Radio continues to be one of the most powerful technology drivers in microelectronics with many evolutionary changes taking place in the last few years. Applications, both consumer and mission critical, require solutions that are smaller, increase functionality and reliability, and improve signal clarity, all the time attaining lower power consumption.

To achieve this, almost all modern radios now use digital modulation schemes instead of standard analog. This also fits with the trend to higher frequencies to make use of the wider bandwidth required for these applications. The higher frequency designs also drive to smaller physical layout because the shorter wavelengths can be accommodated in much smaller packages (i.e. the wavelength at 5.8GHz is nearly 6.5 times smaller than at 900MHz).

Although radio design continues to evolve with increasing complexity and need for security, the actual radio block diagram has remained virtually unchanged.

The basic radio consists of several key components and each has a specific job in the chain: Antenna, Switch, LNA (Low Noise Amplifier), Filter, Mixer, Oscillator, Modulator/Demodulator. As the applications have evolved, so has the component technology that has enabled major downsizing of these elements to take place.

Read more: http://www.avx.com/docs/techinfo/areview.pdf