Multi-Band CMOS RF Front-End Circuit and Architecture Designs for BWA Systems
Date Issued
2005
Date
2005
Author(s)
Li, Wei-Chang
DOI
en-US
Abstract
Multi-band and multi-standard transceivers attract more and more attention for their flexibility and functionality. Typically, the transceivers are realized by using two or more sets of RF blocks, which can handle the desired bands. However, this approach may increase chip area, the number of components, and the cost. A way to alleviate these problems is to use one set of RF block which can be tuned for multiple bands. In this thesis, a multi-band receiver architecture, operating at 2.4 GHz, 3.5 GHz and 5.2 GHz, is proposed for IEEE 802.16-2004 sub-11 GHz applications. The receiver RF front-end can achieve maximum hardware sharing while reducing chip area and cost.
Before going on the circuits of front-end, the design flows and considerations of RF blocks, i.e. LNA and mixer, are discussed. A technique called “Contour-plot methodology” has been published for LNA design, which can clearly provide designers the relations between design parameters and device size. The design flow of mixer is also presented using the contour-plot technique. Based on this methodology, a 5.2-GHz LNA with fully on-chip matching for WLAN systems is designed and implemented. Using a CMOS 0.18μm process, the LNA occupies an area of 0.6x1.29 mm2 and dissipates 5.8 mW from a 1.8 V power supply.
A tri-band LNA for the multi-band receiver RF front-end adopts a inductor-switching technique with a multi-tap inductor to select one of the three desired bands. Inductive switching is superior to capacitive switching since it can achieve better quality factors for each frequency band. Fabricated in CMOS 0.18μm technology, the tri-band LNA has an area of 1.2x1.5 mm2 and dissipates 14.6 mW in 2.4-GHz band and 24.9 mW in 3.5-GHz and 5.2-GHz band without buffer.
The proposed mixer uses a dual-conversion folded topology, which is composed of a single-balanced Gilbert-type mixer cascaded by two additional double-balanced PMOS switching pairs. System simulation shows that this topology can alleviate the noise and linearity requirements. The RF front-end occupies an area of 1.28x1.76 mm2 and dissipates 25.3 mW in 2.4 GHz, 51.2 mW in 3.5 GHz and 39.2 mW in 5.2 GHz, respectively.
Subjects
多頻帶接收機
多頻帶射頻電路
低雜訊放大器
BWA
802.16
WMAN
WiMAX
multi-band receiver
multi-band RF front-end
multi-band LNA
Type
thesis