• Journal of information and communication convergence engineering
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• 제12권3호
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• pp.140-144
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• 2014

A general linearly constrained adaptive array is examined in the weight vector space to illustrate the array performance with respect to the gain factor. A narrowband linear adaptive array is implemented in a coherent signal environment. It is shown that the gain factor in the general linearly constrained adaptive array has an effect on the linear constraint gain of the conventional linearly constrained adaptive array. It is observed that a variation of the gain factor of the general linearly constrained adaptive array results in a variation of the distance between the constraint plane and the origin in the translated weight vector space. Simulation results are shown to demonstrate the effect of the gain factor on the nulling performance.

• 대한전자공학회논문지
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• 제23권6호
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• pp.936-943
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• 1986

The lasing wavelengths and gain characteristics of the array modes of channel-substrate planar(CSP) lasers are presented. The gain values of array modes are determined from the complex coupling coefficients calculated using the fields of neighborig elements of the array. The computations show that for index guided lasers which have fields that are almost real valued, or have only slight phase curvature, the highest order array mode will have preferred oscillation. The inphase or fundamental mode, which produces only one major lobe in the far-field radiation pattern, will have the lowest modal gain of all array modes. Some of the devices discussed have modal gain differences of less than 10 cm**-1 between the highest and fundamental modes. For optical field confinement factors of about 20%, this gain difference corresponds to avtive layer gains of approximately 50**-1.

• ETRI Journal
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• 제46권4호
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• pp.708-715
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• 2024

We propose a 10-GHz 2 × 2 phased-array radio frequency (RF) receiver with an 8-bit linear phase and 15-dB gain control range using 65-nm complementary metal-oxide-semiconductor technology. An 8 × 8 phased-array receiver module is implemented using 16 2 × 2 RF phased-array integrated circuits. The receiver chip has four single-to-differential low-noise amplifier and gain-controlled phase-shifter (GCPS) channels, four channel combiners, and a 50-Ω driver. Using a novel complementary bias technique in a phase-shifting core circuit and an equivalent resistance-controlled resistor-inductor-capacitor load, the GCPS based on vector-sum structure increases the phase resolution with weighting-factor controllability, enabling the vector-sum phase-shifting circuit to require a low current and small area due to its small 1.2-V supply. The 2 × 2 phased-array RF receiver chip has a power gain of 21 dB per channel and a 5.7-dB maximum single-channel noise-figure gain. The chip shows 8-bit phase states with a 2.39° root mean-square (RMS) phase error and a 0.4-dB RMS gain error with a 15-dB gain control range for a 2.5° RMS phase error over the 10 to10.5-GHz band.

• 한국군사과학기술학회지
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• 제20권1호
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• pp.90-97
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• 2017

In this paper, we propose a new array antenna scheme which has an improved side lobe level (SLL) as well as a simplified feeding network and a high gain. The proposed array scheme is based on a non-uniformly excited sub-array. For analysis, we use an array factor of sub-array antenna. In the simulation results, the simulated SLL and gain provide more than 18.43 dB and 26.63 dBi, respectively. For the verification of the proposed design scheme, the prototype antenna with $16{\times}8$ radiating elements was designed by the proposed array scheme. The measured SLL and gain are more than 19.85 dB and 25.53 dBi, respectively. This measurement result indicates that the proposed array scheme is reasonable.

• 전기학회논문지
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• 제63권2호
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• pp.257-260
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• 2014

In this paper, a high gain waveguide array antenna combining horn antenna on slot radiator was designed. And the fabricated antenna showed enough gain, improved efficiency and broadband characteristics for receiving satellite signals, compare to conventional microstrip antenna which has dielectric loss and radiation loss on transmission line. For easy fabrication, the waveguide structure was composed by 3-stages of radiator, signal coupler and transmission line. By experiment, the array waveguide antenna of 4 by 16 showed 28.3[dBi] gain and 2:1 of VSWR. And by combining horn antenna structure, the gain was increased 1[dB]. The received signal from Koreasat 6 by measurement showed 16[dBc] of C/N on BS(Broadcasting Satellite)-band and 14[dBc] of C/N on CS(Communication Satellite)-band.

• 한국통신학회논문지
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• 제25권6B호
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• pp.1092-1099
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• 2000

An adaptive array system can effectively remove all received interferences by using adaptive algorithms even though the received signal condition is not known. The conventional adaptive array systems, however, cannot remove all interferences adaptively and converge very slowly when the eigenvalue spread of the input covariance matrix is large. In the paper, a new adaptive array system called an automatic gain controller (AGC) Applebaum array and its control algorithm are proposed to overcome the performance degradation of conventional Applebaum array in multiple interference conditions. The performance analysis of the proposed AGC Applebaum array is described under the condition of multiple narrowband interferences. Simulation results show the array output signal-to-noise ratio (SNR) of the AGC Applebaum array increases by 30dB compared to that of the conventional Applebaum array in the simulation condition. The gain of the AGC Applebaum array in the incident direction of a weaker interference is also shown to be lower than that of the conventional Applebaum array.

• 전기학회논문지
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• 제60권4호
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• pp.811-816
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• 2011

In this paper, we propose a optimal design using the Evolution Strategy of a high gain $4\times4$ array antenna that have the resonant frequency of a 19.05GHz with 18.86GHz~19.26GHz bandwidth. The proposed array antenna structure is designed to be allocated equally electric power by microstrip patch power splitter. Thus the optimal array antenna with power splitter are determined by using an optimal design program based on the evolution strategy. To achieve this, an interface program between a commercial EM analysis tool and the optimal design program is constructed for implementing the evolution strategy technique that seeks a global optimum of the objective function through the iterative design process consisting of variation and reproduction. The simulation result of $4\times4$ array antenna is confirmed that the Gain is 19.36 dBi at resonance frequency 19.05GHz.

• Journal of information and communication convergence engineering
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• 제15권3호
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• pp.137-142
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• 2017

A general linearly constrained narrowband adaptive array is examined in the eigenvector space. The optimum weight vector in the eigenvector space is shown to have the same performance as in the standard coordinate system, except that the input signal correlation matrix and look direction steering vector are replaced with the eigenvalue matrix and transformed steering vector. It is observed that the variation in gain factor results in the variation in the distance between the constraint plane and the origin in the translated weight vector space such that the increase in gain factor decreased the distance from the constraint plane to the origin, thus affecting the nulling performance. Simulation results showed that the general linearly constrained adaptive array performed better at an optimal gain factor compared with the conventional linearly constrained adaptive array in a coherent signal environment and the former showed similar performance as the latter in a noncoherent signal environment.

• Journal of Information Processing Systems
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• 제13권1호
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• pp.83-94
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• 2017

Near-field source localization algorithms are very sensitive to sensor gain/phase response errors, and so it is important to calibrate the errors. We took into consideration the uniform linear array and are proposing a blind calibration algorithm that can estimate the directions-of-arrival and range parameters of incident signals and sensor gain/phase responses jointly, without the need for any reference source. They are estimated separately by using an iterative approach, but without the need for good initial guesses. The ambiguities in the estimations of 2-D electric angles and sensor gain/phase responses are also analyzed in this paper. We show that the ambiguities can be remedied by assuming that two sensor phase responses of the array have been previously calibrated. The behavior of the proposed method is illustrated through simulation experiments. The simulation results show that the convergent rate is fast and that the convergent precision is high.

• 한국음향학회지
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• 제35권6호
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• pp.427-435
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• 2016

해양에서 배열센서를 사용하여 신호를 수신하는 경우 성능을 측정하는 척도로서 배열이득(Array Gain, AG)을 사용한다. 배열이득은 배열의 형상, 주파수 및 해양환경에 의한 소음의 방향성에 영향을 받는다. 본 논문에서는 배열이득을 모델링하고 예측하기 위하여 공간상관성을 이용하였으며, 해상실험을 통해서 예측모델을 검증하였다. 예측 모델에서는 임의형상의 배열 및 소음의 방향성을 고려할 수 있는 신호와 소음의 공간상관성을 사용하여 배열이득을 계산하였다. 해상실험에서는 예인음원을 이용하여 CW(Continuous Wave)를 수평배열센서로 수신하였으며, 송신신호 사이에 주변 소음을 측정하였고, 이로부터 개별센서와 배열센서의 SNR(Signal to Noise Ratio)을 계산하여 배열이득을 추정하였다. 최종적으로 실험적으로 측정한 배열이득과 예측모델을 이용한 배열이득을 비교 검증하였다.