Journals >Journal of Infrared and Millimeter Waves
Contents
2002
Volume: 21 Issue 2
18 Article(s)
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Research Article
NONDESTRUCTIVE BAND-GAP PROFILE DETERMINATION OF HgCdTe LPE GROWN LAYERS
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Infrared transmission and photoconductivity spectra of mercury cadmium telluride (MCT) epitaxial layers, grown by liquid phase epitaxy (LPE) on CdTe and CdZnTe wide band gap substrates, were investigated both theoretically and experimentally at temperatures T =82 K and T =300 K in the infrared (IR) wavelength region 3 Infrared transmission and photoconductivity spectra of mercury cadmium telluride (MCT) epitaxial layers, grown by liquid phase epitaxy (LPE) on CdTe and CdZnTe wide band gap substrates, were investigated both theoretically and experimentally at temperatures T =82 K and T =300 K in the infrared (IR) wavelength region 3 15 μm. The photoresponse position of the diodes was determined at cryogenic temperatures from the transmission spectra of room temperature. Theoretical calculations of optical density D(h-ω), needed for analysis of experimental optical transmission data, were performed in the framework of WKB approximation..
Journal of Infrared and Millimeter Waves
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 2, 81 (2002)
INFRARED ABSORPTION AT NORMAL INCIDENCE AND RESONANT DISPERSION EFFECT IN THE SiGe/Si MULTIPLE QUANTUM WELL
[in Chinese]
Modulation of mid infrared beam by photo induced intersubband absorption in undoped SiGe?Si quantum wells was investigated at normal incidence. An Ar +laser is used as optcal pumping of interband transitions to photocreate carriers in the wells. The modulated transmission of the sample was measured by a step scan FouriModulation of mid infrared beam by photo induced intersubband absorption in undoped SiGe?Si quantum wells was investigated at normal incidence. An Ar +laser is used as optcal pumping of interband transitions to photocreate carriers in the wells. The modulated transmission of the sample was measured by a step scan Fourier transform spectroscopy. Resonant dispersion associated with intersubband transitions and mutiple reflections effect in the multi quantum wells were clearly evidenced. Theoretical and experimental results show that the phase modulation due to refractive index variations may compensate for amplitude modulation due to absorption..
Journal of Infrared and Millimeter Waves
- Publication Date: Apr. 01, 2002
- Vol. 21, Issue 2, 87 (2002)
Ag DOPING OF p-TYPE HgCdTe GROWN BY LPE
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
SIMS (secondary ion mass spectrum) and variable temperature Hall measurement were employed to study the doping of Ag and the electrical properties of Ag doped HgCdTe films grown by LPE. The results show that the Ag doping in HgCdTe by soaking HgCdTe in AgNO 3 solution is effective and the dopant concentration is equal SIMS (secondary ion mass spectrum) and variable temperature Hall measurement were employed to study the doping of Ag and the electrical properties of Ag doped HgCdTe films grown by LPE. The results show that the Ag doping in HgCdTe by soaking HgCdTe in AgNO 3 solution is effective and the dopant concentration is equal to the Hg vacancy concentration of undoped HgCdTe film. After Ag doping, the acceptor energy of p type HgCdTe has an obvious decrease. It was also found that the electrical properties of Ag doped HgCdTe films can keep stable at room temperature..
Journal of Infrared and Millimeter Waves
- Publication Date: Apr. 01, 2002
- Vol. 21, Issue 2, 91 (2002)
ATTENUATION DUE TO FOG FOR 10.6μm WAVELENGTH*
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Based on gamma fog drop size distribution model and empirical relation of water content and visibility for radiation fog and advection fog, the attenuation due to fog was calculated and analyzed for 10.6μm infrared wavelength. The empirical relations between fog attenuation and water content as well as visibility were Based on gamma fog drop size distribution model and empirical relation of water content and visibility for radiation fog and advection fog, the attenuation due to fog was calculated and analyzed for 10.6μm infrared wavelength. The empirical relations between fog attenuation and water content as well as visibility were derived through regression analysis. The linear relation between fog attenuation and water content for dense radiation fog is in good agreement with available results of experiments and semi empirical formula. Finally, the fog attenuation between 10.6μm and visible wavelength was compared, and the results show that the attenuation at 10.6μm is greater than that at visible wavelength for dense advection fog..
Journal of Infrared and Millimeter Waves
- Publication Date: Apr. 01, 2002
- Vol. 21, Issue 2, 95 (2002)
MEASUREMENT OF TEMPERATURES IN GRINDING OF BRITTLE MATERIALS USING TWO-COLOR INFRARED SYSTEM
[in Chinese], and [in Chinese]
Coupled with an optical fiber,temperature responses at the contact zone during grinding of granite and ceramics with a diamond grinding were measured using a two color infrared detector. It was shown that, compared to a single photocell system, the two color detector is able to measure not only the temperature, but alsCoupled with an optical fiber,temperature responses at the contact zone during grinding of granite and ceramics with a diamond grinding were measured using a two color infrared detector. It was shown that, compared to a single photocell system, the two color detector is able to measure not only the temperature, but also the corresponding apparent emissivity of the workpiece under the grinding conditions. Since the measured temperatures near the surface are somewhat higher than analytical results due to the holes for the optical fiber, the infrared system is suitable for measuring the temperatures at some distance below the workpiece surface. The temperatures on and near the workpiece surface can be calculated from the theoretical thermal model based on the ratio of energy conducted to the workpiece, which can be obtained by a temperature matching technique. The measurement of gridning temperatures is important for understanding the heat transfer at the tool workpiece interface since the energy partition value can be obtained based on the measured temperature..
Journal of Infrared and Millimeter Waves
- Publication Date: Apr. 01, 2002
- Vol. 21, Issue 2, 99 (2002)
REAL-TIME SERIAL ITERATIVE ALGORITHM TO RECONSTRUCT SUPERRESOLUTION IMAGE
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A new real time serial iterative algorithm to reconstruct an image with higher resolution from several low resolution pictures having slight displacement was proposed. By comparing with conventional algorithms, it greatly spares the computation memory for the similar reconstruction quality. Its convergence has been proA new real time serial iterative algorithm to reconstruct an image with higher resolution from several low resolution pictures having slight displacement was proposed. By comparing with conventional algorithms, it greatly spares the computation memory for the similar reconstruction quality. Its convergence has been proved. Computer simulation shows that the results tally with the theoretical analysis. Finally this method was verified in a real system..
Journal of Infrared and Millimeter Waves
- Publication Date: Apr. 01, 2002
- Vol. 21, Issue 2, 104 (2002)
ANALYSIS OF VECTORIAL DIFFRACTION FIELD IN THE FOCAL SPACE OF A SMALL F-NUMBER LENS FOR MILLIMETER WAVE FPA IMAGING SYSTEM
[in Chinese], and [in Chinese]
By assuming that a linearly polarized plane wave was incident obliquely onto a small F number lens, ray tracing and Stratton Chu diffraction formula were used to calculate the vectorial diffracted field in the focal space of the lens. Phase distribution of the field over the exit surface of the lens, which determined tBy assuming that a linearly polarized plane wave was incident obliquely onto a small F number lens, ray tracing and Stratton Chu diffraction formula were used to calculate the vectorial diffracted field in the focal space of the lens. Phase distribution of the field over the exit surface of the lens, which determined the pattern of the diffracted field, was illustrated. The power distributions of the diffracted field in the focal plane of a hyperbolic lens were calculated for different incident angles, which agreed well with the experiments. The vectorial characteristics of the diffracted field were examined. Calculation and experiments were carried out in millimeter wavelength range..
Journal of Infrared and Millimeter Waves
- Publication Date: Apr. 01, 2002
- Vol. 21, Issue 2, 109 (2002)
PARALLEL EMBEDDING AND DETECTION OF MULTIDI-MENSIONAL WATERMARK FOR STILL IMAGE
[in Chinese], [in Chinese], and [in Chinese]
Digital watermarking has become one of the effective solutions to the protection of copyright of multimedia data. Imperceptibility and robustness, which are the basic requirements of digital watermark, conflict with each other. So, looking for a trade off of the pair has become one of the keys in watermarking. A scenarDigital watermarking has become one of the effective solutions to the protection of copyright of multimedia data. Imperceptibility and robustness, which are the basic requirements of digital watermark, conflict with each other. So, looking for a trade off of the pair has become one of the keys in watermarking. A scenario of multidimensional watermark for resolving rightful ownership of digital images was proposed in this paper. The multidimensional watermark, whose vectors are mutually independent, was embedded into image in the DCT domain in parallel by using spread spectrum technology. The robustness of multidimensional watermark was improved without enhancing the watermark energy..
Journal of Infrared and Millimeter Waves
- Publication Date: Apr. 01, 2002
- Vol. 21, Issue 2, 114 (2002)
SUPPORT VECTOR MACHINE FOR 1-D IMAGE RECOGNITION
[in Chinese], [in Chinese], and [in Chinese]
The classification mechanism of support vector machine (SVM) was analyzed in detail. The one dimensional image of radar target was recognized by SVM. The results of the simulation show the advantage of SVM over other methods.The classification mechanism of support vector machine (SVM) was analyzed in detail. The one dimensional image of radar target was recognized by SVM. The results of the simulation show the advantage of SVM over other methods..
Journal of Infrared and Millimeter Waves
- Publication Date: Apr. 01, 2002
- Vol. 21, Issue 2, 119 (2002)
USING SATELLITE DATA TO ANALYZE PROPERTIES OF CLOUD PARTICLES SIZE ON THE TOP OF CLOUD
[in Chinese], and [in Chinese]
Physical properties of cloud particles on the top of cloud were analyzed by NOAA/AVHRR channel 3(3.55～3.93μm) data. Radar and precipitation data were used to validate the analysis results. It was showed that clouds with smaller reflectivity at channel 3 and with bigger size were easy to rain. It was found that there waPhysical properties of cloud particles on the top of cloud were analyzed by NOAA/AVHRR channel 3(3.55～3.93μm) data. Radar and precipitation data were used to validate the analysis results. It was showed that clouds with smaller reflectivity at channel 3 and with bigger size were easy to rain. It was found that there was good corresponding relationship between small reflectivity at channel 3 and radar echo when cloud is a single layer. It was testified that the result of size analyzed from satellite was the same as that from radar data during precipitation..
Journal of Infrared and Millimeter Waves
- Publication Date: Apr. 01, 2002
- Vol. 21, Issue 2, 124 (2002)
DESIGN OF THE TRANSMISSION LINE FOR ECRH SYSTEM IN HT-7 TOKAMAK
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The design of the high power millimeter wave transmission line for Electron Cyclotron Resonance Heating (ECRH) system on the HT 7 Tokamak was given. The waves output from the gyrotron with peak power of 200kW, frequency 60GHz and pulse length around 100ms was transmitted for several tens of meters through this line. InThe design of the high power millimeter wave transmission line for Electron Cyclotron Resonance Heating (ECRH) system on the HT 7 Tokamak was given. The waves output from the gyrotron with peak power of 200kW, frequency 60GHz and pulse length around 100ms was transmitted for several tens of meters through this line. In the transmission process, the wave's mode was converted from initial TE 02 mode to TE 01 and then to the semi linear TE 11 mode by two mode converters. In the end of the transmission line, the wave was coupled to the semi optical antenna and then was launched into plasmas along a special angle..
Journal of Infrared and Millimeter Waves
- Publication Date: Apr. 01, 2002
- Vol. 21, Issue 2, 129 (2002)
SYNTHETIC INFRARED IMAGE OF COMPLICATED TERRAIN BACKGROUNDS
[in Chinese], [in Chinese], and [in Chinese]
A new method was presented for synthesis of infrared images of complicated terrain background and an image segmentation model was established based on the theory of Markov random field. By taking the effects of ambient and meteorological factors into account, the infrared features of different terrain scenes were simulA new method was presented for synthesis of infrared images of complicated terrain background and an image segmentation model was established based on the theory of Markov random field. By taking the effects of ambient and meteorological factors into account, the infrared features of different terrain scenes were simulated and calculated. The segmented visible pictures and the calculated values of the infrared features were synthesized by assigning the different gray scales to the pixels of the corresponding regions of the segmented pictures in order to obtain the infrared images of the complicated terrain scenes..
Journal of Infrared and Millimeter Waves
- Publication Date: Apr. 01, 2002
- Vol. 21, Issue 2, 133 (2002)
5.8GHz BIPHASE MODULATOR MIXER DESIGNED BY UNIPLANAR TECHNOLOGY
[in Chinese], [in Chinese], and [in Chinese]
By considering the high flexibility of uniplanar technology to design complex multifunction subsystems, a design procedure based on a subsystem repartitioned into elementary blocks and very simple electrical modeling was proposed and applied to a uniplanar biphase(0° or 180°)modulator/mixer, which was intendeBy considering the high flexibility of uniplanar technology to design complex multifunction subsystems, a design procedure based on a subsystem repartitioned into elementary blocks and very simple electrical modeling was proposed and applied to a uniplanar biphase(0° or 180°)modulator/mixer, which was intended to be used as a building block in microwave uncontact impact card of Intelligent Transportation System(ITS) at 5.8GHz. Theoretical electromagnetic field calculation methods were combined with conventional transmission line and computer aided design calculations to analyze and design the critical parts of the subsystems. The subsystem designed in this paper has the advantages of small size, compact structure, high performance and low cost..
Journal of Infrared and Millimeter Waves
- Publication Date: Apr. 01, 2002
- Vol. 21, Issue 2, 137 (2002)
SIMULATION AND PROJECT APPLICATION OF Ka-BAND RIDGE WAVEGUIDE TRANSITIONS
[in Chinese], [in Chinese], and [in Chinese]
Ka band rectilinear and curvilinear ridge waveguides were designed and simulated by HFSS based on the analysis of kinds of transitions. The insertion loss is below 0.35dB in the range of 31～38 GHz. The simulated results coincide with that of tests essentially. Rectilinear ridge waveguide is suitable for project applicaKa band rectilinear and curvilinear ridge waveguides were designed and simulated by HFSS based on the analysis of kinds of transitions. The insertion loss is below 0.35dB in the range of 31～38 GHz. The simulated results coincide with that of tests essentially. Rectilinear ridge waveguide is suitable for project application because of its simple structure..
Journal of Infrared and Millimeter Waves
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 2, 142 (2002)
DISCUSSION ON CCD MODULATION TRANSFER FUNCTION OF THE PUSHBROOM SPACE REMOTE SENSOR ALONG TRACK
[in Chinese]
From the point of view of the data quality collected by remote sensors, the selection and determination of the CCD MTF along track are discussed by combining the geometric and radiometric quality of the image with the MTF along track.From the point of view of the data quality collected by remote sensors, the selection and determination of the CCD MTF along track are discussed by combining the geometric and radiometric quality of the image with the MTF along track..
Journal of Infrared and Millimeter Waves
- Publication Date: Apr. 01, 2002
- Vol. 21, Issue 2, 145 (2002)
DEPOLARIZATION DESIGN OF SCANNING SYSTEM
[in Chinese], and [in Chinese]
The linear polarization sensitivity of existing scanning systems is comparatively high and changes with the scanning angle. To overcome the above shortcomings, a new design of scanning system was given. It can reduce the effect of the scanning angle on the linear polarization sensitivity while keeping low linear polariThe linear polarization sensitivity of existing scanning systems is comparatively high and changes with the scanning angle. To overcome the above shortcomings, a new design of scanning system was given. It can reduce the effect of the scanning angle on the linear polarization sensitivity while keeping low linear polarization sensitivity..
Journal of Infrared and Millimeter Waves
- Publication Date: Apr. 01, 2002
- Vol. 21, Issue 2, 148 (2002)
RELATIVISTIC BACKWARD OSCILIATOR WITH VARIABLE COUPLE IMPEDANCE
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The dependence of efficiency of a single step couple impedance jump variation relativistic backward wave oscillator(RBWO) on the relativistic electron beam parameters, couple impedance jump change position and high low couple impedance ratio was analyzed and optimized numerically by means of self consistent RBWO nonlinThe dependence of efficiency of a single step couple impedance jump variation relativistic backward wave oscillator(RBWO) on the relativistic electron beam parameters, couple impedance jump change position and high low couple impedance ratio was analyzed and optimized numerically by means of self consistent RBWO nonlinear theory presented in the paper. The results show that the optimal device efficiency can be up to 50%. A high power X band RBWO with a single step change in the couple impedance was designed and analyzed by using a full electromagnetic particle in cell code to simulate the device output power, efficiency and operating frequency. It was also constructed and investigated experimentally. The efficiency of the device with a single step change in the couple impedance is about twice of the uniform case in the same driving electron beam, beam wave interaction region length and other operating conditions has been achieved in the preliminary experiments..
Journal of Infrared and Millimeter Waves
- Publication Date: Apr. 01, 2002
- Vol. 21, Issue 2, 151 (2002)
ANALYSIS OF WAVEGUIDE DISCONTINUITY BY THE DOMAIN DECOMPOSITION METHOD
[in Chinese], [in Chinese], and [in Chinese]
The Domain Decomposition Method(DDM) in conjunction with FDFD and Modes Expansion was used to analyze the discontinuity of the rectangular recangular waveguide. In the regular part of the rectangular waveguide, the electromagnetic field was analytically developed by the waveguide modes and in the irregular part the equThe Domain Decomposition Method(DDM) in conjunction with FDFD and Modes Expansion was used to analyze the discontinuity of the rectangular recangular waveguide. In the regular part of the rectangular waveguide, the electromagnetic field was analytically developed by the waveguide modes and in the irregular part the equations of the discrete points were built by FDFD method. The Depres transmission condition was used to connect the adjacent subdomains and the whole domain's solution was achieved by the iterative procedure. Several examples of waveguide discontinuity were calculated. The agreement between the results and that from other methods verifies its accuracy..
Journal of Infrared and Millimeter Waves
- Publication Date: Apr. 01, 2002
- Vol. 21, Issue 2, 157 (2002)
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