Abstract:

A terahertz(THz) all-metal metasurface with a high Q-factor has been proposed, consisting of four diamond-shaped holes. By altering the size of adjacent diamond-shaped holes, the symmetry of the structure can be broken, resulting in quasi-Bound states In the Continuum(BICs). By changing the polarization angle of the incident wave, the frequency of the excited quasi-BICs remains unchanged, exhibiting polarization-independent characteristics. Simulation results show that, by optimizing structural parameters, when the size deviation is 3 μm, the quasi-BICs achieved an ultra-narrow bandwidth of less than 1 GHz, corresponding to a Q-factor greater than 1 300. Experimental test results show that the fabricated sample(with a deviation of 30 μm) had a measured Q-factor of 40. Compared to circular hole structures, the diamond-shaped hole structure can achieve stronger bound fields due to its sharp corners. The proposed metasurface with polarization-independent quasi-BICs has enormous practical application potential in real-time chemical and biomolecular sensing.

Abstract:

A wideband terahertz metamaterial absorber is proposed based on the phase transition properties of VO₂, which consists of two VO₂ pattern layers, two polyimide dielectric layers and a metal reflector layer. The absorption characteristics, electric field distribution and tunability of the absorber are simulated and analyzed, and the results show that the bandwidth of the designed absorber with an absorption rate of more than 90% is 2.56 THz. The absorber stacks two layers of periodic cells with the same structure but different sizes, effectively extending the bandwidth. Moreover, by controlling the phase transition of VO₂ from the insulating state to the metallic state, the absorptivity can be continuously adjusted. In addition, by studying the absorption performance of the designed metamaterial absorber under different polarization angles and incident angles, it is found that the absorber is polarization independent and absorption insensitive at large incident angles. The designed absorber is expected to be widely used in areas of terahertz communication, imaging and detector.

Abstract:

In view of the high requirements of electronic countermeasures signal analysis, the large amount of intelligence processing data, and the difficulty of multi-dimensional information analysis and extraction in complex electromagnetic environment, the big data processing method of cross-industry data mining standard process, namely Cross-Industry Standard Process for Data Mining(CRISP-DM), is studied, and an processing and analysis platform for historical data of offline electronic countermeasures electromagnetic signal is designed based on the characteristics of the massive historical reconnaissance data of the electronic countermeasures intelligence system and the existing electromagnetic target knowledge base. By exploring the technical path of mining electromagnetic target parameters, time rules of the target, multi-target association rules and other intelligence analysis, the application of analysis methods such as clustering, the mining of time series and association rules in the processing of electronic countermeasure electromagnetic signal historical data is realized. The information features of unknown electronic target such as clustering, target quantity and scale prediction, multi-target association and co-occurrence rule are analyzed and obtained. The results show that the characteristics and correlation laws of electromagnetic target parameters are obvious, and the fitting correlation degree of target time characteristics reaches 0.825. This work lays a foundation for further research and practical application.

Abstract:

To address the recognition challenge of Multi-h Continuous Phase Modulation (Multi-h CPM) signals with varying modulation parameters, this paper proposes a modulation recognition algorithm grounded in fuzzy entropy theory. This theory transcends the binary approach of distance and count-based similarity in approximate entropy, opting for a membership function to assess similarity and more accurately reflect the complexity of time series. The algorithm separates and calculates the fuzzy entropy of the in-phase and quadrature components of the received signal, utilizing these values as classification features for a Support Vector Machine(SVM). Experiments demonstrate that the algorithm achieves 100% recognition accuracy for full-response rectangular shaped Multi-h CPM signals across various modulation index sets at signal-to-noise ratios above 6 dB, and enables modulation recognition with a minimal number of symbols.

Abstract:

Addressing the issues of low precision in short baseline time-difference direction finding, ambiguity in long baseline phase-difference direction finding, and the difficulty of traditional microwave technologies to meet the long-distance transmission requirements for distributed deployment of electronic warfare equipment, a distributed long-distance single-baseline high-precision direction finding technology based on microwave photonics combining time-difference and phase-difference is proposed. This technology employs direct modulation mode microwave photonic transmission equipment, overcoming the impact of time-difference and phase-difference variations caused by long-distance transmission of microwave signals, ensuring stable transmission of microwave photonics over long distances. Furthermore, an improved time-difference surface fitting interpolation method is adopted to resolve the phase-difference ambiguity issue. Simulations and experimental tests have verified the feasibility of this technology for implementing high-precision distributed long-distance single-baseline direction finding.

Abstract:

In the uplink grant-free access scenario of the satellite Internet of Things(IoT), users directly send data to the satellite without the need for dynamic resource allocation, which makes it difficult for the receiving end to distinguish active users in advance. To recover the transmitted data, Active User Detection(AUD) is required. Currently, code domain methods are commonly used for active user identification, but the density of IoT devices far exceeds that of mobile communication users. Relying solely on code domain identification can lead to a dramatic increase in the dimension of address codes, reducing frame efficiency. Moreover, many collection and monitoring IoT terminals have weak capabilities and cannot report their own positions, resulting in the loss of this dimension of access auxiliary information, which is not conducive to improving the performance of active user detection. Aiming at the future development trend of satellite-borne phased array, this paper introduces the concept of spatial domain identification. By cascading identification in the spatial and code domains, a multi-domain joint method is used for active user detection. Simulation results show that the proposed method can enhance the identification capability when there is an address code conflict.

Abstract:

In response to the issues with existing 3D point cloud object recognition algorithms based on deep learning methods, such as the lack of feature interaction between points in multi-layer perceptrons, reliance on Euclidean distance between point clouds, and failure to consider the correlation at the feature channel level, we propose an attention mechanism-based 3D point cloud(PAttenCls) object recognition algorithm. The spatial attention mechanism based on points is employed to explore the attention values between points, achieving adaptive neighborhood selection for point clouds; meanwhile, the channel attention mechanism based on points adaptively assigns weights to feature channels, enabling feature enhancement. Additionally, a geometric uniformization module is added to the network to address the different feature patterns of different local regions' geometric structures. The proposed algorithm achieves a recognition accuracy of 93.2% on the ModelNet40 dataset and an accuracy of 80.9% on the most difficult subset of the ScanObjectNN dataset, and its effectiveness is verified on real-world data. Experiments have proven that the proposed algorithm can better extract feature information from point clouds, making the point cloud recognition results more accurate.

Abstract:

In response to the development needs of miniaturization and integration of satellite payload technology, as well as the bottleneck issues of high power and low passive intermodulation in space applications, this paper proposes a design method for a TE₁₀₁ mode waveguide filter that is easy to 3D print, based on the characteristics of integrated forming technology of 3D printing and filter synthesis theory. A waveguide filter in the Ka band was designed and processed using 3D printing technology, with the entire filter structure formed in one piece. The measured and simulated results are in good agreement; the weight is 70% of that of the traditional screw fastening scheme of the same size; the filter's return loss is better than 22 dB, the in-band insertion loss is better than 0.3 dB, and the equivalent Q value before plating is about 1 100. Simulation results show that this filter has characteristics such as single-mode operation bandwidth and large power capacity; at the same time, the filter structure is suitable for integrated forming by 3D printing, eliminating the need for assembly and adjustment, and avoiding the nonlinear contact caused by the connection between the traditional filter cavity and the cover plate. The measured passive intermodulation level of the filter is lower than -130 dBm, which verifies the accuracy and feasibility of 3D printing technology for filter processing. It is of great significance for the integrated design and engineering application of 3D printed broadband filters.

Abstract:

The interlayer vertical transition structure is usually utilized to realize the miniaturization and high-density design of module structure, and plays an indispensable role in millimeter wave circuit wiring. In this paper, a vertical transition structure from microstrip to stripline is studied, which can be used in Q-band. A "water droplet" matching structure is adopted at the end of microstrip line, and the vertical transmission of Radio Frequency(RF) signals is carried out in the form of metal through holes connecting transmission lines. The three-dimensional High-Frequency electromagnetic Simulation Software(HFSS) is employed to establish the structure and compare the performance with that of other similar structures. The optimization results show that the reflection coefficient of this structure is less than -20 dB and the in-band insertion loss is better than 0.3 dB in 42~47 GHz, which can meet the requirements of engineering application. Compared with other vertical transition structures of the same type, it reduces the occupied area and maintains good transmission performance.

Abstract:

In response to the increasingly prominent issues of electromagnetic spectrum usage safety for communication and radar equipment, as well as the difficulty in quantifying the risk assessment of electromagnetic spectrum parameter leakage, this paper employs numerical and analytical methods to model the electromagnetic characteristic parameters of emission features, reception sensitivity, and antenna radiation characteristics for both friendly and adversary frequency-dependent equipments. By integrating the complete communication link structure of electromagnetic spectrum parameter leakage, the analysis is conducted from the perspectives of equipment effectiveness and the impact on the radio wave environment. Utilizing the concept of grid division, a method for calculating the probability of electromagnetic spectrum parameter leakage is proposed, and the calculation method is verified through simulation. The leakage probabilities for a ground-based fixed radar L1 and a 1 000-hop transmission station M1 within the ranges of 300~450 km and 350~450 km, respectively, are calculated. This achieves a quantified assessment of the risk of electromagnetic spectrum parameter leakage, solving the problem of difficult risk quantification in electromagnetic spectrum parameter leakage assessment.

Abstract:

A four-channel X-band chip transceiver System in a Package(SiP) module was realized by integrating multiple Monolithic Microwave Integrated Circuits(MMICs) and passive power division network into a very compact volume using silicon-based 3D heterogeneous integration technology. The module is Package on Package(PoP) stacked by two silicon-based packages, and the different packages are interconnected through the Ball Grid Array(BGA) mode. Chips are installed on the upper and lower surfaces of the inner cavity of a single package. The internal package is vertically interconnected using Through Silicon Via(TSV) and the module dimensions are 14 mm×14 mm×3.2 mm. The test results show that within 8~12 GHz, the transmission saturation output power of the module is ≥30.5 dBm, the receiving gain is ≥24.5 dB, the noise figure is ≤3 dB, the receiving input P_-1 is ≥-26 dBm, and it also features 6-bit digital phase shifting and 6-bit digital attenuation capabilities, weighs approximately 1 g. It can be widely used in microwave transceiver system.

Abstract:

Millimeter-wave and sub-millimeter-wave detectors, when operating in geostationary orbit, are influenced by environmental thermal radiation in the performance of their subsystems. Based on in-orbit temperature field data, finite element analysis is employed to simulate the thermal deformation of the quasi-optical feed network; the GRASP software is adopted to fit the positional and surface parameters after the device's thermal deformation, and to simulate the changes in electrical performance when the quasi-optical feed network is subjected to on-orbit environmental thermal radiation. The results show that environmental thermal radiation has a certain impact on the electrical performance of the quasi-optical feed network, and by adopting temperature control measures, it is possible to avoid performance changes caused by temperature variations in orbit.

Abstract:

Composite materials are widely used in general aircraft, with usage rates exceeding 90% in various types of aircrafts. Therefore, defects in composite materials can severely affect flight safety. This paper designs an accurate defect detection method for aircraft composite materials based on infrared imaging detection technology, as well as a prototype non-destructive testing system. The non-destructive testing system consists of a data acquisition system, signal source group, infrared thermal imager group, and infrared image processing reconstruction system, which can identify the type and planar size of defects in the aircraft composite material structure and accurately locate the depth. A light-excited infrared imaging detection system for aircraft composite materials was built, and detection experiments were conducted on composite materials at different temperatures, with research results provided. These research results will expand the application scenarios of domestic infrared non-destructive testing technology, and the commercialization of research findings will be beneficial in solving maintenance and repair issues during the general aviation of aircraft.

Abstract:

Fire disaster can cause great harm to the safety of people and property, and how to detect flame intelligently and efficiently is of great significance. In order to achieve accurate flame recognition under high space conditions, an infrared camera with two degrees of freedom that can detect environmental conditions in all directions is designed, and the target detection algorithm YOLOv5 is improved combined with deep learning. The K-Means clustering algorithm is employed to obtain nine width and height dimensions of clustering center by matching and replace the original network anchor parameters. Considering the relative proportion of the target frame, the loss function is optimized and applied to the Raspberry Pi to achieve flame recognition. The test results show that it takes 2.9 s for the improved YOLOv5 algorithm to detect a single sheet on the Raspberry Pi, which is less than that for the original YOLOv5 algorithm by 78%. The accuracy of the system is 100%, and the confidence of identifying the target frame is above 0.9. The proposed system can identify the flame fast and accurately.

Abstract:

Human pose estimation primarily relies on capturing joint points from visual image information to obtain global posture information of limbs and torso. Currently, depth learning methods based on visible light have high detection accuracy, but the risk of privacy leakage limits their practical application. Infrared detectors of the same cost can highlight human targets more effectively, but due to their lower imaging resolution and poor image quality, the detection accuracy is reduced. Inspired by visual Transformers, this paper introduces MobileViT-FPN to extract key human body points, using MobileViT to capture the relationship between local and global joint features, and then using Fixed Pattern Noise (FPN) to aggregate these representational information at multiple scales. Combined with an improved OpenPose for key point clustering, the estimated results are outputted. In the key point cascading phase, the attention mechanism allows the model to adaptively focus on the area of interest, enhancing the recovery of occluded parts. Experiments show that this method can real-time detect infrared human targets with varying scales and partial occlusions, accurately depicting human posture.

Abstract:

With the development of the 5th Generation Mobile Communication Technology(5G), various application scenarios continue to emerge. Network slicing can construct multiple logically independent virtual networks on a common physical network to meet the diverse service requirements of mobile communication networks. In order to enhance the ability of mobile communication networks to allocate resources on demand according to the traffic of each slice, this paper proposes a network slicing resource management algorithm based on deep reinforcement learning. The algorithm uses two Long Short-Term Memory(LSTM) networks to predict statistical data that cannot be reached in real time, and extracts dynamic characteristics of business data volume caused by user mobility, and then makes bandwidth allocation decisions that match the needs of slice services in combination with the Advantage Actor-Critic(A2C) algorithm. Experimental results show that compared with existing methods, this algorithm can improve the spectral efficiency by about 7.7% while ensuring the user's delay and rate requirements.

Abstract:

After acquiring the power grid dispatching signals, traditional deep confidence identification systems are mostly used for anomaly data extraction, which can only obtain the anomaly information parameters contained in low-dimensional data, resulting in a lower Area Under the Curve (AUC) value of the final data extraction result. Therefore, in order to improve the AUC value of the anomaly data extraction results of the power grid dispatching signals, an anomaly data extraction method for power grid dispatching signals based on data mining algorithms is proposed. The power grid dispatching signals are processed using the Independent Component Analysis(ICA) algorithm to remove noise from the signals. The denoised signals are then subjected to wavelet decomposition to obtain multiple sub-signal datasets. Clustering algorithms in data mining algorithms are employed to analyze the sub-signal datasets to obtain the characteristics of the data samples, and data feature classification is completed considering the attribute feature density index to obtain the anomaly data characteristics. Finally, with the assistance of the Support Vector Data Description(SVDD), the abnormal data in the power grid dispatching signals are detected, and summarizing this part of the data can complete the anomaly data extraction. The experimental results show that the AUC value of the anomaly data extraction results obtained after applying the proposed method is always greater than 0.85, proving its superior application effect.

Abstract:

Effective choice of the solution is essential to achieve a real-time, bi-directional(full- duplex) communication of the smart grid. The Power Line Carrier(PLC) technology provides a low-cost solution, which suits China's own national conditions. In this paper, the advantages of OFDM PLC modulation technology are introduced. A PLC module of system model is established through the analysis of the input impedance under the low-voltage power line channel. The high-speed PLC module based on low-voltage Power Line is also designed according to the studies of power line channel. The results show that the design of the PLC module has featured high receiving sensitivity and anti-noise ability.

Abstract:

With the development of Internet applications, users’ demand for bandwidth is soaring sharply. Meanwhile，along with the development of broadband access technology, the endpoint can also adopt multiple network accesses. But due to one-way communication of traditional Transmission Control Protocol(TCP)，the waste of resources will exist. To this end，IETF has specifically proposed Multi-Path TCP(MPTCP) to implement TCP multiplexing，thereby enhancing the efficiency and robustness. This paper gives a review of the IETF’s research on MPTCP，including MPTCP architecture, routing and congestion control, aiming to provide a reference for deeply studying.

Abstract:

Traditional methods and instruments are not able to measure the true Root Mean Square(RMS) of distortion sine wave or non-sine signal accurately. This article introduces a method to measure the true RMS of any high frequency signal by using the true RMS measurement IC，AD536A，designed by AD corporation. The paper analyses the difference between the RMS measured by the average measure method and the true RMS in theory. It explains the disadvantages of current RMS measure method，and presents the design of true RMS measure circuit. The experiment results prove that the proposed method and circuit can measure the true RMS of any high frequency signal accurately.

Abstract:

Aiming at the problems in existing underground personnel positioning systems, an assisted positioning method based on pedestrian dead reckoning is proposed. Low-cost Inertial Measurement Unit(IMU) and magnetometer are employed to constitute a stable Attitude Heading Reference System (AHRS). The theory of inertial navigation is utilized, an algorithm for step detection is described, and Zero velocity Update(ZUPT) is adopted for velocity and position estimation to compose a pedestrian dead reckoning system. An experiment is performed in the corridor of a laboratory building to emulate the underground mine road environment. The experimental results demonstrate that the dead reckoning performs well and this method is an effective complement to existing underground positioning by improving the positioning accuracy.

Abstract:

The requirements for micro stress measurement of strain gauge are high precision，high linearity，high stability and high gain. One kind of differential amplifier circuit with excellent performance was designed. Some skillful techniques were adopted to avoid common voltage in the circuit and to reduce the temperature drift. The gain linearity is about 0.01%，and its Common-Mode Rejection Ratio(CMRR) is about 129 dB under work conditions.

Abstract:

Terahertz(THz) optoelectronics has promoted the development of the THz generation, transparent control, and detection methods，and hastened many devices in the past decades. Especially, THz metamaterials and metasurfaces will exhibit extraordinary electromagnetic response when the subwavelength scale metal structure is excited by the THz illumination. Therefore, they have been applied to the devices such as wave beam shaper, waveguide, and modulator etc. The THz metamaterials and metasurfaces also show the potential applications in the research fields such as sensors, communications, and radars. In this paper, the works about the spectrum and wavefront modulation with THz metadevices carried out in our group are summarized. The basic theory and corresponding experiment results for different devices are introduced. It is expected these works can pave the avenue of the application of the THz metadevices.

Abstract:

According to the requirements of safe, simple and nondestructive radiation effect investigation of semiconductor devices, the method of laser simulation was proposed and greatly promoted. Compared with large-scale facilities, laser simulation has various unique advantages. It helps understand the ionization radiation effect in depth and is an effective low-cost, table-top supplement for the hardness assurance. Its research shows great significance for radiation effect study in both theory and practice. In this paper, the basic principles of the interactions of γ and laser with semiconductor devices are firstly presented. Then the physical basics and characteristics of laser simulation are given, with the research progress review followed. The existing problems of current research are deeply discussed providing with feasible research approaches. In the end, necessary research contents in the future are proposed.

Abstract:

The background requirements of the fuze antenna in terahertz spectrum as well as its advantages and disadvantages are introduced. The working principles and application characteristics of dielectric lens antenna in terahertz frequency are analyzed in order to implement the terahertz fuze antenna. The longitudinal size of H plane horn antenna can be reduced effectively by using fuze antenna formed by an H plane horn with dielectric lens antenna. The terahertz fuze antenna with different beam angles is achieved by focal technology of lens. The feasibility of the technology solution is verified through simulation.

Abstract:

Radio Frequency IDentification(RFID) series Radio Frequency(RF) card has been applied widely because of its stability，reliability and easy operation features. Aiming at multiple protocols，such as ISO14443 protocol，ISO15693 protocol and Tag-it protocol，this study proposed a new type of circuit design based on Advanced RISC Machine(ARM) for the RFID series RF card reader. The data stream encryption was implemented by using peripheral device in the operation. The system composition，working principle and work flow were introduced. Then，the detailed circuit design of the RF network and encryption hardware were presented，and the test and analysis for the design were performed. The results showed that the circuit could accurately read, write and encrypt various types of card within effective range.

Abstract:

Ultra-wideband(UWB) communication shows its advantages of fast data transfer(100 Mb/s or above) in a relatively short distance(typically below 10 m) with relatively weak power consumption (energy spectrum below -41.3 dBm/MHz). Integrated with Multiple Input Multiple Output(MIMO) technology, channel capacity could be further enhanced. As a critical link in the ultrawideband communication，UWB antenna needs extra efforts in design optimization to boost the performance of the whole system. UWB antenna is defined as the antenna whose bandwidth exceeds 500 MHz or relative bandwidth greater than 20%. This paper takes the most representative Vivaldi antenna as a show case for multi-objective optimization design with statistical methods. The optimized miniaturized antenna(sized130 mm×100 mm) shows a -10 dB bandwidth of 2.4 GHz. The design method provides guidance in common wideband，multi-parameter antenna design.

Abstract:

This article introduces a new type of high speed，multi-modulated digital modulator with adjustable center frequency and bit rate features. It can realize the Quadrature Phase Shift Keying(QPSK) and 16QAM(Quadrature Amplitude Modulation) with 80 MHz center frequency and 7.936 5 MHz bandwidth. The general-purpose modulation arithmetic based on software radio，symbol mapping and the realization of pulse shaping filter are discussed. The measuring results demonstrate that the modulation scheme meets the requirements of practicability and general utilization.

Abstract:

The implementation of TCP/IP protocol stack on TM320DM642 platform could provide technological support for the application of multimedia embedded systems to networks. Both the function of TM320DM642 chip and the hierarchical structure of LWIP(Light Weight Internet Protocol) were analyzed. Network communications for TM320DM642 systems were implemented by the transplantation of LWIP, not by a solution scheme of NDK(Network Developer’s Kit). Testing examples verified the effectiveness of the LWIP transplanted method.

Abstract:

The design of code tracking loop is a key sector of the realization of noncoherent spectrum spread receiver. In order to realize the code tracking in noncoherent spectrum spread receiver, an energy-normalization digital delay-locked loop was designed, the structure of the loop and the calculating procedure of loop parameters were introduced. The characteristic of noncoherent spectrum spread was analyzed first，and then the key point of the loop design was pointed out. Based on this, the design and realization methods of code loop discriminator, loop filter, early and lag code generator were expatiated. A set of specific loop parameters were introduced as well. Modelsim simulation results and FPGA actual measured data prove the precise code tracking ability of the design.

Abstract:

The application of CORDIC(COordinate Rotation DIgital Computing) arithmetic in solving transcendental function has become popular in modern engineering. A brief introduction of CORDIC arithmetic was given in this study. Taking the hyperbolic sine and cosine functions as examples, the method of realizing the arithmetic in FPGA was presented and simulated on ISE(Integrated Software Environment) platform. The result showed this arithmetic was of good precision and instantaneity because of using pipeline. This arithmetic has great practical value in some applications. In addition, a curve of the relationship between the iterative number and the error obtained by the Matlab simulation of the arithmetic can help designers planning the number of iterations for practical applications.

Abstract:

High-speed data acquisition system is an important component in modern radar signal processing. A design of high-speed data acquisition system based on band-pass sampling was presented and applied to the signal processing of wideband receiver. The Virtex Series FPGA was used as the main platform to control the high-speed ADC08D1000 for completing data acquisition, transmission，storage and signal processing. High-speed First Input First Output(FIFOs) were selected as the storage devices to implement data rate conversion. The system realized the software and hardware design，and test results verified the feasibility of the solution.

Abstract:

The Spatial Light Modulation(SLM) technology has been widely applied to the fields of threshold switch, high speed optical interconnection and optical logic operations, which demands good performance on the real-time and fast optical signal addressing. Compared with Electro-Addressing SLM(EA-SLM), Optically-Addressing SLM(OA-SLM) shows great advantages of fast speed and high resolution by parallel addressing. Nevertheless, how to achieve fast and stable optically addressing is the key point in practice. Based on ZnO thin film as a photoconductive layer, Liquid Crystal OASLM(LC-OASLM) is designed and fabricated; the modulation of the readout light intensity and phase distribution in the two-dimensional space is achieved effectively.

Abstract:

The corresponding solutions are proposed to tackle with the disadvantages of conventional oilfield Geographic Information System(GIS), including inconvenience of Client/Server(C/S) mode operation and maintenance, being unable to perform real-time online Point of Interest(POI) rendering, being incapable of segmentation and location according to regions, etc. An oilfield information query system of Browser/Serve(B/S) framework based on AJAX+JSON+HTML5 is designed and implemented. Experimental results show that the POI real-time rendering and regional segmentation improve on their interactivities, and the experiences of users are enriched, which meets the actual requirements of oilfield development. This work has paved the way for the development of diversified network services.

Abstract:

A detector can achieve quick response when it is much smaller than the wavelength of the source signal in THz wave band at the expense of signal coupling capability．Therefore, an antenna is applied to collect signals in order to enhance the signal coupling capability of the detector．The properties of antenna determine the frequency response band，the sensitivity and other parameters of the detector directly. A planar-integrated antenna is adopted for signal acquisition in the Nb5N6 microbolometer detector, which is fabricated by lithography，lift-off and other processes of micro-fabrication. The Nb5N6 microbolometer is placed in the center of the planar antenna. Aiming for the center frequency of 0.32 THz, a special capacitive coupling design is proposed to improve the signal coupling capability．

Abstract:

A double gate setting with priority of Doppler velocity and the Extended Kalman Filter(EKF) based Multiple Hypothesis Tracking(MHT) algorithm are proposed in order to realize Multiple Targets Tracking(MTT) in High Frequency(HF) ground-wave radar, and to effectively improve the performance of MTT by using the Doppler measurement. In the EKF based MHT, parameters obtained in the EKF are adopted directly to calculate the probability of each hypothesis. A simulation scene is built, and the EKF based MHT algorithm is compared with the one which assumes that the Doppler measurement is independent from the radius measurement. Simulation results show that the double gate setting helps induce number of clutter, and the EKF-based MHT algorithm is better than the other one under dense environments of HF ground-wave radar with stronger track-catching and false-alarm-filtering ability and higher efficiency.

Abstract:

The single-channel blind separation of GMSK(Gaussian Minimum Shift Keying) mixing signals is researched. The GMSK mixing signals can not be separated by the Per-Survivor Processing (PSP) algorithm directly, therefore, linear approximation processing of the GMSK signal is considered, which enables GMSK signal to be separated by the PSP algorithm. This algorithm separates the GMSK mixing signals by maximum likelihood estimation in the joint space of the symbol sequential and the channel parameters, reserves the best path and outputs the symbol pairs to get the separated signals. Simulation results show that the bit error rate performance produced by the PSP algorithm on separating the GMSK mixing signals is slightly better than that produced by the particle filtering algorithm; and the complexity of the proposed PSP algorithm is much smaller.

Abstract:

A new usage of Hough Transform is introduced in this paper.Firstly,the position and scope of the license plate is located and the image that contains the license plate is picked up.Then, a two-stage Hough transform algorithm is applied to the image to cal

Abstract:

A forward secure strong proxy signature scheme is proposed on the basis of the proxy signature schemes and forward secure schemes.The security of the proposed scheme relies on the difficulty of solving discrete logarithm problems and the difficulty of com

Abstract:

Wavelet denoising is an important application of wavelet analysis in engineering.The keys of wavelet denoising,namely how to select threshold and how to utilize the threshold to dispose wavelet coefficients,are introduced.Via the noised simulated signal e

Abstract:

Based on three generally accepted basic hypotheses, the definition of environmental factor and restricting conditions of constant failure mechanism are discussed.The research status and common study methods of environmental factor are reviewed. Finally, a

Abstract:

For completing the scheme of hard target smart fuze, several factors influencing the outputting acceleration of the high-G accelerometer such as target material, impact angle, impact velocity, the fixed position of accelerometer, carry plane etc., are put