Ka 波段基波镜像抑制混频器无源电路的设计

本文介绍了Ka 波段基波镜像抑制混频器中无源电路的设计，无源电路包括带直流偏置支路的3dB 同相功分器和带中频输出支路的兰格电桥。运用ADS 软件进行辅助设计，最终得到功分器在频段32~37GHz 的幅度不平衡度小于0.01dB，在中心频率35GHz 的插损约为3.2 dB；兰格电桥在频段32~37GHz 的幅度不平衡度小于0.15 dB，相位差约为85°，相位不平衡度小于0.5°在中心频率35GHz 的插损约为3.4 dB。最终的仿真结果较好地满足了设计要求。     

新型小型化平衡滤波器的设计

结合平衡滤波器性能与LTCC(Low Temperature Co-fired Ceramics)工艺,从滤波器和巴伦的设计理论出发,设计了一款新型小型化的高性能平衡滤波器。该平衡滤波器采用多层带状线结构作为基本的谐振单元同时实现滤波和巴伦功能。仿真结果表明,该平衡滤波器的通带中心频率为4.05 GHz,3 dB带宽为300 MHz,通带3.9~4.2 GHz内插损小于5.5 dB,低阻带1.0~3.5 GHz和高阻带5~8 GHz的衰减均大于30 dB,幅度不平衡度小于±0.25 dB,相位不平衡度小于±6°,平衡滤波器尺寸为3.2 mm×2.5 mm×1.5 mm。     

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.     

一种加载铁氧体磁环的高功率宽带巴伦

针对高功率天线的差分馈电和阻抗匹配问题,文中提出了一种基于同轴线结构加载铁氧体磁环的宽 带巴伦模型。双同轴线具有阻抗变换功能和较好的功率承载能力,铁氧体磁环改善了巴伦在低频时的输入匹配和 两个输出端口不平衡度。仿真和实测表明,此巴伦在0. 05~1. 24 GHz 内回波损耗低于-10 dB,去除3. 0 dB 系统插损 后单端插入损耗在1. 5 dB 以内,两端输出的相位不平衡度在5°以内,幅度不平衡度在2%以内。通过分析巴伦的电 磁热损耗场、温度场和应力形变场,验证了巴伦在高功率馈电下的工作性能,结果表明此巴伦在工作频带内能够承 受500 W 的功率。     

采用次谐波混频技术的毫米波超宽带混频器研制

提出了一种次谐波混频技术结合宽带匹配滤波电路的设计方法,能有效降低本振源的制作难度,并可扩展中频带宽。应用高频场仿真软件以及谐波平衡仿真软件,研制了两个频段的超宽带次谐波混频器。测试结果:K频段混频器,固定本振频率15 GHz,射频频率在18~26.5 GHz的频带内变化时,变频损耗小于10.7 dB,最小变频损耗为7.5 dB;Ka频段混频器,固定本振频率22 GHz,射频频率在26.5~40 GHz的频带内变化时,变频损耗小于11.5 dB,最小变频损耗为8 dB。测试结果指标与传统的双平衡混频器指标相当,证明了电路设计方案的正确性。     

基于新型宽带半模SIW巴伦的双平衡混频器

利用新型宽带半模基片集成波导(SIW)巴伦,设计制作了一个X波段双平衡混频器.利用SIW上下导带电流相位相差180°的原理,经优化设计使该巴伦具有体积小、带宽大、平衡性好等特点.测试结果表明,该双平衡混频器在8.7～9.7GHz的频率范围内变频损耗小于9dB,最小可达7.3dB;噪声系数小于10dB,实物面积为60mm×68mm.     

X波段微波低噪声混合集成接收前端

介绍了低噪声GaAsFET用作单脉冲跟踪雷达前端放大时的持点、系统构成以及低噪声放大器和镜像抑制混频器的设计方法和制作。测试结果性能满意，在近1GHZ频率范围内系统总噪声系数小于2．5dB，放大器增益大于20dB，混频器镜像抑制度大于20dB，三路放大器之间幅度不平衡小于0．8dB，相位不平衡小于7°。该混合集成微波前端已成功地用于某型火控雷达，对海面上低空小目标进行跟踪。     

Ka波段镜像抑制谐波混频器设计

针对现代毫米波接收机和雷达系统高抗干扰能力的需求,分析了具有镜像频率抑制能力的谐波混频器的基本原理,提出了一种Ka波段镜像抑制谐波混频器的设计方案。该混频器由两个混频单元组成,利用输出信号的相位关系识别RF信号和镜频信号,RF混频信号在输出端口同相叠加,镜频混频信号反相抵消。使用Ansoft HFSS和Agilent ADS仿真软件分别完成电路无源部分仿真和谐波平衡仿真设计,制作了混频器并进行了测试。测试结果表明:RF频率为29.4～31GHz,中频(IF)为100 MHz,变频损耗稳定在8.8～10.3 dB,镜像抑制度大于20.1 dB,各个端口隔离度均大于31.4 dB,RF端口和本振(LO)端口驻波比分别小于1.3和2.2,输入功率在1 dB压缩点为-5 dBm。     

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。     

新型LTCC高隔离低插损3dB90°电桥设计

基于宽边耦合带状线结构,该文设计了一种基于低温共烧陶瓷(LTCC)技术的高隔离低插损3 dB 90°电桥。该电桥使用螺旋耦合线有效地减小了器件尺寸,同时以对称式结构建模更便于后期的优化调整。在宽边螺旋耦合带状线垂直方向引入一个伸入式可调隔离电容,极大地提高了该电桥的隔离度,使其可达27 dB,且插入损耗≤0.2 dB,较之传统的定向耦合器结构,其在提升性能的同时大幅减小了器件尺寸。对耦合线直角拐弯处的电场强度进行分析与优化,采用45°斜切的方式使拐角处的电场强度与直线处大致相等。对上接地金属板进行环形镂空处理,这将改善带内的幅度平衡度。该文设计的3 dB 90°电桥通带为0.96~1.53 GHz,插入损耗≤0.2 dB,幅度平衡度≤±0.7 dB,相位平衡度为90°±1°,隔离度≥27 dB,其具有良好的应用市场。     

A 170 GHz 45$^{circ}$ Hybrid for Submillimeter Wave Sideband Separating Subharmonic Mixers

We present a 135deg/45deg phase shifter hybrid intended to be used in subharmonic sideband separation mixer schemes at submillimeter-wave frequencies. The design consists of an increased height 90deg 6-arm branch guide coupler with a three stub loaded differential line 45deg phase shifter at the output. The device has been implemented at G-band in an E-plane WR-05 splitblock design with a center frequency of 170 GHz and 15 % bandwidth. Measured S-parameter are in good agreement with simulations showing an isolation and return loss better than 20 dB and an amplitude and phase imbalance within 0.4 dB and 2deg, respectively.     

A 23–37 GHz Miniature MMIC Subharmonic Mixer

A novel configuration of subharmonic mixer using an anti-parallel diode pair is presented for operating over the 23-37 GHz band. The monolithic microwave integrated circuit is implemented by GaAs 0.15 mum PHEMT technology with the compact size of 0.85 times 0.85 mm². This mixer employs a directional coupler, LC low-pass filter, and a short stub for isolating three ports corresponding to radio frequency (RF), local oscillation (LO) input, and intermediate frequency (IF) output ports. The directional coupler also provides impedance transformation between the diode pair, RF, and LO ports. This makes the subharmonic mixer more compact and flexible. The best conversion loss of the subharmonic mixer is 9.4 dB, and the LO-to-RF and LO-to-IF isolations are better than 22 and 31 dB, respectively.     

Low conversion-loss fourth subharmonic mixers incorporating CMRC for millimeter-wave applications

Low conversion-loss millimeter-wave fourth subharmonic (SH) mixer designs are proposed in this paper. A millimeter-wave (35 GHz) fourth SH mixer with four open/shorted stubs is designed and measured. The conversion loss is less than 15 dB within a 2.4-GHz bandwidth. The minimum loss is 11.5 dB at the center frequency. By replacing two of the shunt stubs with a dual-frequency in-line stub consisting of newly developed compact microstrip resonating cells (CMRCs), the performance of the SH mixer is improved significantly. At 35 GHz, the conversion loss of this new fourth SH mixer is as low as 6.1 dB with a 3-dB bandwidth of 6 GHz. The conversion loss in the whole Ka-band (26.5-40 GHz) is less than 16 dB. The proposed fourth SH mixer incorporating with CMRCs provides a low-cost high-performance solution for RF subsystem design.     

A 9–31-GHz Subharmonic Passive Mixer in 90-nm CMOS Technology

A subharmonic down-conversion passive mixer is designed and fabricated in a 90-nm CMOS technology. It utilizes a single active device and operates in the LO source-pumped mode, i.e., the LO signal is applied to the source and the RF signal to the gate. When driven by an LO signal whose frequency is only half of the fundamental mixer, the mixer exhibits a conversion loss as low as 8–11 dB over a wide RF frequency range of 9–31GHz. This performance is superior to the mixer operating in the gate-pumped mode where the mixer shows a conversion loss of 12–15dB over an RF frequency range of 6.5–20 GHz. Moreover, this mixer can also operate with an LO signal whose frequency is only 1/3 of the fundamental one, and achieves a conversion loss of 12–15dB within an RF frequency range of 12–33 GHz. The IF signal is always extracted from the drain via a low-pass filter which supports an IF frequency range from DC to 2 GHz. These results, for the first time, demonstrate the feasibility of implementation of high-frequency wideband subharmonic passive mixers in a low-cost CMOS technology.     

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 high-performance W-band uniplanar subharmonic mixer

A uniplanar subharmonic mixer has been implemented in coplanar waveguide (CPW) technology. The circuit is designed to operate at RF frequencies of 92-96 GHz, IF frequencies of 2-4 GHz, and LO frequencies of 45-46 GHz. Total circuit size excluding probe pads and transitions is less than 0.8 mm ×1.5 mm. The measured minimum single-sideband (SSB) conversion loss is 7.0 dB at an RF of 94 GHz, and represents state-of-the-art performance for a planar W-band subharmonic mixer. The mixer is broad-band with a SSB conversion loss of less than 10 dB over the 83-97-GHz measurement band. The measured LO-RF isolation is better than -40 dB for LO frequencies of 45-46 GHz. The double-sideband (DSB) noise temperature measured using the Y-factor method is 725 K at an LO frequency of 45.5 GHz and an IF frequency of 1.4 GHz. The measured data agrees well with the predicted performance using harmonic-balance analysis (HBA). Potential applications are millimeter-wave receivers for smart munition seekers and automotive-collision-avoidance radars     

A 10–40 GHz Broadband Subharmonic Monolithic Mixer in 0.18 $mu$ m CMOS Technology

A 10–40 GHz broadband subharmonic monolithic passive mixer using the standard 0.18 $mu$ m CMOS process is demonstrated. The proposed mixer is composed of a two-stage Wilkinson power combiner, a short stub and a low-pass filter. Likewise, the mixer utilizes a pair of anti-parallel gate-drain-connected diodes to achieve subharmonic mixing mechanism. The two-stage Wilkinson power combiner is used to excite a radio frequency (RF) and local oscillation (LO) signals into diodes and to perform broadband operation. The low-pass filter supports an IF frequency range from dc to 2.5 GHz. This proposed configuration leads to a die size of less than 1.1$,times,$ 0.67 mm$^{2}$ . The measured results demonstrate a conversion loss of 15.6–17.6 dB, an LO-to-RF isolation better than 12 dB, a high 2LO-to-RF isolation of 51–59 dB over 10–40 GHz RF bandwidth, and a 1 dB compression power of 8 dBm.      

Millimeter-Wave Lange Coupler Design and Its Application in the Monolithic Image Rejection Mixer Design

This paper reports on the design of a Ka-band monolithic Lange coupler and its application in the monolithic fourth-harmonic image rejection mixer. Detailed design and analysis using Ansoft-HFSS simulator have been carried out. The simulated results of the Lange Coupler show the insert loss is better than ?3.64 dB; the amplitude balance is less than 0.55 dB and the phase balance is less than 0.65° from the 90° phase difference over the 30 to 40 GHz frequency range. The Lange Coupler is employed in a monolithic image rejection mixer that is fabricated by a commercial 0.18-μm pseudomorphic high electron-mobility transistor (pHEMT) process. The chip size is 1.4 mm × 1.9 mm. The image rejection ratio (IMR) is from 15 to 34 dB in the RF frequency range of 30 to 40 GHz.     

A 400–500 GHz Balanced SIS Mixer with a Waveguide Quadrature Hybrid Coupler

We have developed a 400–500 GHz low-noise balanced SIS (Superconductor Insulator Superconductor) mixer, which is based on a waveguide RF quadrature hybrid coupler. The RF quadrature hybrid was designed and fabricated as a broadband hybrid with good performance at 4 K. The fabricated RF quadrature hybrid was measured at room temperature with a submillimeter vector network analyzer to check amplitude and phase imbalance between two output ports. Then the balanced mixer was assembled with the RF hybrid, two DSB mixers, and a 180° IF hybrid. Several important parameters such as noise temperature, LO power reduction, and IF spectra were measured. The LO power reduction is defined as how much LO power the balanced mixer saves compared with a typical single-ended mixer. The measured noise temperature of the balanced mixer was ~ 55 K at the band center which corresponds to ~ 3 times the quantum noise limit (hf/k) in DSB, and ~ 120 K at the band edges. The noise performance over LO frequency was almost the same as that of the worse DSB mixer used in the balanced mixer. In addition the LO power required for the balanced mixer is ~ 11 dB less than that of the single-ended mixers.