深次微米互補式金氧半製程之寬頻射頻接收發射器設計

Abstract

本論文描述一以1.2 V 0.13 μm CMOS 製程實現，應用於超寬頻系統之寬頻射 頻接收發射器設計。接收機設計在3~5 GHz 的頻段。整個接收機是由一3~5 GHz 的寬頻低雜訊放大器、三階槽口濾波器、電流式的降頻混頻器與一頻寬為250 MHz 之類比基頻電路所組成。在類比基頻的電路中，可變增益放大器與濾波器利用電 流式放大器的形式設計達到寬頻、高增益動態範圍、低雜訊與高線性度之特點。 此外一電流式Sallen-Key 低通濾波器被設計用來有效地濾除通道外的干擾訊 號。一個六階的Chebyshev 低通濾波器被設計用來提供通道選擇。一數位輔助的 直流偏移校正電路用來降低整個類比基頻電路的二階諧波失真。整個接收器電路 在1.2 V 的操作電壓下消耗100 mW。

在發射器的設計上，我們涵蓋3~8 GHz 的頻率範圍。整個發射器電路整合了 一類比基頻電路、調變器電路、可變增益放大器、差動轉單端放大器與功率放大 器，並整合了發射訊號強度指標電路。調變器電路並包括一直流偏移消除電路來 增進其載波洩漏的抑制能力。整個發射器提供14 dB 的發射功率可調範圍，並具 有-5 dBm 的最大發射功率與+1.5 dBm 的輸出P1dB。藉由直流偏移消除電路可使得載波洩漏抑制達到40 dB。其高線性度與調變精準度使得在480 Mb/s 下EVM 可達-28 dB，可滿足WiMedia Mode 1 的規格要求。整個發射器電路在1.2 V 的操作電壓下消耗66 mW。

This dissertation presents a wideband RF transceiver for ultra-wideband (UWB) applications implemented in a 1.2 V 0.13 μm CMOS process. The receiver design focuses on mode 1 of multi-band (MB) orthogonal frequency division multiplexing (OFDM) UWB (3~5 GHz) which is defined as essential band by WiMedia Alliance. The receiver chain is composed by a broadband 3~5GHz ESD-protected low-noise amplifier, a 3th-order notch filter, a current-mode down conversion mixer and a 250MHz wideband analog baseband. In the analog baseband, PGAs and filters are carried out by current-mode amplifiers to achieve wide bandwidth and wide dynamic range of gain, as well as low noise and high linearity. Besides, a current-mode Sallen-Key low-pass filter is adopted for effective rejection of out-of-band interferers. A 6th-order Chebyshev low-pass filter realized in Gm-C topology is designed in the baseband chain for channel selection. Digitally-assisted DC-offset calibration improves second-order distortion of the entire chain. The entire receiver consumes 100 mW under a supply voltage of 1.2 V.

In the design of transmitter, we attempt to cover both mode 1 and Band Group 3 of MB-OFDM UWB (3~8 GHz). The 3~8 GHz transmitter chain integrates an analog baseband, an in/quadrature-phase (IQ) modulator, a variable gain amplifier (VGA), a differential-to-single amplifier, a power amplifier, as well as a transmitted signal strength indicator (TSSI). The IQ modulator incorporates DC-offset cancellation circuits to improve carrier leakage suppression. This transmitter provides linear-in-dB output power tuning of 14 dB to fulfill the requirement of WiMedia UWB. Measured maximum output power and OP1dB are -5 dBm and +1.5 dBm, respectively. Measured carrier leakage suppression is over 40 dB after calibration. The high linearity and accurate IQ modulation lead to an error vector magnitude (EVM) of -28 dB under the data rate of 480 Mb/s in WiMedia Mode 1. The entire transmitter consumes 66 mW under a supply voltage of 1.2 V.