Hi,

I am wondering if anyone has data for a directional gain antenna
(DGA). What I would need are the gains and the phase of the antenna as
a function of (phi,theta). I am working with a group that has such an
antenna, but I think that their work is not very good. I am not
looking for anything fancy or even that good in terms of performance:
I am doing some performance analysis using beamforming algorithms for
GPS signal acquisition, and I want to incorporate DGA into my analysis
and get some basic results as to how much the DGA improves
performance. (Of course, any work I do, I would cite the use of your
data).

You can reply either on the ng or to my e-mail address.

Thank you very much,

Matt Brenneman

junoexpress wrote:
Hi,

I am wondering if anyone has data for a directional gain antenna
(DGA). What I would need are the gains and the phase of the antenna as
a function of (phi,theta). I am working with a group that has such an
antenna, but I think that their work is not very good. I am not
looking for anything fancy or even that good in terms of performance:
I am doing some performance analysis using beamforming algorithms for
GPS signal acquisition, and I want to incorporate DGA into my analysis
and get some basic results as to how much the DGA improves
performance. (Of course, any work I do, I would cite the use of your
data).

You can reply either on the ng or to my e-mail address.

Thank you very much,

Matt Brenneman

depends on the specific directional antenna.
Are you looking for approximations?

On Apr 3, 1:55 pm, Jim Lux wrote:
junoexpress wrote:
Hi,

I am wondering if anyone has data for a directional gain antenna
(DGA). What I would need are the gains and the phase of the antenna as
a function of (phi,theta). I am working with a group that has such an
antenna, but I think that their work is not very good. I am not
looking for anything fancy or even that good in terms of performance:
I am doing some performance analysis using beamforming algorithms for
GPS signal acquisition, and I want to incorporate DGA into my analysis
and get some basic results as to how much the DGA improves
performance. (Of course, any work I do, I would cite the use of your
data).

You can reply either on the ng or to my e-mail address.

Thank you very much,

Matt Brenneman

depends on the specific directional antenna.
Are you looking for approximations?

Hi,

I would say that the specifics are not that important. The DGA we
worked with had a cylindrically symmetric gain pattern that resembled
a "skinny" cardiod. The gain at the zenith was about roughly 12 Bic,
which fell to roughly 1 Bic at about 60 degrees (where the angle
measured is not the elevation, but the spherical coord theta). In
fact, you just made me realize that I fit the theta dependence very
well via the equation
0.00002399q^3 - 0.0031083q^2 - 0.025008q+11.0153
and that the phase as a function of theta was very linear, and that
the phase as a function of phi was "about" constant.

Matt

"junoexpress" wrote in message
oups.com...

I would say that the specifics are not that important. The DGA we
worked with had a cylindrically symmetric gain pattern that resembled
a "skinny" cardiod. The gain at the zenith was about roughly 12 Bic,
which fell to roughly 1 Bic at about 60 degrees (where the angle
measured is not the elevation, but the spherical coord theta). In
fact, you just made me realize that I fit the theta dependence very
well via the equation
0.00002399q^3 - 0.0031083q^2 - 0.025008q+11.0153
and that the phase as a function of theta was very linear, and that
the phase as a function of phi was "about" constant.


What's a Bic?

High Matt,

For most antennas, the phase versus angle w.r.t. main lobe is not
given. The same is valid for the phase center. When they give it, you
should have a means to verify it.

As long as you make your array from same antennas, phase variation for
each antenna will be the same and will cancel. Of course this is not
true when you want to make time of arrival measurements for satellites
under different elevation angle.

Another thing that might be of importance is the polarization. This
also varies with antenna orientation.

If it really matters, I would suggest that you use a EM-field solver
to find the full radiation pattern (phase, magnitude and polarization)
for your antenna. If you consider patch like antennas, a NEC based
simulator is not the best choice, probably you have to divert to
expensive commercial packages. If money is available, you may hire
somebody. The learning curve can be lengthy to get trustful results
from simulation.

Technically spoken, it can be measured also, but you need a
combination of good measuring equipment and a person that is very well
into wave propagation. I'm not deep into GPS but is it possible to
calibrate the antennas with the GPS system?

Of course this does not answer your question, but I hope it will help
you a bit in finding an answer.

Wim
PA3DJS.