![]() ![]() This achieves a stronger reception than can be achieved with one antenna alone. The receiver will take the strongest signal from one or the other of the antennas. The polarisation of an antenna is parallel to the long axis of the antenna, and the antenna radiates its energy in perpendicular to this axis, with zones of null power at each end of the antenna.įor the best cross correlation, the pair of diversity antennas should be placed at cross polarisation, different polarisation in space and in polarity. When the antennas are used in a diversity configuration, they are placed to reduce coupling – i.e., the two antennas are placed so that their radiation patterns are completely different to each other. The pair of antennas can be placed on the opposite corners or opposite sides of the PCB. The receiver will then take the stronger of the two signals, which will improve the reliability of the signal received. In a diversity configuration, both antennas transmit simultaneously, but pointing in different directions. The two antennas can share the same ground plane, and they are placed in different spatial zones, this reduces “coupling” – a phenomenon where the two antennas reflect similar signals. With diversity, the first antenna is the main antenna and the second antenna is the diversity antenna. It is a great solution for mobile wireless devices that are moving around in free space, as the two antennas working together in tandem are more likely to provide a reliable link as the device is moves around. (Source: Antenova)ĭiversity is an antenna technique where two antennas are used together on the same frequency to create a more reliable wireless connection. Antenna pattern for the same LTE antenna at 1990 MHz, cross section. 3D antenna pattern for an LTE antenna at 1990 MHz. ![]() The radiation pattern for an antenna is normally measured in the centre of the frequency band where the antenna is to be used.įigure 1. The antenna will radiate around an axis that runs along the length of the antenna, and the electrical energy from the antenna is reflected most strongly in a direction that is perpendicular to that axis. Radiation patterns are usually shown as a 3D pattern and as a two-dimensional cross section of that pattern. The designer’s goal is to place the antennas in a way that achieves isolation between all of the antennas and allows them all to operate correctly together.Įvery antenna has its own radiation pattern, which will be shown on the manufacturer’s datasheet, as the antenna would radiate in perfect conditions, for example in an anechoic chamber. With good design, you can achieve high performance and reliability for all of the antennas on the board. ![]()
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