The fast growing of the wireless market has created an urgent demand for
smaller and cheaper handsets with increased functionality and performance
while still meeting the tight constraints for mass production within a short
product life cycle.
The successful achievement of these conflicting trends has been possible
due to the development of key technical capabilities in the design and
production of each new wireless device generation.
In the baseband section of the handset, the great development
experimented by the CMOS processes in the last decade, has shrunk the
silicon real estate required for the processor, memory and interface ICs.
The advanced chip scale package (CSP) techniques and multi-layer
laminate printed circuit boards (PCB) have minimized the electronic
interconnect and packaging volume. The battery technology has advanced
from the older nickel cadmium and nickel metal-hydride to the lithium ion
and lithium polymer technologies, improving the battery pack size, weight
and performance. The antenna has migrated from outside in the old designs
to inside the plastic housing in the new ones, giving more freedom in the
handset form and design. As it is shown in Figure 1-1, all these
improvements have led to lighter, smaller and compact handsets.
In contrast to this situation, the improvement in the passive component
content of the handset has been much less dramatic compared to other
technical areas. This inertia has not been due to the lack of attention by the
set-makers or in the literature.