1
\$\begingroup\$

I want to make a pcb rf trace to use it as an antenna, for a bluetooth IC. I have already studied the basics of impedance matching and antenna tuning, smith chart and antenna clearance. The specific project is on my github, if anyone is interested: https://github.com/Basilisvirus/QFN48-nRF52811-Bluetooth-5.1-KiCad-and-Altium-Designer ,where i have a folder 'Antenna Design' with whatever i have studied.

My question is,

a) while i am tuning the antenna do i need to have the IC connected to the antenna?

b) while i do the impedance matching, do i need to have the IC connected to the antenna?

I will use a Vector Network Analyzer for tuning. I have a miniVNA Tiny available from a friend for that.

My guess is, probably not, but i wonder since my antenna has a ground connection [see image 2]. But i want to be sure, since the ICs i bought and the pcb printing are expensive for me, and i want to make it right on the first attempt.

I am right now building a pcb antenna without the chip footprint, image below:

Pcb antenna i am building

GND connection of the antenna [design found in github/antenna design folder]: Ground connection of the antenna

Thank you.

\$\endgroup\$
3
  • \$\begingroup\$ You didn't mention how would you tune the antenna. \$\endgroup\$
    – Marko Buršič
    Commented Jul 21, 2019 at 9:37
  • \$\begingroup\$ Thout it was for granted. Using a Vector Network Analyzer. I have a miniVNA Tiny available from a friend for that. I will add it to the question. \$\endgroup\$
    – Basilisvirus Instrector
    Commented Jul 21, 2019 at 10:16
  • \$\begingroup\$ Quite expensive toy. I would rather use a ADALM-PLUTO SDR with a directional coupler for half the price, made by Analog Devices. \$\endgroup\$
    – Marko Buršič
    Commented Jul 21, 2019 at 15:42

1 Answer 1

Reset to default
2
\$\begingroup\$

The short answer no - we are trying to match the output impedance from the chip to the antenna for maximum power transfer (usually 50 ohms)

As you seem to be a beginner, I strongly recommend you to read this short guide, it's awesome. http://colinkarpfinger.com/blog/2010/the-dropouts-guide-to-antenna-design/

I've matched antennas with this guy and just an SMA connector :) https://signalhound.com/

Remember when you are performing your match, to encapsulate the antenna in its intended environment, and watch out for any metal from e.g. tables .. near/below the PCB

\$\endgroup\$
1
  • \$\begingroup\$ Thanks, I remember starting from this guide, i will check it again, with my current knowledge, hope i got something more out of it. I remember you did not included the units [cm, inches] used to measure distances on this guide, i had trouble figuring that out back then. \$\endgroup\$
    – Basilisvirus Instrector
    Commented Jul 21, 2019 at 10:11

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.