F-antenna of MC213x reference design

[ByTheWay]

I'm new to antenna design and I don't pretend to know a thing that I'm talking about. I'm basing my own design on the reference in AN3248 with some success ... but the F-antenna is puzzling me.

After reading up on the subject, I'm wondering why the antenna exists on both layers of the board. Is there a reason why the entire ground plane should just be extended into this region?

Of course, I don't have a physical reference board, so I'm just basing this on what I see in the .pdf file.

-- BTW

[rocco]

Hi, ByTheWay:

Like you, I know nothing about antennas. Unlike you, I often pretend that I do. This is not one of those times.

But I found app-note AN2731 pretty informative. It covers the F antenna in both section 4 and section 8.

http://www.freescale.com/files/rf_if/doc/app_note/AN2731.pdf?fsrch=1

[bigmac]

Hello,

I don't know whether the board that you refer to is similar, but on one of the SARD boards, separate antennas were used for transmit and receive, with each antenna on opposite sides of the PCB, but occupying the same area.

Regards,

Mac