Achieving frequency-agile radio

This paper describes techniques to achieve high bandwidth systems for a frequency-agile radio. A bottom-up approach has been followed where the tunability and bandwidth of the basic building blocks are enhanced, and then these improved elements are introduced into higher-level blocks in order to achieve large bandwidths. The approach has been used to improve the tunability and bandwidth of an active inductor by enhancing the tuning range of a tunable active resistor. This highly tunable active inductor is then used in a VCO that achieves more than 100% of frequency tuning range. All circuits have been fabricated in 0.18 /spl mu/m SiGe BiCMOS process.

I. Introduction

The need to enable the “global roaming” capability between a wide variety of networks operating at different frequencies calls for the development of multi-mode terminals that find application in frequency-agile radios, programmable wireless networks, sensor applications, etc. Efficient, small and cost-effective implementation of such frequency-agile transceivers will require reconfigurable RF blocks rather than switched radio architectures. This can be made possible only with the help of widely tunable and wideband reconfigurable basic elements, such as the resistor, the capacitor, and the inductor.