OFDM跳頻式低雜訊放大器在超寬頻系統中之應用

Abstract

本篇論文主要研究跳頻式低雜訊放大器在超寬頻系統中的應用與分析。 本論文首先用Chebyshev L-C帶通濾波器架構進行輸入端匹配，再經過改良後使輸入阻抗在3.1GHz~10.6GHz間頻寬範圍內依然有良好的低反射係數，再使用單一電壓供給的source inductive degeneration疊接放大器架構，同時也可以達到降低米勒效應且獲得較低之Noise Figure以及較高的reverse isolation的結果，在switch 部份使用NMOS與電容串接,用五個NMOS開關控制電容，與Ld的電感形成LC諧振，使得output gain直接工作於所需的頻帶，以達到跳頻的結果，且輸出增益會因為能量集中的關係而在我們所控制輸出的channel有比較好的增益表現，而輸出端則利用緩衝器自身特性，使電路最終的輸出端能夠具有低輸出阻抗以及大電流的特性，來足以驅動下一級的電路。。

In this thesis, we present a Frequency Hopping Low-Noise amplifier for an MB-OFDM UWB system. First of all, we introduce the Chebyshev L-C band-pass filter architecture implement for input impedance matching use. We modify this architecture and to obtain best reflection coefficient during 3.1GHz~ 10.6GHz frequency range. Then, we implement single power to source inductive degeneration cascade amplifier architecture. In this architecture, we degrade Millier Effect and obtain lowest noise figure and highest reverse isolation. We use 5 set NMOS to make switch function, collocate Ld to choice LC resonance frequency and they can work we want frequency and enhance the output gain. In the output section, we use buffer have low output impedance and large current character to drive next stage circuit