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, <b...@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<t...@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 > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.