it is “the thinnest smartphone on the planet”.
TheiPhone 4 is structured around a stainless steel frame which both acts
as the primary structure for the device, and additionally acts as the
iPhone 4’s antennae. The stainless steel enclosure features three slits
that divide the band into three sections; the left section of band acts
as the Bluetooth, Wi-Fi, and GPS antenna, and the right and lower bands
sections act as the antenna for GSM and UMTS connectivity. There is
some debate as to whether or not this causes issues with signal
strength and availability. The act of touching the gap between the two
antennas with an un-gloved hand potentially bridges these two separate
antennas, leading to poor signal reception.