Antenna for wifi module 1

[Gokkul55]

I am currently involved in a project where data needs to be exchanged between a device with wifi capability and a microcontroller interfaced to a wifi module. The choice of wifi module is RN-171-DS. Its chosen for cost and simplicity.
(If anyone can suggest a much better module at low cost, please do so )

The module has a Transmission power of 12 dBm (max) and receiver sensitivity of -83 dBm

Now by adding an antenna of 2 dBi the transmission power is doubled. Now will the same antenna also double the receiver sensitivity? If not how do i increase receiver sensitivity.

The idea is to increase the range of communication, both transmission and reception.

Attached RN-171-DS datasheer for reference

Thanks
Regards
Gokkul

 

[VEBill]

2dBi is not double. Double (2x) is +3.01dB. 2dB is about 1.6x.

The 'i' in dBi is important. It means isotropic, a hypothetical antenna that could radiate in a perfectly spherical pattern, equally well in all directions. Not just around the horizon (omnidirectional), but ALL directions including straight up and straight down. Such isotropic antenna are more often a hypothetical reference than a real world antenna.

So 2dBi is about 1.6x more gain in some direction (usually omnidirectional) compared to a hypothetical reference antenna that (sort-of!) doesn't really exist. A plain old quarter-wave monopole over a ground plane is usually specified as around +2.1dBi. So 2dBi is basically just "an antenna".

There are many inexpensive high gain 2.4GHz antennas on the market. I've seen even long Yagis for the $20 price class, including S&H. There are also stacked arrays (collinear monopoles) that provide gain and omnidirectional coverage.

Antenna gain helps in both directions. And it helps if applied to both ends of the link.

Keep in mind that gain implies reduced coverage. You have to visualize where the signals are being squirted. If something is mobile and in random orientation, then high gain would need to be dynamically aimed.

 

[Gokkul55]

2dBi is not double. Double (2x) is +3.01dB. 2dB is about 1.6x.

Thanks for the info, you enlightened me .

Also as you said though the gain is mentioned in dBi the antenna's are all dipole most of them. So that being the case how good will these antenna be if the device is to be placed in an office like environment, with doors and walls and lot of
people .
(I do know that no one can exactly predict the signal range as lot of factors are involved)

I would like to know your opinion on the following antenna (Attached datasheet)

Thanks
Regards
Gokkul

 

[VEBill]

A claim of "5dBi" is kind-of middle of the road (it's the sort of antenna included with routers). If your system requires more gain, then there are similar (but taller) antennas with claimed gains like +13dBi.

The claims should be taken with a grain of salt, but it's most likely that there is (these days) a reasonable correlation between claimed gain, design type and length, and real world gain.

With gain comes directionality, and a requirement (on you) to aim the antenna in the required direction. Avoid very high gain antennas if they're not required.

Also, beware "reversed" SMA connectors. It (the choice of reverse or not) varies with product. Most all consumer products are reversed to "prevent you replacing the antenna" (LOL FAIL!), where as many industrial products are normal SMA.

PS: This site has a forum for 'Antenna & propagation engineering'.

 

[Gokkul55]

With gain comes directionality, and a requirement (on you) to aim the antenna in the required direction. Avoid very high gain antennas if they're not required.

Plan to use this antenna initially and then may be move to a higher gain antenna if required. Kind of trial and error based on field requirement.

Also, beware "reversed" SMA connectors.

Yea seen those, and both male and female connectors are easily available.

PS: This site has a forum for 'Antenna & propagation engineering'.

Ahh missed it, must have taken a wrong turn somewhere , but thanks for pointing me the right road .

Thanks
Regards
Gokkul