Attached are some images of two antennas that were removed from wi-fi type devices, they are both for 2.4ghz devices. The J one looks like a Jpole to me, (obviously), the I one looks like a whip with ground aerials on the reverse side, can someone properly characterize the two types of antennas used here? I'm a bit rough in the antenna department, are they both quarter wave?

 

Hello,

The first one looks indeed like a j-pole antenna.
The second one looks like a ground-plane with an impedance adjustment stage.

Bertus

 

I've been informed on another forum and after some brief Google research have found that the first type of antenna is called an Inverted F antenna, it's not a j-pole and after looking at the positioning of the ground plane it's obvious to me now that it can't be a jpole, they said the second appears to be a planar version of a sleeve dipole.