Flat Panel Antennas

A new generation?

Flat panel antennas utilising phased array technology are used for military, naval and commercial aviation radar, and latterly for applications including satellite television. Developments are in hand to make flat panel antennas a more viable option in the maritime marketplace and several technology types are in the running, with ‘phased array’ currently the most viable.

Phased array refers to a group of computer-scanned-and-controlled antennas which can produce a steerable beam of radio waves, even though the antennas remain stationary. In a Passive Electronically Scanned Array (PESA), the antenna elements connect to a single transmitter/receiver, whereas an Electronically Scanned Array (AESA) has a separate transmitter/receiver unit for each antenna element.

Phased array antennas can keep track of multiple satellites, which with today’s networks featuring just a few geostationary (GEO) satellites is not especially interesting for maritime users as parabolic antennas are established as the best performing. However, with several new Low Earth Orbit (LEO) constellations in development, featuring hundreds of cross-linked satellites orbiting the planet, flat panel phased array technology could become more relevant.

Another type of flat panel antenna is made using ‘meta-materials’. Though not so far into development as phased array solutions, these antenna feature passive, tunable elements, which scatter radio frequency energy when the elements are activated to generate a holographic beam, which has potential to improve electronic beam steering. A third technology will use ‘optical beam forming’ and combines both active and passive elements.

Flat panel antennas - Pros and cons

Pros:

  • In the context of the shipping industry, flat panel antennas could be smaller and more discreet than the large radomes generally used on bigger vessels for broadband satellite communication.
  • Flat panel phased array antennas track satellites electronically while the units themselves are stationary, so there are no moving parts to wear out and potentially fail.

Cons:

  • In a maritime setting, it can be trickier for flat panel antennas to maintain a strong link to the satellite because the pitching and rolling of vessels can intermittently result in the antenna not being completely perpendicular to the satellite.
  • Due to the above issue multiple antennas may be needed, which may become more expensive than installing a parabolic antenna. Alternatively, a mechanical steering system could be implemented, making the antennas much larger and essentially, not flat.