0 votes
asked by
How do you measure the impedance of your antenna on a small PCB with a small ground plane?
When connecting a VNA to the PCB with a coax "pigtail", the outer ground of the coax affects the ground plane and changes the measured impedance of the antenna. What type of test setup do you use to reduce this effect?

Max Hendrickson

Please log in or register to answer this question.

3 Answers

0 votes
answered by

I will use  smallest possible  cable   and positioned  outside of the  PCB area. In possible scenario will connect SMA/ small RF  connector directly connect  to the PCB antenna trace after tuning circuit . Need to plan during PCB design to the extend possible

0 votes
answered by
When tune an antennas there should always cut out measuring systems GND. A cable ferrite bead is one easy way.
0 votes
answered by
We use special pigtail cables with U.FL connector and Balun in the cable. This will avoid current in the shielding of the cables. If you drop me an email then we will maybe sell a pair to you. harald.naumann (at)
commented ago by
Hi Harald, I have to tune the antennas for both 868MHz and 2.4GHz. What is the frequency range that your special cable works (maybe it depends of balun,right?)? Can you show to me the special pigtail cable? It is possible to tune the antenna with a special calibration of the plane of the measure. Maybe in this way you can take into account the effect of the system GND. Thank you.

Meet the moderators

Geoff Schulteis

Senior Antenna Apps Specialist at Antenova Geoff is an antenna design-in and OTA measurement specialist. His knowledge of FCC and world carrier requirements is second-to-none.

Dan Dobransky

Senior Antenna Apps Specialist at Antenova Dan is an antenna integration specialist. With years of design-in experience, he helps Antenova's customers wireless designs thrive.


Antennas: The Comparison Guide

Find the perfect antenna for your project