基于HFSS仿真的一种新型大功率同轴信道合成器

论述了一种新的以Wilkinson功分器为原理,采用同轴空气线结构形式,并在相邻端口间采用接地电阻实现隔离的大功率、高隔离度的同轴型宽带信道合成器的设计。通过改进结构形式和输入端口间的阻抗匹配性,使得该信道合成器连续波功率可达到200 W,频带在310 MHz⁴10 MHz。实验过程是先应用HFSS进行三维电磁场模拟仿真,然后对实物进行测试。实验结果表明,模拟仿真结果与实物测试结果相吻合,满足设计指标要求。     

预变形印刷电路板热-力耦合结构优化设计

针对印刷电路板（Printed Circuit Board,PCB）上存在大量异材连接,在元器件自发热和环境温度变化的作用下产生的变形会直接影响PCB组件工作性能的问题,通过PCB预变形热 力耦合仿真分析,以元器件变形后平面度误差为目标函数,结构定位参数为设计变量,运用变尺度法计算出最优结构定位参数.结果表明：采用优化后的结构参数可以使PCB组件产生适当的预变形量,从而有效改善目标元器件工作时的变形程度.     

基于FPGA和LVDS的AOS高速合路器/分路器研究

在对AOS进行功能划分的基础上,介绍了一种基于FPGA和LVDS的高速合路器/分路器,它是空间数据传输标准AOS(高级在轨系统)的仿真和验证系统中一个非常关键的组成部分。该方案采用FPGA对多路信号进行并行处理和调度,并且通过LVDS在合路器、分路器、链路控制器等高速设备之间交换数据。试验结果表明采用该合路器/分路器的系统较好地实现了高速环境下AOS的数据传输,并具有很大的灵活性。     

周期性慢波结构的微带线威尔金森功分器

采用周期性慢波结构加载的开路传输线代替传统的四分之一波长阻抗变换器,设计一种小型化且适用于高频的Wilkinson功分器,有效改善了传统Wilkinson功分器尺寸大且高频时容易出现色散的问题。最后基于FR4基板,设计应用于900 MHz的Wilkinson功分器,测量结果显示,三个端口匹配良好,S11约为-20.58 dB,S22约为-23.62 dB,S21约为-3.28 dB,输出端口的隔离度约为-33.3 dB,仿真结果和测量结果趋势吻合,验证了该方法的可行性。     

折叠式夹层结构压皱性能数值仿真

为研究网格尺寸、加载速率及仿真试件的单元数和单元长度等对夹层板压皱性能的影响,用Abaqus对U-I形折叠式夹层板的压皱性能进行数值仿真,提出精度高、效率高的数值仿真模型化技术,分析不同变形模式和夹层结构尺寸对压皱性能的影响.结果表明:变形模式是决定夹层板压皱性能的关键因素;不同的结构参数组合会形成不同的变形模式,进而影响结构的压皱载荷和吸能特性;存在较优的夹芯壁厚、高度、间距和夹角的尺寸组合使夹层结构的吸能效率较优.     

具有热泵的苯-甲苯精馏过程的建模与控制

研究了热泵精馏塔的建模与控制问题.针对苯-甲苯精馏过程,采用逐板计算的方法进行动态机理建模;在热泵端,基于能量守恒定律等热力学方程建立了热量传递模型.通过对仿真模型结果的分析,研究了热泵精馏塔系统的特性.为了研究热泵精馏塔的控制问题,通过对动态机理模型的阶跃测试和辨识,获得了控制模型.对热泵精馏塔系统,按照单变量PID控制和多变量DMC控制两种结构,分别设计控制系统,通过仿真研究对比了两种控制方案的性能.     

低互调三频同轴腔体合路器的设计与实现

设计了一种低无源互调的三频同轴腔体合路器.通过设计公共腔的抽头结构并对其相对腔体位置进行调谐,优化设计谐振腔之间台阶的高度,以降低互调失真,从而减小三阶互调.在满足设计指标的基础上设计一款基于DCS1800、TD-SCDMA2100、WLAN2600的低互调三频合路器,并进行了加工制作和实际测量.测量结果显示,得到3个...     

汽车空调平流式冷凝器性能仿真分析

为分析汽车空调平流式冷凝器的换热、流动性能,假设制冷剂沿管长方向做一维流动,空气侧流动视为零维流动,忽略制冷剂加速压降,对制冷剂两相区采用均相模型.使用AMESim建立平流式冷凝器仿真模型,并通过与试验对比验证模型的准确性.改变冷凝器结构参数,分析对冷凝器的性能影响,发现合理的制冷剂回路流程布置可以改善平流式冷凝器性能;增加流程数可以增加换热量,但是压降也会增大;制冷剂侧总横截面积相等时,微通道数目增加,换热量增加;空气速度较小时,减小翅片间距可以增加换热量.     

大功率主动拖曳线列阵声纳探测距离仿真研究

大功率主动拖曳线列阵声纳具有脉冲信号频率低、基阵孔径大、作用距离远的特点.为了研究海洋水声环境对其作用距离的影响,根据其作用原理、声纳结构和使用原则,构建了该类声纳在不同海洋水声环境条件下的探测距离仿真模型;采用面向对象程序设计方法设计实现仿真软件,通过模型校验和仿真,研究了入射角、工作频率等参数对声纳作用距离的影响.根据仿真结果分析,该模型对该类声纳探测距离的性能具有较高的仿真度,研究成果为该类声纳的全功能仿真奠定了基础.     

基于PSpice的IGBT功耗分析与仿真

针对大功率感应加热电源功率开关器件IGBT功耗大的特点,给出了3种RCD缓冲电路结构及参数设计,在PSpice仿真软件下对3种缓冲电路中的IGBT和缓冲电阻的功率损耗进行了仿真分析,给出了相应的仿真结果。仿真结果表明,I型缓冲电路的电能损耗大,缓冲电阻发热严重;II型缓冲电路对关断瞬态电压抑制效果好,但不能有效地控制大功率级别IGBT的瞬变电压;III型缓冲电路具有寄生电感较小的优点,可有效地抑制振荡和控制瞬变电压,适用于大功率级别IGBT工作场合。     

Single section,octave bandwidth,high‐power combiner in the UHF band

In this work, a planar broadband high‐power combiner in the ultra‐high‐frequency band (UHF) is presented. The proposed broadband combiner is a modified version of the conventional Wilkinson power combiner. The isolation resistor of 100 Ω in the conventional Wilkinson combiner is replaced by two 50 Ω terminating resistors. Two overlay couplers transform the terminating resistors to a floating resistor between the input branches. Terminating resistors are preferred to a floating resistor because of higher power handling and lower parasitics. Even‐ and odd‐mode method is employed for the analysis. The design goal is 20 dB isolation and ports return loss in an octave bandwidth. To verify the design concept, a high‐power combiner in the frequency range of 470 to 860 MHz used for digital video broadcasting‐terrestrial (DVB‐T) applications is designed and constructed. Full‐wave simulations are compared with measurements. The fabricated power combiner handles 400 W output power. Analytical formulations presented in this work are not restricted to UHF band and can be used to design an octave bandwidth combiner in other frequency bands.     

开槽波导功率合成技术分析

在毫米波频段实现基于固态微波器件的高功率放大器,功率合成是一项不可或缺的技术。介绍了一种基于开槽波导耦合微带1分8的功率分配合成网络。这种结构的主要优点是具有较好的集成度,较高的功率合成效率,还可以为功率单片微波集成电路（MMIC）提供效率比较高的散热。通过软件仿真分析,该结构具有较好的功率分配能力和隔离度。     

功率合成器／耦合器的一体化设计分析

功率合成器和耦合器是功率放大器中的重要部件。提出了功率合成器和耦合器的一体化设计方案。用电路仿真软件和电磁场仿真软件对功率合成器和耦合器进行的高精度的设计,并制作了一个频率范围在900MHz-1300MHz内的四路功率合成器和耦合器,测试指标与仿真高度吻合,说明了设计的有效性,具有工程实用价值。     

Design of wideband microstrip power divider/combiner with input and output impedance matching for RF energy harvesting applications

Lately, it has been seen that wireless communication systems have been more developed and there has been a huge demand for multi‐spectral transactions. Using circuits for more than one function is a serious requirement in communication technology. Especially, it expected from RF output stages to show the same performance on more than one frequency. To that end, it is required to produce a solution with wideband designs. In this study, a novel power divider/combiner design with a layered conic line has been investigated for the RF energy harvesting applications. The center frequency was set at 2 GHz and concluded with three different designs. In each design, bandwidth and S parameter characteristics were compared according to the number of layers of the transmission, and it was observed that as the number of layers increases, the bandwidth also increases. According to the design result, triple layer Wilkinson power divider was selected to connect to Villard voltage doubler circuit. The Wilkinson power combiner circuit inputs were given between ?10 dBm and 5 dBm input power. As a result, when low input power was given, efficiency was observed about 70%.     

A Ka‐band power divider/combiner using two side‐inserted magnetic coupling semicircular ring probes

A Ka‐band power divider/combiner with dual magnetic coupling semicircular ring probes is proposed in this paper. Firstly, a broadband microstrip‐to‐waveguide transition with semicircular ring probe is designed based on the side‐inserted structure of magnetic field excitation in a rectangular waveguide. The insertion loss of the proposed transition is less than 0.7 dB in Ka‐band assisted by the dual symmetrical broadband probes and rectangular waveguide. Then, the divider/combiner is proposed using the new transition with magnetic coupling from narrow wall into the rectangular waveguide. The bandwidth of the divider/combiner is more than 9 GHz (from 27 to 36.7 GHz), and the insertion loss of the single divider/combiner is less than 3.3 dB. Finally, the performance of the proposed divider/combiner is validated through simulations and measurements. The proposed design has potential applications in microstrip circuits.     

一种微带功分器的设计分析

该文介绍了微带wilkinson型等分功分器的基本原理,通过计算得出了初始设计参数,运用电磁仿真软件HFSS,建立了仿真模型.在对模型进行了优化设计后,得出了符合设计要求的功分器的最优模型,并对此模型进行了性能分析、产品加工及性能测试.测试结果表明,采用该方法研制的产品具有性能良好,结构简单、便于集成等特点.     

A 200 W broadband high power amplifier using hybrid power combining network and digital level control

In this article, a 2 to 6 GHz solid‐state power amplifier with 53 dBm output power has been analyzed, designed, and fabricated. To achieve a wideband high output power, we introduce a 16‐way hybrid power combiner based on microstrip planar binary and parallel structures. The simulation and measurement results of the proposed hybrid power combining network (PCN) show that the maximum power combining efficiency is around 86% with the insertion loss of around 0.6 to 1.5 dB and an isolation of 20 dB between the ports. Also, to compensate the output power variations due to the thermal and operating frequency changes across the bandwidth, a digital level control (DLC) unit utilizing an agile control algorithm is proposed which decreases the output power variations to 2% of the desired output power. A cooling heatsink fan system has been also designed in order to transfer the heat generated power to the air. The measured output power for the applied input continuous wave is higher than 52.5 dBm. In addition, the power added efficiency (PAE) is better than 15% across the wide portion of the bandwidth and the measured third‐order intermodulation is about 20 dBc (average).     

一种改进型毫米波开槽波导空间功率分配合成网络

研究了一种改进型毫米波开槽波导空间功率分配合成网络。该功率分配/合成结构具有合成效率高且合成效率基本不受合成路数的限制、尺寸小、设计过程灵活和容易散热等特点。在详细阐述了其原理及设计过程的基础上,设计了一个中心频率为38GHz的Ka频段末端的功率合成器。仿真结果显示此种结构回波损耗小于-12dB的带宽达2.3GHz,相对中心频率带宽约为6%,且插入损耗小于0.3dB,可见具有极低的插入损耗和较低的回波损耗,从而验证了此种结构的可行性。     

六合一功率合成器的设计与实现

为满足雷达对大功率源的要求,我们采用集总参数功率合成法,成功研制出六合一功率合成器.通过微波仿真软件对其进行优化,得到六合一功率合成器元件参数的最佳值.经过测试,该功率合成器在110～140 MHz波段,峰值功率可达到6 kW.实践证明,集总参数功率合成法设计大功率器是可行的.     

Design scheme for broadband Doherty power amplifier using broadband load combiner

This article proposes a design strategy for broadband Doherty power amplifier (PA) using broadband load combiner. The bandwidth of the Doherty PA based on the proposed combiner using packaged transistor is about 2.5 times the bandwidth of conventional Doherty PA using a quarter‐wave transformer. An easy to implement analytical design methodology has been presented for the proposed load‐combiner while describing the bandwidth enhancement strategy. The design methodology is validated with the design of a broadband Doherty PA based on CREE 10 W packaged GaN high electron mobility transistor devices using the proposed load combiner. Measurement results show more than 45% drain efficiency at 6 dB output power back‐off (OPBO) over 400 MHz frequency range, centred around 1.95 GHz. The peak drain efficiency at saturation is better than 60% over this band of operation. At 6 dB OPBO, the maximum improvement of 18.5% in drain efficiency is achieved as compared to the balanced mode PA. Measurement with single carrier wideband code division multiple access modulated signal shows the average drain efficiency of more than 44% at 36.6 dBm average output power at center frequency of operation. The adjacent channel power ratio is better than ?45 dBc after applying digital predistortion. The circuit is realized with microstrip technology, which can be easily fabricated using conventional printed circuit processes. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:655–674, 2015.