Ku波段TE11–HE11光壁模式变换器设计

在耦合波理论的基础上,采用半径渐变、内壁光滑的结构实现TE11模到HE11模的变换,避免了传统的圆周开槽结构在高频段因加工产生的毛刺而导致容易打火的不足。提出一种由正弦与抛物线结合的结构曲线,通过数值计算设计了中心频率为15 GHz的回旋行波管TE11-HE11模式变换器,并利用电磁仿真软件进行对比验证。仿真结果与数值计算的结果一致性较好。设计的模式变换器带宽为1.2 GHz,相对带宽为8%,在15 GHz时的转化效率为98.5%。     

径向双层介质加载圆波导的宽带TE_(11)-HE_(11)模式变换器

应用径向双层介质加载圆波导内可以产生混合模HE_(11)模式的原理,提出一种径向双层介质加载圆波导的宽带TE_(11)-HE_(11)模式变换器。在X波段分析了该变换器内微波模式满足的麦克斯韦方程和边界条件,推导出HE_(11)模式的特征方程及混合方程,最后将特征方程与混合方程联立,应用MATLAB软件进行数值求解得到物理模型的设计参数曲线。应用HFSS软件对设计的模式变换器进行模拟优化仿真,结果显示在8.40~10.16GHz频带内输出HE11模式纯度大于96%,最大为99.59%,相对带宽可达18.7%,理论功率容量达3.3GW。该圆波导TE_(11)-HE_(11)模式变换器具有结构简单、输入输出共轴、转换效率高、转换频带宽、功率容量高等优点,应用于微波辐射系统可以极大地提高辐射系统的紧凑性。     

94 GHz TE_（02）-TE_（11）模式变换链的设计与模拟

本文在电磁场耦合模理论的基础上利用MATLAB优化工具对W波段回旋管用TE02-TE01-TE11模式变换链进行了详细研究与分析。应用编制的仿真程序对W波段TE02-TE01-TE11模式变换链进行了设计和数值模拟,通过结构参数优化,获得了性能良好的模式变换链。TE02-TE01和TE01-TE11模式变换器在中心频率94 GHz处的转换效率分别为96.3%和94.1%,对应带宽分别为4 GHz（转换率95%以上）和2 GHz（转换率90%以上）。为了进一步验证设计的模式变换链的性能,利用高频模拟仿真软件HFSS对优化的模式变换链进行了模拟仿真,模拟结果与利用计算程序得到的结果基本吻合。     

圆波导TE01-TE11模式转换器设计与实现

基于耦合波理论的基础上,分析了TE01-TE11模式转换器的特性和半径渐变指数,讨论了中心轴线弯曲下的圆波导模式转换器,对中心频率33GHz的波导进行了模拟设计、仿真,在保证带宽的前提下,尽力降低转换器的长度和提高转换效率,最后达到了97．82％的转换效率,带宽达到2GHz。     

96GHz边廊模Denisov辐射器

介绍了采用Denisov辐射器将96 GHz边廊模式信号转换为高斯波束的设计、仿真及测试结果.基于耦合波理论给出Denisov辐射器的设计方法.根据96 GHz TE_(6,2)模式Denisov准光模式转换器结构布局的要求,优化得到Denisov辐射器,输入半径6.4 mm,长52 mm,辐射器切割边缘电流幅值为汇聚中心点的10%,输出准高斯能量转换效率达96.51%.由其组成的准光模式转换器冷测输出高斯波束束腰直径22.4 mm,矢量转换效率大于95%.     

Ka波段紧凑型TE01-TE11椭圆波导模式转换器的研究(英文)

本文对椭圆波导TE₀₁-TE₁₁模式转换器进行了研究。选择了合适的椭圆波导截面,在椭圆波导纵轮廓线函数中采用了相位重匹配方法,并利用粒子群算法进行了纵轮廓线优化,所设计的椭圆TE₀₁-TEs₁₁模式转换器在28 GHz时的转换效率为99.16%,在27～29.3 GHz模式变换器的效率大于90%,相对带宽为8.2%。所设计的TE₀₁-TEs₁₁椭圆模式转换器的转换段为现有长度的一半。将设计的椭圆模式转换器与两个过渡段相连,并在CST中进行仿真和验证,其结果与理论计算一致。设计出了一个中心频率点为28 GHz的高效、紧凑、高功率椭圆波导TE₀₁-TE₁₁模式转换器。     

半模基片集成波导馈电的对数周期偶极子天线

设计并研制了一种基于半模基片集成波导(Half-mode Substrate Integrated Waveguide:HMSIW)馈电的单层宽带印刷对数周期偶极子阵列(Printed Log-Periodic Dipole Array:PLPDA)天线.对数周期偶极子阵列(PLPDA)天线具有频带宽、剖面低、重量轻等优点,但是其馈电需要平衡线结构.半模基片集成波导具有平面集成、主模带宽宽、损耗低、尺寸小等优点,同时自身天然具有平衡结构.文中设计并制作了工作频率为15GHz～40GHz的HMSIWPLPDA天线,测试结果和仿真结果吻合.     

一种使用TE11为过渡模的TE01-HE11模式变换器设计

基于弯曲圆波导耦合理论和规则圆波导突变结构模式匹配法, 利用MATLAB软件编写的相关数值计算程序得到波导模式转换结构的优化参量, 最终使用CST软件对模型进行了仿真和验证.该系统主要由三部分组成: 一个TE01-TE01的过渡器, TE01-TE11和TE11-HE11的圆波导模式转换器.计算结果表明, 该TE01-HE11模式转换系统在24.13 GHz的频率有5%的带宽、转换效率超过了99%.计算结果、仿真结果和实物冷测结果是一致的.     

径向线TM01 模激励研究

径向线TM01 模是径向束波互作用中的主模,决定了束波互作用的成败。论文对径向线TM01 模进行了研究：理 论推导了径向线TM01 模的电磁场分布,在此基础上设计了一种由同轴线TEM 模激励产生径向线TM01 模的新型结构,并 通过全电磁仿真软件进行了验证。结果表明：在12GHz 中心频率处转换效率达到99%。     

一种8 mm 模式变换器的设计

提出了一种高效率的模式变换器,将矩形波导的TE10 模式转换为圆波导的TE11 圆极化模式,并采用盒形窗真空封接。使用三维仿真软件进行模拟设计和优化,模拟结果显示,在中心频率35 GHz,驻波比为1.17,在34-36GHz 频率范围内,模式转换效率在83%以上。这种模式转换器可以用在回旋行波管输入耦合器上,结构紧凑、简单,易于加工。     

多频段共用的波纹圆锥喇叭

本文阐述了波纹圆锥喇叭的多频段工作原理,并介绍了一个至少能在4,6和11 GHz三个频段共用的波纹圆锥喇叭。此喇叭在4,6 GHz频段的交叉极化峰值优于-25dB,在11GHz频段的幅度方向图性能优良。理论和实践表明,使用不止在一个工作区工作的波纹圆锥喇叭可以实现多频段共用的馈源喇叭。     

A planar X-band electromagnetic band-gap (EBG) 3-pole filter

A Duroid-based X-band electromagnetic band gap (EBG) Chebyshev 3-pole bandpass filter that is compatible with standard printed circuit board (PCB) fabrication techniques has been designed, fabricated, and tested. The filter consists of three EBG cavities in a multi-layer design. It provides a 5.95% bandwidth response at the resonant frequency f_res=9.72 GHz with a corresponding insertion loss of 0.9 dB. Isolation is higher than 30 dB below 9 GHz and above 11 GHz     

CORRUGATED CONICAL HORN FOR MULTI-FREQUENCY BAND USE

The theory of corrugated conical horn operating at multi-frequency bands is described,and aprqactical corrugated conical horn is constructed.It can operate at three frequency bands(4,6,11 GHz)atleast.The cross polarization peak level is better than -25 dB at 4,6 GHz frequency bands,and the amplitudepattern at 11 GHz frequency band is also very good.It is shown theoretically and experimentally that thecorrugated conical horn operating at multi-frequency bands is the best condidate for multi-frequency bandfeeds.     

基于负载牵引的S波段40W LDMOS功率放大器设计

摘要：针对LDMOS功率放大器在S波段的设计难点,文中介绍了基于负载牵引测试技术的LDMOS功率放大器设计方法。阐述了负载牵引的测试系统和测试原理,并对LDMOS预匹配管进行了负载牵引测试,利用测试结果设计了一个工作频率为2.7～3.1GHz的LDMOS功放。功放的测试结果显示,工作频带内输出功率大于40W,增益超过11dB,效率超过了40%。从而为LDMOS功率放大器在S波段的设计提供了良好的借鉴作用。     

Experimental analysis of an MIM capacitor with a concave shield

A novel shielding scheme is developed by inserting a concave shield between a metal-insulator-metal (MIM) capacitor and the silicon substrate. Chip measurements reveal that the concave shield improves the quality factor by 11 % at 11.8 GHz and 14% at 18.8 GHz compared with an unshielded MIM capacitor. It also alleviates the effect on shunt capacitance between the bottom plate of the MIM capacitor and the shield layer. Moreover, because the concave shields simplify substrate modeling, a simple circuit model of the MIM capacitor with concave shield is presented for radio frequency applications.     

High power mode conversion for linearly polarized HE11 hybrid mode output

Efficient plasma heating by ECR-wave irradiation requires axisymmetric, narrow, pencil-like millimetre wave beams with well-defined polarization. The linearly polarized gaussian-like HE₁₁, mode satisfies these conditions best. This quasi-optical hybrid mode can be generated from TE_0n gyrotron mode compositions by the two multi-step mode conversion processes: (1) ΣTE_0n to TE₀₁ to TE₁₁ to HE₁₁ or (2) ΣTE_0n to TE₀₁ to TM₁₁ to HE₁₁. The first scheme has the advantage that the converters can all be made without bends, allowing an arbitrary choice and fast change of the polarization plane. The second scheme does not exhibit this advantage, but it is more suitable at very high frequencies (e.g. 140GHz) because efficient TE₀₁-to-TM₁₁ transducers can be made considerably shorter than serpentine TE₀₁-to-TE₁₁ mode converters. This paper presents computations on mode converter systems of the first type at 70GHz and of both types at 140GHz (ID = 27 · 8 mm for 200kW transmission lines). The structure of wall perturbations (phase-matched superposition of 2 or 3 different geometrical periods) in the rippled wall mode converters and the curvature distribution in the bent, smooth-walled TE₀₁-to-TM₁₁ mode transducer were optimized by numerically solving the corresponding coupled-mode differential equations. Computer-aided optimization of circumferentially corrugated mode converters has been achieved with a scattering matrix code employing the modal field expansion technique (modular analysis concept (MAC)). In all cases the predicted overall efficiency of the complete mode converter system from ΣTE_0n (predominantly TE₀₂ at 70GHz or TE₀₃ at 140GHz) to HE₁₁ in the desired polarization is approximately 95% at 70GHz and 92% at 140GHz (ohmic attenuation is included). Low-power measurements on the conversion efficiency of the various mode transducers are in excellent agreement with the predicted values. High-power operation has been successfully demonstrated using a pulsed 70GHz gyrotron (200kW, 100ms).     

Design and fabrication of a wideband reflectarray antenna in Ku and K bands

The purpose of this paper is design of a wide band single layer reflectarray antenna using a new broadband cell. The proposed cell consists of two parts. The first part is a circular patch and the second one is a ring with some additional stubs, which are attached to the patch and ring in a symmetrical form. The circular patch and ring elements are designed at frequencies of 20 GHz and 15 GHz respectively. In order to increase the reflectarray antenna bandwidth, at first the dimensions of the patch, ring and stubs are optimized to attain uniform phase response in the frequency range from 11 GHz to 20 GHz. Then an air layer is considered under the dielectric substrate. The reflectarray antenna is designed based on this optimized wideband unit cell. A wideband horn antenna is also designed as a feed antenna for the proposed reflectarray structure. The reflectarray antenna with horn are simulated. The 1 dB gain-bandwidth of 4.66 GHz is obtained (27.4% fractional bandwidth) in the frequency band of 14.72 GHz to19.38 GHz. Finally, the reflectarray antenna is fabricated and tested. It can be seen that there is a good agreement between simulation and measurement results.     

具有谐波抑制功能的宽带圆极化宽缝天线

针对微波无线输能系统中接收天线质量轻、体积小、剖面低、易与微波电路集成的特点,设计了一款新型的具有谐波抑制功能的宽带圆极化宽缝接收天线。通过在长方形缝隙中添加末端具有圆形贴片的交叉结构实现圆极化性能,添加切角结构展宽圆极化带宽。在馈线上添加具有一定长度的开路支节,配合使用缺陷地结构共同实现谐波抑制功能。研究并测试了天线的反射系数、轴比、增益以及远场辐射方向图,仿真与实测基本吻合。仿真结果显示,该天线很好地抑制了基频5.8 GHz的二次谐波和三次谐波,在4.5~6.2 GHz的范围内S11<-10 dB,相对阻抗带宽31.8%;基频5.8 GHz处的轴比AR=1.3 dB,在频率范围4.2~6.15 GHz内轴比AR<3 dB,相对轴比带宽37.7%;基频5.8 GHz仿真增益6.7 dB。     

A Broadband CMOS Frequency Tripler Using a Third-Harmonic Enhanced Technique

A third harmonic enhanced technique is proposed to implement a broadband and low-phase-noise CMOS frequency tripler. It nonlinearly combines a pair of differential fundamental signals to generate deep cuts at the peaks of the fundamental waveform, resulting in a strong third harmonic frequency output. This mechanism has inherent suppression on the fundamental and the other harmonics so that only a low-Q high-pass filter on the lossy silicon substrate is applied at the output to further reject the fundamental and the second harmonic frequencies, in contrast to the high-Q filters used in most of the previous tripler designs. The fabricated circuit using 0.18 m CMOS technology is compact and has an input frequency range from 1.7 GHz to 2.25 GHz, or an output frequency range from 5.1 GHz to 6.75 GHz, resulting in about 28% frequency bandwidth. The optimum conversion loss from the tripler is 5.6 dB (27.5% efficiency) at an input power of 2 dBm. The suppressions for the fundamental, second and fourth harmonics in the measurement are better than 11 dB, 9 dB, and 20 dB within an input power range from 2 dBm to 7 dBm.     

Integration of ultra-wideband slot antenna on LTCC substrate

An ultra-wideband slot antenna realised in low-temperature cofired ceramic (LTCC) technology is reported. The antenna is developed for a single-package solution of ultra-wideband radio. The radiating element of the antenna has a shape of ellipse 11 mm wide and 17 mm long. It shares the ground plane with other radio circuitry and is fed through a microstrip line 41 mm long and 3 mm wide. The experimental result shows that the prototype antenna achieved a bandwidth of 7.6 GHz (return loss S11/spl les/-10 dB or VSWR 2:1 from 3 to 10.6 GHz). The antenna radiation patterns at 3.5, 6.85 and 10.1 GHz are also presented.