increase from 9 million in 2011 to over 560 million in 2016. One of the biggest challenges that operators face is ensuring their base stations can cost-effectively support a variety of frequencies. The time, cost and risk associated with antenna site evolution can negatively impact the operators because replacing or adding antennas to accommodate different technologies or frequencies delays time-to-market and also it is expensive. These challenges are of particular concern for operators moving to LTE, where allocated frequencies may be unknown or may change from the trial stage to the deployment stage. Thus, a new ultra wideband base station antenna will be a perfect solution that can help mobile operators to cover existing radio spectrum, while preparing for bandwidth growth and additional radio spectrum availability in the future. It will allow operators to deploy just one antenna rather than several antennas to cover all frequency bands and it is ideal for supporting additional licensed frequencies that are not currently available.
Conventional arrays of crossed dipoles, that are commonly used as base station antennas for mobile communications, have several problems in moving to LTE. Such arrays have limited frequency bandwidths which are not sufficient for recent expansions in wireless applications. Furthermore, they are heavy in weight and they suffer from high wind loads and, therefore, they need complicated heavy mounting systems. Moreover, they are high in cost and not easy to assemble and disassemble. Therefore, they are shipped and stored in their large-size assembled forms. The currently used base station antennas cannot be upgraded to any new generations of wireless applications if they have different frequency bands where the whole antenna has to be replaced or new antennas have to be added to the existing ones. Furthermore, different cell phone operators must have separate networks of base station antennas since they cannot share the same network of antennas (no co-sitting). As networks grow in size and complexity, more number of heavy weight base station antennas need to be installed. A good cell phone service in urban cities raises concerns that buildings are going to collapse under the overweight of base station antennas. One or more base stations are located on roof tops of the buildings leading to cracks beneath t, which represent a life threat for the residents of the buildings. On the other hand, maintaining and upgrading of cellular towers is considered as one of the most dangerous jobs causing several fall deaths. Thus, veteran climbers predict increase in falls with the build-out of 4G LTE. Base station antennas do not only add load to the towers due to their mass, but also in the form of additional dynamic loading caused by the wind.
In order to overcome all the above problems of conventional base station antennas, a novel foldable/deployable base station antenna with arbitrary beam widths has been developed. It consists of two parabolic cylindrical reflectors and a set of novel small size broadband resonant feeds. An unlimited number of such novels feeds operating at different frequency bands can be used with the same base station antenna. For the first time, the new base station antenna can simultaneously cover an unlimited number of wireless applications, regardless of their frequency bands. It can be easily upgraded to any new generation of wireless technology by replacing the feed instead of replacing the whole antenna which is the case with the current base station antennas. The new base station antenna can simultaneously cover all, current and future, wireless technology generations such as 2G, 3G, 4G (LTE), --- etc. All mobile operators can share the same network of base station antennas (co-sitting) by adding a separate feed for each operator. The new base station antennas can be automatically deployed/folded onsite and they require simple lightweight towers. The reflectors of the new antennas are easy to manufacture with a very high surface accuracy. They are gridded and, therefore, they are transparent and they have low wind-loads and low weights. With all these unique properties, each country can have only one low-cost lightweight network of base station antennas for all, current and future, generations of wireless applications and for all operators. | |