wiki/ news/ 2004-08-18 - VNA test of "v3" CPAs

Overview

Glenn and Andrew tested the v3 cylindrical patch antennas on the HP VNA in the PSU microwave lab. The v3 CPA's PCB's were made last week, and have 1/16" UHMW PE as a dielectric.

Conclusion

The GPS and ATV antennas are dead on. We're very happy with them. The wifi antenna is surprisingly and disapointingly low. It'll still work as a wifi antenna, but it's pretty close to a SWR of 2:1. Why is the wifi different? Is it the 8 feed network? Or?


WiFi Antenna (Design frequency = 2.412 GHz)

FILE00 = 2.362 TO 2.462 GHz CALIBRATION

Antenna was outside of these limits. Moved range from 2.2 to 2.5

SCRN00 = smith
SCRN01 = freq. resp., marker at 2.412 GHz
SCRN02 = freq. resp., marker at resonant

At design: 1.86:1
At resonance: F = 2.3372 GHz, SWR = 1.08:1, BW = 2.2748 GHz - 2.4282 GHz = 153.4 MHz

"knee" of swr curve is at 2.3941 GHz.

Futzing with antenna made absolutely no difference.
SCRN00.JPG
SCRN00 = Wifi angtenna smith chart

SCRN01.JPG
SCRN01 = Wifi antenna with marker on design frequency

SCRN02.JPG
SCRN02 = Wifi antenna with marker on resonant freq.


GPS (Design frequency = 1.57542 GHz)

FILE01 = 1.475 TO 1.575 GHz CALIBRATION

Closer than expected! Moved range from 1.550 to 1.600 GHz

SCRN03 = smith chart with marker at 1.5754 GHz
SCRN04 = freq. resp., marker at 1.57542 GHz
SCRN05 = freq. resp., marker at resonant

At design: SWR = 1.45:1
At resonance: F = 1.5665 GHz, SWR = 1.25:1, BW = 1.5434 GHz - 1.5885 GHz = 45.1 MHz

Futzing with antenna made no difference.
SCRN03.JPG
SCRN03 = GPS angtenna smith chart

SCRN04.JPG
SCRN04 = GPS antenna with marker on design frequency

SCRN05.JPG
SCRN05 = GPS antenna with marker on resonant freq.


ATV (Design frequency = 1.25325 GHz)

FILE02 = 1.2 TO 1.3 GHz CALIBRATION

SCRN06 = smith chart with marker at design freq.
SCRN07 = freq. resp., marker at design freq.
SCRN08 = freq. resp., marker at resonant

At design: SWR = 1.74:1
At resonance: F = 1.2488 GHz, SWR = 1.56:1, BW = 1.2412 GHz - 1.2571 GHz = 15.9 MHz
NO SMITH CHART AVAILABLE

SCRN06 = ATV angtenna smith chart

SCRN07.JPG
SCRN07 = ATV antenna with marker on design frequency

SCRN08.JPG
SCRN08 = ATV antenna with marker on resonant freq.


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