Hi there
I'm happy with using my Arduino WiFi shield (integrated antenna), but I want to increase its access range. Can I attach the antenna to it?
If so, where is the place on the shield to solder the antenna cable?
What impedance the antenna should have?
Thanks.
It looks like you need to solder a surface-mount uFL antenna socket to the board next to the
existing chip-antenna (and remove the chip antenna).
Note that the AdaFruit version of a WiFi shield already has such a socket: Adafruit CC3000 WiFi Shield with uFL Connector for Ext Antenna : ID 1534 : $39.95 : Adafruit Industries, Unique & fun DIY electronics and kits - bottom left above the button.
Hi there
On its face (left image if follow the link below)
the shield has a thingy on its right-most area. It looks greenish and it reminds me a capacitor. Is it the chip antenna?
If it is a capacitor, why should I remove it? Just solder on its outer plate, don't I?
Thanks.
mabanza:
Hi there
On its face (left image if follow the link below)https://www.arduino.cc/en/Main/ArduinoWiFiShield
the shield has a thingy on its right-most area. It looks greenish and it reminds me a capacitor. Is it the chip antenna?
If it is a capacitor, why should I remove it? Just solder on its outer plate, don't I?
Thanks.
Hi.
That greenish "capacitor" is a smd 2.4ghz antenna, most of them ceramics ones., google "smd 2.4 ghz antenna".
Best way is: get a 15cms pig pail cable with rpsma connector. By this way you will be able to attach any 2.4 antenna.
And the perfect spot to solder that pigtail, is near the SMD antenna, shield of the pigtail goes to the edge of the white circle, and the centre core wire of the pigtail, at the midle of the circle, or just at the edge of the smd antenna.
Do you need to remove this smd antenna... don´t know, but on wireless router and AP, usually, they use a tiny inductor/capacitor to switch between SMD/internal antenna and external antenna. So my guess is yes, remove the SMD antenna.
Like this:
Of course you know it may not be FCC compliant with your new
antenna. ( more a worry if it will be a production product ).
It may also not work well if you don't get a good impedance match.
It might work better or it might work even worse.
Receiving isn't as critical but transmitting is fussy about impedance
matching.
Dwight
dwightthinker:
Receiving isn't as critical but transmitting is fussy about impedance
matching.
Not true unless you are talking about high power transmitters where reflected power may damage the circuitry. See the reciprocity theorem of electromagnetics.
Russell.
russellz:
Not true unless you are talking about high power transmitters where reflected power may damage the circuitry. See the reciprocity theorem of electromagnetics.Russell.
The efficiency of even a low power output stage depends on a good match to the load. So although the reciprocity principle applies to the antenna, the transfer function for a transmitter compared to a receiver, considering the antenna system to be the same, isn't reciprocal. It's not just about damage, it's about the power that can be developed. That is a superposition of both the characteristics of the antenna and the power amplifier.
So yes, the transmit is more critical. Think about it. What you say would be true, if the power amplifier output was invariant with the load. But it isn't. Not unless it's isolated with a resistive pad.
aarg:
The efficiency of even a low power output stage depends on a good match to the load. So although the reciprocity principle applies to the antenna, the transfer function for a transmitter and a receiver, considering the antenna system to be the same, isn't reciprocal. It's not just about damage, it's about the power that can be developed. That is a superposition of both the characteristics of the antenna and the power amplifier.So yes, the transmit is more critical. Think about it. What you say would be true, if the power amplifier output was invariant with the load. But it isn't.
Ya, what he said.
Dwight
russellz:
Not true unless you are talking about high power transmitters where reflected power may damage the circuitry. See the reciprocity theorem of electromagnetics.Russell.
Receiving circuits are not the same as transmitting circuits, so the reciprocity theory doesn't apply.