Design Of Horn Research Articles

Ultrawideband TEM horn with inhomogeneous dielectric medium

AbstractThis article presents a novel design of ultrawideband TEM horn with dielectric filling of the space between its leaves. The distribution of dielectric permittivity in the medium is obtained according to the laws of geometric optics. The electromagnetic simulation and experimental measurements are performed; voltage standing wave ratio and radiation patterns at a set of frequencies up to 20 GHz are obtained. The described method allowed to prevent antenna pattern distortion at frequencies from 7.5 to 20 GHz.

Computer-Aided Design of Bezier Horns Using Finite Element Analysis for Rotary Ultrasonic Machine

In this paper, a finite element analysis (FEA) has been used for the design of horn with different Bezier profiles for rotary ultrasonic machine (RUM). First, for validation, the results are compared with available literature. FEA-based MATLAB code is developed for finding the stress components, axial amplitude, and resonance frequency over the domain of horn with different Bezier profiles. In domain of horn with different Bezier profiles, the component of stresses is studied and found that the stress generated is within the endurance strength of the selected material. The amplification of the proposed horns is 24%, and 18% higher than the traditional linear Bezier horn with same length and diameters of surface end. For RUM, effect of inertia (self-weight or gravity of horn) on domain has been studied for horn with different Bezier profiles using FEA. The effect of tool shape and size on the stress distribution for horn have also been studied.

Design and analysis of long-stepped horn for ultrasonic-assisted sintering

ABSTRACT In the recent past, ultrasonic vibrations have been incorporated in sintering to improve the performance of the product and process. The ultrasonic vibration accelerates the diffusion process in the solid-state fabrications. The ultrasonic system consists of ultrasonic generator, transducer and horn. The design of ultrasonic horn is a challenge for ultrasonic-assisted sintering (UAS) due to the involvement of high temperature. In this study, a long step horn was designed as per the sintering furnace requirement. The horn was designed with multi-nodes and anti-nodes working at 20 kHz frequency and having approximate 20 µm vibration at the horn end. The methodology was used to analyse step horn design with the help of modal and harmonic analysis to maximise the amplitude at the horn end. Additionally, modal analysis at elevated temperatures was carried out by coupling thermal dependent properties, and it was observed that the natural frequency and the harmonic amplitude decreased. The designed horn has been used to sinter bronze spherical powder at 700 and 800 sintering temperature for 1 hr of soaking time to study the effect of ultrasonic vibration on the densification behaviour. The results showed better homogeneity and density as compared to conventional sintering process.

Design of Bezier profile horns by using optimization for high amplification

Rotary ultrasonic machine (RUSM) has a lot of applications in industries, with the recent uses of stronger and harder materials. Machining performance of RUSM depends on the design of the horn. A horn also known as a tool holder or concentrator is a waveguide focusing device, which has a decreasing area of the cross section from the upper to lower end. In RUSM, the high amplification factor of the horn is required to increase tooltip vibration for getting a high material removal rate. In this study, the design of the horn using an optimization procedure and finite element analysis (FEA) has been done. FEA-based MATLAB code has been developed for finding all the stress components, axial amplitude, and resonance frequency. Results are validated from the experimental data available in the literature, and it has been found that it is in good agreement with the literature. The amplifications of the horns with cubic and quadratic profiles 23.8% and 19%, respectively, are higher than the traditional horn with the same length and diameters of the ends. Stresses at different locations have been found within the allowable endurance limit. The effect of frequency on the stress distribution has also been studied and found that the variation of stresses over the domain of horn increases with an increase in frequency, but the value of stress is much lower at the resonance frequency.

Design and Realization of a Low Cross-Polarization Conical Horn With Thin Metasurface Walls

A Ku -band low cross-polarization conical horn based on thin metasurface (MTS) walls is presented in this article, along with the relevant design method. The necessary boundary conditions are realized by printing a tensor MTS on the internal walls of the horn, which yields a radiation performance similar to a standard corrugated Gaussian horn yet with the benefits of thin walls. The design method is based on the adiabatic approximate solution for the hybrid mode of a conical waveguide with generic balanced impedance walls, which allows the determination of the impedance profile supporting a single balanced mode. The impedance design is based on the usual locally flat approximation of the wall and on the assumption of plane wave incidence. This approach results in an analytic design method that requires no optimization. The design has been first validated by solving the problem with homogenized impedance boundary conditions through a body of revolution (BoR) method of moments. The actual structure, including impedance wall implementation, is then simulated in full detail with a full-wave fast code. Finally, the horn has been realized and experimentally characterized; measurements show excellent agreement both with theory and with simulations, with a cross-polarization level below −20 dB over a 2 GHz bandwidth.

Design optimization of cubic Bezier horn for ultrasonic machining

In ultrasonic machining (USM), higher amplitude is required for higher material removal rate (MRR). The objective of this research is to develop a new horn design for high displacement amplitude for getting maximum MRR within a working condition. The profile of the horn has been optimized and designed. In this analysis, optimization procedure and finite-element method have been used for the design of horn of USM. In this, the variation of stress components along the length of the horn has been studied. In the middle, maximum stress is found due to a change in cross-section but it is within the endurance limit of the horn material. The cubic Bezier horn as compared with traditional horn is up to 19% more amplified. Finally, an optimized cubic Bezier profile for the horn has been designed, which has maximum displacement amplitude for higher MRR and safe working stresses for the horn material.

Shape optimization of acoustic horns using the multimodal method

This paper presents a method for the shape optimization of an acoustic horn with respect to the impedance matching property based on the discrete multimodal method. The method models the horn as a series of short cylinders and takes mode coupling across the discontinuities into account. The optimization employs a gradient-based algorithm, and allows for analytical derivation of the objective function and its gradient in a numerically workable manner. A case study followed with an experimental validation is presented. With appropriate parameter settings, the method is capable of rapidly finding a smooth and convex horn design that behaves like a high-pass radiator with near-ideal wideband transmission in small dimensions.

Dual-Band Circular-Polarization Horn Antenna With Completely Inhomogeneous Corrugations

A dual-band circularly polarized horn antenna of completely inhomogeneous corrugations is efficiently designed for simultaneous good polarization, aperture efficiency (AE), sidelobe level (SLL), and symmetric radiation pattern (SRP). The method employs two steps to integrate a mode-matching method and a genetic algorithm by introducing a modal expansion of the aperture field as an intermediate interface for optimization, where the selected modes’ weightings are first optimized to resemble the desirable far-field patterns. Afterward, the aperture distribution serves as the goal to subsequently optimize the entire corrugation structure by formatting related scattering matrices using the weighting coefficients of available modes on the aperture and inside the horn section. In the implementation of design, the developed corrugated horn comprises six and 19 completely inhomogeneous corrugations in mode conversion and radiation sections, respectively, providing sufficient design freedom. Simulated and measured results are shown to validate the optimized horn design, which simultaneously meets all above-mentioned requirements in both the K -band (19.6–21.2 GHz) and the Ka -band (29.4–31 GHz).

Professor Peter Clarricoats CBE FREng FRS FIEEE HonFIET, April 1932 – January 2020

Professor Peter Clarricoats CBE FREng FRS, one of the founding Editors of Electronics Letters, died on Friday 17 January 2020 after a short illness. Peter Clarricoats made major fundamental contributions as a microwave engineer in the fields of applied electromagnetics for microwave and optical waveguides, and microwave antenna feeds. He was appointed a Fellow of the Royal Academy of Engineering in 1983 and was awarded the Sir Frank Whittle medal of the Royal Academy of Engineering in 2015. He was educated at Minchenden Grammar School and Imperial College London, receiving his PhD from the University of London in 1958. He started his academic career in 1959 at Queen's University Belfast and was subsequently appointed as a Professor at the University of Leeds in 1963; in each case starting research groups in microwave engineering which still thrive today. In 1967, he moved to Queen Mary College (now Queen Mary University of London), founding the Electromagnetics and Antenna Group which went on to make significant contributions to antenna and microwave research. Peter was also a pioneer of optical fibres, publishing one of the first monographs on this topic in 1975. He established the theory, which has since been widely used in the context of optical fibres, of electromagnetic propagation on dielectric and ferrite structures. In the course of this, he also discovered that such structures can, under some conditions, support ‘backward waves’ and that guides can propagate complex modes. Over 40 years of his academic career, Professor Clarricoats had numerous notable achievements including pioneering designs for shaped reflectors, reconfigurable reflectors and especially corrugated horns for microwave antennas. The latter are now universally used in satellite ground stations and in spacecraft. Peter was one of the first to recognise the radical improvements which arise from the use of a corrugated horn antenna. He went on to publish what became standard reference texts on Corrugated Horns for Microwave Antennas, Microwave Horns and Feeds. His personal research was recognised through many significant awards from the IEE (now IET) and IEEE where he received the highest honour from the IEEE Antenna Society (APS), The Distinguished Achievement Award in 2001. His contribution to microwaves in Europe was recognised through the European Microwave Association's Microwave Prize in 1989 and the Outstanding Career Award in 2004. Professor Clarricoats was vice-president of the Institution of Electrical Engineers, from 1989 to 1991, and vice-president and treasurer of URSI (the International Union of Radio Science) from 1993 to 1999. He was elected Fellow of the Royal Society, the Royal Academy of Engineering, the Institute of Electrical and Electronics Engineers (IEEE) and the Institution of Engineering and Technology (IET). He was awarded the CBE in 1996. Peter worked with other leading figures to establish new journals and conferences. Perhaps the journal he was most proud of was the internationally renowned Electronic Letters, which remains one of the most successful technical publications of all time. Ian White, current co-Editor-in-Chief of the journal, expressed his sympathy: “Professor Clarricoats’ commitment to Electronics Letters was unparalleled and its success owes greatly to his outstanding expertise, enthusiasm and dynamism to his field. He will be sorely missed.” After he retired from his full-time post in 1997, Professor Clarricoats continued to supervise research and through his personal innovation developed a new compact horn design needed for satellites and spacecraft. In September 2015, he was awarded the Sir Frank Whittle medal of the Royal Academy of Engineering. Peter had sparkle, which together with his great intellect never left him and he will be greatly missed by the many Fellows and colleagues he mentored and encouraged throughout his career.

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.

Design, Analysis and Manufacturing of a Bone Cutting Ultrasonic Horn-Tool and Verification with Experimental Tests

Horn is one of the main components of ultrasonic cutting systems. The most important characteristics of the horn design are its resonant frequency and amplification factor. Closed-form equations can be used only for the design of simple horns and do not apply to more complex shapes like surgical tools. In This paper, a designing technique based on the finite element method and experimental tests is presented. The conventional design methods are improved, and designing a high performance surgical ultrasonic horn for bone cutting tools is facilitated. The new and complex bone cutting tool has both the knife-edge and toothed-edge, which could cut the bone easily and accurately. The investigations of cutting forces applied to the tool edges show less force in the toothed edge than the knife edge.

Frequency coupling design of ultrasonic horn with spiral slots and performance analysis of longitudinal-torsional machining characteristics

Longitudinal-torsional (L-T) vibration in rotary ultrasonic machining (RUM) can further reduce the cutting force and improve the machining efficiency compared with the single longitudinal vibration in RUM. In this study, an ultrasonic step horn with spiral slots using the principle of mode conversion was designed to realize L-T vibration. The torsional amplitude to longitudinal amplitude (AT/AL) ratio is proposed to quantify the efficiency of mode conversion. Moreover, a simulation method was used to carry out the frequency coupling design of the ultrasonic horn with spiral slots. The influence of the step position and slot position with a spiral angle of 52° on the resonant frequency and amplitude of the ultrasonic horn were analyzed, respectively. Based on the simulation results, ultrasonic horns with different AT/AL were designed and fabricated. Finally, the results obtained through experiments with milling glass plane revealed that the cutting force was reduced by 48–73%, while the surface quality improved compared with single longitudinal vibration when the torsional vibration is coupled with the longitudinal vibration in RUM. The reasonable AT/AL ratio could effectively reduce the cutting force when the synthetic amplitude was the same. This indicates that the L-T vibration changes the trajectories of the diamond abrasives, which improves the machining performance.

Optimization of the longitudinal-torsional ultrasonic step-like horn design for milling tool applications via the tool load account

Ultrasonic horns are used in the ultrasonic-assisted milling and cutting tools. However, the interaction with tool end vibrations deteriorates the horn performance. In this study, the amplification coefficients and vibration node locations of an ultrasonic horn were determined via the 1D wave theory and optimized by the tool load effect account. By arranging spiral grooves at the straight part of the ultrasonic horn, a longitudinal-torsional modal converter was introduced. This made it possible to convert longitudinal vibrations into longitudinal-torsional coupled ones by the superposition of incident and reflected longitudinal waves with reflected transverse ones at grooves. Orthogonal L9 (33) tests with parameters of spiral grooves as variables were designed and conducted, and longitudinal-torsional ratios (LTR) of the milling tool end under different conditions were assessed using the commercial ANSYS software package. The in-depth analysis of simulation results implies that the LTR values are controlled by the following influence factors in the decreasing order: helical angle, number of grooves, and groove width. Single-factor tests indicate that LTR exhibits an initial drop and a further rise with the helical angle, attaining its minimal value at 30°; it drops with the number of grooves n, and remains practically unchanged with the groove width variation. Finally, the vibration tests of the proposed horn with the optimized parameters corroborated its feasibility and demonstrated its excellent performance in the ultrasonic-assisted milling tool application.

Design of Ultrasonic Conical Horn using Aluminium Alloy and Steel

Horn plays an important role in ultrasonic machining process. The design of horn is critical to its efficiency and quality of machining process. Ultrasonic horns are tuned. Components designed to vibrate in a longitudinal mode at ultrasonic. Frequencies. Reliable performance of such horns is normally decided by the uniformity of vibration amplitude at the working surface and the stress developed during loading condition. The design parameters of horn are calculated from the theoretical derivation of horn. By these parameters, the horn is designed and analyzed using CREO PRO and ANSYS software. In this paper the main object of the project is to Improve the performance of the Horn from the analysis test results, The horn is compared with other available horn results by comparing its natural frequency, amplitude vibration and temperature of the horn.

High-Performance Smooth-Walled Horn Antennas for THz Frequency Range: Design and Evaluation

Traditionally, corrugated conical horn antennas have been the main choice for use in astronomical receivers in the range of millimeter and submillimeter waves. They present low cross-polar level and high coupling efficiency into the fundamental Gaussian mode. However, this type of antenna is difficult to manufacture, inevitably increasing its price and extending the production process. In this article, we present two kinds of feed horn antennas, aimed for use in a frequency range equivalent to atacama large millimeter/submillimeter array (ALMA) Band 6 (211–275 GHz), which can be fabricated in a much simpler way with the conventional machining tools. Specifically, we present the design and performance comparison of smooth-walled spline-profile horns in two geometries, diagonal, and conical. Optimization of the designs has been made by means of an algorithm that allowed us to obtain models whose electrical and mechanical characteristics make them competitive when compared with corrugated horns. In particular, they are $\text{40}\%$ shorter than the conventional corrugated horns suited for this band, representing an advantage given the stringent space constraints of most astronomical receivers. We also demonstrate that they can be coupled efficiently to an astronomical-grade optical system, using ALMA Band-6 receiver as an example. Furthermore, we have constructed the diagonal horn and characterized it thoroughly. Experimental results of the radiation pattern at room temperature show a good cross-polar performance with levels below −20 dB and Gaussicity above $\text{96}\%$ . Our calculations show a good antenna-efficiency level with losses less than $\text{1}\%$ . All these properties demonstrate the feasibility of this type of horns to become the main option at the time of choosing a feed system for cutting-edge astronomical applications.

Theoretical analysis and finite element calculation of ultrasonic horn

With the progress and development of science and technology, it is difficult to adopt traditional machining methods for some special materials and workpieces with complex shapes. For this reason, special machining technology has made great progress, especially ultrasonic machining technology. Ultrasonic horn is the core component of ultrasonic equipment, which has an important influence on ultrasonic equipment. The traditional design of ultrasonic horn is designed by the traditional analytical method, and then revised repeatedly to guide the application requirements. In this paper, the finite element analysis software ANSYS is used to carry out modal analysis and transient analysis of the exponential ultrasonic horn with complex structure. The theoretical value of the designed exponential ultrasonic horn is compared with the results of finite element analysis.

Design and application of compound conical horn with cylinder at big end

Design and application of compound conical horn with cylinder at big end

Eigenfrequency characterization and tuning of Ti-6Al-4V ultrasonic horn at high temperatures for glass molding

Glass molding assisted by ultrasonic vibration is a promising yet challenging technique for microoptics fabrication. During glass molding localized high temperatures (300–600 °C) often result in transformed eigenfrequencies of the ultrasonic horn, and hence decreased electroacoustic efficiencies of the ultrasonic system. This study proposes a systematic methodology to optimally tune the objective eigenfrequency of the horn at elevated temperatures. Theoretical and numerical analyses are first performed to characterize the thermally disturbed modal characteristics of the horn. Numerical results indicate that the longitudinal eigenfrequency of the horn decreases significantly with the increasing molding temperature Tm. To compensate for this eigenfrequency decrease, numerical size optimization is then conducted and a two-segment cylindrical horn with an optimized tool (68.62 mm in length) is obtained. In situ eigenfrequency measurements of the optimized horn are further implemented at varying molding temperatures. Experimental results suggest that the tuned eigenfrequencies of the optimized Ti-6Al-4V horn are within the prescribed frequency-tracking range (35 ± 0.5 kHz) over a wide range of molding temperatures (226–641 °C). Thus, by merely pre-adjusting the theoretical eigenlength of the horn, a well-tuned and adaptable high-temperature ultrasonic vibration system can be effectively developed. In addition to glass molding, the proposed methodology applies to design and optimization of ultrasonic horns for diverse thermally involved processes.

Fully integrated fused quartz acoustic horns for structural health monitoring.

Non-destructive acoustic structural sensing is an imperative technology, applicable to many different fields such as aerospace and civil engineering. To maintain a high sensitivity or to mitigate acoustic loss, it is important to increase the signal-to-noise ratio by improving coupling efficiency from acoustic sources to the object under test, such as an acoustic waveguide. Here, a fully integrated fused quartz horn design is combined with a fused quartz acoustic waveguide. The resulting system is intended to demonstrate a high accuracy low cost alternative to current sensing systems and the present article report on the viability of using a merged acoustic horn and waveguide.

Bio-Matched Horn: A Novel 1–9 GHz On-Body Antenna for Low-Loss Biomedical Telemetry With Implants

We present the Bio-Matched Horn antenna: a novel 1.773 cm3 on-body antenna for very low-loss communication with wireless implants across the 1–9 GHz bandwidth. To achieve this unique performance, the Bio-Matched Horn is composed of water-filled holes used to mimic the frequency-dependent permittivity of the underlying tissue over its entire bandwidth. The horn shape further allows the proposed antenna to communicate efficiently through the biological tissue for both subcutaneous and deep-tissue wireless implants. Measurement results at 2.4 GHz are in good agreement with simulations and show a transmission loss of 8.01 dB to a 4 mm-deep implant and 19.21 dB to a 2 cm-deep implant. Compared to the previous designs, this is a remarkable improvement by 14.5 and 10.8 dB for subcutaneous and deep-tissue communication, respectively. In this paper, we discuss the operation principle and design of the Bio-Matched Horn, its performance for subcutaneous and deep-tissue implant telemetry, sensitivity to rotational and positional misalignments, and specific absorption rate performance.