The quad-band GSM mobile handset requires power amplifiers that meet stringent harmonic rejection at the specified output power with the maximum power-added efficiency (PAE) possible. Worldwide GSM has four bands: GSM 850 MHz and GSM 1900 MHz (Personal Communication Services, PCS) bands are used in America, while GSM 900 MHz and GSM 1800 MHz (Digital Cellular Services, DCS) bands are used in Europe and elsewhere in the world. In the GSM arena, the trend has been towards evolving a GSM mobile phone that supports all the four major GSM frequency bands in a single handset, making it compatible with all the major GSM networks worldwide. In addition, the module needs to perform over a wide frequency band in the smallest possible layout space. The stringent specifications for the different systems have to be met using inexpensive surface-mount plastic modules, which integrate diverse functionality with just a few chips. Recent advances in mobile phone RF modules have been made for the miniaturization and integration of components in such a manner that they can address all of the global standards.
