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Author

A. Dagdeviren

Bio: A. Dagdeviren is an academic researcher from Sakarya University. The author has contributed to research in topics: Radiation pattern & Matrix (chemical analysis). The author has an hindex of 2, co-authored 3 publications receiving 8 citations.

Papers
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Proceedings ArticleDOI
11 Sep 2006
TL;DR: In this paper, the pattern analysis of HF antennas mounted on a ship is presented and the method of moments (MoM) is used to calculate the antenna pattern and inter antenna coupling in 1.6-30 GHz frequency range.
Abstract: In this paper, the pattern analysis of HF antennas mounted on a ship is presented. The method of moments (MoM) is used to calculate the antenna pattern and inter antenna coupling in 1.6-30 Mhz frequency range.

7 citations

Proceedings ArticleDOI
11 Sep 2006
TL;DR: In this article, the analysis of mutual coupling between monopole antennas mounted on the aircraft at UHF band is presented, where the Method of Moments (MoM) and hybridized MoM with Uniform Geometrical Theory of Diffraction (UTD) method are used to calculate the coupling in 225-400 MHz frequency range.
Abstract: In this paper, the analysis of mutual coupling between monopole antennas mounted on the aircraft at UHF band is presented. The Method of Moments (MoM) and hybridized MoM with Uniform Geometrical Theory of Diffraction (UTD) method (MoM/UTD) are used to calculate the coupling in 225-400 MHz frequency range. Numerical results with MoM and MoM/UTD are performed and the reliability of these methods is discussed based on the measurement results.

2 citations

Proceedings ArticleDOI
26 Jun 2006
TL;DR: In this article, the shadowing effect of a ship by using Uniform Theory of Diffraction (UTD) was analyzed by using a high frequency asymptotic method, where the ship body was considered.
Abstract: Reflector antennas are frequently used antennas for X-Band Satellite Communication. An X Band reflector antenna placed on a ship will be subject to pattern blockage when satellite antenna is shadowed by a complex structure, here the ship body. This paper aims to analyze the shadowing effect of the ship by using Uniform Theory of Diffraction (UTD), a high frequency asymptotic method.

2 citations

Journal ArticleDOI
TL;DR: In this article , some properties of hyperbolic numbers are presented and compared with real, dual, and complex matrices, and it is revealed that there are similarities in additive properties and differences in multiplicative properties.
Abstract: In this study, firstly, we will present some properties of hyperbolic numbers. Then, we will introduce hyperbolic matrices, which are matrices with hyperbolic number entries. Additionally, we will examine the algebraic properties of these matrices and reveal its difference from other matrix structures such as real, dual, and complex matrices. As a result of comparing the results found in this work with real, dual, and complex matrices, it will be revealed that there are similarities in additive properties and differences in some multiplicative properties. Finally, we will define some special hyperbolic matrices and give their properties and relations with real matrices.

1 citations

Proceedings ArticleDOI
03 Jun 2022
TL;DR: In this paper , the W Band FMCW radar system developed by ARRALIS is described, which uses a triangular waveform by default, which then can be converted to other waveforms as well.
Abstract: The range resolution capability of the aircraft altimeter is one of the key parameters during the precise height measurements. During the landing of the rotary-wing aircraft, it is vital to detect the obstacles such as power cables, especially in poor visibility conditions like snow (White-out) and dust clouds (Brown-out) to assist a safe landing. For lower height measurements, Frequency Modulated Continuous Wave (FMCW) radars are used to achieve a better resolution with the aid of higher bandwidth. However, this comes with two challenges: (1) the design complexity of the Radio Frequency Integrated Circuit (RFIC) (2) the high rate of atmospheric attenuation caused by the gases and aerosols. Using the frequencies in the neighbourhood of 94 GHz for the transmission significantly reduces the atmospheric attenuation and provides an atmospheric transparency window. In this paper, the W Band FMCW altimeter radar developed by ARRALIS is described. ARRALIS comes with the solution of both integrated circuits and modules used in a transmitter/receiver chain designed for the W Band. This provides a complete FMCW radar system working in the frequency range of 92-96 GHz with the aid of commercial off the shelf analog to digital converters and Digital Signal Processing (DSP) evaluation boards. Thus, by achieving a 4 GHz bandwidth at the centre of 94 GHz, a theoretical range resolution of 3.75 cm is achieved, which is then degraded by the windowing function factor during converting the signal into the frequency domain. The FMCW radar system uses a triangular waveform by default, which then can be converted to other waveforms as well.

Cited by
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Journal ArticleDOI
TL;DR: This paper presents a toolset independent hybrid method for calculating the power at receive antenna terminals relative to the power incident on transmit antenna terminals, validated against full-wave computational electromagnetic (CEM) simulations and measurements.
Abstract: Calculation of the electromagnetic interference (EMI) between electrically large antennas mounted on ships is important for a variety of Navy problems. This paper presents a toolset independent hybrid method for calculating the power at receive antenna terminals relative to the power incident on transmit antenna terminals. The hybrid method coupling results are validated against full-wave computational electromagnetic (CEM) simulations and measurements. An advantage of the proposed hybrid approach is that CEM calculations for antenna near-fields and propagation between antennas can be executed with user-preferred tools. In addition, transmit and receive antenna calculations are executed in transmit mode independent of ship structures. Thus, antenna calculations can be stored in a library for calculation reuse and optimization of antenna placement for EMI reduction.

13 citations

01 Mar 1969
TL;DR: In this article, the Linvill method is used to determine the terminations that a transistor amplifier should have for a specified value of power gain and bandwidth, which is an indication of the stability of the amplifier under various load conditions.
Abstract: : The report discusses a method -- known as the Linvill method -- for determining the terminations that a transistor amplifier should have for a specified value of power gain and bandwidth. Basically, the Linvill method makes use of measured transistor parameters to develop charts from which one can read power gain and input impedance or admittance as functions of the load termination. The report gives a complete geometrical derivation of the Linvill 'stability factor,' whose value is an indication of the stability of the amplifier under various load conditions. In addition, procedure steps are given for using the charts developed for determining input and load admittances.

10 citations

Journal ArticleDOI
TL;DR: In this paper, the coupling analysis of HF antennas mounted on a ship is presented and the method of moments (MoM) is used to calculate the inter antenna coupling in 1.6-30 MHz frequency range.
Abstract: In this paper, the coupling analysis of HF antennas mounted on a ship is presented. The method of Moments (MoM) is used to calculate the inter antenna coupling in 1.6–30 MHz frequency range. Numerical results with MoM are performed and the reliability of these methods is discussed according to the measurement results. The coupling measurements were acquired on 1:50 scale model of the shipboard.

3 citations

Journal ArticleDOI
TL;DR: In this article , a calibration scheme that receives phasedarray antennas for an anchored platform-mounted high-frequency (HF) radar incorporating a model of free rotation was presented, which is called yaw rotation and dominates the six-degree-of-freedom (six-DOF) platform motion.
Abstract: Prior studies have highlighted the importance of calibrating receiver antennas in target direction-of-arrival (DOA) estimation and surface current measurement for high-frequency (HF) radar systems. It is worth noting that the calibration contributes to the performance of both shore-based HF radar and platform-mounted HF radar. Compared with shore-based HF radar, the influence of six-degrees-of-freedom (six-DOF) platform motion should be considered in the calibration of platform-mounted HF radar. This paper initially describes a calibration scheme that receives phasedarray antennas for an anchored platform-mounted HF radar incorporating a model of free rotation, which is called yaw rotation and dominates the six-DOF platform motion in this study. In the presence of yaw rotation, the amplitude and phase of the source calibration signal from the other shore-based radar sites reveal the directional sensitivity of the receiver phased-array antennas. The calibration of receiver phased-array antennas is composed of channel calibration (linking cables and receiver hardware calibration) and antenna pattern calibration. The antenna pattern at each bearing can be represented by the Fourier series. The estimation of channel calibration and antenna pattern calibration depends on an overdetermined HF radar system consisting of observed values and theoretical constraints, so the least-squares fits of the channel calibration coefficients and antenna pattern calibration coefficients are obtained. The experimental results show that the target DOA estimation and surface current measurement can be improved if the phased-array platform-mounted HF radar system is calibrated.

3 citations

Proceedings ArticleDOI
Bin Cao, Hanyu Shan1, Jiahui Qin1, Kaijie Jiang1, Yingsong Li1 
01 Jan 2019
TL;DR: In this paper, a ship model with a short-wave antenna installed which is located on-board together with the fuel tank was simulated, and the radiation power density to established safety criteria was determined through the reasonable setting of its shortwave antenna position, frequency, power.
Abstract: When the fuel is exposed to electromagnetic radiation, an arc or spark of strong electromagnetic energy may cause a burning accident. So, the hazards of the electromagnetic radiation to fuel (HERF) need to be considered in the actual ship electromagnetic compatibility design. In order to prevent the HERF, there must be sufficient safety distance between the fuel zone and the transmitting antenna, and RF power density must meet safety level requirements to eliminate RF arcs or sparks. In this paper, on the basis of analyzing the protection standards of electromagnetic radiation hazards, we simulated a ship model with a shortwave antenna installed which is located on-board together with the fuel tank. According to analysis of the simulation data, the radiation power density to established safety criteria is determined through the reasonable setting of its short-wave antenna position, frequency, power, which satisfied the requirements of the electromagnetic environment effect of on-board systems.

2 citations