Sure, that seems that a reasonable approach.
It's nice because it accounts for the effects of the PC board without
having to use expensive test equipment.
Assuming the tuning of the balun isn't too critical, it might work.
If the balun tuning is critical then it won't be optimum, but give it a
try! You might get lucky, and it might be sufficient for your
particular application.
Not sure what you're describing when you write about the "angular
reflector"(these sorts of things can be difficult without a picture!).
I've never seen the particular unit you're working with.
Basically, regardless of what you use to feed a parabolic reflector, you
want the feed to sit at the focus of the parabola. It turns out that
dipoles, or even Yagi antennas, are very cost effective ways of feeding
parabolic reflectors. I've seen them used as high as 5.8 GHz.
Best Regards,
Greg DesBrisay
On Fri, 2003-01-17 at 10:38, Milla Yegurku wrote:
> ok MMDS is 2.5-2.69GHz, can we assume that the dipole
> is tuned to (2.5+2.69)/2=>2.595GHz, and (some one
> suggested to me) -do 50*2.595/2.450=>53mm?
> there is a angular reflector at the nose -is it
> related to the wavelength/phase/dish_f/D -shall i live
> it alone.
> i dream of making two of these antennas as a passive
> reflector.
> there is an awful amount to read about horn and other
> feeds for dish ant. but not much around dipole feeds.
>
> thank you indeed
> mila
>
>
> --- Greg DesBrisay <[EMAIL PROTECTED]> wrote:
> >
> > The MMDS band is 2.5-2.69 GHz.
> > If the antenna is a dipole, then it's dimension will
> > be half a
> > wavelength (ignoring effects from the PC board). So
> > the wavelength your
> > antenna is designed for is roughly 300 MHz/(.05m *
> > 2) = 3GHz (ignoring
> > effects from the PC board). That's close to
> > 2.5-2.69 GHz.
> > That said, I doubt that the antenna would be
> > effective in the 2.4-GHz
> > ISM band without some tweaking. If the antenna is a
> > plain dipole, then
> > you might be able to solder some extra wire onto the
> > ends of the dipole
> > to lower it's resonant frequency to the ISM band,
> > but that really would
> > require the use of a network analyzer to tell you
> > when you've added the
> > proper amount of wire!
> >
> > Regards,
> >
> > Greg DesBrisay
> > [EMAIL PROTECTED]
> >
> >
> >
> > On Wed, 2003-01-15 at 18:08, Milla Yegurku wrote:
> > > Hi
> > >
> > > I cut open the plastic cover off of a "Gardiner
> > MMDs
> > > downconverter". The ballon/diapole is traced on a
> > > printed circuit board. I measured the diapole end
> > to
> > > end. It is 50mm (+-.5mm) -now that diapole tunes
> > to
> > > 6Gh? Could not use it for 802.11? any remarks?
> > > i thought i would solder a piece of copper to each
> > end
> > > of diapole, so the total length will be 62mm, and
> > > leave the ballon alone??
> > >
> > > Mila
>
>
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