• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.4
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• pp.63-70
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• 2014

Method a target estimation in spatial are mobile wireless communication using network cell and GPS. It have much error that mobile wireless communication depend on cell size. GPS method can't find a target in shadow and inner area. In this paper, we estimate a target as direction of arrival method using adaptive array antenna system. Adaptive array antenna system can obtain desired signal to remove other signal This paper studied digital beamforming method in order to estimation a target. Proposed method is modified optimum weight and antenna error correction to estimation an optimal receive signal. Digital beamforming method decided a signal phase and amplitude from received signal on array antenna element. But if it is not to do error correction of received signal, system performance have decreased. Firstly, we proposed modified optimum weight in order to finding desired target. Secondly, we are error correction of antenna incident signals by optimal weight before digital beamforming method. Thirdly, throughly simulation, we showed that system performance of proposed method compare proposal method with general method. It have improved resolution of estimation target to good performance more proposed method than general method.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.501-505
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• 2003

There are many antenna array errors. They will distort the array beam pattern and result in an increased sidelobe level. A calibration technique is proposed for correcting the antenna array errors such as mutual coupling and unequal feeder characteristics. These are modeled as a matrix representing the interaction between the radiating elements. The matrix is estimated from the measured array response vectors. The antenna array errors are corrected by modifying the beamforming weight vector. It is verified by the electromagnetic simulation and experiment that the proposed technique reduces the sidelobe level and increases the antenna gain.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.2
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• pp.199-205
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• 2004

There are many antenna array errors. They will distort the array beam pattern and result in an increased sidelobe level. A calibration technique is proposed for correcting the antenna array errors such as mutual coupling and unequal feeder characteristics. These are modeled as a matrix representing the interaction between the radiating elements. The matrix is estimated from the measured array response vectors. The antenna array errors are corrected by modifying the beamforming weight vector. It is verified by the electromagnetic simulation and experiment that the proposed technique reduces the sidelobe level and increases the antenna gain.

• Journal of Korea Society of Digital Industry and Information Management
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• v.9 no.4
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• pp.51-57
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• 2013

Research on calibration of array antenna has become a hot spot in the area of signal processing and it is necessary to obtain the phase mismatch of each antenna channel. This paper presents a new calibration method for an array antenna system. In order to calibrate the phase mismatch of each antenna channel, we used primary synchronization signal (PSS) which exists in LTE downlink frame. Primary synchronization signal (PSS) is based on a Zadoff-Chu sequence which has a good correlation characteristic. By using correlation calculation, we can extract primary synchronization signal (PSS). After extracting primary synchronization signal (PSS), we use it to calibrate and reduce the phase errors of each antenna channel. In order to verify the new array antenna calibration algorithm which is proposed in this paper, we have simulated the proposed algorithm by using MATLAB. The array antenna system consists of two antenna elements. The phase mismatch of first antenna and second antenna is calculated accurately by proposed algorithm in the experiment test. Theory analysis and MATLAB simulation results are shown to verify the calibration algorithm.

• ETRI Journal
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• v.26 no.6
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• pp.605-614
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• 2004

In this paper, we investigate array calibration algorithms to derive a further improved version for correcting antenna array errors and RF transceiver errors in CDMA smart antenna systems. The structure of a multi-channel RF transceiver with a digital calibration apparatus and its calibration techniques are presented, where we propose a new RF receiver calibration scheme to minimize interference of the calibration signal on the user signals. The calibration signal is injected into a multi-channel receiver through a calibration signal injector whose array response vector is controlled in order to have a low correlation with the antenna response vector of the receive signals. We suggest a model-based antenna array calibration to remove the antenna array errors including mutual coupling errors or to predict the element patterns from the array manifold measured at a small number of angles. Computer simulations and experiment results are shown to verify the calibration algorithms.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.3
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• pp.217-223
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• 2013

A digital retrodirective antenna system is easy to modify and upgrade because it can control the phase information of the output signal toward opposite direction to input signal without a priori knowledge of the arrival direction. Due to this advantage, it is possible to perform fast beam tracking. In this paper, a design digital retrosirective array antenna system according to the number of antenna array by using only one digital PLL which finds angle of delayed phase and we test BER performance of this system. When we transmit data at actual communication system, the data modulated onto carrier frequency in order to shift spectrum from base band to another band. So we simulate system considering carrier frequency according to the number of antenna array. As a result, carrier frequency has no impact on the performance.

• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.4
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• pp.71-78
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• 2014

Method a target estimation in spatial are mobile wireless communication using network cell and GPS. It have much error that mobile wireless communication depend on cell size. GPS method can't find a target in shadow and inner area. In this paper, we estimate a target as direction of arrival method using adaptive array antenna system. Adaptive array antenna system can obtain desired signal to remove other signal This paper studied digital beamforming method in order to estimation a target. Proposed method is modified optimum weight and antenna error correction to estimation an optimal receive signal. Digital beamforming method decided a signal phase and amplitude from received signal on array antenna element. But if it is not to do error correction of received signal, system performance have decreased. Firstly, we proposed modified optimum weight in order to finding desired target. Secondly, we are error correction of antenna incident signals by optimal weight before digital beamforming method. Thirdly, throughly simulation, we showed that system performance of proposed method compare proposal method with general method. It have improved resolution of estimation target to good performance more proposed method than general method.

• Journal of Korea Society of Digital Industry and Information Management
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• v.9 no.3
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• pp.59-65
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• 2013

This paper presents a novel calibration method for a base station system adopting an antenna array. The proposed technique utilizes Zadoff-Chu sequence, which is included in the LTE pilot signal periodically, in order to compute the phase characteristic of each antenna channel. As the Zadoff-Chu sequence exhibits an excellent autocorrelation characteristic, it is possible for the receiving base station to retrieve the Zadoff-Chu sequence transmitted from each mobile terminal. In addition, we can obtain the phase characteristic of each antenna channel, which is the ultimate goal of the calibration procedure. The proposed calibration algorithm has been implemented using an FPGA (Field Programmable Gate Array). We have applied the proposed algorithm to an array consisting of 2 antenna elements for simplicity. the phase value implied to the first and second antenna path is very accurately calculated from the proposed procedure. From the experimental test, the proposed method provides accurate calibration results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.7
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• pp.625-634
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• 2016

A full digital receiving active phased array antenna generates final receiving beams by digital beam forming of received digital signals in element-level that makes difficult to use typical near-field measurement method. Thus in this paper, a modified near-field measurement method which is suitable for full digital receiving active phased array antenna is proposed. Also the measured results of receiving beam pattern and G/T using developed L-band full digital receiving active phased array antenna are shown for the verification of proposed method.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.215-216
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• 2006

In this paper, the antenna the with linear active phased array of $1{\times}16$ operated in DBS band was designed. The antenna was composed of sixteen radiating elements, sixteen active channels and five Wilkinson power combiners with 4-channel inputs, a digital control board and a stabilizing DC bias board. The radiating element of the array has the structure of a microstrip stack patch with a left-hand circular polarization. And, each active channel consists of a low noise ampilifier, a 3-bit digital phase shifter and a variable analog attenuator. The breadboard of linear active phased array antenna was also fabricated to test the electrical performances. The radiation patterns of the antenna were measured after correcting initial phases of each active channel in aechoic chamber. And also, the beam scanning chracteristcs of $10^{\circ}$, $20^{\circ}$, $30^{\circ}$ were measured.