40 GHz Vertical Transition with a Dual‐Mode Cavity for a Low‐Temperature Co‐fired Ceramic Transceiver Module

A new vertical transition between a substrate integrated waveguide in a low‐temperature co‐fired ceramic substrate and an air‐filled standard waveguide is proposed in this paper. A rectangular cavity resonator with closely spaced metallic vias is designed to connect the substrate integrated waveguide to the standard air‐filled waveguide. Physical characteristics of an air‐filled WR‐22 to WR‐22 transition are compared with those of the proposed transition. Simulation and experiment demonstrate that the proposed transition shows a ?1.3 dB insertion loss and 6.2 GHz bandwidth with a 10 dB return loss for the back‐to‐back module. A 40 GHz low‐temperature co‐fired ceramic module with the proposed vertical transition is also implemented. The implemented module is very compact, measuring 57 mm × 28 mm × 3.3 mm.     

Analysis and applications of a new CPW-slotline transition

A novel broad-band coplanar waveguide (CPW) to slotline transition and several new CPW passive circuits based on this transition are proposed and analyzed in this paper. This transition utilizes CPW-slotline mode-conversion to convert CPW-mode field to slotline-mode field, and the transition bandwidth is broadened by the use of air-bridges. The transition consists of three parts, including a uniform CPW, phase shifter, and slotline. The phase shifter converts the CPW mode to slotline mode and the bandwidth of the transition is broadened due to the modes “bounce back-and-forth” in between the air-bridge and slotline. This new transition is used to realize three CPW passive circuits, including a CPW-fed Vivaldi antenna, CPW power divider, and side-coupled CPW-slotline coupler. The finite-difference time-domain method is employed to analyze those circuits, and good agreements are obtained with measured results     

Ultra-wideband back-to-back CBCPW-to- CBCPW transition

A new ultra-wideband back-to-back conductor-backed coplanar waveguide (CBCPW)-to-CBCPW transition structure is presented and implemented. The design of this transition is based on vertical resonant coupling via a rectangular slot between two stacked CBCPW lines. According to careful design and optimisation, the CBCPW-to-CBCPW transition results show a good performance in terms of bandwidth, which is about 12 GHz     

（英）一种基于新型自组装微带-波导过渡的D波段通信发射机模块

展示了一种基于新型自组装微带-波导过渡的D波段（110-170GHz）发射机模块。过渡结构的仿真平均插入损耗为0.6 dB,回波损耗于带内基本优于10 dB。基于该过渡结构以及阻性混频器和倍频器芯片,设计了一种D波段发射机模块。该发射机模块工作于110-153 GHz,峰值输出功率于150 GHz可达-4.6 dBm,3-dB带宽为145.8-159.3 GHz。使用该模块进行了64-QAM高阶无线通信测试,测试传输速率为3 Gb/s,验证了模块封装方案的实用性。     

Broadband Transition Between Double-Sided Parallel-Strip Line and Coplanar Waveguide

A broadband transition between double-sided parallel-strip line and coplanar waveguide is proposed in this letter. This design is based on tapered structure and vertical coupling, which doesn't require any via hole. The proposed transition has a simple structure for easy fabrication. Several parameters are studied by simulation to optimize the transition. A demonstration back-to-back transition is fabricated and measured. The experimental results show that the insertion loss of less than 1.4 dB and the return loss of better than -10dB is obtained from 1.3 to 9GHz     

一种新型毫米波矩形波导-微带过渡结构

介绍了一种新颖的、适用于毫米波频段的矩形波导-微带过渡电路结构。该过渡电路具有插入损耗低、频带宽、重复性好的特性。其矩形波导E面相对于微带电路面,以及电磁信号传输方向的位置与脊波导-微带过渡相同。该过渡电路的微带线与波导的转换部分采用非接触式结构,并设计了可调节元件,从而在有一定加工误差的条件下改善其产品传输特性。利用高频仿真软件CST,在Ka频段进行了优化仿真,并对利用其优化值所设计的一对背靠背的电路实物进行了测试,在32～40 GHz的频率范围内,插入损耗小于2.36 dB,回波损耗大于7.22 dB;在整个Ka频段内,插入损耗小于3.49 dB。     

A coplanar probe to microstrip transition

A transition between a coplanar probe and a microstrip transmission line is reported. The transition is significant in that it does not require substrate via holes. A set of microstrip impedance standards was developed for the purpose of de-embedding the transition. The latter is suitable for measuring the S parameters of a number of low-cost monolithic microwave integrated circuits with coplanar probes     

Solid-Phase Reactions in the Thermal Oxidation of Ni/GaAs Heterostructures

The thermal oxidation of GaAs covered with an Ni layer is studied experimentally. It is shown that this layer makes for better dielectric performance of the oxide film and inhibits the escape of the volatiles from GaAs. A possible pattern of the oxidation of Ni/GaAs heterostructures is put forward. It includes the formation of a transition layer between NiO and GaAs, which contains nickel–arsenic and nickel–gallium compounds. Reactions at the interface between the transition layer and NiO are considered.     

35GHz三次谐波低电压回旋管理论研究

用动力学理论分析了三次谐波复合腔回旋管中的注-波互作用,选取了工作点;建立了突变复合腔回旋管的自洽非线性理论模型,该模型既考虑了电子和高频场的自洽相互作用又考虑了复合腔过渡部分模式的耦合,基于该理论模型,对一只三次谐波35GHz突变结构复合腔回旋管中电子注与H₆₁-H₆₂高频场互作用进行了数值模拟,当电流20A,磁场为0.442T时,互作用效率为24%,输出功率为210kW.     

Resonant tunneling in quantum cascade lasers

Experimental evidence that in quantum cascade lasers electron injection into the active region is controlled by resonant tunneling between two-dimensional subbands is discussed. A quantitative analysis is carried out using an equation for the current density based on a tight-binding approximation. Electron injection into the active region is optimized when the current density is limited by the lifetime of the excited state of the laser transition. In this regime, quasi-equilibrium is reached between the population of the injector ground state and that of the excited state of the laser transition characterized by a common quasi-Fermi level. The design of the injector depends on the selected laser active region; in particular, the choice of physical parameters, such as doping concentration and injection barrier thicknesses, is in general different for vertical or diagonal transition lasers. The paper concludes with an investigation of the transport properties at threshold and its dependence on stimulated emission; a relationship between the differential resistance above threshold and the value of the slope efficiency is deduced     

Broadband transition between half mode substrate integrated waveguide and rectangular waveguide

A broadband transition between a half mode substrate integrated waveguide and a rectangular waveguide with an antipodal fin-line in its quasi-TEM mode is presented. Experimental results show about 1.3 dB insertion loss and below 215 dB return loss for a back-toback double transition over 10 GHz bandwidth from 26.5 to 40 GHz (the single transition insertion loss is about 0.65 dB). The transition may be used in low-loss and low-noise front-end circuits of the microwave and millimetre-wave bands.     

UWB Bandpass Filter Using Microstrip-to-CPW Transition With Broadband Balun

A novel ultra-wideband bandpass filter (BPF) is presented using a back-to-back microstrip-to-coplanar waveguide (CPW) transition employed as the broadband balun structure in this letter. The proposed BPF is based on the electromagnetic coupling between open-circuited microstrip line and short-circuited CPW. The equivalent circuit of half of the filter is used to calculate the input impedance. The broadband microstip-to-CPW transition is designed at the center frequency of 6.85 GHz. The simulated and measured results are shown in this letter.     

A Transition from Rectangular to Nonradiating Dielectric Waveguide (Short Paper)

A transition between standard X-band waveguide and non-radiating dielectric (NRD) waveguide is described. It consists of a transition from air-filled rectangular waveguide to reduced-width dielectric-filled waveguide, cascaded with a transition to NRD. Both transitions are theoretically designed to provide both mode matching as well as a low reflection coefficient. The composite transition can be used for measurements in NRD while making use of conventional waveguide test equipment.     

Design and modeling of twin-spiral coplanar-waveguide-to-slotlinetransitions

A novel reduced-size twin-spiral coplanar-waveguide-to-slotline transition is proposed in this paper. This twin-spiral transition is based on a modification of quarter-wavelength transformer structure. For design purposes, a hybrid equivalent-circuit model combining transmission-line theory and full-wave simulation is established. Based on this model, various twin-spiral transition structures are carefully examined theoretically and experimentally. Specifically, a twin-spiral transition with 2.26:1 bandwidth and one-quarter the size of conventional ones is achieved. Being simple in fabrication and small in size, the proposed twin-spiral coplanar-waveguide-to-slotline transition is a useful component in uniplanar microwave integrated circuit/monolithic-microwave integrated-circuit applications     

A large bore fast axial flow CO2 laser

A single-tube large-bore fast axial-flow CO₂ laser with a power output of 3.8 kW using a discharge length of 0.6 m is described which operates at currents in excess of 1.2 A. The high-power compact design is made possible by the use of multiple electrodes and by optimizing gas turbulence using high-velocity gas injection at the anodes to suppress the glow-to-arc transition and to fill the discharge tube. The critical parameters in raising the current at which the glow-to-arc transition occurs are shown to be the number and surface area of the cathodes and the effectiveness of the gas turbulence over the discharge length. The importance of the transition regions between the column and the electrodes is shown. Operation at currents in excess of 2 A without a glow-to-arc transition has been achieved     

VO2(A)纳米线相变过程的透射电镜原位观察

VO2作为经典的一级相变材料一直是各领域的研究热点,而其亚稳态相VO2(A)的研究却少有报道.本文通过在透射电镜(TEM)下的原位加热实验,发现VO2(A)的高温相在低温相中产生并沿着纳米线轴向扩展.通过球差矫正扫描透射电镜-高角环形暗场像(STEM?HAADF)技术,揭示了原子尺度下的相界面结构,提出了低温相往高温相的转变机理.     

引入GaN过渡层对Si（111）衬底上生长GaN外延的影响

本文研究了在Si(111)衬底上生长GaN外延层的方法。相比于直接在AlN缓冲层上生长GaN外延层,引入GaN过渡层显著地提高了外延层的晶体质量并降低了外延层的裂纹密度。使用X射线双晶衍射仪、光学显微镜以及在位监测曲线分析了GaN过渡层对外延层的晶体质量以及裂纹密度的影响。实验发现,直接在AlN缓冲层上生长外延层,晶体质量较差, X射线(0002)面半高宽最优值为0.686°,引入GaN过渡层后,通过调整生长条件,控制岛的长大与合并的过程,从而控制三维生长到二维生长过渡的过程,外延层的晶体质量明显提高, (0002)面半高宽降低为0.206°,并且裂纹明显减少。研究结果证明,通过生长合适厚度的GaN过渡层,可以得到高质量、无裂纹的GaN外延层。     

基于LTCC技术的多层垂直转换电路设计

低温共烧陶瓷(LTCC)是实现小型化、高可靠性多芯片组件的一种理想技术方式。多层转换电路实现了微波信号在基板内部传输。文章研究了微带线到带状线背靠背式多层转换电路,优化设计了通孔之间距离以及通孔到带状线之间的距离,仿真结果与实测较为吻合。     

Design of Millimeter-wave Rectangular Waveguide to HMSIW Transition Based on Trapezoidal-shaped Probe

In this letter, a compact rectangular waveguide-to-half mode substrate integrated waveguide (HMSIW) transition is presented. It uses a trapezoidal-shaped probe to couple the energy from rectangular waveguide to HMSIW. A back-to-back test module at Ka-band is fabricated and measured. It provides a return loss better than 15 dB and an insertion loss of 0.85 to 1.3 dB within a frequency range from 25 to 40 GHz. The circuit size of the proposed transition is reduced by approximately 81.8% as compared with the waveguide-to-HMSIW transition using antipodal fin-line. Additionally, no intermediate transition is needed for this transition, which simplify the design of transition circuit. The measurement results agree well with simulation results, which validate the feasibility of the transition. Also, a tolerance analysis is performed via the simulation to verify the reliability of this transition design.     

DS80C411网络微控制器的应用

提出了一种基于DS80C411的串口至以太网接口转换的设计方案,介绍了多个串口设备的入网应用。给出了系统硬件结构,描述了串口与以太网协议的相互转换设计方法,分析了软件设计。该设计可以将RS232/422/485通讯接口的设备和以太网服务器进行数据流传输,通过以太网服务器实现了对串口设备远程管理,实现了串口设备之间的网络互联。