使用標準矽製程整合90°和180°分合波器之吉伯特微混頻器

Abstract

此論文中，以0.35毫米矽鍺雙載子互補式金氧半導體製程展示單端輸入輸出吉伯特微混頻器。因應寬頻操作，在微混頻器中頻級使用電阻回授式轉阻放大器，而在本地震盪級使用寬頻巴倫或是鼠徑耦合器來產生寬頻差動訊號。在研究中，這些微波被動元件儘管實作在具損耗、低阻抗(~10 歐姆•公分)的矽基板上，仍可產生很平衡的訊號。在第二章中，提出系統化的量測方式來評量混頻器每一級的頻率響應。 第三章中提出可調式、電抗式正交相位產生器，其具有定值阻抗、低損耗、雙頻帶實作和高正交相位精確度的特性。在所有頻率中，皆可達成正交相位輸出與輸入匹配；而在設計的兩個頻段中，達成相同振幅輸出。實作的2.4/5.2 GHz正交相位降頻器之輸出振幅差小於1 %、相位差小於1□；而實作的2.4/5.7 GHz單端頻譜升頻器具有高達50 dB單端頻譜抑制比。 第四章中，使用標準矽製程實作一個具有相位反轉器之寬頻鼠徑耦合器，並詳細地分析損耗狀態下的耦合器。將相位反轉器應用在鼠徑耦合器，不僅能增加頻寬，亦可提供等損耗的輸出路徑，以保持輸出平衡；而對稱式螺旋形共平面帶狀傳輸線不僅可以縮小耦合器大小，還可利於建造相位反轉器於其中一個螺旋形共平面帶狀傳輸線上。無失真具損耗的共平面帶狀傳輸線具有實數特性阻抗，使得耦合器在中心頻率可達成匹配。此外，展示了應用此型態鼠徑耦合器之2.5到13 GHz寬頻微混頻器。 第五章中，實現整合本地震盪器級馬爾尚巴倫之寬頻混頻器，具有15 dB轉換增益，操作頻率在3.5到14.5 GHz，此外，縮小化成塊元件馬爾尚之降頻器展示於超寬頻系統中，具有15.5 dB轉換增益。而第六章中，以耦合指數和特性阻抗來分析與設計傳統平面式馬爾尚巴倫與其變化型，此兩種型態在結構上具有雙重性，然而當兩種巴倫以相同特性阻抗設計時，新型態巴倫會較寬頻。此外，而在此章節分析中，發現只要實作在均質材料中，其輸出在所有的操作頻率皆會具有相同的振幅與相反的相位，所以這兩種巴倫即使在具有損耗的環境中，仍可正常運作。在實作結果中，改良式的馬爾尚巴倫明顯地具有較好的效能，其輸出在4到25 GHz相位差約180±5度、振幅差約±0.5 dB，而其分數頻寬大於140 %。為了進一步比較，將此兩型態巴倫整合在微混頻器的本地訊號級，而相較於傳統馬爾尚巴倫，改良型巴倫多提供30 %操作頻寬。即使在具損耗的基板上，巴倫消耗損耗大約只有2~3 dB。

In this dissertation, all single-ended Gilbert micromixers are demonstrated using 0.35-□m SiGe BiCMOS technology. For wideband operation, a transimpedance amplifier with resistive feedback is utilized in the IF stage while a broadband balun or a rat-race coupler is employed to generate wideband differential local oscillator (LO) signals. These microwave passive components in our study can generate truly balanced signals even in the presence of a lossy low-resistivity (~10 Ω•cm) silicon substrate. A systematic approach to measure the frequency response of each individual stage in a Gilbert mixer is developed in Chapter 2. In Chapter 3, adjustable and reactive in-phase/quadrature (I/Q) generators with constant resistance are proposed with the properties of low loss, dual-band implementation, and high quadrature accuracy. The quadrature phase property and input matching of the I/Q generator can be achieved at all frequencies simultaneously. However, the magnitude balance of the dual-band I/Q generator is achieved at two designed frequencies. A 2.4/5.2 GHz I/Q down-converter and a 2.4/5.7 GHz single-sideband up-converter are demonstrated. In Chapter 4, this dissertation realized a broadband uniplanar phase-inverter rat-race coupler using a standard silicon process, and then analyzed this coupler under a lossy condition. A phase inverter is employed in this coupler, not only to extend the operation bandwidth, but also to generate balanced outputs, while symmetrical spiral-shaped coplanar striplines (CPSs) are also utilized to shrink the coupler size, as well as to construct a phase inverter in the middle of one of spiral CPSs. The distortionless lossy CPS has a real characteristic impedance, and thus, perfect port matching of the coupler can be achieved. A wideband Gilbert micromixer with an LO rat-race coupler is demonstrated and works from 2.5 to 13 GHz. In Chapter 5, the wideband mixer with an integrated LO Marchand balun has the conversion gain of 15 dB and works from 3.5 to 14.5 GHz. In addition, a 15.5-dB conversion gain Gilbert mixer with a miniaturized lumped-element Marchand balun is demonstrated for UWB applications. In Chapter 6, a planar Marchand balun and its modification are analyzed and designed with a coupling factor and a corresponding characteristic impedance. The modification has duality with the original Marchand balun in structure. However, this proposed alteration has a much larger operation bandwidth than the prototype. Additionally, based on our analysis, the fact is found that the balun’s outputs are always equal in magnitude and opposite in phase within all frequency ranges, as long as the material is homogeneous. Namely, these baluns, even in a lossy material, still function well. The implemented modified Marchand balun has a better performance with outputs of an 180±5□ phase difference and a ±0.5-dB magnitude imbalance from 4 to 25 GHz. The fractional bandwidth is more than 140%. Also, the modified Marchand balun integrated at the LO stage of the mixer offers more than 30%-operation bandwidth.