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Poor Results for CCANTENNA-DK Antennas on VNA?

Kevin Townsend
Prodigy 10 points


I was testing out the CCANTENNA-DK kit, and looking at some of the antennas on the VNA, but was surprised by the results.

Using the Open/Short/Load boards to calibrate the VNA first (an Agilent N9923A centered on 868MHz with a 100MHz span), the calibration seems good, but when I hook board #10 (Small Flexi Antenna) and board #3 (Mitsubishi Chip Antenna) up after calibration, the results are quite far away from 50 Ohms.

Should I be connecting the test cable after what I assume if the thick 50 ohm transmission line signal (i.e. around the Zxxx discretes)?

This is with the LOAD board attached (post cal):

This is with antenna 3 (868MHz) attached:

This is with antenna 10 attached:

  • 0
    TI__Mastermind 18780 points

    Hi,

    All antennas in the kit are tuned for connecting to an EM board on the EB platform. A matching network is used on each antenna design so the antenna boards can matched for other GND sizes than the EB board. Thus if connecting the antennas directly to the network analyzer, you will have a different GND plane and thus get odd results.