Excitation of a Coaxial Line Through a Transverse Slot

A rocket with removed access plate is simulated by a section of coaxial transmission line with a transverse elliptical slot cut in its sheath. The internal circuit consists of two arbitrary impedances in series with the inner conductor at its ends. The object is to find the currents in these impedances when the cylinder is illuminated from the outside by an electromagneticfield that enters the aperture and excites the internal circuit. The problem is solved by application of the reciprocal theorem. The current in a dipole antenna is determined when this is inthe far field maintained by the slotted coaxial line when driven by a generator in series with one of the load impedances. The field in the aperture is replaced by equivalent electric and magnetic dipoles. The reciprocal theorem gives the current in the load impedance when the distantdipole is driven. A numerical example is given.     

基于新型矩形同轴馈电网络的微带天线阵研究

研究了一种新型的C波段微带天线阵,他采用矩形同轴线(RCL)结构构成的集成化低损耗馈电网络馈电,有效降低了馈电网络损耗,提高了微带天线阵增益。首先分析了矩形同轴线相关理论,并对矩形同轴线馈电网络和微带天线子阵的基本原理和设计方法,分别运用HFSS和CST进行了仿真设计。仿真和实测结果表明,该馈电网络具有损耗低、稳定性好等优点,实测结果与仿真吻合。     

同轴-微带转换器的准静态CAD方法

本文提出一种新的同轴－微带转换器。该转换器通过椭圆截面微带张实现各种型号同轴线－微带的平滑过流，可由ＰＣ设计并控制制造，具有反射系数小且损伤方便的特点。     

椭圆锥带线微带线同轴线的研究

本文首次提出了三种新型传输线－椭圆锥带线，微带线和同轴线，假设传播的是ＴＥＭ或准ＴＥＭ模式，通过坐标变换使球锥坐标系问题简化为二维问题，这样就可利用已知的同轴线和微带线的解而获得上面三种传输一的特性阻抗精确表达式，并给出数值计算结果。     

Input Impedance of Coaxial Line to Circular Waveguide Feed

The expressions for the real, imaginary parts of the input impedance seen by a coaxial line driving a thin cylindrical probe in a dominant TE/sub 11/ mode circular waveguide are derived. The analysis is carried out by assuming that the cylindrical post is replaced by a curvilinear strip having maximum width equal to the diameter of the probe. Theoretical results on input VSWR and input impedance seen by a coaxial line are in close agreement with experimental data.     

一种平衡微带线-槽线馈电的新型引向天线

提出了一种结构紧凑的印刷引向天线,采用平衡微带线-槽线馈电,充分利用了空间,以减小馈电网络面积和天线尺寸.使用电磁仿真软件CST Microwave Studio(R)对天线的结构参数进行了优化设计,并根据仿真所得到的电流结果对天线的宽带特性和定向辐射特性进行了解释.测试结果表明,该天线在1.88～3.06GHz的频带内反射系数低于-10dB,相对带宽达到了47.3％.在工作频段内增益为4.0 ～ 6.3dBi,天线总体尺寸为0.34λ0 ×0.58λ0,其宽频带可以用于PCS/UMTS/WLAN等多个领域,而简单的结构和较小的尺寸对于组成阵列也是有益的.     

On the Excitation of a Coaxial Line by an Incident Field Propagating Through a Small Aperture in the Sheath

A coaxial line having a small aperture in the sheath and terminating in arbitrary impedances is considered to be illuminated by an incident plane wave. The excitation of currents in the termination impedances is shown to depend upon three independent factors. Simple analytical forms are given for equivalent voltage and current sources of the aperture excitation.     

基于改进的垂直型同轴微带转换的Ku频段平衡低噪声放大器

提出了一种垂直型同轴微带转换的宽带补偿方法,并应用于一款Ku频段平衡低噪声放大器(LNA)的研制。放大器包含波导同轴转换、同轴微带转换、由2级pHEMT 管芯及分支线耦合桥组成的前级放大器以及由MMIC 放大器实现的后级放大器。在13.5 ~14.5 GHz 频率范围内,2 批次累计55 套低噪声放大器的噪声系数小于1.5 dB、增益分布在44.5 ~46.5 dB之间,增益平坦度小于0.6 dB,批次间性能一致性良好。     

馈电同轴芯径对微带天线性能的影响

针对同轴线馈电的微带天线,建立了等效电路模型。该等效电路表明,馈入到微带天线内部的导体直径直接影响天线的输入阻抗。为此设计了单频圆极化微带天线,采用电磁计算软件HFSS仿真计算了不同馈电芯径对天线参数的影响,验证了该理论。同时设计了双层介质的双频微带圆极化天线,采用同一个馈点馈电,上层微带介质中馈电导体的直径与下层微带介质中馈电导体直径不同。通过HFSS软件的优化仿真,得到了对应于两个不同频段的最优上下层馈电导体直径,获得了最佳的驻波。研究表明,对于单频和双频微带天线,通过优化馈入到介质中导体的直径可以改善天线的驻波特性。     

一种计算毫米波微带天线阵馈线损耗的方法

微带阵列天线增益的计算必须计入微带线损耗才有可靠精度,为此提出了一种计算毫米波微带天线阵整体馈线损耗的方法,导出了256元并馈阵、192元串并馈阵的损耗计算表达式,计算值与现有实测值相比较证实了本方法的有效性。     

超宽带嵌套同轴波导组合馈源的实验研究

超宽带波导馈源在反射面天线中有着巨大的应用潜力。本文分析设计了一个四腔体60：1带宽(1～60GHz)的超宽带嵌套同轴波导组合馈源。文中详细讨论了馈源的性能，该馈源在整个工作频带内有小于-10dB的反射损耗。馈源的每个同轴波导腔工作于圆极化TE11模。馈源的相关参数由实验测量(1～8GHz)和有限元法仿真(8～60GHz)得到。     

Parallel Line Microstrip Filters in an Inhomogeneous Medium

Parallel coupled microstrip lines in an inhomogeneons medium are studied. The quasi-static capacitance is shown to be linear with regard to the dielectric constant epsilon/sub r/ simplifying the formalism used for analyzing microstrip filters. The electromagnetic advantages of the homogeneous medium carry over to the inhomogeneous medium. This result is obtained by equalizing all the velocities of the propagation modes.     

一种微带线幅度均衡网络的实现

随着射频系统带宽的增加,如何达到良好的幅频特性成为研究的课题之一。介绍了一种用微带线均衡网络改善雷达发射机射频放大器幅频特性的方法,分析了该均衡网络的工作原理。通过仿真分析,对电路模型进行了改进并在某L频段放大器上对结果进行了验证。由于结构简单易调整,此均衡网络可方便地应用于功放组件内部。     

A Nonuniform Coaxial Line with an Isoperimetric Sheath Deformation

For impedance matching in transmission lines, nonuniform lines, obeying laws of taper like the exponential, the Dolph-Chebyshev etc., are used. For the nonuniform coaxial line, constructional advantages can be derived for the same electrical performance if it has a uniform circular inner conductor with an outer conductor having an isoperimetric transition, from circular to elliptic cross section, in conformity with the established laws of taper. This problem has been examined in the paper, and the required design formulas as well as the design charts are developed. The effect of an impedance and geometric discontinuity at the low-impedance junction of such a nonuniform line and the concentric circular uniform line is discussed. The use of the isoperimetric transition line in microwave components is indicated.     

A Simple Model for the Line Parameters of a Lossy Coaxial Cable Filled With a Nondispersive Dielectric

This paper discusses a simple model for approximating the per-unit-length parameters of a lossy cable providing a smooth transition from low to high frequencies. Using Schelkunoff's classical expressions for the transmission-line parameters of a coaxial line, the simple model is postulated and used to provide approximate responses that can be compared with the rigorous solutions. This approximate model is shown to be accurate and offers an alternative to evaluating the Bessel function expressions for the line parameters     

An Infinite Phase Shift Delay-Locked Loop With Voltage-Controlled Sawtooth Delay Line

A wide-range delay-locked loop (DLL) with infinite phase shift and digital-controlled duty cycle is presented. By changing the polarity of the input clock of the voltage-controlled sawtooth delay, this proposed DLL achieves infinite phase shift by only a single loop. The proposed DLL has been fabricated in a 0.18$ mu$m CMOS process and the core area is $hbox{0.45}times {hbox{0.3 mm}}^{2}$. The measurement results show the proposed DLL operates from 50 to 500 MHz. The duty cycle of the output clock can be adjusted from 30% to 60% in the step of 5%. At 500 MHz, the measured rms jitter and peak-to-peak jitter is 1.43 and 11.1 ps, respectively. Its power consumption is 6 mW for a supply of 1.5 V.      

一种新式串行馈电同时多波束微带天线的设计

针对较大规模的串行馈电Blass多波束网络设计的复杂性,通过减少90°耦合器的种类提出了一种简化的设计方法,利用该方法给出了一种新式的微带线结构串行馈电同时多波束网络,并以S频段同时两波束的天线为例进行了设计验证。重点设计了串行馈电同时两波束网络的结构以及馈电网络关键的组成单元90°耦合器,并对简化带来的误差进行了重点的理论和仿真分析,设计了与馈电网络匹配的天线阵。对设计好的两波束天线进行了实物加工和测试,测试结果与仿真结果吻合较好,验证了设计的正确性。     

The Characteristic Impedance of a Slotted Coaxial Line

The propagation of a second type of TEM mode in a slotted coaxial line is analyzed. The characteristic impedance of the slotted line is evaluated by means of variational expressions giving upper and lower bounds to the true value. A two term approximation to the charge distribution and a one term approximation to potential distribution give results accurate to within +-2 per cent. Curves of characteristic impedance against angular slot width are presented.     

Comments on "Input Impedance of Coaxial Line to Circular Waveguide Feed" (Letters)

The author read with interest the above paper in conjunction with the correction to it. While attempting to apply Harrington's well-known development for a coax/rectangular waveguide transition to the coax/circular waveguide transition case, the authors arrived at results and conclusions which are highly erroneous and misleading. As explained below, (4b) and the expression for X/sub 1/ in (6), the reactance part of the input impedance, are both incorrect. Even if the expression for X/sub 1/ in (6) is corrected, the reactance series is clearly divergent.     

宽微带X射线分幅相机的研制

研制了应用于平焦场光栅谱仪系统的宽微带X射线分幅相机,微通道板(MCP)微带阴极的宽度为20mm,由四路选通脉冲同时驱动。分幅相机采用模块化设计,由气室、MCP变像管、电控系统、光学CCD记录系统和内嵌式计算机组成,内嵌PC104模块实现相机的远程控制。对相机进行联调实验,测得该相机的时间分辨率为71ps,空间分辨率为20lp/mm,垂直于选通脉冲传播方向的微带均匀性为1.5…1,平行于选通脉冲传播方向的微带均匀性为5.1…1。