Single ended antenna - piece of wire

[alphacat]

Hello.

The Antenna which I assembled in my PCB, in the microcontroller unit, is a piece of copper wire (single ended antenna).
The operating frequency is 2.4GHz (the microcontroller transmits and receives info in 2.4GHz frequency band).

I asked a wires factory for a copper wire, which can handle RF current of max 10mA @ 2.4GHz.
(I also requested the wire's diameter to be 1.5mm).
The factory has told me that it cannot do that since the operating frequency is too high.

Is that so?
I dont get it, what does the wire care what is the operating frequency?
Up to now, I used a simple piece of wire which i found and the antenna works great.

Thank you.

 

[JimB]

I asked a wires factory for a copper wire, which can handle RF current of max 10mA @ 2.4GHz.
(I also requested the wire's diameter to be 1.5mm).
The factory has told me that it cannot do that since the operating frequency is too high.

There are two possibilities here, either the guys at the "wires factory" are as thick as two short planks, or, they are having a good laugh at someone who asks for a wire which can handle 10mA.

It would have to be a VERY thin wire which could not carry 10mA.
A 1.5mm dia wire would be fine for your application.

I dont get it, what does the wire care what is the operating frequency?

There is something called the "skin effect", as the frequency is increased the current only flows on the outside surface of the wire, thus the AC resistance of the wire is greater than the DC resistance.
This is why RF components such as coils and capacitors are silver plated. Silver being the metal with the highest conductivity.

The skin effect is not just an RF pheneomenon, it starts to be significant at high audio frequencies.

Up to now, I used a simple piece of wire which i found and the antenna works great.

That sounds like a sensible choice to me, dont try and over design the thing you are using a cheap RF module, there are already so many compromises in its design and construction, the wire used for the antenna is not going to make any difference.

JimB

 

[alphacat]

Thank you very much.

How do i order then a 1.5mm copper wire?
I mean, shall I tell this factory that i still want the wire they can supply?

 

[Boncuk]

Hi alphacat,

the diameter of a wire has little effect on the antenna design.

I have examined a remote gate opener circuit. The transmitter (key fob) contains a small etched antenna while the receiver uses a piece of copper wire (0.8mm dia) to connect into the antenna input terminal. The wire is mounted horizontally, bent upwards from the center 90 degrees to take care of polarization.

Use λ/2 or even λ/4 for antenna length. The range of those TX/RX sets is very short, not so much due to a lack of capability, but determined by the user. I haven't seen one trying to open his gate from the city.

Boncuk

 

[Boncuk]

Thank you very much.

How do i order then a 1.5mm copper wire?
I mean, shall I tell this factory that i still want the wire they can supply?

Look out for an electric machine repair shop. They have all wire diameters on stock to repair heavy motors.

I bet they'll give you one meter of the desired copper wire for free (90 cm to play with and 10cm to use).

 

[Ross Craney]

Find yourself an offcut of electrical cable from a lighting cct. This is usuall 1.5mm solid conductor . Strip out either the active or neutral with its insulation & you have a perfect antenna for what you want.

 

[alphacat]

Thank you very much guys.
I prefer to order the wire from that factory since its the same factory that assembles the components on the PCB, so that way I dont need to send him any wire.

So I can actually tell the factory that I agree to use its copper wire? (its probably just like any other copper wire, like the Neutral/Live wire as you said, or repeir shop )

 

[alphacat]

Thank you very much guys.
I prefer to order the wire from that factory since its the same factory that assembles the components on the PCB, so that way I dont need to send him any wire.

So I can actually tell the factory that I agree to use its copper wire? (its probably just like any other copper wire, like the Neutral/Live wire as you said, or repeir shop )

Help on that please.

 

[Boncuk]

Help on that please.

If you prefer the complicated way further help will be in vain.

 

[Mikebits]

If you prefer the complicated way further help will be in vain.

Agreed, a simple piece of wire should suffice, no need to over complicate this.

 

[alphacat]

Got you.

Thank you very much!