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.     

Millimeter-wave and terahertz integrated circuit antennas

A comprehensive review of integrated circuit antennas suitable for millimeter and terahertz applications is presented. A great deal of research was done on integrated circuit antennas in the last decade, and many of the problems associated with electrically thick dielectric substrates, such as substrate modes and poor radiation patterns, have been understood and solved. Several antennas, such as the integrated horn antenna, the dielectric-filled parabola, the Fresnel plate antenna, the dual-slot antenna, and the log-periodic and spiral antennas on extended hemispherical lenses, which have resulted in excellent performance at millimeter-wave frequencies, are covered in detail. A review of the efficiency definitions used with planar antennas is included     

802GHz integrated horn antennas imaging array

This short paper presents the pattern measurements at 802GHz of a single element in a 256-element integrated horn imaging array. The integrated-horn antenna consists of a dipole-antenna suspended on a 1μm dielectric membrane inside a pyramidal cavity etched in Silicon. The theoretical far-field patterns, calculated using reciprocity and Floquet-modes representation of the free-space field, agree well with the measured far-field patterns at 802GBz. The associated directivity for a 1.40 λ horn aperture, calculated from the measured E and H-plane patterns is 12.3dB±0.2dB. This work demonstrates that high-efficiency integrated-horn antennas are easily scalable to terahertz frequencies and could be used for radio-astronomical and plasma-diagnostic applications.     

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.     

Filtenna Consisting of Horn Antenna and Substrate Integrated Waveguide Cavity FSS

An integrated module with filtering and radiation performance realized by covering substrate integrated waveguide (SIW) cavity frequency selective surface (FSS) at aperture of horn antenna has been investigated in this paper. The module has functions of bandpass filter and horn antenna, so it is called a "filtering antenna" (filtenna). It is very suitable for applications in military platforms where FSS is used for antennas and radars' radar cross section (RCS) reduction. The filtenna is simulated and optimized with CST software and its performance is verified by experiments. From simulated and measured results it can be found that the proposed structure keeps characteristics of return loss, radiation pattern and gain of the horn antenna within desired frequency band, meanwhile presents effective reflection to interference signals at out-band. Using this structure the volume and cost of communication systems in military platforms can be effectively reduced     

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     

94 GHz integrated horn monopulse antennas

A monolithic azimuthal monopulse antenna for 94-GHz applications has been developed. The structure consists of a single dipole suspended in one plane of an integrated horn cavity to obtain the sum pattern, and an antiparallel pair of dipoles suspended in a different plane of the same horn cavity to achieve the difference pattern. Pattern measurements of microwave models and on the millimeter-wave antennas show good agreement with theory and exhibit symmetry with a sharp -30-dB null at broadside for the difference antenna. Microwave model measurements show input impedances close to 50 Ω, with greater than -25-dB isolation between sum and difference antennas across a 10% bandwidth     

Scaled model measurements of the sandwiched V-antenna

At frequencies above a few hundred GHz, waveguide mixer blocks become extremely difficult to build, so open structure feeds may be more appropriate. One promising planar antenna structure, which can easily be integrated with SIS junctions, is the sandwiched V-antenna. The antenna is completely enclosed in dielectric by placing it between substrate and superstrate blocks. Using a model scaled to a center frequency of 10 GHz, we investigated the beam pattern as a function of frequency, and measured its dependence on gaps between the super-and substrates. We plan to test the structure at a frequency of 345 GHz and to compare it with waveguide horn antennas for possible use in submillimeter astronomical receivers. The antenna patterns and analysis in this work are substantially more extensive than earlier published results.     

Ku band pattern reconfigurable substrate integrated waveguide leaky wave horn antenna

A dual band substrate integrated waveguide H plane sectoral horn antenna with reconfigurable radiation characteristics has been proposed in this paper. Designed antenna acts as a perfect broadside radiator at 16.1 GHz and perfect endfire radiator at 14.4 GHz frequency. Broadside radiation has been achieved by etching rectangular slots in the flared section of horn exhibiting a gain of 8.87 dBi. To achieve perfect endfire radiation, dielectric loading is done at the edge of horn and at this frequency antenna shows a gain of 11.3 dBi. The horn and the loaded dielectric are integrated by using the same single substrate resulting in easy fabrication and low cost. The proposed design has been fabricated and measured results are in good agreement with the simulated results.     

Radiation patterns of metal and dielectric wall diagonal horn antennas

The radiation patterns and gain of dielectric wall diagonal horn antennas of various thicknesses (0.15cm and 0.32 cm) and dielectric constants (? = 2.54, 2.56 and 3.03) have been experimentally studied and compared with a metal diagonal horn antenna having the same aperture at 9.418 GHz. Radiation patterns of these dielectric horn antennas when used as square horns are also presented and compared with a similar metal horn. The use and applicability of dielectric horn antennas is discussed.     

Short axial length broad-band horns

Ever-increasing antenna frequency bandwidth requirements for countermeasures applications and electromagnetic compatibility measurements have provided the impetus for the development of a series of very broad-band horns. In addition to the broad bandwidth, a substantial reduction in axial length over that of earlier models has been achieved for the two designs discussed in this communication. The first horn described covers the frequency range from 1.0-12.0 GHz with the flared portion of the horn having an axial length of 6 in as compared with 12 in for an earlier model. Although horn antennas are not commonly considered for use at frequencies as low as 0.2 GHz, the short axial length design appeared to be an attractive approach in developing a very reasonably sized antenna operating in the 0.2-2.0 GHz range. The technique of fabricating theHplane walls in the form of a grid was used in both designs as a means of maintaining the requiredH-plane half-power beamwidths. The grid for the 1.0-12.0 GHz horn is of printed circuit form while the grid elements of the lower frequency horn are made of aluminum tubing. Electrical characteristics of both designs are presented, as well as some additional data for recent advances which indicate that a further reduction in axial length or an increase in bandwidth can be achieved with only a moderate rise in VSWR in the lower portion of the frequency range.     

Stacked Microstrip-Patch Arrays as Alternative Feeds for Spaceborne Reflector Antennas

The feasibility of using stacked microstrip-patch arrays as feeds for offset reflector antennas is investigated in this paper. It is shown that patch arrays can be used as alternatives to the conventionally used horn feeds, which tend to be bulky. In particular, patch arrays can be of interest for spacecraft applications where reduced size and light-weight feeds are highly desirable. In this paper, patch arrays were tailored to provide radiation characteristics similar to those of horn feeds by varying the element spacing and excitation. A reduction in weight was mainly realized by the planar construction of the patch arrays. A full-wave analysis of the feed array, using finite-difference time-domain (FDTD) and PO-based UCLA reflector-analysis codes, was used to test the results of the proposed feed, operating at 1.413 GHz for radiometer applications, and 1.26 GHz for radar applications. A dual-polarized and dual-frequency stacked microstrip-patch element was fabricated and tested. It was then demonstrated that a seven-element hexagonal array design seemed to be the best match to the horn feeds for a 12 m offset-reflector antenna.     

FDTD analysis of E-sectoral horn antennas for broad-bandapplications

The finite-difference time-domain (FDTD) method is applied to study the performance of E-plane sectoral horn antennas designed for broad-band applications. These antennas (proposed for 6-18 GHz phased arrays) have a large bandwidth, and they are easily array integrated. These antennas have a highly complicated geometry that is modeled using a polygonal approximation in the curved boundaries. Perfect matched layers (PMLs) combined with first-order absorbing boundaries are employed to simulate the free-space environment in the FDTD mesh     

应用于WLAN/WiMAX的三频单极子天线设计

设计了一种三频段L型单极子平面天线,通过3个L型单极子天线的组合,使其中一个单极子天线工作于3.5 GHz频段,较长一个单极子工作于2.4 GHz频段,较短一个单极子工作于5.8 GHz频段,该天线与其他三频段平面天线相比,结构更为简单。为数值分析和优化,在HFSS建立了该天线的电磁仿真模型,仿真结果表明,该三频段天线在其3个工作频段内的回波损耗都＜-10 dB,实现了2.4 GHz,3.5 GHz和5.8 GHz 三频段同时工作。该天线可在WLAN和WiMAX通信系统中得到良好的应用。     

A horn-reflector antenna for high-performance submillimetre-wave imaging arrays

We have developed an antenna for high-performance submillimetrewave imaging arrays. The antenna comprises a corrugated horn with an off-axis paraboloidal reflector at its aperture. The corrugated horn is machined directly into two halves of a split aluminium block. This approach avoids electroforming and is compatible with E-plane circuit technology. The resulting antenna is light weight and is ideal for space applications. For compatibility with submillimetre-wave optics, the the behaviour has been calculated by using Gaussian-Hermite modes, and the integrity of the theory has been verified by modelling the behaviour of a 17GHz antenna. The manufacturing procedure has been investigated by machining and testing a horn-reflector antenna for 450–500GHz. Our next step is to extend the technique to 1THz.     

Millimeter Wave Substrate Integrated Waveguide Antennas: Design and Fabrication Analysis

The paper presents a new concept in antenna design, whereby a photo-imageable thick-film process is used to integrate a waveguide antenna within a multilayer structure. This has yielded a very compact, high performance antenna working at high millimeter-wave (mm-wave) frequencies, with a high degree of repeatability and reliability in antenna construction. Theoretical and experimental results for 70 GHz mm-wave integrated antennas, fabricated using the new technique, are presented. The antennas were formed from miniature slotted waveguide arrays using up to 18 layers of photo-imageable material. To enhance the electrical performance a novel folded waveguide array was also investigated. The fabrication process is analyzed in detail and the critical issues involved in the fabrication cycle are discussed. The losses in the substrate integrated waveguide have been calculated. The performance of the new integrated antenna is compared to conventional metallic, air-filled waveguide antennas, and also to conventional microstrip antenna arrays operating at the same frequencies.      

Conical-reflector antennas

The mechanical advantages of a singly curved conical reflector are demonstrated by the experimental test of a furlable 1.83 m conical-Gregorian antenna at 16.33 GHz. The measured gain of 47.5 dB corresponds to a net efficiency of over 57 percent. A ray-optics analysis of conical-reflector antennas is presented, and data useful in the design of conical antennas is given. The conical-Gregorian antenna, in which a subreflector is used in conjunction with a conventional horn feed, is considered in detail. A physical-optics analysis of the conical-Gregorian antenna is used to investigate diffraction and other effects, and to analytically confirm the high performance of the antenna. It is concluded that conical antennas are a valuable addition to available antenna-design concepts.     

Ku/Ka四波段共馈低剖面赋形天线设计

针对传统切换式多馈源的低剖面反射面天线结构复杂,不能多频段同时工作的问题,介绍了一款四波段单馈源低剖面环焦反射面天线及设计方法。该天线工作在四波段14~14.5 GHz, 11.45~12.75 GHz,19.6~21.2 GHz,29.4~31 GHz。整体天线采用双槽深波纹喇叭单馈源、通过口面场分布和多项式拟合过渡函数的方法构造的赋形副反射面和主反射面。用电磁仿真软件进行了建模仿真和验证。实测结果表明,整体天线较传统天线的效率提高12%以上,第一旁瓣<-14 dB,指标满足设计要求。     

Compact Chip-Resistor Loaded Active Integrated Patch Antenna for ISM Band Applications

As technology is moving towards miniature structures, demand for designing efficient compact antennas is increasing simultaneously. So it would be valuable to improve the features of small antennas, such as bandwidth and gain. A compact chip-resistor loaded microstrip antenna at 2.48 GHz frequency for industrial scientific and medical (ISM) band, with dimensions of 10 × 10 mm² is presented in this paper. With a novel geometry design, antenna is promoted to an active integrated antenna (AIA) on a two-layer printed circuit board (PCB), which contains passive antenna and active circuitry with a common ground plane. A monolithic amplifier is used to have an improvement around 10 dB in antenna gain. The impedance bandwidth has been increased during chip-resistor loading and adding active circuitry processes. For chip-resistor loaded antenna, that is 5.7 and 9.48% in simulation and measurement respectively. Moreover, the active integrated antenna has the measured impedance bandwidth of 58.7%. Since the low gain and narrow bandwidth of compact microstrip antennas might be a challenge for their operation, by compensating these drawbacks, proposed antenna would become more practical for special medical diagnostic applications, where doctors need stronger signals for monitoring.

     

新型WLAN平面倒F双频天线的设计

提出了一种新型的应用于2.4/5GHz蓝牙和无线局域网的双频内置平面倒F天线。该天线结构紧凑,可以方便地植入无线通信设备中,有较强的实用性。通过加载F形槽和阶梯形槽使天线能够满足无线局域网中小型化双频天线的技术要求。天线在蓝牙频段阻抗带宽达到300MHz(2.21~2.51GHz),在无线局域网频段阻抗带宽达到1070MHz(4.95~6.02GHz),辐射方向图表明该天线全向性能较好,增益在3.1~6.7dBi范围内。