In this paper; the capability of compressed sensing (CS) for near-fleld inverse synthetic apertur... more In this paper; the capability of compressed sensing (CS) for near-fleld inverse synthetic aperture radar (ISAR) imaging is addressed. Considering two-dimensional, millimeter- wave ISAR imaging geometry, a CS-based reconstruction technique is developed and its potential is assessed through numerical simulations and measurements applied to hypothetical as well as various complex targets. It is shown for most cases that the target shapes can be accurately and su-ciently reconstructed from a very low number of samples of the whole collected data (e.g., 1.7%) thereby demonstrating the validity of the CS technique. Nevertheless, it is also shown that, the increasing complexity (i.e., low sparsity) of the target scene may somewhat degrade the success of the approach.
Journal of Electrical and Computer Engineering, 2017
An algorithm for detecting cavities inside a tree-body is presented with simulation and measured ... more An algorithm for detecting cavities inside a tree-body is presented with simulation and measured examples. The details of the imaging algorithm that is based on sinusoidal template focusing routine are given. First, the algorithm is tested with the simulation scenario for which perfect reconstruction of the simulated cavity structure together with tree-body is successfully formed in MATLAB programming environment. Then, the algorithm is applied to the measurement data that have been collected from a laboratory set-up. Collected backscattered measurements from the tree-body (with cavity) structure are used to generate the image of the scene by the help of our proposed algorithm. The resultant radar images of the measured data collected from the laboratory arrangement have shown the applicability of the developed algorithm for the detection of cavity structures inside tree-bodies.
In this work, we present radiometric images for several concealed object experiments that were me... more In this work, we present radiometric images for several concealed object experiments that were measured at TUBITAK - Marmara Research Center (MRC) facilities. The radiometric imaging system that collects the cosmic background radiation from the target is utilized on a 2D data collection grid to have the millimeter-wave image of the target. A detection algorithm is developed to point out the region of the hidden object beneath the cloth. The raw and processed passive millimeter wave images of various targets with concealed objects are shown after applying our detection algorithm. The resultant images have demonstrated that the passive imaging system together with our detection routine produces successful images of the targets.
... 2261-2268. [7] Kucuk K., Kavak A., and Yigit H.: Smart Antenna Module using OMNeT++ for Wirel... more ... 2261-2268. [7] Kucuk K., Kavak A., and Yigit H.: Smart Antenna Module using OMNeT++ for Wireless Sensor Network", 4th IEEE International Symposium on Wireless Communication Systems, Norway, (2007). [8] Nasipuri A ...
International Journal of Infrared and Millimeter Waves, 2007
This paper presents a simple method for determining the dielectric constant of microwave PCB subs... more This paper presents a simple method for determining the dielectric constant of microwave PCB substrates. In the presented method, a bandpass microstrip filter designed on the PCB substrate with a user-predicted dielectric constant value is implemented for a given center frequency. The simulation results of the designed bandpass filter are obtained by the help of microwave design software; XFDTD®. Experimental
2018 Progress in Electromagnetics Research Symposium (PIERS-Toyama), 2018
The microwave backscattering from a complex environment is subject to numerous factors such as wa... more The microwave backscattering from a complex environment is subject to numerous factors such as wavelength, viewing geometry, polarization of the transmitted wave and target attributes including roughness, shape, size, orientation and dielectric properties. Therefore, the characteristics and amount of backscatter data varies from case to case. In an effort to better understand this complex mechanism of backscattering from distributed surfaces, the SAR image characteristics of a typical land area are assessed through a readily feasible polarimetric ground-based synthetic aperture radar (GB-SAR) system working at L-band frequencies. Because of their standard use in data calibration, trihedral corner reflectors (TCR) as well as dipole-like objects are also deployed in the measurements to extract their polarimetric GB-SAR image features.
2018 22nd International Microwave and Radar Conference (MIKON)
Horizontally polarized patch antenna array design is proposed for frequency modulated continuous ... more Horizontally polarized patch antenna array design is proposed for frequency modulated continuous wave (FMCW) marine radar applications. The array consists of series-parallel fed 96 elements printed on microwave substrate. The array configuration is optimized for minimum line loss and maximum aperture efficiency. The target frequency band is 9.3–9.4 GHz. Antenna parameters such as return loss, peak gain, half-power beam width and side-lobe levels are presented for marine radar applications.
This paper presents a simple method for determining the dielectric constant of microwave PCB subs... more This paper presents a simple method for determining the dielectric constant of microwave PCB substrates. In the presented method, a bandpass microstrip filter on the PCB substrate with a user-predicted dielectric constant value is designed for a given center frequency, and it is implemented. The simulation results of the designed bandpass filter are obtained by the help of electromagnetic analysis software; XFDTD. Experimental results regarding the filter frequency characteristic are accomplished by means of a vector network analyzer. The simulation results of the designed filter are modified to overlap with the experimental ones by varying the dielectric constant value. When the simulation and experimental results are overlapped, the value of dielectric constant is accurately selected. In order to illustrate the validity of proposed method, the dielectric constant values of flame resistant-4 (FR4) substrates are acquired at IEEE 802.11b/g and IEEE 802.11a wireless local area networ...
2018 Progress in Electromagnetics Research Symposium (PIERS-Toyama)
In this study, we present Passive Millimeter Wave (PMMW) radiometric images for several concealed... more In this study, we present Passive Millimeter Wave (PMMW) radiometric images for several concealed object experiments. PMMW is an imaging technique that is realized by collecting the existing cosmic background radiation (CBR) from the target and surrounding environment based on their temperatures and electromagnetic wave reflectivity. PMMW imaging, one of the detection and classifying methods for determining and localizing concealed objects in the cases where security is prioritized is presented without employing any active radiation and so preventing the human health. We present a detection algorithm based on the histogram of the raw data and applying an auto-segmentation routine to the data.
In this study, an experimental study on Through-the-Wall radar imagery was ac- complished for the... more In this study, an experimental study on Through-the-Wall radar imagery was ac- complished for the purpose of imaging life-sign symptoms. The proposed system is based on a stepped frequency continuous wave radar with the help of a Vector Network Analyzer (VNA- Agilent E5071B ENA), antenna (C-band), and the control computer. Breathing and heartbeat information is extracted from the backscattering electromagnetic fleld exploiting a change detec- tion routine. The experimental results show that both breathing and the heartbeat signatures from real human beings are gathered. 1. INTRODUCTION Through-the-Wall Radar (TWR) is an emerging technology which is very useful for detecting and identifying unknown objects behind walls. It can be used in difierent applications ranging from survivor detection in rescue, hostage operations, to people localization in anti-terrorist operations or life detecting under earthquake rubble (1). Recently, microwave Doppler radars were developed for remote sens...
In this study, an efficient and practical approach is proposed to increase the bandwidth of narro... more In this study, an efficient and practical approach is proposed to increase the bandwidth of narrow-band antennas by designing lossless impedance matching network with the simplified real frequency technique. Our algorithm does not require prior knowledge of network analytical topology of the load impedance that is to be matched. Any frequency-dependent data such as antenna radiation data (either measurement or simulated) can be easily matched via the proposed algorithm. The matching network realized by this technique is relatively simple and gives superior gain properties compared to that obtained by other methods. The proposed method is tested with various data sets for different antenna configurations. The results validate the effectiveness and the success of the algorithm.
In this paper; the capability of compressed sensing (CS) for near-fleld inverse synthetic apertur... more In this paper; the capability of compressed sensing (CS) for near-fleld inverse synthetic aperture radar (ISAR) imaging is addressed. Considering two-dimensional, millimeter- wave ISAR imaging geometry, a CS-based reconstruction technique is developed and its potential is assessed through numerical simulations and measurements applied to hypothetical as well as various complex targets. It is shown for most cases that the target shapes can be accurately and su-ciently reconstructed from a very low number of samples of the whole collected data (e.g., 1.7%) thereby demonstrating the validity of the CS technique. Nevertheless, it is also shown that, the increasing complexity (i.e., low sparsity) of the target scene may somewhat degrade the success of the approach.
Journal of Electrical and Computer Engineering, 2017
An algorithm for detecting cavities inside a tree-body is presented with simulation and measured ... more An algorithm for detecting cavities inside a tree-body is presented with simulation and measured examples. The details of the imaging algorithm that is based on sinusoidal template focusing routine are given. First, the algorithm is tested with the simulation scenario for which perfect reconstruction of the simulated cavity structure together with tree-body is successfully formed in MATLAB programming environment. Then, the algorithm is applied to the measurement data that have been collected from a laboratory set-up. Collected backscattered measurements from the tree-body (with cavity) structure are used to generate the image of the scene by the help of our proposed algorithm. The resultant radar images of the measured data collected from the laboratory arrangement have shown the applicability of the developed algorithm for the detection of cavity structures inside tree-bodies.
In this work, we present radiometric images for several concealed object experiments that were me... more In this work, we present radiometric images for several concealed object experiments that were measured at TUBITAK - Marmara Research Center (MRC) facilities. The radiometric imaging system that collects the cosmic background radiation from the target is utilized on a 2D data collection grid to have the millimeter-wave image of the target. A detection algorithm is developed to point out the region of the hidden object beneath the cloth. The raw and processed passive millimeter wave images of various targets with concealed objects are shown after applying our detection algorithm. The resultant images have demonstrated that the passive imaging system together with our detection routine produces successful images of the targets.
... 2261-2268. [7] Kucuk K., Kavak A., and Yigit H.: Smart Antenna Module using OMNeT++ for Wirel... more ... 2261-2268. [7] Kucuk K., Kavak A., and Yigit H.: Smart Antenna Module using OMNeT++ for Wireless Sensor Network", 4th IEEE International Symposium on Wireless Communication Systems, Norway, (2007). [8] Nasipuri A ...
International Journal of Infrared and Millimeter Waves, 2007
This paper presents a simple method for determining the dielectric constant of microwave PCB subs... more This paper presents a simple method for determining the dielectric constant of microwave PCB substrates. In the presented method, a bandpass microstrip filter designed on the PCB substrate with a user-predicted dielectric constant value is implemented for a given center frequency. The simulation results of the designed bandpass filter are obtained by the help of microwave design software; XFDTD®. Experimental
2018 Progress in Electromagnetics Research Symposium (PIERS-Toyama), 2018
The microwave backscattering from a complex environment is subject to numerous factors such as wa... more The microwave backscattering from a complex environment is subject to numerous factors such as wavelength, viewing geometry, polarization of the transmitted wave and target attributes including roughness, shape, size, orientation and dielectric properties. Therefore, the characteristics and amount of backscatter data varies from case to case. In an effort to better understand this complex mechanism of backscattering from distributed surfaces, the SAR image characteristics of a typical land area are assessed through a readily feasible polarimetric ground-based synthetic aperture radar (GB-SAR) system working at L-band frequencies. Because of their standard use in data calibration, trihedral corner reflectors (TCR) as well as dipole-like objects are also deployed in the measurements to extract their polarimetric GB-SAR image features.
2018 22nd International Microwave and Radar Conference (MIKON)
Horizontally polarized patch antenna array design is proposed for frequency modulated continuous ... more Horizontally polarized patch antenna array design is proposed for frequency modulated continuous wave (FMCW) marine radar applications. The array consists of series-parallel fed 96 elements printed on microwave substrate. The array configuration is optimized for minimum line loss and maximum aperture efficiency. The target frequency band is 9.3–9.4 GHz. Antenna parameters such as return loss, peak gain, half-power beam width and side-lobe levels are presented for marine radar applications.
This paper presents a simple method for determining the dielectric constant of microwave PCB subs... more This paper presents a simple method for determining the dielectric constant of microwave PCB substrates. In the presented method, a bandpass microstrip filter on the PCB substrate with a user-predicted dielectric constant value is designed for a given center frequency, and it is implemented. The simulation results of the designed bandpass filter are obtained by the help of electromagnetic analysis software; XFDTD. Experimental results regarding the filter frequency characteristic are accomplished by means of a vector network analyzer. The simulation results of the designed filter are modified to overlap with the experimental ones by varying the dielectric constant value. When the simulation and experimental results are overlapped, the value of dielectric constant is accurately selected. In order to illustrate the validity of proposed method, the dielectric constant values of flame resistant-4 (FR4) substrates are acquired at IEEE 802.11b/g and IEEE 802.11a wireless local area networ...
2018 Progress in Electromagnetics Research Symposium (PIERS-Toyama)
In this study, we present Passive Millimeter Wave (PMMW) radiometric images for several concealed... more In this study, we present Passive Millimeter Wave (PMMW) radiometric images for several concealed object experiments. PMMW is an imaging technique that is realized by collecting the existing cosmic background radiation (CBR) from the target and surrounding environment based on their temperatures and electromagnetic wave reflectivity. PMMW imaging, one of the detection and classifying methods for determining and localizing concealed objects in the cases where security is prioritized is presented without employing any active radiation and so preventing the human health. We present a detection algorithm based on the histogram of the raw data and applying an auto-segmentation routine to the data.
In this study, an experimental study on Through-the-Wall radar imagery was ac- complished for the... more In this study, an experimental study on Through-the-Wall radar imagery was ac- complished for the purpose of imaging life-sign symptoms. The proposed system is based on a stepped frequency continuous wave radar with the help of a Vector Network Analyzer (VNA- Agilent E5071B ENA), antenna (C-band), and the control computer. Breathing and heartbeat information is extracted from the backscattering electromagnetic fleld exploiting a change detec- tion routine. The experimental results show that both breathing and the heartbeat signatures from real human beings are gathered. 1. INTRODUCTION Through-the-Wall Radar (TWR) is an emerging technology which is very useful for detecting and identifying unknown objects behind walls. It can be used in difierent applications ranging from survivor detection in rescue, hostage operations, to people localization in anti-terrorist operations or life detecting under earthquake rubble (1). Recently, microwave Doppler radars were developed for remote sens...
In this study, an efficient and practical approach is proposed to increase the bandwidth of narro... more In this study, an efficient and practical approach is proposed to increase the bandwidth of narrow-band antennas by designing lossless impedance matching network with the simplified real frequency technique. Our algorithm does not require prior knowledge of network analytical topology of the load impedance that is to be matched. Any frequency-dependent data such as antenna radiation data (either measurement or simulated) can be easily matched via the proposed algorithm. The matching network realized by this technique is relatively simple and gives superior gain properties compared to that obtained by other methods. The proposed method is tested with various data sets for different antenna configurations. The results validate the effectiveness and the success of the algorithm.
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Papers by Caner Ozdemir