cellphone antenna review

Hi everyone,
I wonder if there is a good review paper on cellphone antenna? I want to learn which antenna is popular currently? Thanks!
Wufeng

Depends on phone system. For multiband antennas are still PIFA most common.
Pictures of many phone antennas can be searched at FCC. Typical antenna: https://fjallfoss.fcc.gov/eas/GetApp...tml?id=1279504