GHz Wireless Local Area Network Research Articles

5-GHz CMOS wireless LANs

This paper first provides an overview of some recently ratified wireless local-area network (WLAN) standards before describing an illustrative 5-GHz WLAN receiver implementation. The receiver, built in a standard 0.25-/spl mu/m CMOS logic technology, exploits several recent developments, including lateral-flux capacitors, accumulation-mode varactors, injection-locked frequency dividers, and an image-reject low-noise amplifier. The receiver readily complies with the performance requirements of both IEEE 802.11a and ETSI HiperLAN. It exhibits a 7.2-dB noise figure, as well as an input-referred third-order intercept and 1-dB compression point of -7 and -18 dBm, respectively. Image rejection for this double conversion receiver exceeds 50 dB throughout the frequency band without using external filters. Leakage out of the RF port from the local oscillators is under -87 dBm, and all synthesizer spurs are below the -70-dBm noise floor of the instrumentation used to measure them. The receiver consumes 59 mW from a 1.8-V supply and occupies only 4 mm/sup 2/ of die area, in no small measure due to the use of fractal capacitors for ac coupling.

Chip-package codesign of a low-power 5-GHz RF front end

Future high-performance wireless communication applications such as wireless local area networks (WLANs) around 5 GHz require low-power and highly integrated transceiver solutions. The integration of the RF front end especially poses a great challenge in these applications, as traditional front-end implementations require a large number of external passive components. In this paper, we present the single-package integration of complete transceivers based on a thin-film multichip module (MCM) technology with integrated passives. The MCM substrate is a a common carrier onto which different ICs are mounted. passive components such as RF bandpass filters, inductors, capacitors, and resistors are directly integrated into the MCM substrate with the use of the multilayer structure of the MCM technology. The "system-on-a-package" approach is illustrated with a voltage-controlled oscillator for Digital European Cordless Telephone (DECT) applications and a 5-GHz WLAN front end. These examples indicate that this approach yields a compact low-power implementation of complete transceivers for high-performance wireless applications.