How to fight over the skin effect on home made antennas ??? - Page 1
Forum section: electronics / rf-microwave

author: Free_WiFi
author_rank: Regular Contributor
timestamp: April 04, 2019, 12:50:33 pm
content: I'm rambling/zapping around the net and there's thousands of beautiful pcb patch antennas...i really wish to make some for my self....but the problem of the skin effect at 2 ghz 5ghz is totally ripping off the purpose to make at least one of them.Do you know some kind of cheap plating material or some kind of trick to fight the skin effect ?Thanks you very much.

author: Free_WiFi
author_rank: Regular Contributor
timestamp: April 04, 2019, 12:54:22 pm
content: P.S I also thought to use some kind of sputtering machine with the graphite brick,so i could be able to plate the copper surface with some kind of graphene layer...

author: Dataforensics
author_rank: Unknown
timestamp: April 04, 2019, 01:39:45 pm
content: Used to use silver plated copper wire many years ago when I was still into amateur radio.There must be silver plating solutions around.

author: Free_WiFi
author_rank: Regular Contributor
timestamp: April 04, 2019, 01:53:06 pm
content: My own problem is that i'm total 0 in chemicals ... so basically i need your help to figure out how i can going forward in this kind process.

author: dmills
author_rank: Super Contributor
timestamp: April 04, 2019, 02:15:42 pm
content: Start by calculating the actual effect of the skin effect, with a reasonably thick trace it is less then you think!Usually dielectric losses will vastly exceed skin effect losses in the mid microwave region.Note that for a line over a ground plane, the skin that matters is the one facing the ground plane, not the one on the top of the board!If I was really bothered, immersion silver is a standard finish from PCB shops.Regards, Dan.

author: radiolistener
author_rank: Super Contributor
timestamp: April 04, 2019, 06:28:24 pm
content: I think skin effect is not an issue here, the main problem will be dielectric loss in the PCB material.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 04, 2019, 06:33:05 pm
content: People seem to be making them successfully without regards to skin effect...Or more aptly: of course skin effect is always a thing. It's what you do about it that matters. What makes you think common designs are fatally flawed in regards to this property?Tim

author: hagster
author_rank: Frequent Contributor
timestamp: April 04, 2019, 09:00:49 pm
content: As others have said, unless you are paying a lot for your substrate, the dielectric losses will dominate.For skin effect you can mitagate it by using wider tracks and a thicker substrate. Lots of antennas use an very thin PCB with an air gap over a ground plane.Plating doesnt do much for microstrip tx lines as the current is flowing on the underside of the track not on the top surface. Also watch is doe ENIG as the nickel is ferromagnetic and lossy.Personally I use normal solder resist to protect the surface from tarnishing over time.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: June 24, 2021, 10:54:22 pm
content: As far as conductivity goes, copper is only beat by silver.Aluminum is third but it has a greater skin depth at higher freq. So it is close to copper.If you silver plate, it has to be thicker than one skin depth. I don't know how to do this with flat traces where the edges are the most conductive and hardest to plate. At GHz freq "skin effect" becomes "edge effect" with the RF concentrating at the edges of traces.I dunno but maybe a round wire instead of a flat trace might be better?I use silver plated craft jewelry wire for some connections because it solders like a dream, but I do not think the silver plate is thick enough to make a difference, maybe someone else knows the answer to this. Maybe at GHz freq the craft wire has enough silver plate to make a difference.Maybe get a scrap piece of coax that has silver plated shield and use a strand (or two or three or..) of that if all you need is a thin wire? I am assuming you are using PCB trace for antenna. Again, I dunno, just some thoughts.Connectors and coax are critical at GHz freq. Use good connectors and coax that are both rated higher than your intended freq.Wally KC9INK

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 25, 2021, 03:29:47 am
content: On PCBs, it doesn't make much difference at all, as the fields are largely within the board, i.e. the rough, oxidized, bonded surface is where most of the current flows. If you're building micro/strip/line yourself, you can use fully plated materials of course.Sharp corners do concentrate current more than round; you would prefer coax to stripline resonators for example. But you might justify the increased insertion loss or reduced maximum Q by the ease of construction or manufacture, and so planar filters are very popular in commercial design.Tim

author: Bud
author_rank: Super Contributor
timestamp: June 25, 2021, 03:37:50 am
content: Skin effect should be the least of your concerns.

author: ahbushnell
author_rank: Frequent Contributor
timestamp: July 03, 2021, 03:36:59 am
content: There are PCB materials designed for this. There is a company called Rogers That makes this material among others. It's probably in your pocket in your cell phone.https://www.rogerscorp.com/advanced-connectivity-solutionsAndy