Analysis Of Radiation Patterns Research Articles

Design of Widebeam Tapered Slot Antenna for Wideband Airborne Active Phased Array Radar

Background/Objectives: Vivaldi antenna is a prime candidate for wide band applications. This work involves a design of miniaturized tapered slot antenna operating with X-band frequency to achieve wide scan capability, wide beam, maximum gain and minimum return loss for active phased array antenna. Methods/Statistical Analysis: The design of Vivaldi Exponentially Tapered Slot Antenna (VETSA) and analysis of radiation patterns, return loss, beam width and scan angle are done through the use of electromagnetic simulation software HFSS. The analysis was carried out in 3D and 2D. Further, testing and measurement of fabricated Vivaldi antenna using Vector Network Analyzer and radiation patterns are observed in Anechoic Chamber. Design of linear array and planar array is also presented. Findings: VETSA satisfies the requirements on the maximum reflection coefficient < -10 dB for ±60o scan from broadside in E-and H-planes. The realized antenna showed a symmetric pattern, minimum return loss, better 3-dB beam width in principal planes with gain of 3-dB, and VSWR ≤ 2 in X-band frequency. The result of linear array with 9-elements demonstrates good radiation characteristics with gain of 13 dB with low SLL including coupling effects in the X-band operating frequency. The uniformly illuminated array beam pattern shows that the array can scan over the desired scan volume of ±60o in E-plane and ±55o in H-plane. VETSA is a promising candidate to operate in wideband frequency with wide scanning performance in airborne radar applications. Application/Improvements: The designed antenna structure and array are good candidates and is expected to find applications in integration with monolithic millimeter-wave integrated circuits on combat aircraft.

Conformal antenna arrays with E3M3 radiators

Design relationships for computer simulation of radiation patterns of conformal antenna arrays are derived. Results of the comparative analysis of radiation patterns of arrays with spherical, hemispherical, and disk-shaped apertures in which the radiators consist of three electric dipoles and three magnetic dipoles (E3M3) are presented. It is shown that application of E3M3 radiators with proper orientation of their axes in conformal antenna arrays can increase the directive gain in the main lobe.

Radiation Pattern of Patch Antenna with Slits

The Microstrip antenna has been commercially used in many applications, such as direct broadcast satellite service, mobile satellite communications, global positioning system, medical hyperthermia usage, etc. The patch antenna of the size reduction at a given operating frequency is obtained. Mobile personal communication systems and wireless computer networks are most commonly used nowadays and they are in need of antennas in different frequency bands. In regulate to without difficulty incorporate these antennas into individual systems, a micro strip scrap transmitter have been preferred and intended for a convinced divergence. There is also an analysis of radiation pattern, Gain of the antenna, Directivity of the antenna, Electric Far Field. The simulations results are obtained by using electromagnetic simulation software called feko software are presented and discussed

Synthesis and Analysis of Linear Array Radiation Patterns of Tompilz Projectors

This work aimed to synthesize, from computer simulations, radiation patterns of linear arrays of acoustic projectors of the piston type (Tompilz). This paper also has the focus to analyze the behavior of these radiation patterns when varying some parameters and characteristics of the array and radiating elements. For the array, it was considered the influence of variations related to the number of elements and the distance between them. For the elements, it was analyzed the changes in the diagrams when the product between the radius of the projector's head and the acoustic wavenumber was varied. These parameters were chosen because of his notorious influence in the shape of radiation patterns. Also, it was investigated the influence of radiation on patterns of multipath and Doppler spread, as well as the efficiency of a LMS (Least Mean Square) filter applied in the received signal. These results find application in the design of linear arrays of projectors and the development of beamforming techniques.

Design and Test of a 0.5 THz Dipole Antenna With Integrated Schottky Diode Detector on a High Dielectric Constant Ceramic Electromagnetic Bandgap Substrate

This paper presents the first analysis of the input impedance and radiation properties of a dipole antenna, placed on top of Fan 's three-dimensional electromagnetic bandgap (EBG) structure, (Applied Physics Letters, 1994) constructed using a high dielectric constant ceramic. The best position of the dipole on the EBG surface is determined following impedance and radiation pattern analyses. Based on this optimum configuration an integrated Schottky heterodyne detector was designed, manufactured and tested from 0.48 to 0.52 THz. The main antenna features were not degraded by the high dielectric constant substrate due to the use of the EBG approach. Measured radiation patterns are in good agreement with the predicted ones.

군 지연 및 충실도를 이용한 IR-UWB용 테이퍼 슬롯 안테나 방사패턴 분석

본 논문에서는 IR-UWB를 위한 테이퍼 슬롯 안테나를 Ansoft인 HFFS을 사용하여 설계 및 제작 하였고 안테나의 군 지연 및 충실도를 사용하여 광대역 안테나의 빔 폭에 대해 연구를 제안하였다. 이를 위해 Network Analyzer에서 획득한 데이터를 Chirp Z-transform을 사용하여 시간영역에서의 분석을 하였고 시뮬레이션은 CST microwave studio를 이용하여 이를 확인 하였다. 안테나의 방사패턴의 분석은 두 안테나를 0.5 미터 간격으로 이격시킨 후 송신 안테나를 고정 후 수신 안테나를 10° 간격으로 360° 회전하여 각각의 충실도를 획득하여 안테나의 성능 분석하였다. 분석한 결과 ±40° 미만일 경우 90%이상의 양호한 충실도를 얻었고 ±40° 이상은 90%이하의 낮은 결과를 얻었다. 이러한 충실도를 이용한 방사패턴을 사용함으로 광대역 안테나의 빔 폭을 보다 정확한 분석을 할 수 있다.

E‐plane radiation pattern analysis of rectangular horn antennas with V‐shaped corrugations by UTD‐PO formulation

A new method for the calculation of the radiation pattern of corrugated E‐plane rectangular horn antennas based on a hybrid uniform theory of diffraction‐physical optics (UTD‐PO) formulation is presented. The method, which allows for the analysis of horns in which V‐shaped corrugations have been considered, has been validated with numerical data obtained through the application of both an electric field integral equation (EFIE) solved by the method of moments (MoM) and the finite element method (FEM)‐based full‐wave electromagnetic analysis software, HFSS. In this sense, the proposed solution is mathematically less complex and computationally more efficient than existing techniques.

Measurement and analysis of sound radiation patterns of the chinese Ruan and the Yueqin

The chinese Yueqin and Ruan are among the oldest documented asian string instruments. Both have a long tradition in chinese music and are commonly played in orchestral music, smaller ensembles as well as solo instruments. Eventhough both instruments have similar geometrical features, like a cylindric resonance body made out of wood, they differ in several design aspects like the fixation of the strings or the presence of sound holes. In this work the effect of these differences on the radiated and percieved sound is researched. Both instruments are measured using a 11x11 microphone array. The resulting density plots of the sound radiation over the audible spectrum are compared and analyzed.

Radiation Pattern Analysis and Advanced Phase Shifter Development for designing Phased Smart Antenna Arrays

This paper presents an analysis of beamforming and radiation pattern of various phased antenna arrays configurations which are intended for use in low cost Radio Frequency Identification or Wireless Sensor Networks applications for wireless process monitoring and location. The location process is based on the estimation of direction-of-arrival by determining the angle-of-arrival of radio signals. The beamforming and the steering of the antenna’s lobes are obtained via a linear phase excitation of the signal applied to the array elements. Several configurations of various geometries and sizes are analyzed in order to obtain an array with narrow main beam and good scanning capabilities. Finally, the main elements of the developed hardware implementation involving phase shifter based on vector modulators are discussed. Ill. 14, bibl. 14 (in English; abstracts in English and Lithuanian). DOI: http://dx.doi.org/10.5755/j01.eee.117.1.1063

Detection of chemical interfaces in coherent anti-Stokes Raman scattering microscopy: D-CARS II Arbitrary interfaces

We address the general problem of detecting chemical interfaces arbitrarily oriented in space in coherent anti-Stokes Raman scattering (CARS) microscopy. Such a task is accomplished by using a beam reversal scheme, as recently demonstrated experimentally [J. Biomed. Opt. 16, 086006 (2011)]. We develop a full vectorial theoretical analysis of the situation and show that transverse chemical interfaces are readily highlighted without special care in the CARS signal detection. In addition, a finer analysis reveals that adequate angular analysis of the CARS far-field radiation pattern enables the detection of axial interfaces. Background-free CARS microscopy and spectroscopy are thus achievable through the combined application of excitation beam reversal and angular analysis of the CARS far-field radiation pattern. This differential CARS (D-CARS) technique is relevant for fast detection of interfaces between molecularly different media.

Detection of chemical interfaces in coherent anti-Stokes Raman scattering microscopy: Dk-CARS I Axial interfaces

We develop a full vectorial theoretical investigation of the chemical interface detection in conventional coherent anti-Stokes Raman scattering (CARS) microscopy. In Part I, we focus on the detection of axial interfaces (i.e., parallel to the optical axis) following a recent experimental demonstration of the concept [Phys. Rev. Lett. 104, 213905 (2010)]. By revisiting the Young's double slit experiment, we show that background-free microscopy and spectroscopy is achievable through the angular analysis of the CARS far-field radiation pattern. This differential CARS in k space (Dk-CARS) technique is interesting for fast detection of interfaces between molecularly different media. It may be adapted to other coherent and resonant scattering processes.

Low profile meander line Printed Quadrifilar Helix Antenna

In this paper, a new approach of meander line technique for Printed Quadrifilar Helix Antenna (PQHA) is studied. Compared with other meander line techniques, this approach has lowered the axial height of antenna greatly and improved the efficiency of model-building in simulation processing. We have focused on the analysis of radiation pattern, axial ratio, and design graph for the Meander line Printed Quadrifilar Helix Antenna (MPQHA). Finally, we have reduced successfully 67% size in geometry compared with traditional PQHA method, and obtained rather reasonable results.

Accessing OLED emitter properties by radiation pattern analyses

The optical features of the internal dipole radiation have major impact on the emission pattern and overall device efficiency of organic light-emitting diodes (OLEDs). We provide some general directives on how the OLED layered stack should be designed in order to enable precise measurements of the active optical properties of the emissive material (namely internal electroluminescence spectrum, profile of the emission zone and dipole moment orientation) by radiation pattern analyses. We discuss a model layered system and deduce universal emitter positions most suitable for the determination of the particular OLED internal features of interest. Furthermore, we evaluate the real benefit of conducting radiation pattern analyses utilizing a substrate index-matched glass-hemisphere.

A Summary of Instrumental Data on the Recent Strong Vrancea Earthquakes, and Implications for Seismic Hazard

The paper is intended to summarize the most important instrumental data of direct relevance for engineering activities, obtained in connection with the strong Vrancea earthquakes of 4 March 1977, 30 August 1986, 30 May 1990, and 31 May 1990, and to point out some significant consequences and conclusions derived on this basis. Two main objectives of this analysis may be emphasized: (a) in-depth analysis of the radiation pattern; and (b) analysis of the spectral contents of ground motion in connection with the features of local conditions, and with the intention of assessing the relative importance of two main factors: source mechanism and long-distance wave propagation, versus features of local geological conditions. Some specific methodological developments used in this context may be mentioned: (a) use of a new approach to the quantification of ground motion intensity on the basis of instrumental (accelerographic) information; (b) analysis of radiation pattern in spectral and directivity terms; (c) parametric analysis of site-specific transfer functions for the local sequences of geological layers; and (d) a critical view on the outcome of post-earthquake survey techniques, keeping in view the implications of the spectral features of ground motion. The main results obtained are related to: (a) ground motion radiation features that have to be taken into account in connection with the data on the source mechanisms of the successive events dealt with; (b) expected spectral features of future strong ground motion at different sites; (c) methodological developments proposed for the assessment of local transfer functions; and (d) implications for microzonation activities.

Analysis and synthesis of fractal antenna radiation patterns

A problem of fractal antenna radiation pattern synthesis is considered. The problem of synthesis of fractal antenna radiation patterns is solved for two kinds of antennas (discrete and linear) in one- and two- dimensional cases. With the use of the theory of fractal synthesis, new modes with new properties are obtained in fractal electrodynamics. Fractal radiation pattern synthesis was conducted by means of the Weierstrass function.

Specificities of shaping of aperture antenna irradiation, specified by turbulent non-uniformities

For the first time it is carried out an analysis of aperture antennas radiation pattern along field, taking into account an influence of wave appearance fluctuation angle. We have derived formulas for average RP along field, taking into account angle bias of irradiation maximum direction.

Numerical and experimental study of F-4 aircraft antenna patterns

In this paper, the radiation pattern analysis of monopole antennas mounted on the aircraft is presented. The method of moments (MoM) is used to calculate the pattern in 30–400 MHz frequency range. Numerical results with MoM are performed and the reliability of these methods is discussed according to the measurement results. The pattern measurements were acquired on 1/10 scale model of the F-4 aircraft.

Analysis of radiation patterns and feed illumination of the reflector antenna using the physical and geometrical optics

Reflector antennas are characterized by very high gains (30 dB and higher) and narrow main beams. They are widely used in satellite and line-of-sight microwave communications as well as in radar. Reflector antennas operate on principles known long ago from the theory of geometrical optics. The first reflector system was made by Hertz back in 1888 (a cylindrical reflector fed by a dipole). The radiation fields from aperture antennas, such as slots, open-ended waveguides, horns, reflector and lens antennas, are determined from the knowledge of the fields over the aperture of the antenna. In this paper, we analyzed the effects of feeds relating to the parabolic reflectors such as waveguide and horn. We show the variations of the gain in the electric and magnetic planes (E and H) according to the angle of incidence. In our case, we use the origin to be at the focus.

Analysis of fractal radiation patterns from concentric-ring hexagonal arrays

Analysis of fractal radiation patterns from concentric-ring hexagonal arrays

Analysis of radiation patterns of rectangular microstrip antennas with uniform substrate

Abstract. Microstrip antennas are useful as antennas mounted on moving vehicles such as cars, planes, rockets, or satellites, because of their small size, light weight and low profile. Since its introduction in 1985, the features offered by this antenna element have proved to be useful in a wide variety of applications, and the versatility and flexibility of the basic design have led to an extensive amount of development and design variations by workers hroughout the world.