Abstract:

A terahertz parametric radiation source based on Stimulated Polariton Scattering(SPS) is an optically coherent terahertz source, characterized by high coherence, frequency tunability, and operation at room temperature. The basic principle of terahertz parametric radiation based on SPS, commonly used nonlinear crystals, and coupling techniques are firstly introduced. Then typical techniques and research achievements in recent years, both domestical and international, are summarized regarding gain enhancement and output performance improvement. Additionally, the progress in the application of terahertz radiation sources in material concentration detection is reviewed. Finally, the key technical issues and development trends of terahertz parametric radiation sources are analyzed.

Abstract:

In recent years, terahertz photonics of gases (such as air plasma) has developed rapidly, but there are relatively few research reports on the generation of terahertz waves by liquids, especially liquid water, which exhibits significant absorption performance in the terahertz frequency range, leading researchers to believe that liquids cannot be sources of terahertz waves. Recently, experiments have confirmed that broadband terahertz waves can be generated by exciting liquids with femtosecond lasers, and liquids have unique characteristics as terahertz wave radiation sources. The density of liquids is close to that of solids, and they perform excellently in interactions with laser pulses, with effects far exceeding those of gas sources. The fluidity of gases and liquids ensures that each laser pulse can interact with a new target area, greatly avoiding damage or degradation of the medium, a function that is difficult to achieve with solid materials. It is these unique characteristics that make gases and liquids show great potential in the research of high-energy-density plasmas and the development of next-generation terahertz wave sources. This article reviews the research progress of gases and liquids as broadband terahertz sources and compares various methods of generating terahertz waves using gases and liquids. Terahertz gas and liquid photonics reveal the potential for developing new types of terahertz wave sources and open up new research directions for studying the interactions between lasers and liquids.

Abstract:

A high-Q all-silicon structured metasurface is proposed, consisting of two layers of silicon square pillars. By adjusting the lateral offset distance between the upper and lower layers in the x -direction, the out-of plane σz symmetry is broken, allowing for the free control of perfect Bound states In the Continuum(BIC) states, polarization-sensitive quasi-BIC states, and Unidirectional Guided Resonance(UGR) states at different lattice vectors kx. Notably, since the proposed metasurface operates in momentum space, there are no strict spatial position restrictions for the incident light in real space. Simulation results indicate that after breaking the structural geometric symmetry and the symmetry of the external incident angle, quasi-BIC can achieve a Q value of the order from 10³ to 10⁴. The energy leakage of the generated quasi-BIC can be explained by the incomplete destructive interference of magnetic dipoles. By changing the lateral spacing between the upper and lower layers, unidirectional radiation with a maximum unidirectional radiation efficiency of 97.5% can be achieved at off-Γ point. This work demonstrates significant application potential in the fields of biochemical sensing, high-performance communication, and efficient grating coupling.

Abstract:

Thermal stability is a key indicator for polymeric materials. Using Terahertz Time-Domain Spectroscopy(THz-TDS) technology combined with a temperature control device, two types of thermoplastic polyurethane elastomers(TPU) solid samples are tested. At room temperature, there are differences in the terahertz absorption coefficients and refractive index values of different types of TPU. During the process of heating from 20 ℃ to 160 ℃, as the temperature increases, the terahertz absorption coefficient gradually increases, while the refractive index decreases. The turning point of the linear fit corresponds to the reported Vicat transition temperature of the material, and the sample with higher thermal stability maintains its optical constants more stable after heating and cooling. The research results indicate that terahertz spectroscopy technology can provide a new approach for detecting the thermal stability of polymeric materials.

Abstract:

By revealing the THz spectral characteristics of glioma and contralateral normal brain tissue, and analyzing the spectral differences in tumor space, this study provides theoretical support for non-invasive tumor diagnosis. Using an orthotopic U87 glioma cell tumor-bearing mouse model, terahertz spectroscopy is employed to characterize the absorption properties of the glioma lesion area and the contralateral brain tissue. Single-factor Analysis Of Variance(ANOVA) and Tukey's Honestly Significant Difference(HSD) post hoc test are adopted to assess the significant differences in spectral absorption between different layers of the tumor. Immunofluorescence results show differences in cell proliferation ability and vascular density in the glioma lesion area. THz spectral analysis indicates that above 2 THz, the absorption coefficient of the tumor area is significantly higher than that of normal brain tissue, especially with the peripheral surrounding area (L(6-7)) having a higher absorption coefficient than the tumor enhancement area (L(1-2)). ANOVA analysis confirms that the spectral absorption differences between different layers of the tumor are statistically significant(p<0.05), and Tukey's HSD test further confirms the specific differences between each layer within the tumor. Homogeneity of variance test shows significant heterogeneity within the tumor layers, while the normal brain tissue area exhibits more consistent spectral characteristics. The study demonstrates that terahertz spectroscopy can effectively identify the internal heterogeneity of glioma, especially the absorption differences between the lesion center and the infiltration area, providing important evidence for noninvasive tumor diagnosis and showcasing its application potential.

Abstract:

Precise diagnosis and personalized treatment of neurological diseases are crucial for improving patient outcomes. Terahertz(THz) metamaterials, due to their unique spectral properties, have become essential tools for studying different functional areas of brain tissue. THz metamaterials are employed to detect brain tissue sections, with a focus on analyzing key functional areas such as the amygdala, motor cortex, auditory cortex, hippocampus, hypothalamus, and thalamus. By measuring the resonant frequencies and amplitude changes in each area, the ability of THz metamaterials to identify different brain regions is verified. The resonant frequencies and amplitudes in each brain functional area have undergone significant changes. Among them, the hippocampus shows the largest change in resonance peak amplitude(ΔA), increasing from 7.62% to 20.35%. The motor cortex, auditory cortex, and amygdala show significant resonance frequency shifts, with a shift amount(Δf) reaching (369±4.4) GHz, while the hypothalamus shows a shift of 23.77 GHz. These differences are closely related to the biophysical properties of each brain area. The study indicates that THz metamaterials can effectively distinguish the spectral characteristics of brain functional areas.

Abstract:

In response to the difficulties in setting the peak detection threshold for signal acquisition and the decrease in acquisition accuracy of satellite navigation receivers in dynamic scenarios or scenarios with weak navigation signal strength, a satellite navigation signal acquisition peak detection method based on improved Support Vector Machine(SVM) is proposed. This method first reduces the dimensionality of sample features through Principal Component Analysis(PCA), then classifies the acquisition correlation results of satellite navigation signals, and finally determines whether the navigation signal is successfully acquired by judging whether there is a peak in the correlation results. Simulation results show that, compared with existing traditional threshold setting methods, standard SVM methods, and logistic regression classification learning methods, the detection method proposed in this paper has the advantages of low false alarm rate and high true alarm rate, and the acquisition success rate is also better than existing methods.

Abstract:

In the rapid development of wireless communication technology, Quadrature Amplitude Modulation(QAM) has become a key modulation technique in the fields of satellite communication and mobile communication. The research on reducing the Bit Error Rate(BER) which is a core indicator for evaluating the reliability of wireless communication systems is particularly important. To optimize QAM technology and reduce BER, an improved method of QAM is introduced. The core of this method lies in transforming the two orthogonal carrier signals in traditional QAM technology into three pseudo-orthogonal carrier signals within the same frequency band. After modulation, these three carrier signals are superimposed with a digital signal. Through this design, the amount of data carried by each signal is reduced, thereby maximizing the minimum distance between any two points in the three-dimensional space constellation diagram. This change not only enhances the noise tolerance but also effectively reduces the system's BER. To verify the effectiveness of this improved method, it is simulated and compared with Phase-Shift Keying(PSK) and traditional QAM. The simulation results show that the proposed three-channel QAM method is consistent with the expected performance, verifying its feasibility and advantages in practical applications.

Abstract:

A 32-way wideband and high-efficiency power combiner operating at the W-band is designed. The component employs a hybrid E-H plane T-junction to enhance the compactness of the power combiner. To extend the combining bandwidth, ridge waveguide transmission lines are introduced, along with multi-section impedance matching steps and gradual transitions. This structure features compactness, wideband matching, and high efficiency. To validate the proposed method, a 32-way back-to-back power combiner was fabricated and tested. Experimental results show that the structure achieves a return loss better than 15 dB, an insertion loss below 1.05 dB, a relative bandwidth of 37.8%, and a combining efficiency exceeding 78.4% across the W-band. These results confirm the effectiveness of the proposed design method, demonstrating significant application potential for multi-channel power combining scenarios.

Abstract:

This paper presents a compact strip-type soft surface structure, designed by introducing an aperture ring onto the foundation of the classical strip-type soft surface. Through guided wave transmission simulations, the capability of the soft surface to suppress surface waves is assessed. By analyzing the S-parameters and surface currents before and after incorporating the aperture ring, it is demonstrated that the designed soft surface in this study exhibits superior suppression capability against surface waves. Furthermore, simulations indicate the potential for electromagnetic transmission suppression at lower frequency bands, achieving structural miniaturization. When applied between microstrip antennas, the proposed soft surface can effectively suppress coupling between them. The novel miniaturized soft surface, featuring an added aperture ring on the basis of the classical strip-type soft surface, is highly symmetrical in structure with a low profile. This structure reduces the coupling between two microstrip antennas by more than 7 dB within the operating bandwidth, effectively suppressing the propagation of surface waves between the microstrip antennas and achieving decoupling effects.

Abstract:

In response to the therapeutic challenges of Acute Ischemic Stroke(AIS), a wireless power supply system for sphenopalatine ganglion electrical stimulation has been designed to address the limitations of traditional treatment. By employing near-field magnetic resonance coupling technology and an S-S topology with constant current characteristics, a stable current supply is provided. To ensure stable transmission at a constant frequency, the coil coupling is controlled near the critical coupling point to suppress the frequency splitting effect. The system uses a receiving coil with a diameter of 10 mm, achieving a Power Transfer Efficiency(PTE) of 25% in air and 12% in biological tissue, and maintaining over 90% of the alignment efficiency when the receiving coil deviates from the center of the transmitting coil by 5 mm, demonstrating good misalignment tolerance. This innovative solution is expected to meet the power supply needs of sphenopalatine ganglion electrical stimulation instruments, offering new possibilities for the treatment of AIS.

Abstract:

A low-profile, compact dual-band rectifier circuit is proposed, which can be used in scenarios such as radio frequency energy harvesting and microwave power transmission. The proposed rectifier circuit does not employ an impedance matching network, and achieves dual-band characteristics using only two microstrip transmission lines: the first microstrip transmission line connects the Schottky diode(HSMS-2850) with the load and filter at the rear end of the rectifier circuit; the second microstrip transmission line is a half-wavelength microstrip transmission line, adding a second frequency band to the designed rectifier circuit. This design approach not only reduces the overall size of the rectifier circuit(0.14λ₀×0.11λ₀, where λ₀ is the wavelength corresponding to the lowest frequency), but also minimizes the losses introduced by additional matching structures. After theoretical analysis, simulation, and fabrication, the measured results of the rectifier circuit are essentially consistent with the simulated results. When the input power is 0 dBm, the operating frequency bands of the rectifier circuit are 1.44~1.66 GHz(14.2%) and 3.35~3.54 GHz(5.5%), with maximum rectification efficiencies achievable within the bands being 73.7% and 69.5%, respectively.

Abstract:

In order to solve the problem of significant errors in the classic Distance Vector-Hop(DV-Hop) positioning algorithm, an improved DV-Hop extension algorithm based on multi-communication radius correction for calculating unknown node positions is proposed. By grading and refining the number of hops between multiple communication radii and neighboring/beacon nodes in Wireless Sensor Network(WSN), the precise number of hops for mobile Internet of Things(IoT) sensing positioning is determined, which corrects the irregular multi-level communication radii of the network topology. The research results show that under different communication radii, the positioning error of this algorithm is reduced by about 36.78%, 10.63% and 21.15% compared to that of traditional DV-Hop, Improved Salp Swarm Algorithm DV-Hop(ISSA_DV-Hop) and Differential Evolution DV-Hop(DEDV-Hop) algorithms, respectively; under different numbers of beacon nodes, the positioning error of this algorithm is reduced by an average of about 33.17%, 15.36%, and 21.07% compared to that of the three algorithms mentioned above. This indicates that the DV-Hop correction algorithm can improve the positioning accuracy of mobile IoT sensing, reduce data errors without adding hardware, and ensure that the average hop distance of unknown nodes in WSN is more in line with the actual DV-Hop positioning algorithm and network sensing requirements.

Abstract:

The implementation scheme of Convolutional Neural Network(CNN) based on Von Neumann architecture is difficult to meet the requirements of high performance and low power consumption. Therefore, a CNN accelerator based on storage-computing integrated architecture is designed. By using the circuit structure of Resistive Random Access Memory(RRAM) to realize the storage-computing integrated architecture, and using efficient data input pipeline and CNN processing unit to process large-scale image data, high-performance digital image recognition is realized. The simulation results show that the CNN accelerator has faster computing capability and its clock frequency can reach 100 MHz; in addition, the area of the structure is 300 742 μm², which is 56.6% of that of the conventional design method. The acceleration module designed in this paper greatly improves the speed and decreases the energy consumption of CNN accelerator. It shows guiding significance for the design of high performance neural network accelerator.

Abstract:

Affected by the complexity of the power Internet of Things(IoT) and the stealth of terminal vulnerabilities, the traditional vulnerability correlation mining methods currently in use exhibit local biases in correlation feature parameters. This leads to insufficient overall mining scale and low global optimization efficiency of the algorithms, which severely impacts the normal operation of power IoT terminals. To address the aforementioned issues, starting from the structural characteristics of IoT, a black-box genetic algorithm is introduced. By completing the global parameter reconstruction and optimization of the overall mining method through four parts: power IoT terminal status perception, terminal vulnerability correlation mining rule generation, introduction of black-box genetic algorithm parameters, and terminal vulnerability correlation mining, the accuracy and scale of mining are enhanced. Simulation tests indicate that the mining curve values of the proposed method are relatively large, and the mean deviation index difference is 0.1. This demonstrates that the black-box genetic algorithm has high feasibility and effectiveness in the mining of security vulnerabilities in power IoT terminals, and the mining stability is sufficient to meet the current terminal vulnerability mining task requirements.

Abstract:

In response to the current issue of low prediction performance in the remaining service life of electric vehicle lithium batteries, a hybrid deep learning model for predicting the remaining service life of electric vehicle lithium batteries is proposed. The model employs Empirical Mode Decomposition(EMD) to decompose battery data, forming high-frequency and low-frequency components of the battery capacity sequence. It utilizes Multilayer Long Short-Term Memory(MLSTM) and Elman neural networks to learn high-frequency and low-frequency battery capacity characteristics, extracting high-level representations of battery capacity. It combines high-frequency and low-frequency prediction results through stacking rules to achieve high-precision prediction of the battery's remaining service life. Experimental results show that the loss generated by the proposed hybrid deep learning detection model in the training set is approximately 7.87%. Compared with Support Vector Machine(SVM), Logistic Regression(LR), Recurrent Neural Network(RNN), and LSTM models, the proposed hybrid deep learning model demonstrates superior comprehensive performance indicators, with an Mean Absolute Percentage Error(MAPE) of only 1.438%. The experiments validate the effectiveness and practicality of the proposed model.

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:

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:

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:

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:

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:

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:

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:

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 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:

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 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:

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 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:

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

Abstract:

Blind source separation (BSS) is a recently developed methodology used to separate unknown source signals from their mixtures. It has been applied to many fields widely and effectively. The theory and two types of implementation methods-independent compon