Design and simulation of metamaterial-based hybrid-mode horn antennas

The design and analysis of novel hybrid-mode soft and hard horn antennas with a low index metamaterial wall liner are presented. Metamaterial horn antennas have the potential for considerably larger bandwidth than the current state-of-the-art horns. The optimal or required metamaterial dispersion curve for these horns is qualitatively similar to the Drude dispersion, which indicates that the metamaterial horns are realisable.     

The strip-loaded hybrid-mode feed horn

A novel typed of hybrid-mode feed horn is presented. It comprises a hollow conical dielectric waveguide whose outer surface is metallized, and whose inner surface is coated with circumferentially oriented conducting strips. It may be designed to have mimimal cross polarization at two arbitrarily separated frequencies, as for a dual depth corrugated horn. Compared to the corrugated horn, it has the potential of lower weight and lower price. Small horns will have some cross polarization due to undesired radiation from the fields transmitted within the dielectric.     

Design realization and measurements of a high performance wide-band corrugated horn

We report on the design and realization of horn antennas required to achieve high performances with respect both to the return loss and the cross polarization level over a wide band.     

First-order theory of MOSFET hybrid-mode operation

For specified bias conditions, measurements and theory justify the first-order representation of an enhancement-mode MOS transistor operating with forward source-substrate bias (‘hybrid-mode’ operation) as a parallel combination of two non-interacting devices—an MOS transistor with zero source-substrate bias, and a bipolar junction transistor.     

Optimum geometry and performance of a dual-mode horn modification

We have carried out the optimization of the simplest dual-mode horn that does not include the special cylindrical phasing section. Calculation of the horn characteristics has been performed by using a stepped representation of the conical section, with a subsequent application of the method of generalized scattering matrices, which more accurately accounts for all of the effects taking place when exciting the horn, The objective of the optimization has been the minimization of the maximum crosspolar level. The optimum horn parameters obtained as a result, and the corresponding radiation characteristics, can serve as additional reference information in the development of antenna systems using dual-mode horns     

Fabrication and performance of MMW and SMMW platelet horn arrays

Future spaceborne millimeter and sub-millimeter wave sensing systems will require the sensitivity and resolution only achievable with large focal plane array receiving systems. A technique has been developed for the low cost fabrication of large arrays of millimeter and sub-millimeter wave corrugated feed horns. These arrayed horns exhibit high efficiency and symmetrical receiving patterns and are compatible with integrated receivers. W-band test results of a 3×3 array are presented.     

Modeling of the body current in a Bi-MOS hybrid-mode environment

The body current I_B of deep submicron lightly doped drain pMOSFETs has been investigated. Based on the experimental results, an analytical I_B model, applicable for devices operating in a Bi-MOS hybrid-mode environment, has been developed for the first time. The proposed model is able to effectively characterize the measured I_B results over a wide range of independently applied biases (gate, drain and body) and gate lengths (from 1 μm down to 0.25 μm). The possibility of minimizing or even eliminating the undesired I_B is also explored and discussed for the first time.     

Construction technique and performance of a 2 GHz rectangularcorrugated horn

A large rectangular horn antenna with a center frequency of 2.0 GHz, corrugated on the E-plane walls, made out of aluminium sheet, has been designed, constructed, and tested. A technique has been developed to solder thin aluminium strips onto the back plane to form the corrugations. The radiation beam pattern shows half-power beamwidths of 12° and 14° in the H- and E-planes, respectively, and sidelobe response below -40 dB at angles greater than 50° from the horn axis. The measured return loss is greater than 20 dB (VSWR<1.22) between 1.7 and 2.3 GHz; insertion loss is less than 0.15 dB     

A review of the early developments of circular-aperture hybrid-mode corrugated horns

The simultaneous but independent development in the United States and Australia of circular-aperture corrugated horns in the early 1960's is reviewed. The features of this development include the wide flare-angle corrugated "scalar" horn and the characteristics of focal-region fields of reflector antennas and the single- and multimode cylindrical corrugated horns necessary to feed them.     

Improved radiation pattern performance of Gaussian profiled horn antennas

A new horn antenna profile is presented. This new profile based on Gaussian techniques offers the best solution when the requirements related to the radiation pattern are very stringent. Short-horn antennas with high-conversion efficiency to a fundamental Gaussian beam, and therefore, very low sidelobe and cross-pol levels in a wide-frequency band, could be obtained by using the design technique presented here. Once the theoretical principles of the Gaussian profiled horn antennas (GPHA) are presented, some other possibilities involving Gaussian profiles are studied and compared with their conventional counterparts. Finally, as an example of the design technique proposed, a particular design of a GPHA for HISPASAT 1C and now also valid for the new HISPASAT 1D satellite is presented, showing the excellent agreement between the theoretical and experimental results.     

宽频带角锥脊喇叭天线的设计方法

主要研究了角锥脊喇叭天线的工作原理,给出了脊波导的截止波长、特性阻抗;提出了一种脊喇叭天线的设计方法,并运用该方法给出了设计实例。最后给出了实际测试曲线,验证了设计的正确性。     

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%.     

Optimization of the symmetric E-mode horn profile for a performance directivity pattern

The rigorous theory of excitation of an irregular electrodynamic system is used to formulate and solve the problem of determining the profile of a horn operating on symmetric E modes that provides a required mode structure at the output and an optimum directivity pattern.     

Metallization thickness effect of striplines with anisotropicmedia: quasi-static and hybrid-mode analysis

The effect of metallization thickness in striplines is investigated on the basis of the quasi-static and frequency-dependent hybrid-mode formulations. The formalism utilizes the aperture fields as source quantities and uses the extended version of the network analytical methods of electromagnetic fields. It is therefore applicable for the general structure, i.e., coupled thick strips with uniaxially anisotropic media. Numerical computations include comparisons with available data for the simpler cases to show the accuracy of the present method and the quasi-static and frequency-dependent hybrid-mode solution for single and coupled thick strips with anisotropic media     

基于COMSOL的喇叭天线仿真设计

利用COMSOL软件设计一种高频喇叭天线作为测试天线。文章对天线设计进行说明,利用COMSOL软件计算了S参数、方向性、驻波比以及远场辐射图,并对结果进行分析,得出这种天线结构简单、方向性好,可以很好地作为模拟计算中的测试天线。     

Design and analysis of quasi-integrated horn antennas formillimeter and submillimeter-wave applications

The authors present a systematic process for the design of multimode quasi-integrated horn antennas, and provide a full range of practical antenna designs for millimeter- and submillimeter-wave applications. The design methodology is based on the Gaussian beam approach and the structures are optimized for achieving maximum fundamental Gaussian coupling efficiency. For this purpose, a hybrid technique is used in which the integrated part of the antennas is treated using full-wave analysis, whereas the machined part is treated using an approximate model. This results in a simple and efficient design process. The design procedure has been applied to the design of 20-, 23-, and 25-dB quasi-integrated horn antennas, all with a Gaussian coupling efficiency exceeding 97%. The designed antennas have been tested and characterized using both full-wave analysis and 91/370-GHz measurements. The quasi-integrated horn antennas are also examined as feed elements for Cassegrain antenna systems and are proved to be comparable to the traditional machined corrugated horn feeds     

Experimentally-based analytical model of deep-submicron LDDpMOSFETs in a Bi-MOS hybrid-mode environment

The hybrid-mode operation of deep-submicron LDD pMOSPETs has been investigated experimentally. Based on the experimental results, analytical models for the threshold voltage, the device currents, the transconductance, and the output conductance were derived. The various current components in this mode of operation were extracted and identified. The effects of independently biasing the source, drain, gate, and body potentials on the device currents and parameters were examined. The body-induced-barrier-lowering (BIBL) effect, which is one of the V_SB effects and introduced for the first time, has been used to account for the changes in both the threshold voltage and the device currents caused by the forward source-body bias     

74GHz毫米波透镜喇叭天线的设计与仿真

设计了一种应用于毫米波段的透镜喇叭天线,基于几何光学的原理建立透镜和喇叭之间的几何关系,减少了独立的设计变量,并对天线进行了仿真。结果表明:当天线的中心频率为74 GHz时,天线的口径为38.63 mm;在72.5~76 GHz频带范围内,带内电压驻波比VSWR均小于1.5,天线增益大于28 d B,并且E面和H面中的半功率波束宽度分别小于6.5o和8.5o。喇叭天线在加载介质透镜前后三维方向图的仿真结果表明介质透镜可以减小喇叭口面相位误差。所设计的天线具有良好的方向性和增益。     

Design of rectangular horn arrays with oversized aperture elements

The possible existence of blind spots, due to forced aperture resonances, is demonstrated theoretically and experimentally at 14 GHz in rectangular grid arrays of tapered rectangular horn elements with oversized (overmoded) apertures. The dominant contributor to these blind spots is the resonance of the equivalent transverse magnetic (TM_12) waveguide mode. The numerical results based upon our approximate methods of formulation and solution of the array boundary value problem agree well with experiments. A method for eliminating the blind spots by proper taper design is presented and experimentally verified. The analytical methods used in this work could possibly be extended to conical horus and other tapered-structure arrays as well as other periodic grid geometries. New simple and accurate formulas for the zeros of Bessel and Legendre functions and their derivatives are obtained as a result of this analysis.     

Design of multiple-edge blinders for large horn reflector antennas

Attaching blinders to the sides of pyramidal horn reflector antennas and other large aperture antennas is one method of controlling high sidelobes for horizontal polarization. This paper describes analysis and design procedures for arriving at a useful multiple-edge blinder for reducing undesirable sidelobes of a pyramidal horn reflector antenna. Several blinders have been designed and tested for use with a pyramidal horn reflector antenna. They are directed at reducing a high sidelobe near90degin the azimuth plane where levels (referred to the main lobe) of -52 dB at 3.74 GHz and -58 dB at 6.325 GHz are presently typical. A 14-edge blinder designed using these techniques reduced these levels by 20 dB at 3.74 GHz and 12 dB at 6.325 GHz and did not significantly degrade antenna performance for other angles and other polarizations.