[time-nuts] pin-wheel antenna

[Mark Kahrs]

I'm surprised no one has mentioned the patent of interest:

http://www.freepatentsonline.com/7250916.html

An antenna is provided for acquiring RF signals from various satellite
ranging systems including GPS, GLONASS, GALILEO and OmniSTAR®. The antenna
configuration includes a radiating structure of multi-arm spiral slots
terminated with fractal loops. A leaky wave microstrip spiral feed network
is used to excite the radiating structure of the antenna. The fixed beam
phased array of aperture coupled slots is optimized to receive a right hand
polarized signal. The proposed antenna is made out of a single PCB board.
The antenna has a very uniform phase and amplitude pattern in the azimuth
plane from 1.15 to 1.65 GHz, therefore providing consistent performance at
GPS, GLONASS, GALILEO and OmniSTAR® frequencies. The antenna also has a
common phase center at the various frequencies from 1175 MHz to 1610 MHz
and substantially the same radiation pattern and axial ratio
characteristics.



On Mon, Apr 22, 2013 at 10:57 AM, <bg at lysator.liu.se> wrote:

> > Hi Dave,
> >
> > On 04/21/2013 10:32 AM, David Kirkby wrote:
> >> On 20 April 2013 20:52, Tom Van Baak<tvb at leapsecond.com>  wrote:
> >>
> >>> For the rest of you:
> >>>
> >>> http://www.leapsecond.com/images/gps-pinwheel-1.jpg
> >>> http://www.leapsecond.com/images/gps-pinwheel-2.jpg
> >>>
> >>> It's a thing of mysterious beauty. And the GPS World photo saves me
> >>> from the temptation to break open my own pinwheel antenna just to see
> >>> what's hidden inside.
> >>>
> >>> /tvb
> >>
> >> Does the antenna work better than other types?
> >
> > You should get close to choke-ring antenna performance at a much smaller
> > size. For many purposes its good enough.
>
> Note that the traditional JPL type choke-ring is beeing replaced by more
> advanced designs in the money-is-no-problem market.
>
> http://www.topconpositioning.com/sites/default/files/PN-A5_white_paper.pdf
>
> http://www.novatel.com/assets/Documents/Papers/3D_choke_ring.pdf
>
> --
>
>     Björn
>
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