The world of wireless communication and its applications have begun to grow rapidly. The driving force behind this lies in the introduction of digital coding and digital signal processing in wireless communications. This digital revolution is driven by the development of high‐performance, low‐cost
CMOS
technologies that allow for the integration of an enormous amount of digital functions on a single die. As
CMOS
is mainly a digital technology, placing all digital functions on a single die is merely a matter of handing the system complexity. To achieve a truly single‐chip solution, the analog part also has to be integrated in
CMOS
.
The telecommunication market is generally considered to be a business where a single‐chip solution in a cheap (
CMOS
) technology results in a huge cost benefit; the main reason is the high volume of user equipment. Furthermore, in these systems, small size, low board area, low power consumption, and high talktime are crucial, and therefore it is of utmost importance to achieve a high level of integration. This trend toward single‐chip, fully integrated systems can clearly be seen in the development of RF systems such as
GSM
,
EDGE
, Bluetooth, and wireless
LAN
. In all these sytems, the analog part mainly consists of an
RF
front end. Deep submicrometer technologies allow for the operation frequency of
CMOS
circuits above 1 GHz, which opens the way to fully integrated
RF
systems. Several research groups have developed high‐performance downconverters, low‐phase‐noise voltage‐controlled oscillators, and dual‐modulus prescalers in standard
CMOS
technologies. The research has already demonstrated fully integrated receivers and synthesizers with no external components, nor tuning or trimming. Further research on low‐noise amplifiers, power amplifiers, and synthesizers has resulted in fully integrated
CMOS
RF
transceivers for DCS1800, Bluetooth, and wireless
LAN
.
In this article, we focus on the evolution from the well‐known heterodyne receiver topology to the zero‐ and low‐IF topology used in modern receivers. We also discuss the interaction between the analog part and the digital part regarding substrate noise and decoupling.