Design and numerical simulation of miniaturised COBRA lens horn

Proposed is a novel miniaturisation method of a coaxial beam-rotating antenna (COBRA) lens horn for high power application. Generally, a miniaturised horn increases the phase error at the aperture because of large flare angle which causes gain decrease. However, since the proposed COBRA lens horn compensates phase error with a modified COBRA lens, radiation characteristics such as gain and radiation pattern of the miniaturised COBRA lens horn are similar to the conventional one while the length of the horn is reduced by more than 50%.     

Neural Computation of Wide Aperture Dimension of Optimum Gain Pyramidal Horn

A new method based on the multilayered perceptron neural network architecture for computing the wide aperture dimension of the pyramidal horn is presented. The computed wide aperture dimension is used in successfully designing optimum gain pyramidal horn. The other design parameters of the horn are determined from the simple and explicit analytical formulas. These formulas do not need the application of the iterative methods, and are not restricted to the high gain horn designs. The gain of a designed pyramidal horn is determined with no path length error approximation. Better accuracy with respect to the previous design methods is obtained for various pyramidal horn design examples.     

Gain of corrugated conical horns

The absolute gain of a corrugated horn which is designed as a 100-GHz gain standard for the Crawford Hill 7-Meter offset reflector has been calculated and measured. The measured gain is determined from "three horn" transmission measurements. The other two horns are a TRG Model W869 corrugated horn and a dual mode horn. Correction factors were computed from the near field power transmission formula. The measured gain of the gain standard is30.8 pm 0.16 dB. Comparison between measured and calculated gains indicate very low ohmic loss in a corrugated horn. The condition of maximum gain for a given length has been found to be a half wavelength phase deviation in the horn aperture. Calculated gain data as well as near field correction factors for two identical corrugated conical horns are given here as reference information.     

Near-field gain of a horn and an open-ended waveguide: Comparison between theory and experiment

Generating a standard electromagnetic field requires knowledge of the gain of the transmitting antenna. The theory and supporting experimental measurements of the near-field gain of a pyramidal horn and an open-ended waveguide (OEG) at 450 MHz are given. The empirical near-field gain for the OEG is derived from experimental results obtained by a two-antenna method at about 2 GHz. The theoretical nearfield gain for the rectangular pyramidal horn is derived from Schelkunoff's formula. Two independent near-field gain measurements of these antennas are made using a three-antenna method and a transfer-standard-probe method. The discrepancy between theoretical and experimental results is typically less thanpm 1dB.     

Antenna designer's notebook-design of pyramidal horns for fixedphase center as well as optimum gain

A method for designing a pyramidal horn with optimum gain and a phase center that is insensitive to horn rotation over a wide frequency band is presented. The optimum gain comes out to be about 14 dB; ways to increase the optimum gain are suggested. The design is based on a far-field formulation and is useful for common applications. However, a parallel procedure based on a near-field formulation and using more exact gain expressions can be developed     

Ka 波段EBG 天线阵列的仿真与分析

电磁带隙(EBG)天线是一种可以提高天线辐射口径及增益的新型天线,本文首先以FSS 结构作为EBG 反射面,角 锥喇叭作为辐射源,设计了一种可以工作在29.7-30.2GHz,最大增益为23dB 的EBG 天线;其次,研究了7 个喇叭构成六 边形阵列时的阵列特性;最后,将EBG 天线用作单反射面多波束天线的馈源研究了波束的覆盖特性,结果表明,当波束 大小为1.12°时,多波束天线的峰值增益为44.5dB,边缘交叠电平为40.4dB,载干比大于12dB。证明了这种EBG 天线 具有良好的工作性能,为将来小型化反射面多波束天线的设计提供了一种新的思路。     

超宽带脉冲横电磁波喇叭的数值模拟

本文用时域有限差分方法分析和优化了前端是平行板传输线的横电磁波喇叭天线（其激励源是由同轴线馈入的超宽带电磁脉冲），优化了平行板传输线和横电磁波喇叭的尺寸，给出了天线的一些特性参数随频率的变化关系、天线的辐射场分布、天线辐射的能量方向图以及天线长度对增益的影响等。     

Front-to-back ratio of a smooth metallic-wall conical horn

By expressing the front fields of the subject conical horn in terms of its gain, and by explicit evaluation of the known GTD expressions for its back field, a concise formula for its front-to-back (F/B) ratio is obtained. The much lower level of back field produced by a corrugated-wall horn as compared to a smooth metallic-wall horn of the same gain is then pointed out.     

一种超宽带高增益的透镜喇叭天线的设计

该文提出了一种适用于微波通讯系统的超宽带(UWB)高增益透镜喇叭天线。该天线由一个E面喇叭天线,一个球面介质透镜和双楔形金属脊构成,并由同轴线馈电及采用HFSS软件仿真。仿真结果表明,双楔形金属脊可有效增加喇叭天线的带宽,有效频率带宽达到2～12 GHz。当仅使用双金属脊来改善喇叭天线的性能时,喇叭天线的增益会下降。文中使用一种球面介质透镜来补偿双金属脊对喇叭天线增益的负面影响。仿真结果表明,该透镜可有效提高喇叭天线在工作频带内的增益。采用透镜和金属脊结构后,该喇叭天线拥有超宽带,高增益和较强的定向辐射性能,可以应用于各类通信系统中。     

Parametric analysis of flare edge rolling throat bending and asymmetric flare effects for H-plane horn radiator

In this paper, radiation characteristics of H-plane sectoral horn antenna are treated systematically by investigation of main structural design parameters and, flare edge rolling, throat bending and asymmetric flare effects. The analytical regularization method (ARM) is used to solve the problem of E-polarized wave diffraction in a fast and accurate way. The numerical procedure is initially verified by the analytical solutions, and then the calculated directivity gain patterns are demonstrated for the modeled horn antenna configurations. Proper choices of the antenna parameters, such as horn depth, aperture length, feeder waveguide width, flare angle, wall thickness, flare edge rolling and throat bending are proposed for the designers to reach high directivity gain, narrow beam width, suppressed side lobe levels, increased front-to back ratio and improved aperture efficiency.     

手动VSAT站天线接收增益的诊断测量

阐述了利用卫星信标和高增益标准喇叭天线,测量手动VSAT站天线接收增益的方法。由测量的天线接收增益计算天线接收效率,从而实现对天线发射增益进行估算。最后,给出了工程测量实例,证明了该方法的可行性,并对增益测量误差进行了分析,其均方根误差±0.28dB。     

A simple design substrate-integrated waveguide horn antenna with reduced back lobe

ABSTRACT

A simple technique to design stable gain and low back lobe substrate-integrated waveguide (SIW) horn antenna is proposed. Matching is achieved by placing a metallised via in a specific distance from the aperture of the horn. The proposed design method is based on the analytical equivalent circuit that derived for the impedance of the antenna aperture and the matching metallic via in SIW. The aperture impedance and metallic via in SIW are studied and design curves are extracted for a specified substrate. Also, to reach a directive pattern and reduce the back lobe of the antenna, some chokes are used on the aperture of the horn. The effect of chokes on some parameters such as power flow and radiation pattern, the front to back ratio (FBR), side lobe level (SLL) and increasing directivity of the antenna is reported. The measurement results confirm simulation, appropriately. The proposed structure has high compactness due to the matching technique and design. The proposed SIW horn has compact dimensions as 18.7 * 23.34*7.62 mm (0.93 * 1.16 * 0.37 λ₀) and the measured gain of the horn is about 5.5 dB at 15 GHz and bandwidth of six percent.     

Gain enhancement of a pyramidal horn using E- and H-plane metalbaffles

A technique for enhancing the gain of a wide-flare angle pyramidal horn is described. The gain of the antenna is increased by placing simple metal strips or baffles inside the horn near its throat. Two baffles, an E- and an H-plane baffle, are described and analyzed. The baffles are first analyzed through two-dimensional (2-D) numerical calculations and then through measurements in an experimental X-band horn. Each baffle enhances the antenna's gain in the respective plane. When the baffles are implemented together the gain enhancement is additive in decibels. The numerical calculations and measurements show that baffles can he used to significantly reduce the size of pyramidal horn antennas     

Design of short e-plane sectoral horns

A method combining the `generalised telegraphist's equations? with a mode-matching technique is proposed well suited for the calculation of short horn antennas. Curves are given for the optimum flare angle, gain and reflection coefficient of a plane sectoral horn excited in the TEM mode. It is shown, that for short horns the aperture-throat interactions cannot be neglected.     

Contour path FDTD method for analysis of pyramidal horns withcomposite inner E-plane walls

The contour path finite-difference time-domain (FDTD) method is used for modeling pyramidal horn antennas with or without composite E-plane inner walls. To model the pyramidal horn surface, a locally distorted grid is used. Modified equations are obtained based on the locally distorted grid and the assumptions of the contour path method. The developed algorithm is validated by comparing computed antenna gain patterns, with and without the presence of composite material, with available measurements     

Pyramidal horn gain calculation with improved accuracy

Previously published methods for pyramidal horn gain calculation have used an approximate expression for the path length error that gives rise to aperture quadratic phase error. In this study pyramidal horn gain is calculated without approximating the path length error. These improved accuracy gain calculations give results equal to the previous approximate calculations for large apertures (A or B>50 λ) or small peak aperture phase error in wavelengths (S or T<0.2). For intermediate aperture size (5 λ⩽A⩽8 λ or 5 λ⩽B⩽8 λ) and intermediate peak aperture errors in wavelengths (0.2⩽S⩽0.6 or 0.2⩽T⩽0.6) the improved accuracy calculations will always yield higher gain than the previous approximate calculations by as much as a few tenths of a decibel, and by as much as 0.6 dB in the E plane. For large values of peak phase error in wavelengths (S or T>0.6) the improved accuracy method can yield lower gain than the previous calculations, especially for an E-plane flare     

Preliminary examination of a modified three-antenna gain-measurement method to simplify uncertainty estimation

Uncertainty estimation in any measurement is an involved process. As an idea towards simplifying this process in respect of the gain measurement and secondary calibration of antennas, in this article, a modified three-antenna measurement method is suggested. This method may be particularly effective when the reference antenna is chosen so that its gain is comparable with that of the test antennas. As an illustration, the gain measurement of an E-plane sectoral horn is considered.     

基于3D打印技术的梯形凹槽双脊喇叭天线

该文提出了一种带有梯形槽的双脊喇叭天线,天线在口径面和外侧壁引入梯形槽结构,抑制了喇叭外壁上的电流,从而达到降低喇叭天线旁瓣的目的。天线采用3D打印技术,有效地解决了传统方式加工难及一致性差的问题。仿真和实测表明,该天线设计可有效提高天线增益,在工作频带5～10 GHz内天线增益大于10.32 dBi,回波损耗小于-10 dB;在9.6 GHz时峰值增益可达14.61 dBi。将天线喇叭壁设计成空心结构,天线质量减小了74%。测试结果与仿真结果基本一致。     

The Design of Potter Horns for THz Applications Using a Genetic Algorithm

We describe the design and performance of Potter horns at millimetre and submillimetre wavelength employing a novel software package that we have developed, using Genetic Algorithm. The horn is easy to fabricate and exhibits excellent beam circularity and low cross polarization over a 15% bandwidth which is sufficient for many applications. Excitation of the required higher order modes is done by either a step or a flare discontinuity at the horn throat. In each case we provide design curves that give the optimum parameters of the horn geometry as a function of frequency and beamwidth. The range of values provided covers the parameters required for the design of horns for telescope feeds and various other instruments. The design curves show clearly that the flare-step performance is superior to the traditional groove-step Potter horn. The simulations for designing these horns were carried out at millimetre and submillimetre wavelengths but the results can be scaled to lower or higher frequencies. A key component in the design method is the optimization software that searches for the correct magnitude and location of the flare discontinuities. We have developed a software package based on the combination of modal matching, a genetic algorithm (GA) and downhill simplex optimization. The genetic code is first used to locate the proximity of the global minimum. The set of parameters obtained are then used as a starting point for the simplex method, which refines the parameters to the required accuracy.     

紧缩场静区校准用超宽带天线性能的分析

紧缩场是天线天线罩辐射特性、目标散射特性测试的重要设备,在使用前需要对其静区平面波幅度锥削、幅度波 纹及相位变化等电磁性能参数进行校准。紧缩场的静区性能校准离不开全频段的探头接收天线,校准天线的性能会影响紧缩 场静区电磁参数的校准结果。文中阐述了校准紧缩场静区性能的扫描法原理,利用本单位研制的紧缩场校准系统,在某研究 所的紧缩场环境内,比较了标准增益喇叭天线与超宽带双脊喇叭天线分别作为接收探头的差异。实验证明,设计完成的超宽 带双脊喇叭天线具有驻波低、增益适中、更换方便、频带宽等优点,完全可以替代六个波段标准增益喇叭天线的功能。