[time-nuts] Smaller, and smaller antennas

[Bruce Griffiths]

2.4/0.1 = 24 not 240 !!!

Bruce
> On 06 March 2019 at 17:36 jimlux <jimlux at earthlink.net> wrote:
> 
> 
> On 3/5/19 3:05 PM, Charles Steinmetz wrote:
> > Ho, hum, yet another fantastical claim for magical gain from a 
> > tiny-for-wavelength antenna.
> > 
> > See the many discussions of same by Kurt N. Sterba over the last several 
> > decades, among many, many others.
> > 
> > The laws of physics are stubborn things....
> 
> 
> these don't violate the theoretical limits.. 100 MHz BW at 2.4 GHz is 
> pretty high Q (240).
> 
> What I'm interested in is the internal construction -  lambda at 2.4 GHz 
> is 122 mm, and these things are 3x3x4mm.  If you tried to dielectrically 
> load a half wavelength from 61 down to 3mm, that's a factor of 20, which 
> implies an epsilon of 400.  Clearly, that's not what they're doing.
> 
> I'm a bit suspicious about that long feedline in the test fixture.
> 
> 
> Johansen has lots of these in various frequencies and sizes
> https://www.johansontechnology.com/antennas
> 
> Tons of WiFi (2.45 GHz) antennas in all sizes and shapes.
> 
> GPS/GLONASS antennas too
> https://www.johansontechnology.com/datasheets/1575AT54A0010/1575AT54A0010.pdf
> 12x4mm
> 
> 
> 
> 
> > 
> > Best regards,
> > 
> > Charles
> > 
> > 
> > On 3/5/2019 1:48 PM, jimlux wrote:
> >> On 3/5/19 9:33 AM, Gregory Beat via time-nuts wrote:
> >>> No, this is not an “L-band”, GNSS antenna ... BUT it demonstrates the
> >>> shrinking size.
> >>>
> >>> NEW Molex 206513 Antenna for 2.4 GHz, 3x3x4 mm in size.
> >>> Less than $1.00 for quantity 1, both Mouser and Digi-Key now stocking.
> >>> https://www.digikey.com/en/product-highlight/m/molex/2-4-ghz-ceramic-antenna 
> >>>
> >>>
> >>>
> >>> Molex’s 206513 series is a 2.4 GHz embedded ceramic antenna with high
> >>> efficiency over 55% on all frequency bands. This miniature SMT ceramic
> >>> component requires a very small (4 mm x 4 mm) keep-out area and is
> >>> designed to be mounted directly at the corner of the main device PCB.
> >>> It has a frequency range of 2.4 GHz - 2.5 GHz, return loss of <-6 dB,
> >>> and peak gain (max) 3.6 dBi. It features an omnidirectional radiation
> >>> pattern.
> >>>
> >>
> >> One needs to carefully look at the 55% claim with these kinds of things.
> >>   Are they including that in the gain, 50% efficiency is a gain hit of
> >> 3dB? Peak gain of 3.6dBi (is that circular or linear?) (is that
> >> directivity, or gain?). Does the efficiency count the 25% of the power
> >> reflected back from the 6dB return loss?
> >>
> >> https://www.molex.com/pdm_docs/ps/2065130001-PS.pdf is more about 
> >> packaging
> >>
> >> https://www.molex.com/pdm_docs/as/2065130001-AS.pdf has the antenna
> >> patterns..
> >>
> >>
> >>
> >> Also, what's the axial ratio off boresight...
> >>
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