Highly integrated, re-configurable RF front-ends in deep sub-micron CMOS

Various RF bands, standards, modulation schemes, duplex mechanisms and signal bandwidths needed for the mobile terminal call for a highly adaptable and reconfigurable RF receiver. The biggest bottleneck in achieving this goal lies with the RF pre-select filter at the antenna, which is band specific and creates a bottleneck in being able to share the hardware. Solving this multi-band programmability is the biggest challenge in achieving a RF Receiver for software defined radio. A few of the possible architectures and their limitations are presented. However, designing a multi-mode RF receiver for a given RF band with highly reconfigurable performance is an achievable goal. A WCDMA/EDGE receiver without inter-stage SAW filter in 90nm digital CMOS is used as an example in illustrating the architecture, circuit and system considerations for such a receiver.