• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.3
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• pp.194-201
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• 2014

This paper is able to be solved by improving degradation in multi-path environment by adjust beam pattern angle through modifying pulse phase of each antennas by using TRM (Transmitter Receiver Module). Beam Scanning Array Antenna, which is transmitter/receiver that improves degradation in multi-path environment without any signal distortion, is designed and manufactured. Beam Scanning Array Antenna should be able to send/receive signal at the antenna's longitudinal part without distortion and should not influences other systems. Also, it should include target detecting ability by beam steering.Dispersion characteristic of Beam Scanning Antenna, which is designed, is analysed by using fidelity, and steering and radar resolution performance is verified by using $1cm{\times}1cm$ sized target. To manufacture Beam Scanning Array Antenna, control board and GUI, which is able to control Vivaldi Antenna for IR-UWB, Tri-Band Wilkinson power divider, and TRM (Transmitter Receiver Module), is designed. Throughout this research, developed Beam Scanning UWB Array Antenna system is adoptable for radar application field. and time domain analysis techniques by using network analyser made the antenna characteristics analysis for setting up antenna more accurate. In addition, it makes beam width checking without difficulties.

• Journal of electromagnetic engineering and science
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• v.10 no.3
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• pp.138-145
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• 2010

In this paper, we report the test results of a small-scale prototype that implements an analogue-beam-formed phased antenna array in the E-band. A four-channel dual-conversion receive RF module for 71~76 GHz frequency band has been developed and integrated with a linear end-fire antenna array. Measured performance is very close to the simulated results. An ad-hoc wireless communication system has also been demonstrated. Low BER was measured for an 8PSK data stream at 1.5 Gbps with the receive array beam formed in the direction of arrival of the transmitted signal. To our knowledge this is the first steerable antenna array reported to date in the E-band.

• Journal of electromagnetic engineering and science
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• v.18 no.3
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• pp.175-181
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• 2018

The array patterns of a patch array antenna were calculated using an active element pattern (AEP) method that considers ground edge effects. The classical equivalent radiation model of the patch antenna, which is characterized by two radiating slots, was adopted, and the AEPs that include mutual coupling were precisely calculated using full-wave simulated S-parameters. To improve the accuracy of the calculation, the edge diffraction of a ground plane was incorporated into AEP using the uniform geometrical theory of diffraction. The array patterns were then calculated on the basis of the computed AEPs. The array patterns obtained through the conventional AEP approach and the AEP method that takes ground edge effects into account were compared with the findings derived through full-wave simulations conducted using a High Frequency Structure Simulator (HFSS) and FEKO software. Results showed that the array patterns calculated using the proposed AEP method are more accurate than those derived using the conventional AEP technique, especially under a small number of array elements or under increased steering angles.

• Smart Structures and Systems
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• v.4 no.4
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• pp.449-464
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• 2008

An array based, outward monitoring, ultrasonic guided wave based SHM technique using a single transmitter and multiple receivers (STMR), with a small footprint is discussed here. The previous implementation of such SHM arrays used a phase-reconstruction algorithm (that is similar to the beam-steering algorithm) for the imaging of reflectors. These algorithms were found to have a limitation during the imaging of defects/reflectors that are present in the "near-field" of the array. Here, the "near-field" is defined to be approximately 3-4 times the diameter of the compact array. This limitation is caused by approximations in the beam-steering reconstruction algorithm. In this paper, a migration-based reconstruction algorithm, with dispersion correction in the frequency domain, is discussed. Simulation and experimental studies are used to demonstrate that this algorithm improves the reconstruction in the "near-field" without decreasing the ability to reconstruct defects in the "far-field" in both isotropic and anisotropic plates.

• The Journal of the Korea institute of electronic communication sciences
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• v.3 no.3
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• pp.158-164
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• 2008

This project investigates an optimum phase design implementing a 256 phase Opto-ULSI processor for multi-function capable optical networks. The design of an 8 phase processor is already in construction and will provide the initial base for experimentation and characterization. The challenge is to be able to compensate for the non-linearity of the liquid crystal, find an optimum phase, and implement a larger scale Opto-ULSI processor. This research is oriented around the initial development of an 8 phase Opto-ULSI processor that implements a Beam Steering(BS) Opto-ULSI processor(OUP) for integrated intelligent photonic system(IIPS), while investigating the optimal phase characteristics and developing compensation for the non-linearity of liquid crystal.

• Journal of the Korean Society for Nondestructive Testing
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• v.25 no.6
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• pp.467-474
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• 2005

The expanded multi-Gaussian beam model has recently been developed that can calculate the radiation beam field from a single, rectangular transducer with great computational efficiency. In this study, this model is adopted to calculate the radiation beam field for a phased array transducer with various time delays to achieve steering and/or focusing. The calculation beam fields are compared to those obtained by well known Rayleigh-Sommerfeld integral that provides the exact solution in order to explore the validity of the expanded multi-Gaussian beam model And then, this study proposes a complete ultrasonic measurement model including the expanded beam model, far-field scattering model and system efficiency, Using the proposed model, phased array ultrasonic testing signals for a flat-bottomed hole with/without focusing were performed.

• Journal of the Korean Society for Nondestructive Testing
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• v.28 no.6
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• pp.531-537
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• 2008

One of the fundamental features of time reversal acoustic (TRA) techniques is the ability to focus the propagating ultrasonic beam to a specific point within the test material. Therefore, it is important to understand the focusing properties of a TR device in many applications including nondestructive testing. In this paper, we employ an analytical scheme for the analysis of TR beam focusing in a homogeneous medium. More specifically, a nonparaxial multi-Gaussian beam (NMGB) model is used to simulate the focusing behavior of array transducers composed of multiple rectangular elements. The NMGB model is found to generate accurate beam fields beyond the nonparaxial region. Two different simulation cases are considered here for the focal points specified on and off from the central axis of the array transducer. The simulation results show that the focal spot size increases with increasing focal length and focal angle. Furthermore, the maximum velocity amplitude does not always coincide with the specified focal point. Simulation results for the off-axis focusing cases do demonstrate the accurate steering capability of the TR focusing.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.11
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• pp.1309-1315
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• 2011

The design process for obtaining the reliable steeraxle casting beam of fork lift truck is studied in this paper, as the casting beam is major component of steeraxle which has a steering function at driving. In this study, the driving mode and damage pattern of casting beam which could be occurred from the customer site were analyzed and it established the design process to predict the fatigue life by FEA(Finite Element Analysis) so that the reliability of steeraxle casting beam could be verified at DVT(Design Validation Test) mode. This paper provides guidance on the process of designing the reliable steeraxle casting beam at the initial design stage and also, provides guidance on the process of solving the problem when the failure is occurred in the field.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.12A
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• pp.1214-1222
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• 2006

In this paper, an efficient direction-r)f-arrival based adaptive beamforming algorithm for orthogonal frequency-division multiple-access smart antenna systems is proposed. The proposed algorithm provides a high performance by steering main beams to the directions of a desired signal, whereas steering nulls to the directions of the interference, using the estimated directions. The beamforming outputs obtained by steering the main beams to the distinct directions of resolvable multipath signals are combined in a maximal ratio manner to exploit angular diversity gain. The performance elf the proposed algorithm is finally evaluated in cellular mobile environments to verify its efficiency and is compared with that of least-squares beamforming algorithm, by taking the WiBro system as a target system.

• Journal of Positioning, Navigation, and Timing
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• v.6 no.2
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• pp.43-51
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• 2017

In this study, the effect of the steering vector model mismatch due to array uncertainties on the performance of array processing was analyzed through simulation, along with the alleviation of the model mismatch effect depending on array calibration. To increase the reliability of the simulation results, the actual steering vector of the array antenna obtained by electromagnetic simulation was used along with the Jahn's channel model, which is an experimental channel model. Based on the analysis of the power spectrum for each direction, beam pattern, and the signal-to-interference-plus-noise ratio of the beamformer output, the performance deterioration of array processing due to array uncertainties was examined, and the performance improvement of array processing through array calibration was also examined.