K波段单平衡上变频器的设计

文中介绍了一种应用于宽带无线接入系统发射机的K波段单平衡上变频器的设计方法,并给出了仿真结果和电路版图。电路选用Alpha公司的砷化镓肖特基势垒二极管,采用易于实现的环形电桥结构。通过在环形电桥的一个端口附加45。相移实现了上边带单平衡混频,变频损耗小于6dB,三阶交调系数为39dB,输入1dB压缩点为10dBm。整个电路具有低成本、低变频损耗的特点。     

一种新型宽带环形电桥耦合器设计

传统四端口环形电桥耦合器的带宽只有10%到20%。为了获得更大的带宽,本文提出了一种改进型环形电桥耦 合器。通过额外增加一个隔离臂,新设计可以工作在整个W波段。在此基础上,本文在输入臂上加入了一个切角来改善 输出信号的隔离度。仿真研究结果表明,在75GHz 到110GHz,两输出信号的幅度不平衡度小于0.07dB,相位不平衡度小 于0.37 度。相比于未作切角处理的五端口环形电桥,新设计输出端口的隔离度在全频段内大于15.07dB。改进型耦合器 可以应用于W波段平衡调制器以及其他需要高输出隔离度的W波段功率分配系统。     

Q 波段波导环形电桥的设计与实现

本文介绍了一种采用波导来实现的环形电桥的设计与实现方法。它是在基于微带环形电桥的奇偶模分析的基 础上,用矩形波导代替微带线,实现了Q 波段的环形电桥,环路电桥的输入输出端口均为BJ400 波导。其中为了改 善输入端口的反射,在输入端口的不连续性处加入了一个销钉,销钉的尺寸由HFSS 优化仿真确定。实测结果得到, 在43-46GHz 范围内,环形电桥的反射小于-20dB,输出端口的传输系数均大于-3.4dB,隔离度大于20dB。从测量结 果可以看出,与微带线的实现方式相比,波导环形电桥具有更小的传输损耗。     

X波段低变频损耗混频器设计

采用商用肖特基势垒二极管HSMS-2822,研制了低变频损耗、高隔离度X波段单平衡混频器。为实现所需要的混频带宽,本振信号和射频信号采用三分支定向耦合器耦合输入,仿真研究表明其能有效地改善工作频率带宽,提高本振端口与射频端口间的隔离度。通过设计合理的空闲频率回收电路,回收利用空闲频率能量,能有效地降低混频器变频损耗,提高本振信号、射频信号及空闲频率信号到中频端口的隔离度。在10.6GHz,测得最小变频损耗5.67dB;在10～11.5GHz,混频器变频损耗为6.4±0.7dB,变频损耗平坦度好,RF-IF隔离度优于27dB,LO-IF隔离度高于24dB,LO-RF隔离度优于14dB。     

一种改进型Ka波段宽带耦合器设计

基于LTCC工艺技术,分析并设计了一款改进型Ka波段宽带带状线耦合器,耦合器采用两个8.34 dB带状线耦合器级联实现,并用调谐电容片和弧形带状线改善隔离度与回波损耗。利用三维电磁场分析软件HFSS对耦合器三维结构进行了建模仿真和分析改进。结果表明,该耦合器的回波损耗和隔离度在17.7~29.0 GHz都大于20 dB。     

宽带混频器的优化设计

采用0.25μm GaAs赝配高电子迁移率晶体管(PHEMT)工艺设计并实现了一款单片宽带混频器.该混频器采用双平衡混频器结构,以串联的两个漏源相连的PHEMT作为环形二极管电桥中的二极管以提升混频器线性度.本振巴伦和射频巴伦均采用螺旋线式Marchand巴伦,为降低巴伦的幅度及相位不平衡度,采用遗传算法对巴伦的几何参数进行了优化设计.该混频器电路采用0.25 μm GaAs PHEMT工艺实现,芯片面积为1.5mm×1.1 mm.测试结果表明,当本振功率为20 dBm时,变频损耗小于7 dB,输入三阶交调点ⅡP3大于22 dBm.本振端口到射频端口和中频端口的隔离度均大于30 dB.     

GaAs MMIC宽带双平衡混频器的研制

采用GaAs肖特基二极管工艺,设计并制造了一款宽带无源双平衡混频器,射频、本振频率为1.5～3.7 GHz,变频损耗小于10 dB,本振到射频隔离度大于35 dB,中频带宽DC～0.8 GHz.该混频器采用了环形二极管和螺旋式巴伦结构,在获得良好的变频损耗与隔离度的同时,显著减小了芯片面积,整体芯片尺寸为1.2 mm × 1.2 mm.     

W 波段单平衡混频器的设计

本文设计并制作了一种微带形式W 波段单平衡混频器。该混频器采用微带环形电桥结构,射频和本振信号分别从环形电桥的隔离端口由标准波导BJ-900 输入,经对脊鳍线微带波导过渡输入到微带电路,中频信号通过跳线方式连接并通过一段高阻抗线引出到输出口。该电路使用两只DMK2790 肖特基二极管制作在介电常数为2.2,厚度为0.127mm 的RT/Duriod5880 基片上,在固定本振94.5GHz,射频90GHz 到98GHz 范围内,变频损耗小于14.5dB。     

一种新型螺旋宽边耦合的定向耦合器

设计了一种新型螺旋宽边耦合结构的微型定向耦合器,并用电容补偿法改善了回波损耗和隔离度。利用三维电磁场分析软件对定向耦合器三维结构进行了建模分析和仿真优化,回波损耗和隔离度在600~900 MHz时大于25 dB,试验样品的测试结果与仿真结果吻合。     

新型四次谐波混频电路

本文介绍了一种适用于高次谐波混频的电路原理图,基于空闲频率相位抵消理论,该混频电路结构可以避免复杂的空闲频率回收电路设计,同时能获得很高的端口隔离度。基于该结构,设计了新型的Ka波段四次谐波混频器,该混频器在38.4 GHz测得最小变频损耗 8.3 dB,在34-39 GHz 变频损耗小于10.3dB, LO-IF、RF-LO、 RF-IF 端口隔离度分别优于30.7 dB、 22.9dB、46.5dB。     

A Novel 94-GHz MHEMT Resistive Mixer Using a Micromachined Ring Coupler

In this letter, we present a high performance 94-GHz millimeter-wave monolithic integrated circuit resistive mixer using a 70-nm metamorphic high electron mobility transistor (MHEMT) and micromachined ring coupler. A novel three-dimensional structure of a resistive mixer was proposed in this work, and the ring coupler with the surface micromachined dielectric-supported air-gap microstrip line structure was used for high local oscillator/radio frequency (LO–RF) isolation. Also, the LO–RF isolation was optimized through the simulation. The fabricated mixer has excellent LO–RF isolation, greater than 29 dB, in 2-GHz bandwidth of 93–95GHz. The good conversion loss of 8.9dB was measured at 94GHz. To our knowledge, compared to previously reported W-band mixers, the proposed MHEMT-based resistive mixer using a micromachined ring coupler has shown superior LO–RF isolation and conversion loss.     

High-performance 94-GHz single balanced mixer using 70-nm MHEMTs and surface micromachined technology

We reported 94-GHz, low conversion loss, and high isolation single balanced active gate mixer based on 70-nm gate length InGaAs/InAlAs metamorphic high-electron mobility transistors (MHEMTs). This mixer showed that the conversion loss and isolation characteristics were 2.5/spl sim/3.5 dB and under -29 dB in the range of 92.95/spl sim/94.5 GHz, respectively. The low conversion loss of the mixer is mainly attributed to the high-performance of the MHEMTs exhibiting a maximum drain current density of 607 mA/mm, an extrinsic transconductance of 1015 mS/mm, a current gain cutoff frequency (f/sub t/) of 330 GHz, and a maximum oscillation frequency (f/sub max/) of 425 GHz. High isolation characteristics are due to hybrid ring coupler which adopted dielectric-supported air-gapped microstrip line structure using surface micromachined technology. To our knowledge, these results are the best performance demonstrated from 94 GHz single balanced mixer utilizing GaAs-based HEMTs in terms of conversion loss as well as isolation characteristics.     

超宽带谐波混频器的设计

叙述了一种超宽带谐波混频器的原理、设计以及测试结果。该混频器主要由微带线巴伦、倍频器、单平衡混频器三部分组成。按中心频率为4.5 GHz设计出微带线巴伦结构,平衡端口输出相位差180°,具有尺寸小、损耗低、幅度相位一致性好等优点;采用AEROFLEX公司的MSPD2018型相位检波器作为混频器,该混频器采用阶跃恢复二极管倍频器与单平衡混频器并联结构,先倍频n次谐波后再与信号进行混频;传输线为四分之一波长线以提高端口间隔离度;利用微波电路仿真软件ADS对混频器进行基波和谐波分析。测试结果表明,在3～25 GHz的频率范围内,本振至中频的隔离度优于66 dB,其变频损耗的实测结果满足设计要求,在现有的宽带混频器中具有较好性能。     

Analysis and Optimization of Current-Driven Passive Mixers in Narrowband Direct-Conversion Receivers

Properties of the current-driven passive mixer are explored to maximize its performance in a zero-IF receiver. Since there is no reverse isolation between the RF and baseband sides of the mixer, the mixer reflects the baseband impedance to the RF and vice versa through simple frequency shifting. It is also shown that in an IQ down-conversion system the lack of reverse isolation causes a mutual interaction between the two quadrature mixers, which results in different high- and low-side conversion gains, and unexpected IIP2 and IIP3 values. With a thorough and accurate mathematical analysis it is shown how to design this mixer and its current buffer, and how to size components to get the best linearity, conversion gain and noise figure while alleviating the IQ cross-talk problem.     

带有小型化Balun的C波段单片GaAs pHEMT单平衡电阻性混频器

 本文介绍了一种带有小型化无源Balun的C波段单片GaAs pHEMT单平衡电阻性混频器.Balun 采用集总—分布式结构,使其长度与常用λ/4耦合线Balun相比缩小了11倍,大大降低了将无源Balun应用于C波段单片集成电路中所需的芯片尺寸.混频器采用单平衡电阻性结构,在零功耗的情况下实现了良好的线性和口间隔离性能.测试结果显示,在固定中频160MHz,本振输入功率0dBm条件下,在3.5~5GHz RF频带内,最小变频损耗为8.3dB,1dB压缩点功率为8.0dBm,LO至IF之间的隔离度为38dB.     

A Low-Voltage 5-GHz Downconversion Mixer Employing A Second Harmonic Injection Linearization Technique

In this paper, a low-voltage CMOS mixer topology, appropriate for operation in the 5-GHz frequency band, is presented. The mixer combines several design techniques in order to achieve high linearity performance with minimum current consumption in a restricted 1-V supply. The proposed mixer utilizes an integrated transformer to improve the high frequency performance and to achieve large LO to RF isolation. In addition, a novel linearization technique based on second harmonic injection, is introduced to optimize linearity performance. The design is being implemented in a 0.13-mum CMOS technology.     

双平衡混频器设计与研究

在射频电路的前端,混频器是实现频谱搬移的重要器件,是十分重要的模块。采用Win公司砷化镓工艺,设计了一款二极管双平衡混频器,其中巴伦采用平面螺旋式结构,用ADS软件进行各部分电路设计、仿真,从功能仿真图中看到输出信号的频谱中有需要的中频频率成分,验证了混频器频谱搬移的功能,在所设计的频段耦合度和隔离度能够满足要求。其中射频端口和本振端口的频率为0.8~1.2 GHz,中频频率DC~300 MHz,变频损耗8~10 dB,噪声系数9 dB左右,芯片面积0.9 mm×1 mm。