Compact multimode horn with low sidelobes for global Earth coverage

A new multimode corrugated horn is described for full-Earth coverage from a geostationary satellite. The horn has low sidelobes, low cross polarization, and is compact. We outline the design of this horn and compare its performance with other circular horn types, including conventional single and multimode-corrugated horns and dielectric loaded horns. A design was fabricated and measured results are described for return loss, radiation patterns, and axial ratio. These measurements demonstrate excellent agreement with computer predictions using mode-matching software     

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.     

A dielectric hybrid mode antenna feed: A simple alternative to the corrugated horn

A hybrid-mode horn antenna has been analyzed theoretically and experimentally. It consists of a conical metal horn with a dielectric core inside, separated from the metal wall by another dielectric layer with lower permittivity than for the core material. It is characterized by a very simple design and excellent electrical performance. The horn can support the balanced hybrid HE11-mode, and exhibits low cross polarization and low sidelobes over a wide frequency range. Compared to corrugated horns, the new horn has a simpler design, is easier to analyze, and has the potential of similar cross-polar bandwidth as for corrugated horns with ring-loaded corrugations. Drawbacks are the effects of dielectric losses. Thus the new horn represents an attractive alternative to the corrugated horn antenna.     

Broad-band elliptical beamshape horns with low cross polarization

Horn antennas with an elliptical beam and low cross polarization are discussed. A new class of elliptical-beamshape horns has been investigated. The horns are based on the dielectric core approach, using a dielectric core inside a smooth-walled horn. Horns with rectangular as well as elliptical cross sections have been studied. Experiments show that they have considerably larger cross-polar bandwidth than that obtained from corrugated horns with an elliptical beam. They are also potentially much cheaper to manufacture     

一种Ka频段超低交叉极化宽频带波纹喇叭天线

波纹喇叭天线是一种结构紧凑、具有良好辐射性能的馈源天线,特别是轴向槽波纹喇叭天线可以在宽频段内实现极低的交叉极化,对扩展工作频段、实现极化复用有重要的价值。文章对轴向槽波纹喇叭天线的设计方法进行了研究,利用模式匹配法和全波算法软件设计了一种Ka频段超低交叉极化宽频带轴向槽波纹喇叭天线。实测数据表明,该喇叭天线工作频段可覆盖整个Ka频段（26.5~40 GHz）,在频段内回波损耗小于-20 dB、交叉极化小于-45 dB,同时天线具备良好的方向图对称性和相位中心稳定性,在卫星通信领域具有广阔的应用前景。     

Design and performance of the magnetic hybrid-mode horn

Design techniques are presented for a class of circular magnetic hybrid-mode (MHM) horns together with experimental results. In comparison with earlier techniques, this design method is simpler and more amenable to physical interpretation. The horns designed exhibit performance comparable to that of the corrugated horn except that they have an ohmic loss of 0.8 to 2.7 dB. However, it appears feasible to reduce the gain loss to less than 1 dB     

一种Ka/EHF频段分波器(OMJ)的设计

针对传统分波器影响高频方向图的问题,提出了一种新型的Ka/EHF频段分波器设计方法。与传统分波器相比,该分波器具有低损耗、低驻波、高频段隔离的优点,其通过使用皱褶波纹滤波器和sin^2曲线过渡,实现了Ka、EHF频段信号的低损耗分离,分布式参数综合设计的波纹滤波器对高频信号产生了极佳短路面,sin^2函数曲线过渡较好地抑制了高次模。设计、加工和测试了样机,接收频段的回波损耗小于-22 dB,发射频段的回波损耗小于-25.2 dB,仿真结果与测试结果基本吻合,验证了方法的正确性和有效性。     

准太赫兹波段角锥波纹喇叭天线的设计

波纹喇叭天线是20世纪70年代出现的用于微波天线的一种新型器件,它结构紧凑、加工方便、成本较低。不仅如此,它还是一种高效率的馈源,它的方向图具有低旁瓣、轴对称、交叉极化小等一系列优点,因而得到广泛的应用。文中介绍了准太赫兹角锥波纹喇叭天线的基本设计思想。设计了一种工作在140 GHz左右频段的E面波纹角锥喇叭天线。计算机模拟达到了相对于平壁角锥喇叭来说较小波瓣宽度,极低旁瓣电平,E,H面波瓣图趋同的效果。     

An offset reflector antenna with low sidelobes

The corrugated conical horn is considered to be an ideal feed for low sidelobe reflector antennas because of its unique characteristics. Analysis is carried out to show that low flare horns are preferred over high flare horns to give rise to low sidelobe performance for a given offset reflector antenna system.     

High-Q resonances due to surface waves and their effects on theperformances of corrugated horns

We present a study of high-Q resonance phenomena that occur in corrugated horn structures. It is found that high-Q resonances occur within certain frequency bands where two types of modes, i.e., space-wave and surface-wave modes, simultaneously propagate. A simple model is presented to explain the resonance mechanism. The model yields the conditions for resonance, explains the Q of the resonance, and provides the associated resonant frequency. Approximate formulas for the upper and lower bound frequencies of a resonant band are obtained. It is found that the high-Q resonances deteriorate the gain and crosspolar performances of a horn even if the return losses are acceptable at some resonant frequencies. Rectangular corrugated horns are more susceptible to these resonances than circular corrugated horns, and the reasons for such a difference are explained     

Profiled corrugated circular horns analysis and synthesis via anartificial neural network

In many reflector and lens antennas profiled corrugated circular horns constitute one of the best feed solution thanks to their polarization purity and small size. In this paper, a method for the design of these feeds by using an artificial neural network (ANN) approach is described. The results obtained with such an approach are investigated both for the analysis and for the synthesis problem, and compared with the standard methods. This unconventional solution gives a good level of accuracy and shorter processing times especially for the synthesis problem, where there is still a lack of affordable and fully automated procedures     

Application of rectangular and elliptical dielcore feed horns toelliptical reflector antennas

The pattern characteristics of elliptical reflector antennas are investigated when they are fed by rectangular and elliptical horns partially filled with a dielectric. The bandwidth characteristics of these dielcore horns are superior to those of their corrugated horn counterparts. Representative reflector patterns are computed to properly demonstrate the utility of these feeds for reflector antennas with elliptical apertures. This reflector antenna exhibits high efficiency and low cross polarization, and may be suitable for radar and satellite antenna applications. The antenna configuration may become useful in relatively small antennas where more than 10% cross-polar bandwidth is required. The efficient dielcore horns may also be used as feeds for elliptical nonshaped dual-reflector antennas     

Analysis of soft and hard strip-loaded horns using a circularcylindrical model

Strip-loaded horns with transverse (soft) and longitudinal (hard) strips are analyzed theoretically. The method is based on a circular cylindrical and uniform waveguide model with a periodic strip structure. The field is represented by an infinite series of space harmonics (Floquet modes) in the air-filled central region and in the dielectrically filled wall region. The tangential field is forced to be continuous across the air-dielectric boundary. The propagation constant and the total field (including the hybrid factor) can be determined by solving the resulting matrix equations. The convergence of the solution has been accelerated by calculating the higher-order terms analytically. It is shown that the soft-strip-loaded horn in principle exhibits the same electrical behavior as a corrugated horn. The horn represents an interesting alternative to the corrugated horn in wide-band or dual-band applications, in particular for millimeter waves and for lightweight applications onboard satellites. The hard-strip-loaded horn has potentially high gain and low cross polarization over a certain frequency range, dependent on the horn dimensions, thickness of the dielectric wall and on how strongly the stripline modes are being excited     

Design of conical corrugated feed horns for wide-bandhigh-frequency applications

This paper presents a new analytical procedure for the design of the conical corrugated feed horns used in the millimeter and submillimeter wavelength range, which could achieve wide-band single-mode operation and wide-band, low return-loss impedance matching simultaneously. A test model of the feed horn designed using this procedure displayed excellent performance, and agreed well with the theoretical predictions     

Antenna Performance of a Directly Dug Corrugated Feedhorn for the 150-GHz Band

We have developed a 150 GHz band corrugated feed horn. These corrugated feed horns have been established by a new machining method, which involves digging corrugations through a metal material. We were able to realize E plane and H plane symmetry, low side lobe level, and low cross-polarization level. Measured co-polarization beam patterns above ??35 dB were consistent with the simulated patterns within a designed frequency range. The peak levels of cross-polarization beam patterns were less than ??30 dB. And, the performances were uniform in several horns. In the present paper, we describe the corrugated horn produced by this methods.     

Hard waveguide feeds with circular symmetry for aperture efficiencyenhancement

Hard horns or waveguide feeds with circular symmetry have been studied with respect to gain (aperture efficiency) and crosspolarisation. The corrugated or strip-loaded representations of these feeds give almost identical radiation properties when surface waves are neglected. The contribution from the wall region increases the gain and crosspolar bandwidth of the feed. The gain increases and the crosspolar bandwidth decreases with increasing waveguide diameter and wall permittivity. The hard horns may be useful in cluster feeds and limited scan arrays due to reduced size and weight     

波纹波导极化器的分析

极化器是天线馈电系统中的重要器件,但传统的极化器带宽一般很窄。介绍了一种新型的宽带极化器(波纹波导极化器),其结构是在方波导的两壁加载横槽波纹,使波导中的2个正交模产生了90°的相位差。因而将线极化信号转化成圆极化信号。波纹波导极化器在超过30%的带宽内仍然有很好的相移特性,因此他在宽带反射面天线馈电系统中有着很广阔的应用。     

Cross coupling in a five horn monopulse tracking system

A model is developed which explains the observed effects of secondary pattern crosstalk in a five horn circularly polarized monopulse tracking system. The model predicts unstable operation and loss of track for sufficiently depolarizing targets as well as polarization dependent uncertainties in the angular location of off-axis targets. The cross coupling is characterized by two complex coupling coefficients between adjacent horns in the monopulse feed system. This characterization is assumed to be valid irrespective of whether the observed secondary pattern effects are the result of mutual couplings within the feed structure itself or caused by cross-polarized backscatter from the paraboloidal reflector. A "ridge" and "nonridge" polarization terminology is adopted which is physically related to the fact that the error horns in a five horn circularly polarized system are heavily ridge loaded for one linear polarization and not the other.     

改善单偏置天线交叉极化劣化的C-band馈源

描述了用波纹喇叭中的 HE_(21)模抵消单偏置抛物面天线非对称平面交叉极化分量的基本原理,介绍了 TE_(21) 模激励器、波纹喇叭的设计方法和展宽馈源抑制单偏置天线交叉极化分量频带宽度的设计方法,给出了 C 波段 2．4m 单偏置抛物面天线的实验测试数据,单偏置抛物面天线非对称平面交叉极化电平改善了10dB,抑制交叉极化分量的馈源相对工作频带宽度大于8％。这种 TE_(21)模激励技术和与主模 TE_(11)模相位差的调整方法,对馈源的电压驻波比几乎没有影响。     

Radiation and matching characteristics of a novel dual-band dielectric loaded coaxial horn

Copolar and crosspolar radiation as well as matching characteristics of a novel dual-band coaxial hybrid-mode feed horn with partial dielectric loading [1] for reflector antennas have been numerically and experimentally investigated. In comparison with dual-band corrugated horns this horn has higher crosspolar level, but provides larger band separation and rather good electrical performances over a wide frequency range (20% and more) within each operational frequency band. Furthermore, the main concept of the coaxial feed system can be easily extended for multi-band cost-effective applications in reflector antennas with polarization diversity.