标题: 应用于解决CMOS闪烁杂讯之低中频接收机架构和深N型井双极性接面电晶体直接降频接收机
CMOS Flicker Noise Solutions by Low-IF Receiver Architecture and Deep-N-Well BJT Direct-Conversion Receiver
作者: 徐金详
Syu, Jin-Siang
孟庆宗
Meng, Chinchun
电信工程研究所
关键字: 互补式金氧半导体;闪烁杂讯;吉伯特混频器;次谐波混频器;低中频接收机;直接降频接收机;CMOS;flicker noise;Gilbert mixer;sub-harmonic mixer;low-IF receiver;direct-conversion receiver
公开日期: 2010
摘要: 本论文中分作五个章节,包含了各式混频器和接收机之效能改善。在第二章中提出单频带和双频带之高线性度吉伯特升频器。利用输入端之偏压偏移交错耦合对与输出端之并联回授缓冲放大器,使升频器之输出端三阶交调截点与输出端1-dB压缩点差距高达22 dB。
第三章利用相量表示方式完整地分析和比较各式被动正交信号产生器,包含了振幅和相位与频宽的关联。此外,双极性接面电晶体之主动混频器比互补式金氧半导体之主动或被动混频器拥有更宽的转换增益平坦区,因此有着更佳的正交本地振幅不平衡之容忍度。应用于吉伯特混频器本地振荡源埠之正交耦合器若直接在高损耗矽基板上制作,可缩小面积但会有输出振幅不相等的特性,正好可以利用选取适当之本地振幅而改善。另一方面,利用LR-CR正交相位产生器并配合双极性接面电晶体主动混频器成功地实现一接收机,并且在超宽频应用频带中输出端之信号振幅与相位误差分别低于±1dB和±2°。
在第四章中,于0.35毫米矽锗异质接面电晶体制程中利用补偿相位延迟技术实作一个高隔离度之次谐波降频器。在相同偏压条件、电晶体大小和操作频率下,使用补偿相位延迟技术与传统无使用此技术之电路可得到相似之转换增益、杂讯指数和线性度,却额外改善了34/35 dB的2LO至RF/IF埠隔离度,8/9 dB的LO至RF/IF埠隔离度和22 dB的RF至IF埠隔离度。
第五章则利用了相量分析方式来讨论在双降频低中频接收机中镜像抑制效能衰减之原因。因此,分别在射频输入端或两级混频器中间适当地摆放额外的多相位滤波器均可以大大地改善镜像抑制效能,使得在本地振荡源之正交信号误差和元件不匹配仍然存在的情况下,达到接近中频多相位滤波器之镜像抑制比的理论极值。
第六章则介绍了在低成本0.18毫米互补式金氧半导体制程下应用于低功率低杂讯直接降频接收机。在标准互补式金氧半导体制程中,深N型井双极性接面电晶体因为其超低之闪烁杂讯和较佳之转导而被有效地应用于混频器和基频放大器中,然而其相对低的截止频率在混频器的应用上也造成了额外的挑战。因此,透过详尽地分析操作在低截止频率之吉伯特混频器,电感式突起技术被用以降低本地振荡输出之损耗和增加混频器之转换增益。另一方面,次谐波混频机制为另一解决低截止频率之方式并搭配低损耗的八相位多相位滤波器实作一低功率低杂讯次谐波直接降频接收机。最后,利用可调频式双级低杂讯放大器和宽频之八相位本地振荡产生器,实作了一涵盖完整U-NII频段之低功率低杂讯接收机,其中同时利用电感式突起和次谐波混频机制成功让接收机之射频频率可以为深N型井双极性接面电晶体之三倍截止频率。
This dissertation consists of five chapters, including performance improvements of various mixer topologies and receivers. Chapter 2 introduces single-/dual-band highly linear Gilbert upconverters. The difference of OIP¬3 and OP1dB, widely used as a criterion for mixer linearity, is over 22 dB by using an input bias-offset cross-coupled pair and output shunt-shunt feedback buffer amplifier.
In Chapter 3, passive quadrature signal generators are deeply discussed, including amplitude/phase relations by using phasor analyses. Further, a bipolar-juncion- transistor (BJT)-based Gilbert mixer inherently has a wider flat-gain region and more toleration of LO amplitude imbalance than MOS active/passive mixers. Thus, the loss imbalance of the LO quadrature coupled-line coupler directly implemented on a lossy silicon substrate can be simply solved by choosing proper LO power in the common flat-gain region. On the other hand, an ultra-wideband (UWB) Gilbert downconverter using an LR-CR quadrature generator, which has always perfect quadrature phase but balanced amplitudes only at the center frequency. However, the BJT mixer successfully compensates this drawback and achieves amplitude/phase imbalance below ±1dB/±2° covering whole UWB bands, respectively.
In Chapter 4, a 0.35-μm SiGe heterojunction bipolar transistor (HBT) high-isolation sub-harmonic mixer is proposed using a delay compensation technique. The sub-harmonic mixers with and without delay compensation are demonstrated at the same bias condition, device sizes and operating frequency. As a result, similar conversion gain, noise figure and linearity are achieved. However, the 2LO-to-RF/IF isolation is improved by 34/35 dB, the LO-to-RF/IF isolation by 8/9 dB and the RF-to-IF isolation by 22 dB.
Chapter 5 fully discusses the reasons for the degradation of the image rejection performance in a dual-conversion low-IF receiver by using phasor analyses. By inserting the poly-phase filters (PPFs) at proper positions (RF stage or inter-stage between two downconversions), the image-rejection ratio (IRR) can nearly reach the theoretical limit of the IF PPF even if the LO quadrature imbalance and device mismatches still exist.
Finally, Chapter 6 introduces various techniques in designing a low-power low-noise direct-conversion receiver (DCR) in a low-cost 0.18-μm CMOS technology. Deep-n-well (DNW) BJTs in standard 0.18-μm CMOS process are used for lower flicker noise and higher transconductance than standard NMOS devices. But the relatively low cut-off frequency (fT) becomes a big challenge for the mixer application. Thus, the current switching operation of the BJT switching function operating near or even higher than the device fT is fully analyzed. An inductive peaking technique is then used to compensate the loss of the LO generator and the mixer conversion loss. On the other hand, a sub-harmonic mixing is another straightforward solution for the low-fT operation, but a low-loss octet-phase PPF is analyzed and employed to generate well-balanced octet LO signals. Furthermore, a low-power sub-harmonic DCR covering whole U-NII bands is also demonstrated in this chapter by using a two-stage tunable-band RF low-noise amplifier (LNA) and a wideband octet-phase generator.
URI: http://140.113.39.130/cdrfb3/record/nctu/#GT079513570
http://hdl.handle.net/11536/41103
显示于类别:Thesis


文件中的档案:

  1. 357001.pdf

If it is a zip file, please download the file and unzip it, then open index.html in a browser to view the full text content.