antennabluetoothfieldfrequency
I have seen too many tutorials on how to increase HC-06 bluetooth module range. They all involve cutting the on-board antenna and adding an external one (a piece of wire or a 2.4GHz antenna). I was wondering how this affects the bleutooth module, for example, the power consumption, the frequency. And the relation between the length of the wire and the transmission range. Can anybody help?
Thanks in advance,
A Yagi antenna for bluetooth may increase your gain. Keep in mind that Yagi antennas are directional antennas so if you move your target around you will have to move your antenna.
In order to use an external antenna, you would have to take following into consideration:
First, I would look up the datasheet of the RF chip to make sure that the output impedance is 50 Ohms (it doesn't have to be).
Then, peel the coax of your antenna in such a way that it looks like a 3 toothed fork with the inner conductor being in the middle. This is really important for best performance (otherwise your antenna may not work well due to poor balancing).
Using a sharp knife, razor blade (etc) remove the mask on the a small section of the trace leading up to the antenna so that bare copper is visible.
Cut that trance after to pad to isolate your old antenna.
Expose copper on both sides of the center trace (your ground).
Solder the center conductor of your coax to the former antenna trace pad and solder the coax outer shield grounds to the pads.
Keep these unwound wires as short as possible.
Keep in mind, that you will still lose a couple of dB in the transition and cabling.
Best Answer
Looking at an HC-06 module:
what seems "odd" to me is the shape of the antenna. For 2.5 GHz I do not expect that a meandering shape like this (the gold colored part) is any good. My guess is that it is "designed" by someone who doesn't have a clue about antennas at 2.5 GHz.
Other 2.5 GHz antennas are often F-shaped or T-shaped. I saw another meander shape:
but note how is has two connection points, part of it is F-shaped.
My conclusion is that not much thought was put into the HC-06 module's antenna and that probably makes it a very poor antenna. So there's a lot of room for improvement, anything even remotely better will improve performance.
Power consumption wise you would not notice the difference. The actual RF power is quite low and insignificant compared to what the rest of the circuit (modem etc.) uses. Also with a bad antenna most of the RF power reflects back into the chip and is lost. A good antenna will radiate that RF power making things more efficient.