Scientists have confirmed the 'death grip' issue that afflicts Apple's iPhone 4 and some other smartphones, but they have also pointed out that trying to solve the problem with plastic cases will not make much difference.
According to researchers at the University of Bristol's Centre for Communications Research (CCR), their study demonstrated how signal levels change due to obstruction, position and motion. The study was published on Monday in the journal IEEE Antennas and Wireless Propagation Letters under the title, "Slot Antenna Performance and Signal Quality in a Smartphone Prototype".
"The results from the study indicate a 100-fold reduction in sensitivity of the device when held, or when the user's thumb is mimicked by phantom material," the CCR said in a statement. "This de-tuning of the antenna was found not to significantly alter the shape of the radiation pattern, but dramatically worsened the electrical match between the antenna and the electronic circuitry."
The researchers noted that using a layer of plastic electrical insulator to create a gap between the antenna surface and the hand "did not restore the matching and operational sensitivity of the phone for the antennas under evaluation".
"Thus, some phone covers in the market place may not improve the situation," the scientists concluded.
When Apple launched the iPhone 4 in the middle of last year, it was eventually forced to acknowledge widespread complaints about signal being dropped due to the combination of the handset's antenna band and the user's hand. The company ended up shipping free 'bumper' cases to customers afflicted by the problem.