Plastic enclosure over reference design

RE: Plastic enclosure over reference design

Asbjørn — Thu, 12 Mar 2015 17:13:04 GMT

Great answers by Locky here! In addition I would like to point you towards two white papers we have. One for tuning the matching network and one for tuning the antenna.

Since you are thinking of using an intergrated balun, the first might not be relevant, but perhaps it would hive you some more insight to what the tuning is. Good luck on your project.

RE: Plastic enclosure over reference design

Victor Nascimento — Thu, 05 Mar 2015 22:01:53 GMT

Really thanks for your time and effort =)

RE: Plastic enclosure over reference design

Locky — Thu, 05 Mar 2015 20:36:01 GMT

Its more than a just in-case. In 99% of the time, you will need the matching circuit to optimize your Antenna performance. Otherwise you are likely to have poor range and be sensitive to proximity loading.

RE: Plastic enclosure over reference design

Victor Nascimento — Thu, 05 Mar 2015 10:43:56 GMT

Oh, ok! In the case, just [Chip -- balun (johanson, bandpass + matching) -- antenna] how bad it is if I don't put the pi-network? The antennas sometimes offers a range of 2.4 to 2.5 GHz... will that still be a major problem?

RE: Plastic enclosure over reference design

Locky — Thu, 05 Mar 2015 02:29:58 GMT

I balun is simply for converting the Differential RF signal into a single-ended signal. Though it is matched to the chip, your Antenna is not matched to the PCB. Therefore you need a Pi or T matching network between your antenna and balun

RE: Plastic enclosure over reference design

Victor Nascimento — Thu, 05 Mar 2015 01:05:41 GMT

But then, whats the advantage of having a BALUN?

RE: Plastic enclosure over reference design

Locky — Tue, 03 Mar 2015 22:35:00 GMT

The balun is only for providing a Single-Ended Signal from the Chip to the Antenna. However due to your PCB and Enclosure there will be additional loading seen by the antenna. Therefore it is always recommended you have a Pi-Network between your Balun and Antenna to further match Antenna to the PCB. This will also allow you to adjust your center frequency to offset for the detuning of the plastic enclosure.

RE: Plastic enclosure over reference design

Victor Nascimento — Tue, 03 Mar 2015 11:15:20 GMT

But in this case, my matching circuit is done by the BALUN, right? Do some extruded cuts near the antenna make any difference (like holes)?

RE: Plastic enclosure over reference design

Locky — Tue, 03 Mar 2015 02:22:58 GMT

Typically it will cause loading, which will shift your matching center frequency down. You will need to adjust your matching circuit to offset the center frequency above 2.45Ghz. That way when you place it in the enclosure it will center