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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