2.4GHz (BT / 802.11) PIFA / PCB antenna design information to share? - Page 1
Forum section: electronics / rf-microwave

author: evb149
author_rank: Regular Contributor
timestamp: July 11, 2017, 06:06:03 pm
content: Hello,I am wondering if anyone has any specific PCB antenna designs to share for 2.4GHz band Bluetooth / 802.11 usages? And of course any information about your experiences / successes / failures / tips would be interesting also.Specifically interesting would be ones that have been tested in production and which have had any needed optimization done for the normal production design. Any hints relative to how much / what kind of tuning may be required to handle specific PCB material or stackup or environmental effects (plastic enclosure proximity or size of attached PCB or whatever) would also be quite interesting.I have seen some application notes and reference designs about 2.4 GHz PCB antenna designs from vendors like TI and Cypress but I'm still asking because:1: Maybe some of you have different and perhaps better design ideas. Or maybe just better characterization / explanation of some particular details.2: I have sometimes seen some self-contradiction errors and omissions in some of these reference designs / application notes that still left me with questions as to their actual design is and how well it performs under X conditions. Yes I could ask but my interest is just hobbyist / academic and not commercial mass production of their ICs in a device so I'm looking for generalities rather than how to optimize a specific design for mass production which is not relevant to my interest.3: Typically they did not really cover multiple cases of parameter variations like different antenna sizing vs efficiency, different meandering vs. straight options, different PCB materials / stackups enough to cover some interesting variants, and also effects of different passive components used to get an understanding of any sensitivity to those. Also often not discussed is how much variance in parameters vs production exists depending on +/- X% PCB impedance performance changes whether controlled impedance or controlled dielectic or not PCB design is used.I know you can approximate the correct design of these things in EM modelling software but still I almost always see it said that the theoretically derived antenna design must be fabricated and then iteratively measured and tuned by at least a couple of cycles of iteration to achieve the desired specification. So that's why I'm asking "in actual practice what really works" for whatever PCB stackup and test conditions applied to your own tested implementations.It almost seems like someone could have done some modelling and then measurement and then refinement of the models until they could get a pretty good formulaic cookbook for PCB antenna design indicating the relevant target dimensional relationships for X variations of A, B, C chosen PCB / antenna parameters. Maybe someone did a thesis about it or something but I have not seen anything other than "in this exact reference design, this exact gerber file produced this exact performance with very few or no variations considered.". So if there is a good "cookbook" or "formula" that really works in practice for commodty PCB materials / design rules etc. I'd like to hear about it.

author: Neganur
author_rank: Unknown
timestamp: July 12, 2017, 08:01:47 pm
content: In actual practice you have to do all of the things you saidEasy to make antenna work. Not so easy to make it work well.And once you've done the PCB remember that everything nearby detunes it again (enclosures etc)