FAQ

Frequently Asked Questions

Yes. Plasma Antennas’ is able to customize our antenna designs to allow them to be tightly integrated directly with our customer’s radios. This integration can provide a number of advantages, including the elimination of cable losses and a reduction connector costs.

Plasma Antennas’ selectable multi-beam antennas provide electronically-steerable beamforming by selecting and forming one or more beams from a set of beam patterns. Please follow this link for an introduction to selectable multi-beam antennas. Because the set of beam positions are fixed for any particular design, the lowest gain apparent at any point in the Azimuth coverage pattern is determined by gain at the positions where two adjacent beams “cross over”. At Plasma Antennas’ we refer to this as the “Cross over gain”. The level of cross over gain relative to the gain at the peak of the beam is determined by a number of factors including the beam width, field of view and number of beams.

Follow this link to find out more about the Key Product Options available for the products in our portfolio and which are best suited to your application.

Plasma Antennas’ selectable multi-beam antennas are available in single polar, cross polar and dual slant designs to provide system designers with maximum flexibility and choice. For many applications, simple vertical polarization provides the best solution. Our dual slant designs allow beams for each polarization can be controlled independently. This offers the option of an additional communication channel (effectively doubling the throughput) or provides two very well de-correlated channels for 2xN MIMO operation.

Selectable deep nulling allows selection of derivative beam patterns that contain deep nulls at various positions adjacent to a main directional beam. These deep nulls enable suppression of particularly powerful or close-in sources of interference. Using a similar approach and interface to that used for beam selection, the controlling radio can select the null settings that provide optimal carrier-to-interference-plus-noise-ratios (CINR).

Yes. Many of Plasma Antennas’ selectable multi-beam antennas designs also incorporate omnidirectional or sectoral “floodlight” modes in cylindrical and planar designs respectively. An omnidirectional mode provide approximately even power distribution acrross 360° in azimuth. A “floodlight” mode provides a beam with an approximately even power distribution across an entire sector. These modes support both transmit and receive operation.

The gain provided in an omnidirectional or floodlight mode will be lower that the gain in “directional” mode. In addition, in omnidirectional or floodlight mode, signals will be received from the entire sector with approximately the same level of gain – including interference. In directional mode, there will be rejection of signals outside of the narrow main beam due to the low sidelobes and selectable nulling (if used).

Most of our customers use omnidirectional or floodlight modes for broadcast, node discovery and registration scenarios – which are typically performed at lower data rates. High data rate communication is carried out in directional mode, taking advantage of the higher gain and improved link budget available.

Yes. There are a number of possible approached to using MIMO processing with Plasma Antennas’ selectable multi-beam antennas. Multiple antennas (or apertures) can be used at each end of the link. Independent beam control can be used to exploit multipath effects and enhance de-correlation between the signals received by each aperture. In addition, Plasma Antennas’ selectable multi-beam antennas are available in designs incorporating dual slant polarization, providing excellent levels of cross-polar discrimination. Each polarization provides a separate channel for MIMO processing. The dual slant approach has the advantage of very good de-correlation between the channels but with both channels being sent and received from a single aperture.

The optimal beam is typically selected by another part of the overall system to which the antenna is connected – generally the radio. A particular beam is selected by sending a beam selection data word to the antenna via a straightforward serial (SPI), parallel or network interface. Typically, the controlling system maintains a look-up table to associate beam numbers and positions with a set of target network nodes. Various algorithms are used to populate this table based on, for example, signal strengths and carrier-to-interference-plus-noise-ratios (CINR). Depending on the network scenario, this table may need to be updated dynamically to reflect mobility or changes in interference patterns.