Design of optimum gain pyramidal horn using self‐adaptive differential evolution algorithms

In this work, we apply classical and new self‐adaptive differential evolution (DE) algorithms to the design of optimum gain pyramidal horns. The application of DE algorithms to pyramidal horn design allows the accurate calculation of their physical dimensions in a short amount of time. Moreover, self‐adaptive DE does not require the prespecified choice of control parameters reducing significantly the users' effort. Representative examples demonstrate the applicability of our proposal. Our study shows that self‐adaptive DE algorithms outperform or produce similar results with other methods in the literature in terms of solution accuracy and convergence speed. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011.     

Multiband feed using coaxial configuration

We present design, analysis and test results of a dual‐aperture coaxial multiband feed horn that operates at S, Ku, K and Ka bands. The design objectives are to achieve aperture efficiencies of 85% for S and Ku bands and 60% for K and Ka bands and cross‐polarization level of ?20 dB within 30 degree off‐boresight for all bands. These values are deduced primarily from the reflector geometry, ?10 dB reflector edge taper and moderate cross‐polarization requirements for the secondary patterns. In our design the Ku, K and Ka bands are launched through a multiflared circular horn while the S band is launched through a coaxial horn. A method of moment based software is developed to analyze the structure including mutual coupling between the apertures. It is found that the aperture impedance significantly affects the S‐band performance. For the high frequency bands, the mutual coupling between the circular and coaxial apertures plays an important role. The simulated results including mutual coupling effects agree well with the measured data. The multiband feed design allows a compact, low weight, single offset reflector configuration as opposed to a Cassegrain antenna system that requires two separate feeds and a dichroic subreflector to accommodate such widely separated bands. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011.     

Radiation pattern of modified box‐horn antenna

The expression for radiation field of modified box‐horn antenna is derived using plane wave spectra for three‐dimensional fields. Modified box‐horn is a modified version of conventional box‐horn, in which the horn exciting the box is flared in both E‐ and H‐planes to increase its aperture size. It supports TE₁₀‐ and TE₃₀‐modes at its aperture. The radiation patterns of modified box‐horn antenna in E‐ and H‐planes are computed at 10 GHz and corresponding radiation parameters are extracted from the plots and compared for different flare angles in E‐plane of pyramidal horn exciting the box. The results for half power beam‐widths in E‐plane demonstrate that the radiation pattern of modified box‐horn in E‐plane can be made narrower by increasing the flare angle in E‐plane of pyramidal horn exciting the box. The radiation patterns of modified box‐horn are also compared with those for TE₁₀‐mode open ended waveguide of same aperture size and it is found that the former is narrower beam in H‐plane than the latter. The analysis has been validated against the experimental results available in the literature. The antenna presented here may find potential application as an element in a phased array for microwave wireless communication/radar beam steering, a feed for reflectors in point‐to‐point microwave communication/satellite communication. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2008.     

Radiation pattern and properties of double‐flared diagonal horn antenna

This article is concerned with analytical model for radiation pattern of a new double‐flared diagonal horn antenna using “plane wave spectra technique for 3D fields”. The double‐flared diagonal horn antenna is accomplished by adding one more set of flares in E‐ and H‐planes with equal flare angles into conventional diagonal horn. The copolarized and cross‐polarized radiation patterns in E‐, H‐, and D‐planes have been computed utilizing the analytical model and reported in the article. The parametric studies on peak cross‐polarization level have carried out. The radiation performance of double‐flared and conventional diagonal horns for same length and aperture size are also compared. It is investigated that double‐flared diagonal horn antenna posses better peak cross‐polarization level (≈?16.5 dB) in D‐plane (±45° plane) in comparison of conventional diagonal horn (≈?15.5 dB) at design frequency and retains almost circularly symmetric radiating beam at lower values of elevation angles. Also, double‐flared diagonal horn has better matches with free‐space and has slightly lower gain (≤0.5 dB) in comparison of conventional diagonal horn. The work presented here can provide useful design guidelines for development of prototypes of double‐flared diagonal horn, which may find potential application in satellite communication and imaging applications etc. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.     

Microwave conical horn antenna with dual circular polarization—Close‐form design equations

In this article, we have proposed the closed form expressions for the optimized dimensions of different parts of the metallic stepped septum in a circular waveguide. Using these relations, a dual circularly polarized (CP) horn can be realized with good AR bandwidth, impedance bandwidth, and interport isolation. The relations are generalized for application at all frequency bands. Using these relations, horns have been designed and simulated at different frequency bands. Prototypes have been fabricated at some frequency bands and are experimentally validated. This design yields impedance bandwidth (S₁₁ ≤ ?10 dB) of about 18%, AR bandwidth more than 15%, and interport isolation about 24 dB at the band center. Experimental data for the Ka‐band prototype are provided in detail. At the design frequency, the measured axial rations are <1 dB revealing cross‐polar discrimination over 25 dB.     

Double‐ridged conical horn antenna for wideband applications

In this article, the design and analysis of a double‐ridged conical horn antenna with high gain and low cross polarization for wideband applications is presented. Double‐ridged pyramidal horn antennas have been investigated in many references. There are no papers in the literature which are devoted to design and analysis of double‐ridged conical horn antenna. The designed antenna has a voltage standing wave ratio (VSWR) less than 2.1 for the frequency range of 8–18 GHz. Moreover, the proposed antenna exhibits extremely low cross polarization, low side lobe level, high gain, and stable far‐field radiation characteristics in the entire operating bandwidth. A new technique for synthesizing of the horn flare section is introduced. A coaxial line to circular double‐ridged waveguide transition is introduced for coaxial feeding of the designed antenna. The proposed antenna is simulated with commercially available packages such as CST microwave studio and Ansoft HFSS in the operating frequency range. Simulation results for the VSWR, radiation patterns, and gain of the designed antenna over the frequency band 8–18 GHz are presented and discussed. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.     

Improved design method for optimum gain pyramidal horns

A technique, simple and easy to use, is presented to design the optimum gain pyramidal horn. The optimum gain pyramidal horn design equation available in the literature is improved. Design parameters are computed from the simple and explicit analytical formulas. The pyramidal horn gain is determined with no path length error approximation. Several design examples are given to show the performance of the improved design technique. © 2001 John Wiley & Sons, Inc. Int J RF and Microwave CAE 11: 188–193, 2001.     

Quasi‐corrugated substrate integrated waveguide H‐plane horn antenna with wideband and low‐profile characteristics

A wideband H‐plane horn antenna based on quasi‐corrugated substrate integrated waveguide (SIW) technology with a very low profile is presented in this article. Open‐circuited microstrip stubs are applied to create electric sidewalls of the quasi‐corrugated SIW structure. The quasi‐corrugated SIW H‐plane horn antenna shows high performance and simple structure. A specify‐shaped horn aperture is utilized, so that the poor impedance matching owing to the structure restriction can be smoothened. The structure is simulated by ANSYS HFSS and a prototype is fabricated. The measured results match well with the simulated ones. An enhanced impedance bandwidth ranging from 5.3 GHz to 19 GHz (VSWR < 2.5) is achieved. The presented antenna also brings out stable radiation beam over the same frequency band.     

Compact wideband circularly polarized horn antenna with tapered slot‐coupled feeding for Ku‐band applications

A compact wideband circularly polarized (CP) horn antenna with slot‐coupled feeding structure at Ku band for satellite communication is devised. The proposed design is based on a square aperture horn antenna with two orthogonal ridges, which is fed by nonuniform curved slot along the diagonal of the horn on the bottom cavity. And in order to improve the impedance matching, a staircase typed ridge is connected the feeding probe as a matching network. Moreover, two orthogonal ridges are excited with a tapered slot coupled by the staircase ridges via feeding probe. Wideband CP performance is achieved with an overall physical dimension of 9 mm × 9 mm × 14 mm (0.045λ₀ × 0.045λ₀ × 0.07λ₀ at frequency of 15 GHz). It is experimentally demonstrated that the proposed antenna achieves: a wide 10‐dB return loss bandwidth of about 2.4 GHz, a 3‐dB axial ratio bandwidth of 1 GHz, and a peak gain of 6.5 dBi.     

Design of optimum gain pyramidal horn with improved formulas using particle swarm optimization

In this article, a new method to design an optimum gain horn antenna is presented. This method is based on improving existing design equations along with the use of particle swarm optimization technique. The obtained results are more accurate than those available in the literature since no path length error approximation is involved. Improved horn dimensions, for different 15 designs, are obtained which give the desired gain almost exactly. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007.     

A compact feed horn with wide‐distributed operating bands of Ku/Ka/W

This paper presents a design of a compact tri‐band feed horn for reflector, which has sufficient wide‐distributed operating bands at 14.5, 35, and 94 GHz. A single cavity is used to downsize and simplify the whole structure, replacing multiple transition sections, or dielectric rods. To maintain a good isolation, two 3‐order low‐pass filters are applied in the waveguide ports of Ku/Ka‐band respectively, meanwhile retaining a good coupling and minimal destruction on transmission modes. The prototype of the proposed tri‐band feed horn is fabricated and measured, showing an adoptable candidate for multiband reflector antennas.     

Improved diffraction model and numerical validation for horn antenna gain calculations

In this study, the diffraction model for on‐axis gain calculations of rectangular horn antennas has been improved, mainly through refining the expressions for the aperture fields of the horn to more accurately reflect the astigmatic nature of the wave that emanates from the throat of the horn. As the availability of accurate swept‐frequency measurement results for horn antennas is very limited, the method of moments, employing the multilevel fast multipole method, has been used to validate the improved diffraction model for horn antennas with widely varying flare dimensions. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.     

几种常用喇叭天线的计算机计算和计算机设计

论文的工作在于取定尽量精确而又尽量简单的、便于应用的、与测试结果吻合程度好的计算式;不涉及计算的具体程序,但将提及计算的大致步骤和计算过程中可能出现的一些现象以及要注意的问题,并在必要时给出实例或典型数据。     

汽车喇叭检测仪表数据提取系统设计

针对现有汽车喇叭检测仪表不能自动提取测试数据的问题,设计了一套基于单片机的汽车喇叭检测仪表数据提取系统。主要探讨了该系统的硬件连接和软件设计,并将其应用于实际生产。实践证明：该系统不仅电路简单、工作可靠,而且可实现汽车喇叭生产过程的自动化。     

Pattern squint elimination for quad‐ridged conical and pyramidal horn antennas using bended probes

This article describes a new technique for pattern squint elimination of quad‐ridged conical and pyramidal horn antennas by introducing bended coaxial probes. Because of the phase difference and mutual coupling between vertical and horizontal polarizations, the radiation patterns of the conventional quad‐ridged conical and pyramidal horn antennas squint over a wide bandwidth. The proposed technique substantially reduces the phase difference and coupling between the two probes, so a significant improvement in the radiation patterns over the frequency band of 8–18 GHz can be achieved. The designed modified horn antennas are most suitable as a feed element in reflectors of radar systems and EMC applications. The proposed modified antennas have a voltage standing wave ratio (VSWR) less than 2.2 for the frequency range of 8–18 GHz. Moreover, the proposed antennas exhibit high gain, dual‐polarization performance, good isolation, low SLL, low back lobe, low cross polarization, and satisfactory far‐field radiation characteristics for the entire frequency band. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE 2010.     

GSM filtering of horn antennas using modified double square frequency selective surface

In this work, a dual‐band frequency selective surface (FSS) is proposed to be placed perpendicularly into the apertures of horn antennas for prefiltering 900 and 1800 MHz GSM signals interfering during the signal reception, with the enhanced return loss, gain, and directivity at the desired frequencies. For this purpose, the microstrip double square loop MDSL is modified in the first stage. As for the second stage, an FSS array (2 × 2) is built up arranging the unit MDSLs in a periodic structure and finally these FSS unit arrays are fixed perpendicularly covering the aperture of a ridged horn antenna which is a part of the available radar system operating between 0.5 and 3 GHz in our laboratory, to construct an integrated module having both bandstop prefilter and horn antenna called “filtenna.” The simulated and experimental results are agreed that the proposed FSS structure attenuates GSM signals at the 900 and 1800 MHz through the high reflection and very poor transmission mechanisms meanwhile enhances return loss characteristics, radiation pattern, and gain of the horn antenna in the desired band. Thus, it can be concluded that these simple microstrip FSS structure can be effectively adapted to the horn antennas which need the GSM prefiltering.     

3D-feed horn antenna-coupled microbolometer

In this paper, we proposed a microbolometer coupled with 3D feed horn antenna. It is a new device that enhances the performance of the microbolometer by coupling 3D horn shape antenna. We designed the optimum horn antenna size that has 20.08 dB directivity. And we designed the microbolometer as a circular shape in order to reduce the coupling loss between the horn antenna. We confirmed that the detectivity of the designed microbolometer would be improved as the noise characteristics of the microbolometer are enhanced by coupling feed horn antenna which acts as a cold shield. The detectivity of the designed 3D antenna-coupled microbolometer was improved about seven times more than that of the conventional microbolometer in state of background limited infrared performance. Fabrications of the microbolometer are carried out by a surface micromachining method. We achieved the thermally good isolated floating structure. And the 3D feed horn antenna was constructed by using a mirror-reflected parallel beam illuminator (MRPBI) system which is invented for rotating and tilted illumination. Using this method, we acquired the feed horn shape antenna mold. And we also acquired antenna plate by using PDMS injection method. Finally, to couple the antenna and the microbolometer, we proposed the PDMS injection bonding method.     

基于传递函数的汽车喇叭支架结构优化

针对某试验样车在喇叭工作状态下离合器踏板产生振动的问题,通过有限元分析和试验测试分别得出传递路径的加速度频率响应函数.通过NVH试验测得离合器踏板处的加速度频率响应,并与用有限元法计算传递函数得到的结果对比,二者吻合较好.在已有设计空间内优化喇叭支架结构,并比较喇叭支架优化前、后离合器踏板处的加速度频率响应.对喇叭支架优化后离合器踏板的加速度频率响应测试结果表明,离合器踏板振动问题基本消除.     

Quad‐ridged conical horn antenna for wideband applications

This article presents a quad‐ridged conical horn antenna with high gain and low side lobe level for broadband applications. To the best of authors' knowledge, the proposed structure presented in this article is completely new. The designed antenna introduces a low VSWR, which is lower than 2.2 for the frequency range of 8–18 GHz, and simultaneously achieves high gain as well as dual‐polarizations with high isolation between the corresponding excitations. The common impedance exponential tapering is used at the flare section of the horn, and a coax to waveguide transition, namely quadruple‐ridged circular waveguide, with a conical cavity is used to improve the VSWR. The proposed antenna structure is designed and simulated by two well established packages, namely the CST microwave studio and the Ansoft HFSS, showing there is a close agreement between the results obtained by the aforementioned softwares. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.     

A compact substrate integrated waveguide H‐plane horn antenna with dielectric arc lens

An H‐plane horn antenna constructed into SIW (substrate integrated waveguide) is proposed. It has a dielectric arc lens for better directivity and a simple microstrip transition as feed. The horn, the lens and the transition share the same substrate. The resulting formula from optical principles shows that the suitable dielectric lens can improve the directivity of the antenna significantly. A prototype was fabricated; the antenna size is 39.175 × 14 × 2 mm³. The frequency band is from 25.5 to 28.5 GHz. The measured gain of this antenna is about 9 dB; the bandwidth, at 10 dB return loss, is over 12%. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007.