enter image description hereReferring to the above picture, can an antenna array mounted on Node A direct beams towards Node B and Node E, without the need for an antenna rotator (or manually orienting the antenna array towards the respective nodes)? In other words, can the antenna array orient its beam along the vertical direction (along the line joining Node B and Node E)?

The motive for this question is related to the upcoming IEEE 802.11ad standard. By operating at 60 GHz, users communicate with one another through directional beams pointing at each other. Without the use of mechanical rotators for the antennas, how could these users possibly orient their beams in a changing/moving environment?

  • this is impossible to answer without knowing what specific array we're talking about. As you can imagine, the geometry of the array defines the geometry of possible directions. If you're dealing with 60 GHz waves, I'm pretty confident you should first gather basic understanding of aperture antennas and inherently on antenna arrays. – Marcus Müller May 14 at 18:21
  • 1
    Agreed. One thing missing from the diagram is the effects of phase-delay in feeds to secondary towers. It would require new charts for various combinations of added inductance and capacitance. Always remember ELI the ICE man. In an inductive (L) reactance adjusted in, E comes before I. In capacitive (C) circuits then I leads E. So the goal is to adjust to balance out total feed reactance (Z) at the same time you alter relative phase of feed to the next tower in the array. In other words, to give a definitive answer requires knowing more than just the relative locations of towers. – SDsolar May 15 at 8:40
  • One good place to start is a comparison of feedlines to secondary towers as related to the wavelength being transmitted. Some phase change will happen in the feedline if it is not cut correctly. And here is a hint: In a directional AM station array, FCC inspections only are concerned about the readings at the operator position. So your instruments can be showing perfect adjustment but if the feedlne is wrong it will not be properly directional. That is why the FCC designates monitoring points for a single-point field-strength measurement in their inspections. – SDsolar May 15 at 8:45
up vote 2 down vote accepted

A practical approach for steerable patterns at these frequecies is to use electronically steerable arrays. These can take on various forms but a simple example consists of 2 or 4 vertical elements that are phased to steer the major lobe in the desired direction.

On the other hand, a dish or high gain yagi on 60 GHz has a very small footprint. This could be placed inside a radome and turned with a simple servo motor arrangement. Since the entire antenna is protected from the elements, no special considerations for a motor enclosure is warranted.

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