Pub Date : 2013-06-23DOI: 10.1109/MSMW.2013.6622085
L. Kniazkov, N. Ruzhentsev
Proposed in recent years Foamy-Dielectric Lens Transmission Line (FDLTL) is a waveguide consisted of lenses made of foaming dielectric which has value of refraction index near 1. The lenses of such line are situated very close to each other. Thanks to these the lenses are capable of holding a Gaussian beam within a fairly narrow channel. In this FDLTL has a small amount of running losses due to low values of the coefficient of reflection from the surface of the lens and due small absorption coefficient of the lenses material. In view of these, the total losses of FDLTL are smaller of 0.7 dB/m.
{"title":"Characteristics of the radiation from the end of the Transmission Line on the basis of spherical lenses made of foam dielectric","authors":"L. Kniazkov, N. Ruzhentsev","doi":"10.1109/MSMW.2013.6622085","DOIUrl":"https://doi.org/10.1109/MSMW.2013.6622085","url":null,"abstract":"Proposed in recent years Foamy-Dielectric Lens Transmission Line (FDLTL) is a waveguide consisted of lenses made of foaming dielectric which has value of refraction index near 1. The lenses of such line are situated very close to each other. Thanks to these the lenses are capable of holding a Gaussian beam within a fairly narrow channel. In this FDLTL has a small amount of running losses due to low values of the coefficient of reflection from the surface of the lens and due small absorption coefficient of the lenses material. In view of these, the total losses of FDLTL are smaller of 0.7 dB/m.","PeriodicalId":104362,"journal":{"name":"2013 International Kharkov Symposium on Physics and Engineering of Microwaves, Millimeter and Submillimeter Waves","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125117817","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-06-23DOI: 10.1109/MSMW.2013.6622093
L. Yatsuk, I. Kichigin, A. Lyakhovsky, Yury Penkin
Narrow slots in waveguide walls are widely used in super high frequency technique as coupling elements or antenna radiators. Their physical properties are well studied theoretically and experimentally and described in scientific literature. But the techniques development requires broadening of slot performing possibilities, for example control of its resonance frequency. For this purpose the slot can be completely or partially filled with dielectric. The way of scattering problem solving for fully filled slot does not differ from one in the case of empty slot. When the slot is partly filled with dielectric some difficulties of their study appear. This problem was solved in [1] for such slot coupling two half-infinite rectangular waveguides over their common end wall. In [2] the similar problem was solved when the transverse slot with dielectric slab couples two infinite rectangular waveguides over their common broad wall. Of great interest are the scattering and directional properties of above mentioned slot radiating into free half-space. The following report deals with this question.
{"title":"Narrow waveguide-slot radiator filled with layered dielectric","authors":"L. Yatsuk, I. Kichigin, A. Lyakhovsky, Yury Penkin","doi":"10.1109/MSMW.2013.6622093","DOIUrl":"https://doi.org/10.1109/MSMW.2013.6622093","url":null,"abstract":"Narrow slots in waveguide walls are widely used in super high frequency technique as coupling elements or antenna radiators. Their physical properties are well studied theoretically and experimentally and described in scientific literature. But the techniques development requires broadening of slot performing possibilities, for example control of its resonance frequency. For this purpose the slot can be completely or partially filled with dielectric. The way of scattering problem solving for fully filled slot does not differ from one in the case of empty slot. When the slot is partly filled with dielectric some difficulties of their study appear. This problem was solved in [1] for such slot coupling two half-infinite rectangular waveguides over their common end wall. In [2] the similar problem was solved when the transverse slot with dielectric slab couples two infinite rectangular waveguides over their common broad wall. Of great interest are the scattering and directional properties of above mentioned slot radiating into free half-space. The following report deals with this question.","PeriodicalId":104362,"journal":{"name":"2013 International Kharkov Symposium on Physics and Engineering of Microwaves, Millimeter and Submillimeter Waves","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132365718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-06-23DOI: 10.1109/MSMW.2013.6622158
Z. Dombrovskaya
Optical properties of photonic crystals (PhCs) can be controlled by changing physical parameters of materials and geometry of structure elements. At the present time a special attention is put to study tunable PhCs. Practically, their possible applications are based on reconstruction in temperature, magnetic or light fields. On the other hand, the simplest way for making changes in spectral characteristics (coefficients of transmission and reflection) is putting local inhomogeneities in structure. Due to fractal objects' unique property of self-similarity, a particular interest is represented by PhCs with fractal defects. Within the present paper, temperature tunable two-dimensional PhC with fractal defects of two main types, notably Cantor-based and Peano curve-based are considered.
{"title":"Research of spectral characteristics for photonic crystals with fractal defects","authors":"Z. Dombrovskaya","doi":"10.1109/MSMW.2013.6622158","DOIUrl":"https://doi.org/10.1109/MSMW.2013.6622158","url":null,"abstract":"Optical properties of photonic crystals (PhCs) can be controlled by changing physical parameters of materials and geometry of structure elements. At the present time a special attention is put to study tunable PhCs. Practically, their possible applications are based on reconstruction in temperature, magnetic or light fields. On the other hand, the simplest way for making changes in spectral characteristics (coefficients of transmission and reflection) is putting local inhomogeneities in structure. Due to fractal objects' unique property of self-similarity, a particular interest is represented by PhCs with fractal defects. Within the present paper, temperature tunable two-dimensional PhC with fractal defects of two main types, notably Cantor-based and Peano curve-based are considered.","PeriodicalId":104362,"journal":{"name":"2013 International Kharkov Symposium on Physics and Engineering of Microwaves, Millimeter and Submillimeter Waves","volume":"78 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113989230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-06-23DOI: 10.1109/MSMW.2013.6622119
Y. Kovtun, A. I. Skibenko, E. Skibenko, V. Yuferov
The investigation of the rotating plasma is of interest for solving a wide range of scientific and applied problems in the plasma physics. To investigate the multicomponent gas-metal plasma the most preferable are the methods of measurement without contact: optical and microwave correlation and Doppler reflectometry [1]. In the plasma investigations the microwave correlation reflectometry (MCR) has been used rather frequently, however, in the most of cases the errors of plasma rotation velocity measurements were not analyzed. The estimation of the accuracy of the plasma rotation velocity by MCR is an intricate problem which should be solved individually in every particular case with taking into account the measuring circuit, plasma characteristic and structural specificity of the experimental facility. In the present paper we consider some typical measurement errors of the rotation velocity by the MCR method and estimate the measurement errors of the monocomponent plasma rotation velocity upon the pulsed reflex discharge.
{"title":"Analysis of errors in the plasma rotation velocity measurement by the method of microwave correlation reflectometry","authors":"Y. Kovtun, A. I. Skibenko, E. Skibenko, V. Yuferov","doi":"10.1109/MSMW.2013.6622119","DOIUrl":"https://doi.org/10.1109/MSMW.2013.6622119","url":null,"abstract":"The investigation of the rotating plasma is of interest for solving a wide range of scientific and applied problems in the plasma physics. To investigate the multicomponent gas-metal plasma the most preferable are the methods of measurement without contact: optical and microwave correlation and Doppler reflectometry [1]. In the plasma investigations the microwave correlation reflectometry (MCR) has been used rather frequently, however, in the most of cases the errors of plasma rotation velocity measurements were not analyzed. The estimation of the accuracy of the plasma rotation velocity by MCR is an intricate problem which should be solved individually in every particular case with taking into account the measuring circuit, plasma characteristic and structural specificity of the experimental facility. In the present paper we consider some typical measurement errors of the rotation velocity by the MCR method and estimate the measurement errors of the monocomponent plasma rotation velocity upon the pulsed reflex discharge.","PeriodicalId":104362,"journal":{"name":"2013 International Kharkov Symposium on Physics and Engineering of Microwaves, Millimeter and Submillimeter Waves","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131579045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-06-23DOI: 10.1109/MSMW.2013.6622163
J. Niemeyer, O. Kieler, F. Muller, J. Kohlmann, R. Behr, L. Palafox, D. Schleussner, M. F. Beug, J. Schurr
The report describes the most recent PTB developments and applications of large Josephson arrays for the generation of very precise sine waves and arbitrary waveforms. By means of large70 GHz sine-wave-driven binary arrays, AC voltages with frequencies up to 1 kHz and amplitudes of more than 10 V were generated with an uncertainty of better than 1μV/V. For the fabrication of this array type with up to 70000 junctions in series connection, an SNS junction technology with NbxSix-1 barriers is now completely installed and permanently in use. With pulse-driven arrays of Josephson junctions, arbitrary waveforms were generated with a level of higher harmonics smaller than -120 dBc for frequencies from 150 Hz to 100 kHz at rms voltages less than 100 mV. These results were achieved with extended arrays of up to 4795 very small SNS junctions with Hf0.5Ti0.5 barriers. Also the NbSi-technology technology has successfully been applied for the fabrication of pulse-driven Josephson arrays. As it seems to be difficult to considerably increase the wave amplitude by enhancing the junction number of the arrays, experiments were performed to combine a binary array system with a pulse-driven system with the goal to make use of the high amplitude of stepwise generated waves without losing the low noise and precision of quantum based rf waveforms generated by pulse trains at a clock frequency of 15 GHz.
{"title":"PTB's status of AC voltage metrolgy by microwave- and pulsetrain-driven josephson junction arrays","authors":"J. Niemeyer, O. Kieler, F. Muller, J. Kohlmann, R. Behr, L. Palafox, D. Schleussner, M. F. Beug, J. Schurr","doi":"10.1109/MSMW.2013.6622163","DOIUrl":"https://doi.org/10.1109/MSMW.2013.6622163","url":null,"abstract":"The report describes the most recent PTB developments and applications of large Josephson arrays for the generation of very precise sine waves and arbitrary waveforms. By means of large70 GHz sine-wave-driven binary arrays, AC voltages with frequencies up to 1 kHz and amplitudes of more than 10 V were generated with an uncertainty of better than 1μV/V. For the fabrication of this array type with up to 70000 junctions in series connection, an SNS junction technology with NbxSix-1 barriers is now completely installed and permanently in use. With pulse-driven arrays of Josephson junctions, arbitrary waveforms were generated with a level of higher harmonics smaller than -120 dBc for frequencies from 150 Hz to 100 kHz at rms voltages less than 100 mV. These results were achieved with extended arrays of up to 4795 very small SNS junctions with Hf0.5Ti0.5 barriers. Also the NbSi-technology technology has successfully been applied for the fabrication of pulse-driven Josephson arrays. As it seems to be difficult to considerably increase the wave amplitude by enhancing the junction number of the arrays, experiments were performed to combine a binary array system with a pulse-driven system with the goal to make use of the high amplitude of stepwise generated waves without losing the low noise and precision of quantum based rf waveforms generated by pulse trains at a clock frequency of 15 GHz.","PeriodicalId":104362,"journal":{"name":"2013 International Kharkov Symposium on Physics and Engineering of Microwaves, Millimeter and Submillimeter Waves","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132670628","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-06-23DOI: 10.1109/MSMW.2013.6622099
O. Drobakhin, G. Sherstyuk
Through-the-wall radars development is very actual problem. For instance, the equipment of such sort can be used for testing the state of valve situated behind a wall. Using wideband microwave signals of millimeter range allow us to detect objects positioned behind barrier non-transparent in optical range and to obtain their radio images. This equipment operates in the frequency band of 38 - 52 GHz. The pyramidal horn as radiating and receiving antenna is used. The main idea of corresponding approach is the combination of the synthesis of time-domain (spatial) signal from frequency data for obtaining longitudinal information along y-axis and scanning for obtaining transversal one along x-axis. Thus, 3-D radio image with data about insert reflection along z-axis can be formed. The advantage of this approach in contrast to single-frequency signals is possibility of separation of reflection from the object under consideration and the wall. As result, the image of the object similar to the one for the object in free space can be obtained. The purpose of the paper is to investigate possibility to recognize groups of objects situated behind dielectric barrier at the various distances. The objects under recognition have been metal parallelepipeds and cylinders with variation of sizes. The bases of the parallelepipeds were 25, 45 and 55 mm. The diameters of the cylinders were 25, 45 and 75 mm. The height of objects was 110 mm. Object recognition has been implemented using neural networks and correlation techniques. As the result of the study, it has been found the best settings for the recognition of objects of different geometric shapes.
{"title":"Recognition multifrequency microwave images of simple objects behind dielectric wall using neural networks","authors":"O. Drobakhin, G. Sherstyuk","doi":"10.1109/MSMW.2013.6622099","DOIUrl":"https://doi.org/10.1109/MSMW.2013.6622099","url":null,"abstract":"Through-the-wall radars development is very actual problem. For instance, the equipment of such sort can be used for testing the state of valve situated behind a wall. Using wideband microwave signals of millimeter range allow us to detect objects positioned behind barrier non-transparent in optical range and to obtain their radio images. This equipment operates in the frequency band of 38 - 52 GHz. The pyramidal horn as radiating and receiving antenna is used. The main idea of corresponding approach is the combination of the synthesis of time-domain (spatial) signal from frequency data for obtaining longitudinal information along y-axis and scanning for obtaining transversal one along x-axis. Thus, 3-D radio image with data about insert reflection along z-axis can be formed. The advantage of this approach in contrast to single-frequency signals is possibility of separation of reflection from the object under consideration and the wall. As result, the image of the object similar to the one for the object in free space can be obtained. The purpose of the paper is to investigate possibility to recognize groups of objects situated behind dielectric barrier at the various distances. The objects under recognition have been metal parallelepipeds and cylinders with variation of sizes. The bases of the parallelepipeds were 25, 45 and 55 mm. The diameters of the cylinders were 25, 45 and 75 mm. The height of objects was 110 mm. Object recognition has been implemented using neural networks and correlation techniques. As the result of the study, it has been found the best settings for the recognition of objects of different geometric shapes.","PeriodicalId":104362,"journal":{"name":"2013 International Kharkov Symposium on Physics and Engineering of Microwaves, Millimeter and Submillimeter Waves","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133425945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-06-23DOI: 10.1109/MSMW.2013.6622015
L. Angermann, V. Yatsyk
Nonlinear dielectrics with controllable permittivity begin to find broad applications in device technology and are subject of intense studies in the range of both radio and the optical frequencies. We focus on the development of a mathematical model, an effective algorithm and a self-consistent numerical analysis of the multifunctional properties of resonant scattering and generation of oscillations by nonlinear, cubically polarisable structures.
{"title":"Nonlinear layers with controllable permittivity at frequencies of scattering and generation","authors":"L. Angermann, V. Yatsyk","doi":"10.1109/MSMW.2013.6622015","DOIUrl":"https://doi.org/10.1109/MSMW.2013.6622015","url":null,"abstract":"Nonlinear dielectrics with controllable permittivity begin to find broad applications in device technology and are subject of intense studies in the range of both radio and the optical frequencies. We focus on the development of a mathematical model, an effective algorithm and a self-consistent numerical analysis of the multifunctional properties of resonant scattering and generation of oscillations by nonlinear, cubically polarisable structures.","PeriodicalId":104362,"journal":{"name":"2013 International Kharkov Symposium on Physics and Engineering of Microwaves, Millimeter and Submillimeter Waves","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133602187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-06-23DOI: 10.1109/MSMW.2013.6622173
A. Solovjov, V. Svetlov, V. B. Stepanov, S. L. Sidorov, V. Tarenkov, A. D’yachenko
The interplay between superconductivity and magnetism has been a long-standing fascinating problem [1], and relation between the spin-density wave (SDW) and superconducting (SC) order is a central topic in the current research on the FeAs-based high-Tc superconductors. However, the clear nature of the complex interplay between magnetism and superconductivity in FeAs-based HTS's is still rather controversial [2].
{"title":"Pseudogap in SmFeAsO0.85 in comparison with s-wave symmetry theory","authors":"A. Solovjov, V. Svetlov, V. B. Stepanov, S. L. Sidorov, V. Tarenkov, A. D’yachenko","doi":"10.1109/MSMW.2013.6622173","DOIUrl":"https://doi.org/10.1109/MSMW.2013.6622173","url":null,"abstract":"The interplay between superconductivity and magnetism has been a long-standing fascinating problem [1], and relation between the spin-density wave (SDW) and superconducting (SC) order is a central topic in the current research on the FeAs-based high-Tc superconductors. However, the clear nature of the complex interplay between magnetism and superconductivity in FeAs-based HTS's is still rather controversial [2].","PeriodicalId":104362,"journal":{"name":"2013 International Kharkov Symposium on Physics and Engineering of Microwaves, Millimeter and Submillimeter Waves","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131926299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-06-23DOI: 10.1109/MSMW.2013.6622077
M. Tani, T. Kinoshita, T. Nagase, S. Ozawa, S. Tsuzuki, D. Takeshima, E. Estacio, K. Kurihara, K. Yamamoto, M. Bakunov
Cherenkov radiation mechanism is an established technique to achieve phase matching between ultrashort optical pulses and terahertz (THz) waves having a large collinear velocity mismatch, in a nonlinear optical material such as LiNbO3 (LN). Phase matching is achieved with the optical and THz pulses propagating at angle with respect to each other. Recently, we have experimentally demonstrated that Cherenkov phase matching mechanism can also be used for efficient electro-optics (EO) sampling of broadband THz pulses [1]. In the detection case, the phase matching is achieved between an optical and THz pulse propagating non-collinearly at the Cherenkov phase-matching angle θC, satisfying the following equation: equation Here, ngLN is the group index of the EO crystal at the sampling optical wavelength and nTHzLN is the refractive index of the EO crystal in the THz frequency region. An advantage of the non-collinear Cherenkov phase matching is that we can find a corresponding Cherenkov phase matching angle, θC, for any electro-optic crystal at a given optical sampling wavelength. When the EO crystal has a much larger refractive index in THz frequency region compared to that in optical region, a coupling prism is used as illustrated in Fig. 1. Moreover, using a low-loss coupling prism can also reduce absorption in the EO crystal. Silicon is an ideal coupling prism material owing to low absorption losses and is non-dispersive in the THz frequency region. From Snell's law, the incident angle α of THz wave with respect to the prism- EO crystal interface is given as follows: equation Equation (2) leads to the relation, sin β = cosθC. Therefore, Eq. (1) reduces to the following equation for the apex angle of the coupling prism (α) at the Cherenkov phase-matching condition given by the ratio of the group index of the EO crystal at the sampling optical wavelength ngLN, and the refractive index of Si, nTHzSi, in the THz frequency region: equation.
{"title":"Techniques of non-collinear electro-optic sampling for efficient detection of pulsed terahertz radiation","authors":"M. Tani, T. Kinoshita, T. Nagase, S. Ozawa, S. Tsuzuki, D. Takeshima, E. Estacio, K. Kurihara, K. Yamamoto, M. Bakunov","doi":"10.1109/MSMW.2013.6622077","DOIUrl":"https://doi.org/10.1109/MSMW.2013.6622077","url":null,"abstract":"Cherenkov radiation mechanism is an established technique to achieve phase matching between ultrashort optical pulses and terahertz (THz) waves having a large collinear velocity mismatch, in a nonlinear optical material such as LiNbO3 (LN). Phase matching is achieved with the optical and THz pulses propagating at angle with respect to each other. Recently, we have experimentally demonstrated that Cherenkov phase matching mechanism can also be used for efficient electro-optics (EO) sampling of broadband THz pulses [1]. In the detection case, the phase matching is achieved between an optical and THz pulse propagating non-collinearly at the Cherenkov phase-matching angle θC, satisfying the following equation: equation Here, ngLN is the group index of the EO crystal at the sampling optical wavelength and nTHzLN is the refractive index of the EO crystal in the THz frequency region. An advantage of the non-collinear Cherenkov phase matching is that we can find a corresponding Cherenkov phase matching angle, θC, for any electro-optic crystal at a given optical sampling wavelength. When the EO crystal has a much larger refractive index in THz frequency region compared to that in optical region, a coupling prism is used as illustrated in Fig. 1. Moreover, using a low-loss coupling prism can also reduce absorption in the EO crystal. Silicon is an ideal coupling prism material owing to low absorption losses and is non-dispersive in the THz frequency region. From Snell's law, the incident angle α of THz wave with respect to the prism- EO crystal interface is given as follows: equation Equation (2) leads to the relation, sin β = cosθC. Therefore, Eq. (1) reduces to the following equation for the apex angle of the coupling prism (α) at the Cherenkov phase-matching condition given by the ratio of the group index of the EO crystal at the sampling optical wavelength ngLN, and the refractive index of Si, nTHzSi, in the THz frequency region: equation.","PeriodicalId":104362,"journal":{"name":"2013 International Kharkov Symposium on Physics and Engineering of Microwaves, Millimeter and Submillimeter Waves","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124499084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-06-23DOI: 10.1109/MSMW.2013.6622149
O. Lebedeva, E. Martinez Vera, V. Golikov, M. Rodríguez Blanco
This work presents a novel generalized likelihood ratio (GLR) methodology to design a detection algorithm for a sequence of images in the presence of Gaussian structured background and noise. We focus on the detection of a subpixel target both with small target's energy and without it (dark target). It is assumed that the background power is known a priori under the null hypothesis and is unknown under the alternative hypothesis. This situation is typical in the case of subpixel detection. We derive the GLR test (GLRT) for this problem. The designed detector is theoretically justified and numerically evaluated. The structure of the designed detector consists of two detectors. The first detector is the known matched subspace detector and the second is the background's power change detector. The second detector help to detect the black subpixel targets (without reflected energy). Both the theoretical and computer simulation results have shown that the proposed detector outperforms the conventional one.
{"title":"Video-based detection of subpixel no-reflecting objects in the presence of fluctuated background","authors":"O. Lebedeva, E. Martinez Vera, V. Golikov, M. Rodríguez Blanco","doi":"10.1109/MSMW.2013.6622149","DOIUrl":"https://doi.org/10.1109/MSMW.2013.6622149","url":null,"abstract":"This work presents a novel generalized likelihood ratio (GLR) methodology to design a detection algorithm for a sequence of images in the presence of Gaussian structured background and noise. We focus on the detection of a subpixel target both with small target's energy and without it (dark target). It is assumed that the background power is known a priori under the null hypothesis and is unknown under the alternative hypothesis. This situation is typical in the case of subpixel detection. We derive the GLR test (GLRT) for this problem. The designed detector is theoretically justified and numerically evaluated. The structure of the designed detector consists of two detectors. The first detector is the known matched subspace detector and the second is the background's power change detector. The second detector help to detect the black subpixel targets (without reflected energy). Both the theoretical and computer simulation results have shown that the proposed detector outperforms the conventional one.","PeriodicalId":104362,"journal":{"name":"2013 International Kharkov Symposium on Physics and Engineering of Microwaves, Millimeter and Submillimeter Waves","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123698658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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