Surface Plasmon Polaritons(SPPs) has promoted the development of applications such as strong radiation sources, super-resolution imaging, sensitive sensing, and on-chip integration. It will inevitably bring more fascinating functions when it is applied to the terahertz(THz) band which has advantages of strong-penetration, high-bandwidth, and so on. Due to the low frequency of THz radiation, many distinctive phenomena of SPPs have occurred in this range. By controlling the interaction between the subwavelength metal structures or semiconductor materials with the THz radiation, the approach for modulating SPPs in such low-frequency domain has been realized. In this paper, the basic principles and research history of SPPs in the THz range are reviewed, then the hot topics carried out in recent years are introduced, such as electric field modulation, on-chip waveguides, and tunable devices. At last, the bottleneck problems are summaried and the future trends are expected.

With the development of terahertz technology, low-temperature electronics and radio astronomy, the demand for integrated transimpedance amplifier chips working in low-temperature environment increases. The electrical performance of a Ge-Si based transimpedance amplifier in deep low temperature environment is studied. The current-voltage curves of the typical ports and gain curve of the amplifier chip at 8 K, and a relatively flat gain effect in the 0.1 GHz-3 GHz band are obtained. In order to verify its amplification function of terahertz photoelectric signal, GN1068 is integrated with terahertz Quantum-Well Photodetector(QWP), and a terahertz pulse laser detection system is built. A photoelectric signal, with a pulse width of 2 μs, is successfully amplified at 8 K. The transimpterahertzedance gain is about 560 Ω. The current amplification gain is 1.78 mA/V. The above results verify the feasibility of commercial transimpedance amplifier in deep low temperature environment for the first time, and provide an effective technical means for integrated transimpedance amplifier in the field of terahertz high-speed detection and high-frequency communication.

With the rapid development of new services such as 5G mobile Internet and Internet of Things, the transmission capacity, transmission speed and bit error rate of future communication system are required to be higher. Terahertz(THz) band, which is between millimeter wave and far-infrared light, has the advantages of both microwave and light wave like low quantum energy, large bandwidth and good penetration. THz communication system has become one of the research hotspots in recent years. However, terahertz wireless communication has the disadvantages of line of sight propagation and large path loss. It is important to combine wireless link with wired link. This paper analyzes the devices and technologies involved in the process of photonic terahertz signal generation, photonic terahertz wireless link transmission and fiber link transmission, and focuses on the research status of terahertz cable transmission. Finally, the experiment shows the great potential of terahertz wired transmission through real-time transmission of 1 m terahertz fiber with transmission rate of 1.485 GBaud and carrier wave of 350 GHz based on intensity modulation and direct detection.

The miss detection is liable to occur when detecting stationary targets in complex strong ground clutter. Based on the Double-Parameter-Constant-False-Alarm-Rate(DP-CFAR) detection method, this paper proposes a Multi-Time-Scale Constant False Alarm Rate(MTS-CFAR) detection based on pre-detection recognition. Before the detection, based on the difference in the multi-time-scale statistical results of various types of targets, the moving targets, stationary targets and clutter are distinguished and identified, the interferences of clutter statistics and target statistics are reduced, and the detection performance of stationary targets is improved. Based on the application of traffic radar, the performance of MTS-CFAR algorithm and DP-CFAR, TS-CFAR and CAG-CFAR are analyzed and compared quantitatively through simulation and measured data, which proves the superiority and engineering application value of static target detection of the proposed algorithm.

Testbench for satellite communication terminals is required to be more universal since satellite communication systems are becoming multi-band and multi-system integrated. General-Purpose-Processor based Software Defined Radio(GPP-SDR) is suitable to solve this problem yet the high-speed data transmission between the processor and RF front-end of GPP-SDR is still one of the main bottlenecks. In this paper, to satisfy the requirements of satellite communication terminals testing, a high-speed transmission method based on interrupt mechanism is proposed. The real-time of the transmission interface is also optimized by utilizing the Xenomai Operating System(OS). A series of experiments are designed to test the actual transmission data rate, interrupt loss probability and other indexes, verifying that the proposed approach has good performance in high speed and low latency and can meet the current requirements on universal testing of satellite communication terminals.

There are large amount of Morse signals of interest in shortwave environment. In order to reduce the workload of the related personnel, an automatic identification technique of Morse signals in shortwave narrowband channel is put forward. Based on analyzing the problems of Morse signal identification in short wave narrowband channel, a fast identification method combining with the characteristics of time and frequency domains is proposed and a new Morse signal identification process is designed. By using the proposed method, Morse signal can be identified very quickly with high identification probability, low leak alarm rate and false alarm rate.

In the microphone array sound source localization, different microphone arrays and different source frequencies will have certain impacts on the results. In this paper,Time Difference of Arrival(TDOA) method is employed, and 16 microphones are utilized to form cross array, concentric circle array, square array, L-type array and Y-type array respectively. The positioning errors of microphone array with different shapes under different frequency sources are discussed. Simulation analysis is carried out on Matlab to obtain more accurate sound source positioning results. A concentric circle array for sound source location of microphone array is proposed, which has the smallest error.

The Ergodic Capacity-based Scheduling Algorithm(ECSA) is proposed to solve the problem of user access to the Satellite-Unmanned Aerial Vehicle(UAV) -Terrestrial Network(SUTN). Satellites transmit data to UAV via Free Space Optical(FSO). The UAV transmits data to the user via a wireless communication Radio Frequency(RF) link. ECSA algorithm firstly derives the Signal-to-Noise Ratios(SNRs) of UAV terminal and the client, then derives the Probability Density Function(PDF) of SNRs, and then calculate the user's Ergodic Capacity(EC) on the basis of probability density function. In the end, it calculate the objective function of the user based on the principles of fairness, combining with the EC of the user.The user with the greatest objective function value will access the channel. Simulation results show that compared with the rotational scheduling algorithm, the proposed ECSA algorithm can effectively improve the system capacity.

A Modified Sparsity Adaptive Stagewise Weak Orthogonal Matching Pursuit (MSASWOMP) algorithm is proposed to solve the problem of a priori sparsity and pilot resources for the actual underwater acoustic channel. Firstly, the initial sparsity estimation is used as the size of the initial support set, and the atom support set is obtained as the candidate set of backtracking screening by threshold weak selection of atoms. Then, the initial support set size is used as the initial condition value of backtracking to conduct secondary screening. Finally, the variable stage step size method is utilized to estimate the sparsity gradually and update the backtracking start condition value adaptively. The simulation results show that the proposed algorithm can obtain more accurate channel estimation with less pilot number, which can save pilot resources, and its Mean Square Error(MSE) is smaller than that of the traditional algorithm.

In response to the need for IPv6 protocol access to the spatial communication network, the implementation of the Neighbor Discovery Protocol(NDP) on the FPGA-based IPv6 over CCSDS-AOS gateway is discussed. It is proposed to build the NDP protocol module on the IPv6 over CCSDS-AOS gateway system to realize the gateway address resolution. The function of NDP protocol module is realized through state machine control. Experiments show that the design solves the problems of IPv6 over CCSDS-AOS gateway's active and passive address resolution, neighbor cache table lookup and management without requiring the gateway to perform protocol conversion and forwarding on the NDP protocol. It has been applied in IPv6 over CCSDS-AOS gateways.

Complexity of the railway operation environment makes it possible to break the contact line, and the broken contact wire falling on the surface of the motor train unit will lead to the overvoltage of the cab body. In order to evaluate the over-voltage damage of Carbon Fiber Reinforced Polymer/Plastic (CFRP) cab body due to its poorer conductivity than that of traditional aluminum alloy cab body, the circuit model of CFRP train body is established based on the semi-CFRP semi-aluminum alloy structure design. The transmission characteristics of surge overvoltage in different positions of the cab body are solved by simulation. The maximum voltage reaches 26 kV, and attenuates rapidly in 60 μs, which is a potential safety hazard for on-board equipment. It is proposed that the grounding wires of on-board equipment should be connected directly near the grounding brush of cab body, which provides a theoretical basis for the design of overvoltage protection of CFRP cab body.

Aiming at the problem of robust transmission in Distributed Video Coding(DVC) system, a DVC system transmission framework based on layer restoration is designed. Firstly, this transmission framework uses the High Efficiency Video Coding(HEVC) frame encoding and Wyner-Ziv coding to encode Key frames(K frames) respectively, and the checking information(Wyner-Ziv codes) is stored in the cache as a layer repair code stream. If the current Key frame is lost, the corresponding layer repair code stream of the frame is requested at the encoding end, and the error block is repaired at the decoder end to obtain the improvement of Key frame decoding quality. At the same time, the algorithm of layer repair coding rate estimation is also studied and the successfully decoded bit plane is employed to complete the algorithm reconstruction. The experimental results show that the transmission framework takes advantage of layer repair code stream of Key frame to repair the distortion part of Key frame. The qualities of Key frame and side information are improved(for example, when the "Kendo" sequence is lost by 5%, the Peak Signal-to-Noise Ratio(PSNR) is increased by 3.5 dB at the bit rate of 1 000 kbps), so as to realize the robust transmission of distributed video coding system.

A remote sensing image fusion method is proposed based on multi-stream fusion generative adversarial network with radiation index. This method extracts feature maps from the Multi-Spectral(MS) image and Panchromatic(PAN) image according to specific rules, and uses the generator sub-network to refine the input multi-source image, then fuses images through the main network of the generator after superimposing the features. According to the characteristics of multi-spectral and panchromatic images in the remote sensing field, the Modulation Transfer Function(MTF) is introduced into the discriminator to simultaneously discriminate the spectral information and spatial structure information of the fused images. In order to evaluate the effectiveness of the proposed method, its visual analysis is conducted and it is compared with other algorithms for objective evaluation. Experimental results show that this method is superior to other algorithms in visual effects and objective evaluation.

A kind of irregular scaling equations with physical feasibility is introduced and studied to describe the rational iterative process of fractional-order operators. Several new Frantance Approximation Circuits(FACs) are put forward and described by generalized irregular scaling equations. A class of irregular scaling equations based on the unknown parameters mn is extended, and the characteristics of the rational iterative processes of the fractional order operators described by this type of equation are studied. Four new FACs are obtained by replacing the position of the components of the known FACs, and described by the corresponding generalized irregular scaling equations. Research shows that generalized irregular scaling equations have different approach solutions. Finally, the optimization methods for the algebraic iterative processes of impedance functions described by generalized irregular scaling equations are introduced. Based on the new FACs, several design schemes of arbitrary-order scaling fractal FACs with high operational constancy are proposed. A simulation experiment of fractional-order differential circuit is designed to verify the operational performance of the new FACs.

Dynamic pricing is one of the most effective ways to encourage customers to change their consumption pattern. Therefore, Reinforcement Learning-based Optimizing Dynamic Pricing(RLODP) algorithm is proposed for energy management in a hierarchical electricity market by considering both service provider's profit and customers' costs. Using Reinforcement Learning, the SP can adaptively determine the retail electricity price. Dynamic pricing problem is formulated as a discrete finite Markov Decision Process(MDP), and Q-learning is adopted to solve this decision-making problem. Simulation results show that the RLODP algorithm can reduce energy costs for customers, balance the energy supply and the demands in the electricity market.

As an important technical equipment in the emerging field of additive manufacturing technology, 3D printer has been finding its way into more fields. In the working process of a 3D printer, the temperature control of the printing material ensures the printing quality and printing effect. For the development of a droplet jet array print head, considering the strict constraints in terms of device size, power consumption and other aspects, conventional methods with Field Programmable Gate Array(FPGA) or Microcontroller Unit(MCU) based architectures are no longer applicable, and the develoment of a temperature control Application-Specific Integrated Circuit(ASIC) becomes necessary, which will be included in an integrated package with other control circuits. Targeting the need of the development of an array print head, this paper proposes the architecture of a temperature control ASIC, and completes the front-end design, prototype verification, and backend design. The chip layout area is 740 μm×740 μm, which meets the design requirements and is applicable for use in the 3D printing head.