Pub Date : 2022-04-25DOI: 10.1109/piers55526.2022.9793072
G. Shu, J. Liao, Jingcong He, J. Ren, Junzhe Deng, Wenlong He
Our recent research regarding sheet beam extened interacion oscillators (SB-EIOs) are presented in this paper. In recent years, we have conducted the research of terahertz-band SB-EIOs around two issues: (1) to increase the output power, and (2) to extend the tunable frequency bandwidth. For the first issue, the idea of combining the advantages of a ladder-like interaction circuit (high gain per unit length) and a pseudospark-sourced sheet electron beam (high beam current density and large beam cross-sectional area) is proposed. Such an idea was experimentally verified by using hot-test results. For the second issue, the concept of multiple-mode operation has been proposed to replace the traditional single-mode operation. Such a methodology so far has been initially confirmed by using cold-test results.
{"title":"Study of Terahertz-band Sheet Electron Beam Extended Interaction Oscillators","authors":"G. Shu, J. Liao, Jingcong He, J. Ren, Junzhe Deng, Wenlong He","doi":"10.1109/piers55526.2022.9793072","DOIUrl":"https://doi.org/10.1109/piers55526.2022.9793072","url":null,"abstract":"Our recent research regarding sheet beam extened interacion oscillators (SB-EIOs) are presented in this paper. In recent years, we have conducted the research of terahertz-band SB-EIOs around two issues: (1) to increase the output power, and (2) to extend the tunable frequency bandwidth. For the first issue, the idea of combining the advantages of a ladder-like interaction circuit (high gain per unit length) and a pseudospark-sourced sheet electron beam (high beam current density and large beam cross-sectional area) is proposed. Such an idea was experimentally verified by using hot-test results. For the second issue, the concept of multiple-mode operation has been proposed to replace the traditional single-mode operation. Such a methodology so far has been initially confirmed by using cold-test results.","PeriodicalId":422383,"journal":{"name":"2022 Photonics & Electromagnetics Research Symposium (PIERS)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122836723","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 : 2022-04-25DOI: 10.1109/piers55526.2022.9792765
H. Ma, J. Qiu, Y. Wang
Land use and land cover (LULC) is an important factor affecting runoff and sediment yield of watershed. Dongjiang River is the main source of drink water for Hong Kong and cities in the Pearl River Delta Area, which experienced a rapid urbanization and blooming economy growth. Studying the land use changes using time series remote sensing and their influences on runoff and sediment yield in watershed-scale can provide valuable information for the formulation of land use plans in Dongjiang Watershed. This study constructed a SWAT (Soil and Water Assessment Tool) model of the Dongjiang River basin and analyzed the LULC changes from 2001 to 2012 using MODIS land use data products (MCD12Q1). The influence of LULC changes on the runoff and sediment yield in the Dongjiang basin was analyzed by simulating the runoff and sediment yield under different LULC scenarios. Our results show that the main types of land use in the Dongjiang River basin were evergreen woodland, grassland and agricultural land from 2001 to 2012, accounting for more than 80% of the total area of the basin. During the period of study, the evergreen forest land increased by 14.46%, while grassland, agricultural land and mixed forest decreased by 4.78%, 4.54% and 3.97%, respectively. These changes led to an increase of 0.22 mm in the average monthly runoff in the basin, which reached by 2.39 mm in flood season (April-September). At the same time range, the average monthly sediment yield decreased by 0.79 t/ha with a more significant decreasing by 6.29 t/ha in flood season (From April to September). Our results indicate that long term conversions of grassland, agricultural land and mixed forest to evergreen woodland in watershed will lead to the increasing runoff and decrease of sediments of river, which is important for catchment-scale resource planning and environmental management.
土地利用和土地覆被是影响流域产流产沙的重要因素。东江是香港及珠江三角洲城市的主要饮用水源，而珠江三角洲地区正经历着快速的城市化和蓬勃的经济增长。利用时间序列遥感技术研究东江流域土地利用变化及其对流域产流产沙的影响，可为东江流域土地利用规划的制定提供有价值的信息。利用MODIS土地利用数据产品(MCD12Q1)，构建了东江流域SWAT (Soil and Water Assessment Tool)模型，分析了2001 - 2012年东江流域土地利用价值变化。通过模拟不同情景下的径流产沙量，分析了东江流域径流产沙量变化对径流产沙量的影响。结果表明:2001 - 2012年东江流域土地利用类型以常绿林地、草地和农用地为主，占流域总面积的80%以上;研究期间，常绿林地面积增加14.46%，草地、农用地和混交林面积分别减少4.78%、4.54%和3.97%。这些变化导致流域月平均径流量增加0.22 mm，汛期(4 - 9月)增加2.39 mm。同期，月平均产沙量减少0.79 t/ha，汛期(4 - 9月)减少幅度更大，为6.29 t/ha。研究结果表明，流域内草地、农用地和混交林向常绿林地的长期转变将导致河流径流量的增加和沉积物的减少，这对流域尺度的资源规划和环境管理具有重要意义。
{"title":"Time Series Remote Sensing of Land Use Changes and Influences on Runoff and Sediment Yield in Dongjiang River Basin, China","authors":"H. Ma, J. Qiu, Y. Wang","doi":"10.1109/piers55526.2022.9792765","DOIUrl":"https://doi.org/10.1109/piers55526.2022.9792765","url":null,"abstract":"Land use and land cover (LULC) is an important factor affecting runoff and sediment yield of watershed. Dongjiang River is the main source of drink water for Hong Kong and cities in the Pearl River Delta Area, which experienced a rapid urbanization and blooming economy growth. Studying the land use changes using time series remote sensing and their influences on runoff and sediment yield in watershed-scale can provide valuable information for the formulation of land use plans in Dongjiang Watershed. This study constructed a SWAT (Soil and Water Assessment Tool) model of the Dongjiang River basin and analyzed the LULC changes from 2001 to 2012 using MODIS land use data products (MCD12Q1). The influence of LULC changes on the runoff and sediment yield in the Dongjiang basin was analyzed by simulating the runoff and sediment yield under different LULC scenarios. Our results show that the main types of land use in the Dongjiang River basin were evergreen woodland, grassland and agricultural land from 2001 to 2012, accounting for more than 80% of the total area of the basin. During the period of study, the evergreen forest land increased by 14.46%, while grassland, agricultural land and mixed forest decreased by 4.78%, 4.54% and 3.97%, respectively. These changes led to an increase of 0.22 mm in the average monthly runoff in the basin, which reached by 2.39 mm in flood season (April-September). At the same time range, the average monthly sediment yield decreased by 0.79 t/ha with a more significant decreasing by 6.29 t/ha in flood season (From April to September). Our results indicate that long term conversions of grassland, agricultural land and mixed forest to evergreen woodland in watershed will lead to the increasing runoff and decrease of sediments of river, which is important for catchment-scale resource planning and environmental management.","PeriodicalId":422383,"journal":{"name":"2022 Photonics & Electromagnetics Research Symposium (PIERS)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131477188","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 : 2022-04-25DOI: 10.1109/piers55526.2022.9792959
C. Daveau, Molka Kacem, Soumaya Oueslati, S. Bornhofen, Brice Naisseline
In this paper, we implement the high order boundary condition (HOIBC) in the integral equations to solve the scattering problem. We study the HOIBC operators that appear in the boundary integral equations and we propose a discretization of these operators in spaces H(div) and H(curl). Then, we give validations of the HOIBC by calculating the radar cross section (RCS), that show the improvement in accuracy over the standard impedance boundary condition (SIBC). The computation code implements the H-matrix approach with Adaptive Cross Approximation (ACA) and MPI parallelization.
{"title":"Higher Order Impedance Boundary Condition with Integral Method for the Scattering Problem in Electromagnetism","authors":"C. Daveau, Molka Kacem, Soumaya Oueslati, S. Bornhofen, Brice Naisseline","doi":"10.1109/piers55526.2022.9792959","DOIUrl":"https://doi.org/10.1109/piers55526.2022.9792959","url":null,"abstract":"In this paper, we implement the high order boundary condition (HOIBC) in the integral equations to solve the scattering problem. We study the HOIBC operators that appear in the boundary integral equations and we propose a discretization of these operators in spaces H(div) and H(curl). Then, we give validations of the HOIBC by calculating the radar cross section (RCS), that show the improvement in accuracy over the standard impedance boundary condition (SIBC). The computation code implements the H-matrix approach with Adaptive Cross Approximation (ACA) and MPI parallelization.","PeriodicalId":422383,"journal":{"name":"2022 Photonics & Electromagnetics Research Symposium (PIERS)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132707882","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 : 2022-04-25DOI: 10.1109/piers55526.2022.9792886
D. Inserra, G. Wen
This paper deals with the application of self-accelerating beams for obstacle circumvention in communication applications. Particularly, although recent research works have proposed to take advantage of the self-healing property of self-accelerating beams like the Airy beam to circumvent obstacles and enable data transmission in non-line-of-sight (non-LOS) scenarios, the analysis presented in this paper shows that this is not a viable approach, at least when the transmission aperture dimension is comparable or smaller than that of the obstacle. Ray-optics interpretation, equivalent point source propagation models which take into account the presence of obstacles of different sizes, and full-electromagnetic wave simulation results will be provided to confirm this fact.
{"title":"Demystifying Self-healing Property of Accelerating Beams for Obstacles Circumvention in Communication Applications","authors":"D. Inserra, G. Wen","doi":"10.1109/piers55526.2022.9792886","DOIUrl":"https://doi.org/10.1109/piers55526.2022.9792886","url":null,"abstract":"This paper deals with the application of self-accelerating beams for obstacle circumvention in communication applications. Particularly, although recent research works have proposed to take advantage of the self-healing property of self-accelerating beams like the Airy beam to circumvent obstacles and enable data transmission in non-line-of-sight (non-LOS) scenarios, the analysis presented in this paper shows that this is not a viable approach, at least when the transmission aperture dimension is comparable or smaller than that of the obstacle. Ray-optics interpretation, equivalent point source propagation models which take into account the presence of obstacles of different sizes, and full-electromagnetic wave simulation results will be provided to confirm this fact.","PeriodicalId":422383,"journal":{"name":"2022 Photonics & Electromagnetics Research Symposium (PIERS)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134322291","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 : 2022-04-25DOI: 10.1109/piers55526.2022.9792773
D. Ji, B. NIu, H. Tao, T. S. Chen, W. B. Wang
In this paper, a D band zero bias detector chip using InGaAs Schottky barrier diode (SBD) is proposed. The Schottky barrier diode with 3.5 THz cut-off frequency and 0.16 eV barrier height is realized based on the low barrier Schottky junction formed by contact between InGaAs and Ti. The detector chip is fabricated on a 50 micron InP substrate using the MMIC technology, and the microstrip structure is realized by processing the metal layer on the back of the InP substrate. The RF grounding of the Schottky barrier diode is completed by connecting the metal through hole with the back metal layer. The experimental results show that the voltage sensitivity of the D band detector chip is more than 2100 V/W in the range of D band, and more than 12000 V/W at 122 GHz, when the input RF power is −30 dBm.
{"title":"A D Band Zero Bias Detector Chip Using Schottky Diode","authors":"D. Ji, B. NIu, H. Tao, T. S. Chen, W. B. Wang","doi":"10.1109/piers55526.2022.9792773","DOIUrl":"https://doi.org/10.1109/piers55526.2022.9792773","url":null,"abstract":"In this paper, a D band zero bias detector chip using InGaAs Schottky barrier diode (SBD) is proposed. The Schottky barrier diode with 3.5 THz cut-off frequency and 0.16 eV barrier height is realized based on the low barrier Schottky junction formed by contact between InGaAs and Ti. The detector chip is fabricated on a 50 micron InP substrate using the MMIC technology, and the microstrip structure is realized by processing the metal layer on the back of the InP substrate. The RF grounding of the Schottky barrier diode is completed by connecting the metal through hole with the back metal layer. The experimental results show that the voltage sensitivity of the D band detector chip is more than 2100 V/W in the range of D band, and more than 12000 V/W at 122 GHz, when the input RF power is −30 dBm.","PeriodicalId":422383,"journal":{"name":"2022 Photonics & Electromagnetics Research Symposium (PIERS)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134354545","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 : 2022-04-25DOI: 10.1109/piers55526.2022.9792799
D. P. Egorov, B. Kutuza
Results of atmospheric downwelling radiation brightness temperature spectral measurements in the band of water vapor resonant absorption near 22.235 GHz line are considered. The experiment has been going on for over four years. Ground-based observations have been carrying out by means of special multichannel microwave radiometer-spectrometer with improved fluctuation sensitivity and high temperature stability of gain coefficient. Two meteostations located nearby have been registering near-surface meteorological parameters change in addition to radiometric data. All the data obtained have been properly calibrated and divided by seasons. A part of data have been categorized by cloud species observed by video recordings. Atmospheric moisture content parameters (total water vapor mass and cloud liquid water content) have been retrieved using multi-frequency radiometric method. Kolmogorov’s structural functions for brightness temperatures at different frequencies and structural functions of moisture content parameters have been evaluated for a wide range of temporal intervals. The square root of structural function for a parameter is taken as a native measure of the parameter’s fluctuation intensity in this work.
{"title":"Spatio-temporal Fluctuations in Downwelling K-band Radiation of Atmosphere in the Presence of Clouds","authors":"D. P. Egorov, B. Kutuza","doi":"10.1109/piers55526.2022.9792799","DOIUrl":"https://doi.org/10.1109/piers55526.2022.9792799","url":null,"abstract":"Results of atmospheric downwelling radiation brightness temperature spectral measurements in the band of water vapor resonant absorption near 22.235 GHz line are considered. The experiment has been going on for over four years. Ground-based observations have been carrying out by means of special multichannel microwave radiometer-spectrometer with improved fluctuation sensitivity and high temperature stability of gain coefficient. Two meteostations located nearby have been registering near-surface meteorological parameters change in addition to radiometric data. All the data obtained have been properly calibrated and divided by seasons. A part of data have been categorized by cloud species observed by video recordings. Atmospheric moisture content parameters (total water vapor mass and cloud liquid water content) have been retrieved using multi-frequency radiometric method. Kolmogorov’s structural functions for brightness temperatures at different frequencies and structural functions of moisture content parameters have been evaluated for a wide range of temporal intervals. The square root of structural function for a parameter is taken as a native measure of the parameter’s fluctuation intensity in this work.","PeriodicalId":422383,"journal":{"name":"2022 Photonics & Electromagnetics Research Symposium (PIERS)","volume":"196 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115185076","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 : 2022-04-25DOI: 10.1109/piers55526.2022.9793069
Jieying He, Guo-zhen Yang, Shengwei Zhang, Na Li
The MWHTS onboard FY-3C/D/E satellite has 15 channels at frequencies ranging from 89-191GHz, which allows simultaneous retrieval of the atmospheric temperature and humidity profiles with good temporal and spatial sampling under all weather and all day. On-orbit, without the benefit of known calibration sources at intermediate brightness temperatures (such as were available during T/V testing), it is not possible to directly measure the nonlinearity. But, the nonlinearity correction is a function of the physical temperature of the detectors. So, on-orbit, we will rely on temperature readings from temperature sensors located near the detectors to determine the correction values to apply. Depending on the magnitude of the estimated nonlinearity and its rate of change, a decision can be made regarding how often the correction value needs to be updated. This has potential implications for climate data records.
{"title":"Investigation on Calibration and Validation for FY-3 Series Microwave Humidity Sounders","authors":"Jieying He, Guo-zhen Yang, Shengwei Zhang, Na Li","doi":"10.1109/piers55526.2022.9793069","DOIUrl":"https://doi.org/10.1109/piers55526.2022.9793069","url":null,"abstract":"The MWHTS onboard FY-3C/D/E satellite has 15 channels at frequencies ranging from 89-191GHz, which allows simultaneous retrieval of the atmospheric temperature and humidity profiles with good temporal and spatial sampling under all weather and all day. On-orbit, without the benefit of known calibration sources at intermediate brightness temperatures (such as were available during T/V testing), it is not possible to directly measure the nonlinearity. But, the nonlinearity correction is a function of the physical temperature of the detectors. So, on-orbit, we will rely on temperature readings from temperature sensors located near the detectors to determine the correction values to apply. Depending on the magnitude of the estimated nonlinearity and its rate of change, a decision can be made regarding how often the correction value needs to be updated. This has potential implications for climate data records.","PeriodicalId":422383,"journal":{"name":"2022 Photonics & Electromagnetics Research Symposium (PIERS)","volume":"395 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115213277","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 : 2022-04-25DOI: 10.1109/piers55526.2022.9793306
Yury G. Pasternak, V. Pendyurin, I. Popov, S. Fedorov
In this paper, we propose a design of the multibeam antenna for cellular base stations operating in frequency band 1.7–2.2GHz. The antenna consists of a uniform linear array of 12 slot elements with rectangular directors and modification of Rotman lens used as beamforming network. Rotman lens was folded in half to reduce its dimensions: the ground plane was placed in the center of the lens; the halves of the lens body and exponential strip transformers were placed on both sides of the ground plane. To reduce the sidelobe level in receiving mode, we formed additional virtual antenna elements by array interpolation and extrapolation. Moreover, number of virtual antenna elements can exceed number of “real” antenna elements while its physical size stay the same. This property is especially useful in case of limited installation space. In addition, extrapolated antenna array can be used to increase the directivity of a receiving antenna system and resolve radio sources which are not resolvable by “real” antenna array.
{"title":"Extrapolated Virtual Antenna Array for Enhancement of Resolution of Uniform Linear Array","authors":"Yury G. Pasternak, V. Pendyurin, I. Popov, S. Fedorov","doi":"10.1109/piers55526.2022.9793306","DOIUrl":"https://doi.org/10.1109/piers55526.2022.9793306","url":null,"abstract":"In this paper, we propose a design of the multibeam antenna for cellular base stations operating in frequency band 1.7–2.2GHz. The antenna consists of a uniform linear array of 12 slot elements with rectangular directors and modification of Rotman lens used as beamforming network. Rotman lens was folded in half to reduce its dimensions: the ground plane was placed in the center of the lens; the halves of the lens body and exponential strip transformers were placed on both sides of the ground plane. To reduce the sidelobe level in receiving mode, we formed additional virtual antenna elements by array interpolation and extrapolation. Moreover, number of virtual antenna elements can exceed number of “real” antenna elements while its physical size stay the same. This property is especially useful in case of limited installation space. In addition, extrapolated antenna array can be used to increase the directivity of a receiving antenna system and resolve radio sources which are not resolvable by “real” antenna array.","PeriodicalId":422383,"journal":{"name":"2022 Photonics & Electromagnetics Research Symposium (PIERS)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115568272","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 : 2022-04-25DOI: 10.1109/piers55526.2022.9792955
V. Anand, S. H. Ng, T. Katkus, S. Juodkazis
Holography technologies (HOLOTECH) are attractive than lens-based direct imagers due to the capabilities of HOLOTECH to record and reconstruct complete three-dimensional information of an object or an event with one or a few camera shots. In the past, HOLOTECH was mainly associated with coherent light and as a matter of fact, the development and application of HOLOTECH waited several years until the invention of laser even though the idea of holography was introduced much earlier. As the initial HOLOTECH concepts were based on two-beam interference, the lack of spatial and temporal coherence in incoherent light introduced numerous challenges and demanded stringent optical configuration requirements. For this reason, HOLOTECH was mostly applied with coherent light sources and for the “light in/from space” which is spatially and temporally incoherent, HOLOTECH could not be applied efficiently for three-dimensional imaging. In the recent years, there has been a transformation in the concepts of HOLOTECH which is rapidly reshaping the field of incoherent imaging. The invention of inter-ferenceless coded aperture correlation holography (I-COACH) has rekindled the area of spatially incoherent holography and the two-beam interference is no longer a requirement to record and reconstruct three-dimensional information. I-COACH concept was adapted into satellite telescope applications as partial aperture imaging technique and synthetic aperture imaging method. Both have proven to perform better than lens-based imagers under extreme imaging conditions. In this study, we extend the concept of I-COACH to a land-based telescope. This concept is called as 3D telescope with sparse coded apertures (3D-TELESCA). The 3D-TELESCA concept consists of quasi-random coded apertures with different sizes that are sparsely distributed within the aperture. Every coded aperture consists of two phase functions: quadratic and linear to generate carrier waves to deliver the intensity distribution to the sensor within the sensor area. The linear and quadratic phase depends upon the radius vector of the coded aperture to the center of the sensor. This aperture consists of circular zones capable of rotating about the center independently of one another. The above rotation enables multiple aperture configurations that can generate intensity distributions with cross-correlation significantly lower than autocorrelation which is desirable for statistical averaging. The imaging process consists of four steps: PSF training, PSF engineering, recording and reconstruction in which the first two are one-time offline procedure and the next two are online procedures and so only the final two steps impact the temporal resolution of the system. In the first step, a pinhole is scanned axially, and the corresponding PSF intensity distributions are recorded and saved as a library. The PSF library is engineered using phase-retrieval algorithms and computationally processed to reduce background noise.
{"title":"White Light Correlation Holography Using a Random Lens for Astronomical Imaging Applications","authors":"V. Anand, S. H. Ng, T. Katkus, S. Juodkazis","doi":"10.1109/piers55526.2022.9792955","DOIUrl":"https://doi.org/10.1109/piers55526.2022.9792955","url":null,"abstract":"Holography technologies (HOLOTECH) are attractive than lens-based direct imagers due to the capabilities of HOLOTECH to record and reconstruct complete three-dimensional information of an object or an event with one or a few camera shots. In the past, HOLOTECH was mainly associated with coherent light and as a matter of fact, the development and application of HOLOTECH waited several years until the invention of laser even though the idea of holography was introduced much earlier. As the initial HOLOTECH concepts were based on two-beam interference, the lack of spatial and temporal coherence in incoherent light introduced numerous challenges and demanded stringent optical configuration requirements. For this reason, HOLOTECH was mostly applied with coherent light sources and for the “light in/from space” which is spatially and temporally incoherent, HOLOTECH could not be applied efficiently for three-dimensional imaging. In the recent years, there has been a transformation in the concepts of HOLOTECH which is rapidly reshaping the field of incoherent imaging. The invention of inter-ferenceless coded aperture correlation holography (I-COACH) has rekindled the area of spatially incoherent holography and the two-beam interference is no longer a requirement to record and reconstruct three-dimensional information. I-COACH concept was adapted into satellite telescope applications as partial aperture imaging technique and synthetic aperture imaging method. Both have proven to perform better than lens-based imagers under extreme imaging conditions. In this study, we extend the concept of I-COACH to a land-based telescope. This concept is called as 3D telescope with sparse coded apertures (3D-TELESCA). The 3D-TELESCA concept consists of quasi-random coded apertures with different sizes that are sparsely distributed within the aperture. Every coded aperture consists of two phase functions: quadratic and linear to generate carrier waves to deliver the intensity distribution to the sensor within the sensor area. The linear and quadratic phase depends upon the radius vector of the coded aperture to the center of the sensor. This aperture consists of circular zones capable of rotating about the center independently of one another. The above rotation enables multiple aperture configurations that can generate intensity distributions with cross-correlation significantly lower than autocorrelation which is desirable for statistical averaging. The imaging process consists of four steps: PSF training, PSF engineering, recording and reconstruction in which the first two are one-time offline procedure and the next two are online procedures and so only the final two steps impact the temporal resolution of the system. In the first step, a pinhole is scanned axially, and the corresponding PSF intensity distributions are recorded and saved as a library. The PSF library is engineered using phase-retrieval algorithms and computationally processed to reduce background noise.","PeriodicalId":422383,"journal":{"name":"2022 Photonics & Electromagnetics Research Symposium (PIERS)","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114675302","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 : 2022-04-25DOI: 10.1109/PIERS55526.2022.9793091
Xin He, Yonghui Zhang, Zhenjia Chen, Lihui Wang
The difficulty of spectrum detection and signal source perceivement is growing because of the increase in electromagnetic interference. Due to the complexity of the electromagnetic environment and the diversity of system components, micro or even weak signals sometimes submerge in noise and interference, difficult to detect. Aiming at a problem that the signal is not easy to detect, a signal detection algorithm based on electromagnetic spectrum monitoring combined with adaptive filtering method is proposed. In terms of theoretical verification, simulation analysis using analog simulation platform, and the algorithm performs performance testing. The main research contents of this paper are as follows: LMS algorithm simulation experiments are performed on the sinusoidal cycle signal. In response to the limitations of the fixed step LMS algorithm on convergence speed, the wavelet transform is used to perform frequency band separation, and the wavelet transform method is combined with the LMS algorithm to perform signal detection simulation. The simulation results show that the proposition combined with the wavelet transform and the LMS algorithm can detect useful signals. The convergence speed of the adaptive filtering algorithm is effectively improved compared to the LMS algorithm before the improvement. And the scheme can reduce steady state disorders, while effective elimination of interference on the spectrum, enhanced noise elimination capability.
{"title":"Least Mean Square Adaptive Filter Detection Based on Wavelet Transform in Spectrum Monitoring","authors":"Xin He, Yonghui Zhang, Zhenjia Chen, Lihui Wang","doi":"10.1109/PIERS55526.2022.9793091","DOIUrl":"https://doi.org/10.1109/PIERS55526.2022.9793091","url":null,"abstract":"The difficulty of spectrum detection and signal source perceivement is growing because of the increase in electromagnetic interference. Due to the complexity of the electromagnetic environment and the diversity of system components, micro or even weak signals sometimes submerge in noise and interference, difficult to detect. Aiming at a problem that the signal is not easy to detect, a signal detection algorithm based on electromagnetic spectrum monitoring combined with adaptive filtering method is proposed. In terms of theoretical verification, simulation analysis using analog simulation platform, and the algorithm performs performance testing. The main research contents of this paper are as follows: LMS algorithm simulation experiments are performed on the sinusoidal cycle signal. In response to the limitations of the fixed step LMS algorithm on convergence speed, the wavelet transform is used to perform frequency band separation, and the wavelet transform method is combined with the LMS algorithm to perform signal detection simulation. The simulation results show that the proposition combined with the wavelet transform and the LMS algorithm can detect useful signals. The convergence speed of the adaptive filtering algorithm is effectively improved compared to the LMS algorithm before the improvement. And the scheme can reduce steady state disorders, while effective elimination of interference on the spectrum, enhanced noise elimination capability.","PeriodicalId":422383,"journal":{"name":"2022 Photonics & Electromagnetics Research Symposium (PIERS)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116963305","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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