Hi,
I'm looking for some help in a field that is super technical and I don't fully understand.
I'm planning on using a bunch of these seeed studio Esp modules for some home automation projects, especially because they have a lipo battery charger making it great for portable stuff.
The thing is the the ESP32s have U.FL SMD antenna connectors. Most of the antennas that you can buy with U.FL connections while are reasonably small, come with 50-150mm leads, which sort of makes the small size of the module a little less valid.
What I'd like to do is get a female U.FL SMD connector and make a small daugherboard with an 2.4GHz SMD antenna on it, for instance a Janson 2450AT42B100 or a Molex 479480001.
They go over the circuit board requirements quite thoroughly so I don't think designing it will be too difficult, but what I don't know is, they say that you need impedance matching on the circuit, and I see that there appears to be something that looks like it on the ESP circuit diagram, but I'm not actually sure if it is or not:
You can see it in the middle near the bottom of the diagram here: Seeeduino-XIAO-ESP32C3-SCH
So my questions are:
1: Is this a dumb idea, having a direct plug-on SMD antenna?
2: Is that an impedance matchning circuit between LNA_IN on the ESP chip and U.FL-R-SMT-1?
3: If I can't get a female U.FL SMD connector, would using one with a lead and shortening it to make the daughterboard able to be much closer to the connector affect anything? Do I need to ensure that the lead length matches the wavelength at all?
Edit: Found this SMD female U.FL, so they do exist.
I have no concrete answer to your post...
However I would be interested to know where I can earn more abt the topic of electronics, I am very interested in learning it and it would be nice to get some guidance. ty in advance
I.. Don't actually know, I've just cobbled together information over the years. My dad worked in an electronics workshop but never taught me anything. There's a good intro to electronics course on udemy and if you're serious about it, try get the book The Art of Electronics, its like an electronics bible.
i don't know what are you looking for so i'm just gonna drop some resources that i've used:
starter: https://www.antenna-theory.com/antennas/main.php
more comprehensive: https://www.microwaves101.com/encyclopedias
and on top of that, various amateur radio pages, some are indexed in dxzone.com
there seem to be two hard limits on antennas in general. one is for approx lossless antennas that are large compared to wavelength: gain, beamwidth and size are related through diffractive limit https://en.wikipedia.org/wiki/Diffraction-limited_system it's really about capture area, which is intuitive for things like parabolic reflectors, but for things like yagi antennas there's some defined capture area that ultimately depends on their length
the other one is on non-directional antennas that are small compared to wavelength. basically one good antenna that you can make is halfwave dipole, you can try various trickery to make it smaller, but this comes at a cost of either smaller bandwidth or increased losses, or both to lesser degree. it might make sense to make an antenna with 70% efficiency which is 3x smaller for example. it all depends on precise requirements
at the end of the day the most important material in any antenna are tradeoffs