• The Transactions of The Korean Institute of Electrical Engineers
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• v.68 no.1
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• pp.83-89
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• 2019

In this paper, beam forming using moving least squares method (MLSM) is studied. In the previous research, the least squares method (LSM), one of the data interpolation methods, was used to determine the desired beam pattern and obtain a beam pattern that minimizes the square of the error with the desired beam pattern. However, LSM has a disadvantage in that the beam pattern can not be formed to satisfy the exact steering angle of the desired beam pattern and the peak sidelobe level (PSLL) condition. To overcome this drawback, MLSM is used for beam forming. In order to verify, the proposed method is applied in beam forming of Bezier platform array antenna which is one of conformal array antenna platform.

• ETRI Journal
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• v.41 no.6
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• pp.715-730
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• 2019

We propose a switched beam-forming antenna that satisfies not only ultra-wideband characteristics but also beam-forming in the WLAN frequency band using an ultra-wideband antenna and passive parasitic elements applying a broadband optimal reactance load algorithm. We design a power and phase estimation function and an error correction function by re-analyzing and normalizing all the components of the parasitic array using control system engineering. The proposed antenna is compared with an antenna with a pin diode and reactance load value, respectively. The pin diode is located between the passive parasitic elements and ground plane. An antenna beam can be formed in eight directions according to the pin diode ON (reflector)/OFF (director) state. The antenna with a reactance load value achieves a better VSWR and gain than the antenna with a pin diode. We confirm that a beam is formed in eight directions owing to the RF switch operation, and the measured peak gain is 7 dBi at 2.45 GHz and 10 dBi at 5.8 GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.4
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• pp.431-440
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• 2012

In this paper, new beam-forming array antenna is proposed. The proposed beam-forming array antenna has control ability for beam-direction/width by employing low loss reconfigurable power divide and three-dimensional array structure. The reconfigurable power divider is key idea in the proposed antenna, because it has reconfigurable RF power distribution ability to each antenna. And, for research and verification of the proposed antenna, 3-dimensional beam-forming array antenna is implemented, and the experimental results show that the proposed antenna has various radiation modes from 1:1 to 1:N by adjusting RF power distribution.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.4
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• pp.59-65
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• 2022

In this paper, a digital active phased array antenna is briefly introduced and beam forming method for a dual-channel side-lobe blanking applied to blank the side-lobe of the main beam is described. Next, the antenna performance was verified from results of design and antenna near-field measurement for the antenna main beam and side-lobe blanking beam. Then, a single-channel side-lobe blanking beam forming method was proposed to reduce the number of channels than the existing system operating dual-channel side-lobe blanking beam and weight distribution for each element of the side-lobe blanking antenna was designed with the proposed method. Finally, the designed single-channel side-lobe blanking beam pattern and blanking ability were verified and compared with the dual-channel side-lobe blanking beam. In addition, by comparing/verifying the conventional dual-channel and the proposed single-channel side-lobe blanking beam patterns measured through the receiving near-field test of the digital active phased array antenna and their ability to blank side-lobe of the main beam, validity of the proposed method for forming single-channel side-lobe blanking beam was confirmed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.1
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• pp.62-67
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• 2003

This paper is concerned with the design of the beam forming module that is a key unit of the active phased array antenna(APAA) system for mobile satellite communications. This module includes two blocks for main signal and tracking signal. Main signal block has the role of transmitting input signal from phased array antenna to tracking signal block. And, tracking signal block executes main roles, beam forming of tracking signal and electronic beam control. The several electrical performances of this module, phase characteristics and linear gain, etc., agreed with specifications needed fur APAA, and for more clear verification of the performances, the satellite communication test of the APAA including the modules was accomplished in the outdoors.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.7A
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• pp.603-610
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• 2005

Beam-forming method based on the estimated channel information at the base station degrade the performance mismatching directional vector in case of systems which Frequency Division Duplex (FDD) center frequency of uplink and downlink are different. Also blind estimation technique which is to obtain directional vector of reverse link through received signal has disadvantage of hardware complexity increase. To solve these problems, in present paper, a smart antenna algorithm which is to improve the beam-forming complexity increase due to user number by appling the spatial fourier transform to be able to beam- forming toward a wanted direction through adjusting a obtained uplink weight function by estimating Angle-of-Arrival (AoA) to the competable form at the downlink is proposed. The proposed algorithm is integrated to the CDMA downlink transmitter and simulations are performed to confirm the performance as frame error rate at the receiver. As a result, the beam forming effect is confirmed and the performance gain with the proposed algorithm is comparable to ordinary smart antenna system.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2002.11a
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• pp.118-122
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• 2002

This paper is concerned with the design of the beam forming module that is a key unit of the active phased array antenna(APAA) system for mobile satellite communications. This module includes two blocks for main signal and tracking signal. Main signal block has the role of transmitting input signal from phased away antenna to tracking signal block. And, tracking signal block executes main roles, beam forming of tracking signal and electronic beam control. The several electrical performances of this module, phase characteristics and linear gain, etc., agreed with specifications needed for APAA, and for more clear verification of the performances, the satellite communication test of the APAA including the modules was accomplished in the outdoors.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.3
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• pp.587-592
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• 2018

An adaptive beam forming system using a phased array antenna improves communication quality by beam forming adaptively to a communication environment having an interference signal. For adaptive beam forming, a good combination of the phases of the excited signals to each radiating element of the phased array antenna should be calculated. In this paper, improved particle swarm optimization algorithm that adds a re-spreading procedure according to particle density was proposed to increase the probability of good phase shift combination output.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.11
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• pp.3137-3143
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• 2009

In this paper, a single arm spiral antenna has been investigated about the characteristics of polarization and tilt beam. If a circumference length of spiral is bigger than a wavelength, it have a characteristic of varying maximum radiation beam direction. In addition, circular polarizations (RHCP, LHCP) can be variable by the feeding points (inner, outer). Also maximum beam directions tilt in different direction according to the circular polarizations, LHCP and RHCP. These characteristics of single arm spiral antenna are able to apply in the beam forming, diversity, MIMO application which has dual polarization using an antenna element.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.6
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• pp.2777-2784
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• 2011

In this paper, DOA(direction of arrival) of multiple incident signals received from linear array antenna and circular array antenna, which is based on nonparametric estimation algorithm, and adaptive beam-forming algorithm are studied and analyzed. In nonparametric estimation algorithm, we minimize a regularized objective function for finding a estimate of the signal energy as a function of angle, using nonquadratic norm which leads to supper resolution and noise suppression. And then, DOA is estimated by the signal and noise spatial steering vector, and adaptive beam-forming pattern is improved by weight vectors obtained from the spatial vector. Especially, the discrimination ability of DOA and the adaptive beam-forming ability according to antenna array methods and the number of array elements are compared and considered.