An Approach of RF-MEMS Technology Platform For Multi-band Multi-mode Handsets

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  • Author: Christophe Pavageau, Olivier Millet, Ariel Cao

Wireless communication is a growing and very competitive worldwide market. Technologies are evolving at a rapid pace, especially for this sector's flagship product, the mobile handset. Handsets are becoming lighter weight, more attractive, highly compact and have extended talk-time. Technical advancements also include enhanced functionality such as GPS, WiFi, Bluetooth, digital TV, multimedia and Internet. The introduction of new wireless standards (3GWCDMA/HSPA+, LTE) dictate the need for multiband multi-mode mobile handsets that can accommodate backward-compatibility with the existing 2G infrastructure (GSM/EDGE or CDMA) and support roaming needs for extending connectivity with regional specific allocation of frequency-bands.

As a result, a mobile handset must handle an increasing number of operating frequency-bands, each having its own specific characteristics and constraints. In general, today's multi-band multimode handset contains multiple stacked RF frontend
modules (FEM), each optimized for a single frequency band. This leads to component duplication and complex RF hardware as well as larger component count. On top of that, the phone platform customization of each end application and regional variant requires advanced engineering, further escalating the development costs. Until now, size reduction and increased functionality per unit area have been addressed by continuing chip scaling to the point where off-chip, bulky passive RF components (like high-Q inductors, ceramic filters, SAW filters, varactor diodes and PIN diode switches) have become limiting.

More than ever, new solutions for increased RF hardware integration (more compact) and optimal performance are needed. Rather than duplicating mode-specific RF transceivers for each new standard being supported, a more viable solution is to make them reconfigurable. This solution promises to lower material costs by increasing re-use of components, resulting in space saving, cost efficiency and reduced overall current consumption.