Antenna with a special radiation pattern

[frankqt]

I am mainly a digital guy so sorry if this is really a stupid question.

Is it conceivable to build an antenna for a 60GHz system where the radiation pattern is a plane? In other words the waves will just propagate in XY axis but never in Z axis.

Thx

 

[ferdows]

radiation pattern is 3D and i didn't get u mean

 

[frankqt]

radiation pattern is 3D and i didn't get u mean

What I mean is that it radiation is moving only on two directions not in third. Think of it as an 60GHz 2D plane. It has some 3D component but waves are not moving that direction.

Think of it as an invisible plane. Antenna is designed such that the waves are expanding in X and Y dimensions but not in Z. It is not ominidirectional, probably called bidirectional.

 

[streamlet]

Recall the omni-directional radiation pattern of a dipole, which likes a donut, there is no radiation along the z axis (assuming that the dipole is oriented along the z axis). You can try to decrease its beamwidth using a dipole array. Then the donut seems to be compressed onto the xy plane.

 

[RF_Jim]

I am mainly a digital guy so sorry if this is really a stupid question.

Is it conceivable to build an antenna for a 60GHz system where the radiation pattern is a plane? In other words the waves will just propagate in XY axis but never in Z axis.

Thx

frankqt,

Not really ... the closest is stacked vertical, there is still some Z component that will be present, as _all_ beams (including light!) diverge.

For instance, the vertical beamwidth for four (4) stacked dipoles is approximately 30 deg, eight stacked dipoles approx 15 deg and so on ..

Jim

 

[frankqt]

I can understand this for 2.4GHz but is it still the same for 60GHz?

 

[enjunear]

I can understand this for 2.4GHz but is it still the same for 60GHz?

Yes, electromagnetic waves follows the same laws of physics at 2 MHz, 2.4 GHz and 60 GHz. Agree with streamlet on the dipole/dipole array being the simplest way to get radiation on the XY plane, and minimal propagation in Z.

Dipole radiation pattern

 

[ferdows]

we dont have 2D radiation and all radiation in 3D pattern and all of antenna has same rule
and pattern made by E*H which made 3D environment

 

[biff44]

Yes, all real world antennas have 3D radiation! But there are some antennas that have most of the energy confined to a small plane. At lower frequencies, a colinear dipole (one with many elements stacked along a rod) has very high gain toward the horizon. I suppose one could construct something siimilar to that with a circular waveguide standing vertically, with radiational slots cut in it at half wave lenghts with a load at the far end.

 

[jiripolivka]

Yes, all real world antennas have 3D radiation! But there are some antennas that have most of the energy confined to a small plane. At lower frequencies, a colinear dipole (one with many elements stacked along a rod) has very high gain toward the horizon. I suppose one could construct something siimilar to that with a circular waveguide standing vertically, with radiational slots cut in it at half wave lenghts with a load at the far end.

You are apparently in need of an omnidirectional antenna that radiates in the X-Y plane but not much in "Z" plane. At microwaves it is physically impossible to radiate the energy like it is done in optics, to create a narrow "line" in X-Y plane. Still, with light, there will be some light in the "Z" plane.

Omnidirectional antennas concentrate the radiated energy into a "disk" in the X-Y plane but the radiation in the "z" plane is squeezed into some 20-30 degrees. Try to look at "www.sage-mm.com" they have commercial omnis also for 60 GHz. I guess the cost is high. The typical radiation plane is similar to a vertically squeezed dipole pattern. In the desired X-Y plane, you can have a reasonable gain or directivity.

You can also make an interferometric stack of similar antennas; they will radiate a thinner main disk but more "weaker" disks above and below it.

 

[ferdows]

hi biff
i agree with jiripolivka its impossible and you don't have any energy in z plane