340GHz 四次谐波混频器的研制

太赫兹波是电磁波谱中最后一个未被全面研究开发的频率窗口,它的开发和利用具有重大的科学价值。介绍了一种太赫兹频段内340GHz基于肖特基势垒二极管的四次谐波混频器设计。应用高频场仿真软件(HFSS)以及谐波平衡仿真软件(ADS),对反向并联二极管对进行3D建模及阻抗频率特性分析,并在此基础上对混频器进行优化。最后,对该混频器进行加工和测试,结果表明,在327~343GHz频带范围内,变频损耗小于15dB,最优值为12.7dB。     

A New Mixer Design for 140-220 GHz (Short Papers)

A new Schottky-diode mixer is described which has low noise and conversion loss in the 140-220-GHz band. At 170 GHz mixer noise temperatures of 1100-1300 K [Single sideboard (SSB)] have been measured, with 6.2-7.2-dB SSB conversion loss. The design should be usable up to -300 GHz with appropriate scaling. The mixer has been successfully used in airborne radiometers on the NASA Convair 990 and C-141 aircraft.     

A Weak-Inversion Low-Power Active Mixer for 2.4 GHz ISM Band Applications

This work describes a fully integrated active mixer designed in 0.18 $mu{rm m}$ CMOS technology for 2.4 GHz Industrial, Scientific and Medical (ISM) band applications. The mixer uses a source driven local oscillator (LO) to integrate the RF-LO buffering with the active mixer, and weakly inverted input MOSFETs to improve the gain and noise performance. The double-balanced quadrature mixer has a measured conversion gain of 32 dB with a double sideband (DSB) noise figure (NF) of 8.5 dB at 30 MHz intermediate frequency (IF) while consuming only 0.56 mA of current from a 1.8 V supply.      

The Measured and Computed Performance of a 140--220 GHz Schottky Diode Mixer

In this paper, we compare the measured and theoretical performance of a room-temperature single-ended Schottky diode mixer in the WR-5 (140-220-GHz) waveguide band. Using the computer program GISSMIX, combined with measurements made on a 100X scale model of the WR-5 mixer, we have been able to predict the millimeter-wave mixer performance over a wide tuning range with unprecedented accuracy. In addition we have examined the sensitivity of the mixer performance to various diode and mount characteristics. Our rneasured conversion loss and mixer noise temperature, single sideband, are 5.7 dB and 750 K at 180 GHz, and 5.7 dB and 500 K at 150 GHz, which we believe to be the best reported for a room-temperature mixer at these frequencies.     

A Harmonic Mixer for the 20-40-GHz Range

The design and performance of a wide-band harmonic mixer are described. The circnit is built on a microstrip substrate and uses a single GaAs Schottky-barrier diode.     

An Integrated Sideband-Separating SIS Mixer Based on Waveguide Split Block for 100 GHz Band with 4.0–8.0 GHz IF

We have developed an integrated sideband-separating SIS mixer for the 100 GHz band based on the waveguide split block. The measured receiver noise temperatures with 4.0–8.0 GHz IF are less than 60 K in the LO frequency range of 90–110 GHz, and a minimum value of around 45 K is achieved at 100 GHz. The image rejection ratios are more than 10 dB in the frequency range of 90–110 GHz. We have installed the sideband-separating SIS mixer into an atmospheric ozone-measuring system at Osaka Prefecture University and successfully observed an ozone spectrum at 110 GHz in SSB mode. This experimental result indicates that the sideband-separating SIS mixer is very useful for astronomical observation as well as atmospheric observation.     

Full Band Millimeter-Wave Power-Combining Amplifier Using a Lossy Power-Combining Network

This paper presents a millimeter-wave broadband power-combining amplifier using a novel lossy waveguide-based power combiner. The lossy combiner has a performance of broadband low-loss combining symmetrically and has properties of good match and high isolation at and between ports, because lossy planar lines are embedded in the lossy combiner and even-mode excitations are weakened. The measured results show that the lossy combiners has a loss of about 0.14 dB and achieves reflection and isolation of about—15 dB in 26.5–40 GHz. And then, using the lossy combiner, a compact lossy waveguide-based four-way-combining network is fabricated. The lossy network has a measured loss of about 0.25 dB and achieves good improvements of match and isolation in the full Ka-band. The improvements can enhance stability of amplifying units when the lossy combining network used in multi-way power-combining amplifier. Using the lossy combining network, a solid-state power-combining amplifier is developed, and corresponding experimental results show that output power is more than 30 dBm and combining efficiency is more than 80 % in the full Ka-band.     

矢量网络分析仪电子校准件设计与实现

为深入研究矢量网络分析仪校准技术,促进电子校准件低成本、通用化应用,基于通用的射频开关模块和开源的Arduino 控制模块搭建了电子校准件硬件系统;为适应电子校准件的非理想工作状态,基于分式变换特性推导了系统误差项的求解算法。最后利用E5071C 矢量网络分析仪和商用E4431B 电子校准件搭建对比测试系统,并选用移动通信滤波器作为测试对象,验证了所设计电子校准件硬件的正确性和误差修正算法的有效性。此研究成果可为电子校准件低成本、通用化应用提供参考。     

基于TMS320C54x的电网谐波分析系统

随着市场经济的发展,电网的安全以及谐波问题已经越来越受到人们的关注.目前已经存在很多的电网谐波分析系统方案,但其中多数是以单个微处理器为核心的.本文针对TI公司的DSP TMS320C54x的性能特点,介绍了一种将TMS320C54x与微处理器相结合的多处理器电网谐波分析系统.首先,文章介绍了整体系统的设计方法和工作原理,并着重说明了TMS320C54x以及其周边电路的功能作用.然后,在硬件设计和软件设计的两个方面给出了具体的设计方法和设计流程.     

Optical design of a dual-polarization receiver for 220–280 GHz

A 220–280 GHz dual polarization receiver has been built for the James Clerk Maxwell Telescope. Schottky diode mixers cooled to ～15K by a closed-cycle refrigerator are used to give DSB noise temperatures of 300K and 420K in the two channels. The optical design is based on gaussian-beam optics, and is frequency independent; it allows the significant higher order gaussian modes to propagate unhindered, thus offering the prospect of very high aperture efficiency. The receiver includes a number of novel optical components, including a completely symmetric dual polarization Martin-Puplett interferometer, used as the L.O. injection diplexer; a dielectric waveplate used as an in-line variable polarization splitter; and a dual-polarization in-line tunable Fabry-Perot SSB filter. Measurements of the performance of the optical system are presented.     

Superconductor-Insulator-Superconductor Mixers for the 2 mm Band (129-174 GHz)

We present the design, construction and performance of backshort-tuned Single Side Band (SSB) and of fixed-tuned Double Side Band (DSB) Superconductor-Insulator-Superconductor (SIS) mixers covering the frequency range of 129-174 GHz (2 mm band). Receivers employing these SSB mixers have been continuously operated for astronomical observations on the six antennas of the IRAM Plateau de Bure Intereferometer (PdBI) since 2007 and on the IRAM 30 m Pico Veleta (PV) radio telescope since 2009. The DSB version of the mixer was employed in a prototype of a four-element focal plane array that was tested on the IRAM 30 m radio telescope. Both SSB and DSB mixers employ the same chip and are based on a wideband single ended probe transition from WR6 full-height waveguide to thin-film microstrip line and on a series array of two Nb/Al-AlO_x/Nb junctions. The measured receiver noise for the four-element DSB mixer array pumped by a Gunn oscillator cascaded with a frequency doubler was in the range 25-35 K across the 135-168 GHz LO band. The PdBI and PV receivers equipped with the SSB mixers have measured noise temperatures in the range of 30 K to 60 K and an image sideband rejection below -10 dB over the 129-174 GHz RF band. The measurement results agree well with the predictions obtained through detailed simulations of the SIS receivers based on the standard theory of quantum mixing.     

一种基于10项误差模型的二端口矢量网络分析仪校准方法

在三通道二端口矢量网络分析仪(Vector Network Analyzer,VNA)的校准过程中,引入长度未知的50欧姆传输线段作为校准件代替常见的短路-开路-匹配-直通(Short-Open- Load-Thru,SOLT)校准算法中的匹配校准件,减少了校准件数量且不需要已知校准件的全部特性,不仅降低了测试成本,同...     

基于矢网的行波管AM/PM转换系数的测试

分别用传统测试方法和用矢网测量S参数法测试了行波管的调幅调相转换系数,对两次测试结果进行了比较,并重点对矢网测试的误差进行了分析和讨论,确定了用矢网测量行波管AM/PM参量的方法.实际测试结果表明通过调整状态设置参量,用矢网测试行波管AM/PM参量的方法是高效可行的.     

220C协议中网络接入控制的分析与研究

文中叙述了MIL-STD-188-220C协议的网络接入控制(NAC)过程,详细分析了该协议的确定自适应网络接入延迟(DAP-NAD),并在此基础上给出了一个DAP-NAD的实现方法.     

Design of a 24 GHz, 25-50 kW Technology Gyrotron Operating at the Second Harmonic

The preliminary design of a moderate (25-50 kW) gyrotron operating at the ISM (industrial, scientific, medical) frequency of 24.1 GHz is presented. Operation at the second harmonic is considered so that one can obtain radiation at the given frequency with only half the magnetic field required.     

Design and Characterization of a 211–275 GHz Sideband Separating Mixer for the APEX Telescope

We present the final results of the development and characterization of the sideband separating superconductor-insulator-superconductor (SIS) mixer for the APEX telescope band 1 (211-275 GHz). The sideband separation is achieved by using a quadrature scheme where the radio frequency (RF) and a local oscillator (LO) power are applied to two identical double sideband SIS mixers. All mixer components, including the LO and RF distribution circuitry, are integrated into a single mixer block. To achieve a compact design we developed a superconducting Lange coupler, based on Nb thin film, which is used as an intermediate frequency hybrid. Typical single sideband noise temperature of 100 K and sideband rejection ratio of about 12 dB and are measured.     

802.11 a/b/g和4.9GHz频段设备的SAR测试方法

在分析802.11和4.9 GHz频段设备技术特点和现有SAR测量系统的基础上,介绍了测试模式的要求、测量信道的选择和数据传输速率的要求。为减小测量误差,对不同占空比和功率下的线性缩放原则,以及使用分集技术、MIMO和波束成形天线技术的设备的SAR测量方法也进行了分析和说明。     

Performance of the Production Band 3 receivers (84-116 GHz) for the Atacama Large Millimeter Array (ALMA)

This paper presents the performance of production Band 3 receivers (84-116 GHz) for the Atacama Large Millimeter Array (ALMA) that operate in Chile at 5000 m altitude. The fabrication, and testing of a total of 73 receivers necessitated stringent quality control during assembly and custom designed automated test set for accurate and reproducible measurement results. Interfaces to the ALMA receiver system are described in details. The average single side band noise temperature of band 3 production receivers is 33.2 K, with a minimum of 24.4 K and a maximum of 45.5 K. As for image rejection, the average is 18 dB, with a minimum at 12 dB and a maximum of 21 dB. Other performances with test methodology are described such as gain variation within the IF band, the gain and phase stability, gain compression, and beam patterns. This paper also describes the interfaces to the ALMA front end system, the testing methodology used, and the test results.     

一种基于神经网络的矢量量化零冗余度信道编码方法

本文提出一种新的基于神经网络的矢量量化零冗余度信道编码方法,该方法能有效地降低矢量量化编码系统在有噪信道下的平均失真。