Linear array of woodpile EBG sectoral horn antennas

A technique is described for creating linear array antennas that conform to the natural stacking sequence of the woodpile electromagnetic bandgap (EBG) material. Each element in the linear array consists of a woodpile EBG sectoral horn antenna. The electromagnetic confinement mechanism within each horn antenna relies wholly on the 3-D EBG of the woodpile material. The array element has a typical sectoral horn pattern with a directional beam in one principal plane and a broader beam in the other. The bandwidth of the sectoral horn is almost equal to that of the defect EBG waveguide. Measured and theoretical results for radiation patterns, impedance bandwidth and gain of a sectoral horn antenna made from alumina are described, and theoretical results for a design made from silicon are presented. It is shown that the layer-by-layer nature of the woodpile EBG material enables sectoral horn antennas to be easily stacked together in the E-plane to create linear arrays. Analysis of the mutual coupling as a function of element separation and its effect on reflection coefficient are presented for a two-element linear array in silicon. Theoretical analyses for fixed and scanned beam linear arrays of silicon woodpile EBG sectoral horns are described and finite-difference time-domain results are compared with array theory. The fixed beam arrays are designed for high directivity while the scanned beam array enables wide angle beam steering through the use of parasitic array elements.     

一种新型的双波束指向馈源喇叭

文章介绍了一种新型的馈源喇叭,这种馈源的设计,利用了喇叭反射面天线原理,实现了馈源的双频、双极化、双波束指向功能。文中重点讨论了这种喇叭的设计思想及波束特性的修正方法,给出了这种馈源喇叭特性的实际测量结果。     

Fabrication of Silicon Microlens Arrays Using Ion Beam Milling

A spherical mask for the fabrication of microlens arrays was prepared by melt-ing photoresist,and the spherical photoresist shape was transferred into a silicon substrate using ion beam milling.The ion beam milling process was computer simulated using the Sig-mund ion beam sputtering theory of collision cascades.The experiment results show that mi-crolens arrays can be effectively formed at low substrate temperature of less than 200℃，Shapes and dimensions of photoesist masks and silicon microlens arrays were examined by the scanning electron microscope and tested by the surface stylus measurement.     

On selective electroplating of gold in fabrication of MIC's

The analysis of the reasons causing degradation observed in resist layer during selective gold plating on patterns for MIC's has resulted in an excellent combination of electrolytic bath and photoresist type. Thick layers of gold (i.e. more than 10 μm) have been deposited by the method presented here over a period of about 1 h without any deterioration in the photoresist property. This combination can be used in the fabrication of beam lead devices with better results.     

The hexagonal horn as an efficient Gaussian beam launcher

A new type of feed horn-the hexagonal horn-is proposed and investigated by means of Gaussian-Hermite beam-mode analysis. The electric-field distribution at the horn aperture plane is approximated. The polarization efficiency is 88.66%. The fractional power in the fundamental beam mode is about 85%. The near- and far-field radiation patterns are calculated. The high fractional power in the fundamental beam mode of the horn indicates that it can be used as an efficient Gaussian beam launcher in quasi-optical systems     

High-gain step-profiled integrated diagonal horn-antennas

Dipole-excited integrated horn antennas are limited by their large flare angle of 70°, which is inherent in the anisotropic etching process of 〈100〉 silicon wafers. The large flare angles does not allow for integrated horns with gain higher than 13 dB and for 10-dB beamwidths less than 90°. A step-profiled horn is proposed which reduces the effective flare angle of the horn and allows gains in the region 17 dB to 20 dB to be achieved. The symmetry of the horn's radiation pattern is enhanced by positioning the exciting dipole along the diagonal of the horn cavity. A specific design example is shown with a gain of 18.4 dB and a 10-dB beamwidth of 37° in the E, H and 45° planes. The coupling efficiency of this horn to a Gaussian beam is calculated to be 83%. An equivalent smooth envelope-horn was built at 12.1 GHz and the measured patterns agree well with theory. The integrated step-profiled horn is well suited for millimeter-wave and terahertz focal plane imaging arrays requiring a large number of elements     

Su-8胶-金属复合材料电热微驱动器

针对以金属嵌入式Su-8光刻胶作为新型弯曲梁式微驱动器结构材料的特点,在仿真分析过程中,考虑了狭小空气间隙中热传导机制的影响。分析结果表明,器件的工作电压随着悬空高度的增加而降低;当悬空高度达到270μm时,可忽略热传导机制。在微加工工艺流程中,引入新的牺牲层材料,显著提升了工艺流程的兼容性和加工效果的稳定性。在此基础上研制的新型电热微驱动器实测位移由11.5μm增大至13.9μm,这一结果与传统多晶硅材料弯曲梁式微驱动器的驱动位移5μm相比有显著提高,而能耗亦从180mW降至21.6mW,器件性能得到改善。     

Pattern analysis of corrugated horn antennas

The corrugated horn has been established as an antenna with low sidelobes and backlobes, rotationally symmetric patterns (for square pyramidal and conical horn shapes), and broad-band performance [1]-[9]. These properties make this horn useful for many applications. Previous studies have used conventional aperture integration techniques to evaluate the patterns of the corrugated horn. In general, the near axisE-plane radiation pattern of a pyramidal corrugated horn may be adequately predicted from standard analysis established for theH-plane patterns of conventional horn geometries [3]. This method, however, fails to predict the far-out sidelobe and backlobe radiation levels. The work presented here uses a knowledge of the aperture fields to predict the pattern using aperture integration and diffraction theory. The assumptions made concerning the aperture fields were verified by probing the internal fields and aperture fields of anXband corrugated horn. The results of this field probing are contained in the Appendix. The method of solution used in this paper parallels that used in previous publications [10]-[12]. Specifically, the pattern in the main beam region is computed using conventional aperture integration procedures, the contribution of theH-plane edges is found using a slope diffraction analysis, and the contribution of theE-plane edges is found by use of duality.     

A High Performance 700?GHz Feed Horn

We present a design of a high performance horn operating at 700 GHz. The feed, which comprises three smooth-walled conical sections, is easy to machine and yet has comparable performance to a corrugated horn. The measured radiation patterns show high main beam circularity, low sidelobe level and good agreement with theoretical predictions. The cross-polar level is below −20 dB across a frequency bandwidth of 140 GHz. The new design allows the fabrication of high performance, large format feed arrays cheaply and rapidly.     

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     

非赋形双偏置高性能椭圆波束天线

分析了非赋形双偏置天线产生椭圆波束的机理,将馈源的椭圆波束照射到轮廓线为椭圆形的付反射面上,通过双偏置天线的对称转换原理,主反射面产生椭圆波束.馈源波束由矩形口径的多模喇叭产生,它提供了等化的方向图.给出了馈源及天线的方向图计算公式.实验结果表明,实测方向图基本与理论计算一致.与其他类型的椭圆波束天线相比,本天线加工简单,同时天线效率也较高.     

Investigation of the Photoresist Pattern Profile Contrast Improvement in Interference Lithography Technique Using 488-nm Laser

The interference lithography technique at 488 nm is explored theoretically and experimentally, and the effect of photoresist pattern profile contrast improvement is presented. In order to produce high contrast photoresist patterns using interference lithography, the system setup and process have to be optimized strictly, and process optimization can be facilitated by simulation. In the proposed simulation method, the absorption coefficient of photoresist varying with wavelength is considered by using photoresists with lower absorption coefficients, or, for the same photoresist, using laser sources with longer wavelengths. The visibility of aerial fringe patterns of the photoresist can be improved greatly. However, after developing, the contrast of photoresist patterns was not improved. The reason is that the photo sensitivity and etching rate V of photoresist decrease at 488 nm. This offsets the effect of lower absorption coefficients even though a 488-nm argon ion laser source is useable for some photoresists. This opens up a new window for the interference lithography technique.      

GTD analysis of the radiation patterns of conical horns

The far-field radiation patterns of conical horns of arbitrary flare angles excited in theTE_{11}mode are obtained employing the geometric theory of diffraction (GTD) based on the theory of Kouyoumjian and Pathak [3] and the slope diffraction technique [4]. The analysis presented enables one to predict accurately radiation patterns over the main beam, near and far sidelobes, and the becklobe of the horn. Validity of the analysis is established by satisfactory agreement between the calculated and measured patterns of an experimental conical horn. The radiation patterns of wide-flare corrugated conical horns excited in theHE_{11}mode of operation have also been calculated over the main beam, which contains most of the radiated energy (up to -40 dB with respect to boresight field), employing slope diffraction technique, and a good agreement is noticed between the calculated and measured radiation patterns.     

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.     

An open-boundary quad-ridged guide horn antenna for use as a source in antenna pattern measurement anechoic chambers

The present paper introduces a new antenna design to be used in anechoic chambers. When measuring three-dimensional patterns, the receiving antenna in the anechoic chamber must be able to sense the two orthogonal components of the field that exist in the far field. This can be accomplished by mechanically rotating the source horn in the chamber. A better and faster approach is to use a dual-polarized antenna and to electronically switch between polarizations. This new design is a broadband (2-18 GHz) antenna with dual polarization. The antenna is a ridged guide horn. The novel part is that the sides have been omitted. Numerical analysis and measurements show that this open-sided or open-boundary horn provides a better and more stable pattern behavior for the entire band of operation, as well as good directivity for its compact design. The radiation and input parameters of the antenna are analyzed in this paper for the novel design as well as for some of the early prototypes to show some of the ill effects of bounded quad-ridge horn designs for broadband applications. Mechanically, the antenna is built so that it can be mounted onto the shield of an anechoic room without compromising the shield integrity of the chamber.     

Integrated horn antennas for millimeter-wave applications

The development of integrated horn antennas since their introduction in 1987 is reviewed. The integrated horn is fabricated by suspending a dipole antenna, on a thin dielectric membrane, in a pyramidal cavity etched in silicon. Recent progress has resulted in optimized low- and high-gain designs, with single and double polarization for remote-sensing and communication applications. A full-wave analysis technique has resulted in an integrated antenna with performance comparable to that of waveguide-fed corrugated-horn antennas. The integrated horn design can be extended to large arrays, for imaging and phased-array applications, while leaving plenty of room for the RF and IF processing circuitry. Theoretical and experimental results at microwave frequencies and at 90 GHz, 240 GHz, and 802 GHz are presented     

Integrated horn antennas for millimeter-wave applications

This paper reviews the development of integrated horn antennas since their introduction in 1987. The integrated horn is fabricated by suspending a dipole antenna on a thin dielectric membrane in a pyramidal cavity etched in silicon. Recent progress resulted in optimized low and high-gain designs with single and double-polarizations for remote-sensing and communication applications. A fullwave analysis technique have resulted in an integrated antenna with performance comparable to that of waveguide-fed corrugated horn antennas. The integrated horn design can be easily extended to large arrays for imaging and phased array applications while still leaving plenty of room for the rf and w processing circuitry. Theoretical and experimental results at microwave frequencies and at 90, 240 and 802 GHz will be presented.     

Design,Analysis and Measurement of a Millimeter Wave Antenna Suitable for Stand off Imaging at Checkpoints

A systematic method is proposed to design a novel beam-scanning antenna with fan-beam, which is suitable for stand off imaging at millimeter wave band. The antenna has not only an elliptical main-reflector to generate thin fan beam, but also a rotating sub-reflector to realize beam scanning function. All these structures are embedded between two parallel metal plates. A Reversed Ray Tracing Algorithm (RRTA) was introduced to optimize the positions and dimensions of the subreflector and the feed horn. A modified Physical Optics method based on Discrete Real Mirror Image theory (DRMI-PO) was developed to efficiently analyze and optimize the field patterns of the antenna with specific structures. Based on above methods, an antenna working at 200 GHz is designed and fabricated. The measured patterns are in well agreement with the calculated results. It’s found that, the total beam scanning range is about 60 cm with its minimum half -power beam widths about 1.7 cm in the scanning direction. All the results validate the design method and potential applications of the antenna in the stand off imaging systems.     

激光直写系统制作掩模和器件的工艺

激光直写系统是国际上９０年代制作集成电路光刻掩模版的新型专用设备。微细加工光学技术国家重点实验室从加拿大引进了国内第一台激光直写系统。利用这台系统，通过高精度激光束在光致抗蚀剂上扫描曝光，将设计图形直接转移到掩模或硅片上。激光直写系统的应用，可以分成一次曝光制作光刻掩模和多次套刻曝光制作器件两个方面。介绍使用激光直写系统制作光刻掩模和套刻器件的具体工艺，并给出利用激光直写工艺做出的一些掩模和器件的实例     

A dual doubly curved reflector antenna having good circular polarization characteristics

A new type of shaped-beam radar antenna having good polarization characteristics is described. This antenna is composed of a dual doubly curved reflector system and a feed horn with good axial ratio, such as a dual-mode horn. The rotationally symmetrical beam of the feed horn can be converted into a shaped beam by the reflector system without degradation of the axial ratio. The design of this type antenna is discussed and the experimental results of a model antenna with a cosecant squared beam are shown. Integrated cancellation ratio of the model was 22 dB.