最新刊期
卷 49 ， 期 12 ， 2021
- 摘要：Cross eye jamming is one of the most effective jamming methods for monopulse radar, and cross eye gain is an important index to measure the performance of cross eye jamming. Based on the gain models of two source retro-directive cross-eye jamming(TRCJ) and linear array multi-source retro-directive cross-eye jamming(LMRCJ), the maximum gain value of LMRCJ under the same amplitude ratio is deduced by taking the cross eye interference of 4-source linear array as an example, and the calculation method of overall phase tolerance of LMRCJ is proposed. Considering the phase control mode between different loops of LMRCJ, amplitude phase fluctuation and platform echo, the gain value and amplitude compatibility limit of LMRCJ and TRCJ are compared and analyzed. The simulation results show that， without considering the platform echo, the maximum gain of TRCJ is not lower than that of LMRCJ under the same amplitude ratio, and the phase tolerance of TRCJ is more relaxed than that of LMRCJ when the gain is high; when the amplitude and phase control capabilities of LMRCJ and TRCJ are the same and weak, the gain of LMRCJ is higher than that of TRCJ; when considering the platform echo, the gain and phase tolerance of LMRCJ and TRCJ are consistent with those of isolating platform echo at high JSR. The paper can provide guidance for the engineering design of the cross-eye jammer.关键词：monopluse radar;cross eye;multi-source linear array;global phase tolerance;JSR(Jam-to-Signal Ratio)2|16|3更新时间：2025-12-08
- 摘要：Current resources management schemes of persistent memory cannot take advantage of data persistence and byte-addressability of PM(Persistent Memory) at the same time. We propose VMFS(Virtual Memory File System), a unified management system based on the virtual memory subsystem and a file system of OS kernel. VMFS provides memory allocation and file storage services for applications using a single PM partition. Based on the unified management of virtual memory and file storage, VMFS supports the data re-mapping between memory and files. As the re-mapping mechanism reduces the number of data copying times, file read and write latency performance is improved. The test results show that compared with the system using PM as memory and storage sperately, the proposed method can accelerate file reading and writing while the native system call interface was maintained. Under two realistic workloads, VMFS also shows cost and performance advantages over the scheme using DRAM(Dynamic Random Access Memory) as memory and PM as storage.关键词：persistent memory;non-volatile memory;file system;virtual memory;data storage;operating system4|18|0更新时间：2025-12-08
- 摘要：Aiming at the requirement of high reliability, low cost and fast response of the private commercial launch vehicle "Hyperbola-1", a high-integrated launch vehicle integrated modular avionics is designed. This paper describes the task requirements of integrated modular avionics, the principle composition of each function module, the structure design of laminated board, real-time operating system and flight control software. Emphasis is given to the design of minimum system and communication interface of the main control module based on Zynq, the design of custom high-speed serial bus architecture. With the success of the first flight test of Hyperbola-1, integrated modular avionics, as a control center, works normally and meets the requirements of high real-time, high reliability and high precision control of private commercial launch vehicles.关键词：hyperbola-1;integrated modular avionics（IMA）;main control module;Zynq;high-speed serial bus5|22|0更新时间：2025-12-08
- 摘要：The traditional array diagnosis methods for multiple-input multiple-output(MIMO) radar may fail in the presence of impulse noise. The traditional matched filter based on second-order statistics is modified to obtain a reliable performance in the non-Gaussian noise, and then the array diagnosis method based on tensor decomposition and K-means clustering is proposed. The coefficients of the matched filters are adjusted with the Gaussian kernel function values of the echo signal observed at each receive element, which makes the MIMO radar form a virtual array successfully in the presence of impulsive noise. To further utilize the inherent multidimensional structure of the matched filter output data of the damaged and normal antennas, a third-order parallel factor(PARAFAC) model of the virtual array covariance matrix is formulated. By exploiting the complex parallel factor analysis(COMFAC) algorithm on the third-order covariance tensor, the manifold matrices of the transmit and receive arrays are obtained. The similarity of manifold matrix data is measured using Euclidean distance, and the clustering centers of the two clusters corresponding to the normal and fault elements are determined. The abnormal cluster data is selected to diagnose the location of the fault elements in MIMO radar array. Numerical simulation results confirm the effectiveness of the proposed algorithm.关键词：MIMO radar;array diagnosis;impulsive noise;matched filter;tensor decomposition;K-means clustering4|17|1更新时间：2025-12-08
- 摘要：Multi-fractal detrended fluctuation analysis(MFDFA) deals with the problem that non-stationary time series has trend items that are difficult to accurately remove. For this reason, this paper introduces empirical mode decomposition(EMD) and adopts trend items The automatic determination method extracts the trend item, and then uses the least squares(LS) method to refit the trend item(EMD-LS), and then proposes a new multi-fractal analysis method(EMD-LS-MFDFA), and the binomial multi-fractal sequence(BMS) of theoretical value verifies the validity and stability of the EMD-LS-MFDFA method, and then conducts simulation analysis. Research shows that compared with the MFDFA method, EMD-LS-MFDFA has higher precision in removing trend, and the calculated generalized Hurst index and quality index have a smaller root mean square error. The calculation accuracy of the second-order EMD-LS-MFDFA is 1.8 times higher than that of the first order. The multiple scale curve is consistent with the theoretical curve by analysis of the BMS sequence of different parameters, which proves that the algorithm has good stability and accurate analysis ability.关键词：multi-fractal;detrended fluctuation analysis;non-stationary time series;empirical modal decomposition;least squares;BMS signal2|14|4更新时间：2025-12-08
- 摘要：To improve the accuracy of moving object detection under complex dynamic background, based on the theory of low-rank and sparse decomposition, a group sparse based moving object detection method is developed. The proposed method decomposes the observed video into a low-rank static background, a group sparse foreground and a dynamic background. Regarding the problem that the nuclear norm over-penalizing large singular values leads to the optimal solution of the obtained minimization problem cannot be obtained and then the detection performance is decreased，the gamma norm is introduced to acquire almost unbiased approximation of rank function. In order to utilize the object boundary prior to enhance the moving target detection performance, each frame is over-segmented into homogeneous regions which are taken to define the group sparse norm to constrain the foreground matrix. Moreover, to prevent the moving object from appearing in the sparse foreground and dynamic background simultaneously, the incoherence term is introduced to enhance the separability of them. Finally, the obtained non-convex objective function can be solved using the alternating direction multiplier method（ADMM）. The experimental results show that, compared with the state-of-the-art moving target detection algorithms, the developed method can suppress the dynamic background considerably and then improve the accuracy of moving object detection significantly under complex dynamic background.关键词：moving object detection;dynamic background;low-rank;group sparse;superpixel2|14|1更新时间：2025-12-08
- 摘要：To address the problem that the clutter suppression performance of a multichannel synthetic aperture radar ground moving target indicator(SAR-GMTI) system is reduced due to non-uniform clutter in a complex geographical scene, we propose a multichannel SAR-GMTI clutter suppression method assisted by Range-Doppler-Band three dimension adaptive weighted penalty markov random field(3D-AWP-MRF) classification. Firstly, an adaptive weighted penalty function is constructed using the markov properties of the feature types in the Range-Doppler-Band 3D SAR image domain. Spatial distance, inter-class Fisher distance, local roughness distance, and gradient direction distance are included. Subsequently, in the Bayesian framework, iterated conditional mode(ICM) algorithm is used to solve the maximum posterior probability of the feature type of the Range-Doppler unit, so as to accurately classify the multiband SAR images. Then, the image classification results are obtained by image morphology operation. Finally, the clutter covariance matrix is estimated separately for each closed region, and adaptive clutter suppression processing is performed. Compared with the traditional method, the proposed method not only can improve the suppression performance about 10~15 dB for the strong clutter in undulating areas, but also reduce the output signal power loss about 2.5dB of the moving targets in flat areas.关键词：SAR-GMTI;clutter suppression;multiband;Markov;clutter classification;Adaptive penalty weighting4|13|2更新时间：2025-12-08
- 摘要：For the insufficient energy efficiency(EE) in mmWave massive MIMO(Multiple-Input Multiple-Output) systems, a method with mixed-resolution phase shifters is proposed. Considering that the closed expression for EE is difficult to solve directly, the EE optimization problem is converted into norm minimization form through the Dinkelbach method. Then it is further decoupled into the hybrid precoding matrix and the mixed-resolution ratio problems to realize the convex optimization transformation of non-convex EE and low norm sum. Finally, in order to maximize the EE of the system, the unitary matrix relaxation constant modulus constraint is introduced to solve the full-resolution hybrid precoding matrix, and the incremental search algorithm is used to solve the optimal mixed-resolution ratio vector. The simulation results show that the spectrum efficiency performance of the proposed mixed-resolution algorithm is better than that of the traditional finite-resolution algorithm, and it has higher EE performance. Meanwhile, the system performance of the proposed mixed-resolution quantization structure is close to the full-digital structure when multiple data streams are transmitted.关键词：mmWave communication;hybrid precoding;finite-resolution phase shifter;spectral efficiency;energy efficiency;incremental search algorithm;mixed-resolution quantization2|23|0更新时间：2025-12-08
- 摘要：Conventional joint source-channel coded modulation is based on bit-level or fix-length symbol-level demodulation and decoding, derived from Shannon’s separation theory in 1940s. Uniform distribution and equiprobable constellation mapping are used, but they are not suitable for dynamic multipath channels. Meanwhile, the assumption of separation theory cannot be satisfied in source limited communication networks, and obstacles such as reliability and power consumption cannot be surmounted faced by the development of communication technology. The limitation of bit-level and fix-length symbol-level modulation/demodulation and decoding is paid attention. By combining variable-length joint source-channel coding with non-equiprobable and optimized unequal APSK(Amplitude Phase Shift Keying) modulation constellation mapping, a method of joint source-channel coding modulation for non-equiprobable variable-length symbols is proposed. The simulation experiments show that the proposed method obtains an SNR(Signal Noise Ratio) gain over 2.5dB compared to the existing symbol-level 2D-8PSK method, and an SNR（Signal Noise Ratio） gain over 1.1dB compared to existed bit-level 16APSK method, under the SER(Symbol Error Rate) of the order of -5 of 10.关键词：joint source-channel encoding/decoding;modulation for non-equiprobable symbols;unequal constellation mapping4|13|1更新时间：2025-12-08
- 摘要：In order to improve the global and local fine search capabilities of the particle swarm algorithm and accelerate the convergence speed, hybrid particle swarm optimization algorithm based on intuitive fuzzy entropy is proposed. The algorithm constructs an adaptive function of intuitive fuzzy entropy by using the information of the historical optimal solution of particles, and uses the entropy value as a disturbance factor to dynamically adjust the inertia weight. At the same time, it establishes an adaptive global optimal particle learning strategy to train the disturbed particles, chooses learning objects based on maintaining the diversity of propagation, enables the particles to explore more new areas, and realizes the cooperation and parallel evolution among populations. Through simulation experiments, the algorithm is compared with two derivation algorithms and other improved particle swarm optimization algorithms on 11 test functions. The results show that the algorithm performs better in solving accuracy, convergence speed and optimization efficiency.关键词：intuitionistic fuzzy entropy;disturbance factor;particle swarm optimization;adaptive learning;collaboration and parallel evolution3|13|9更新时间：2025-12-08
- 摘要：Bitcoin introduces a new P2P(Peer to Peer) trading method to the public and relies on its protocols to achieve decentralization. However, due to the lack of fine-grained formal analysis and systematic modeling of bitcoin, the security of bitcoin protocols is not guaranteed. We provide a comprehensive symbolic analysis of bitcoin protocols. Our work develops bitcoin model rules and model lemmas with the abstraction of in-protocol interactions and inter-protocols interactions. We refine the modeling of bitcoin protocol entities and their related protocol operations compared to the previous work, along with the comprehensive design of the security lemmas that bitcoin protocols should guarantee. The symbolic model rules and lemmas developed in our work are inputted into the automatic formal verification system SmartVerif. We find the computational power stealing attack and no additional manual work is needed for the model verification with the help of the SmartVerif.关键词：bitcoin;blockchain;protocol security;symbolic model;formal analysis2|16|3更新时间：2025-12-08
- 摘要：Limited by environment, resources, energy consumption, heterogeneity, etc., the development of maritime wireless data network technology is backward. A model of cloud-edge cooperative service scheme for maritime edge computing(MCECS-MEC) is proposed. Based on edge computing, it constructs an intelligent cloud-edge cooperative service network framework in maritime edge computing. The abstracted behavior characteristics of nodes in maritime edge computing are clustered into different cooperative service pools by restraining the joint cheating trust evaluation and recommendation quantitative comprehensive evaluation models. Based on the priority evaluation and the theory of load balancing of cooperative service, the rules of building cooperative service pool and the algorithm of segment page adaptive lightweight and heavy load avoidance are designed to discovery cooperative node. The state evolution of MCECS-MEC cooperative service is described and analyzed by state machine. Based on router view open data set, simulation results show that our algorithm reduces 57.7% and 55.04% redundant transmission traffic compared with ad hoc on-demand distance vector routing(AODV) and stochastic routing(SR). The link retransmission rate is less than 3%, and the load rate is stable at 65%. It can effectively alleviate node overload and hot region, and improve the efficiency and quality of service of cooperative service of maritime edge computing.关键词：maritime edge computing;intelligent cloud-edge cooperation;trusted recommendation;adaptive over hot avoidance;the state evolution of cooperation4|17|2更新时间：2025-12-08
- 摘要：Aiming at a kind of widely existing distributed permutation flow-shop and vehicle transportation integrated scheduling problem(DPFVTISP), this paper establishes the problem model and proposes a hyper-heuristic three-dimensional estimation of distribution algorithm(HH3DEDA) to solve it. Firstly, a novel coding and decoding rules adopting the greedy strategy is designed via analyzing the characteristics of DPFVTISP. Secondly, in order to search different regions in the solution space of DPFVTISP, ten kinds of low-layer heuristic operations, i.e., ten kinds of effective neighborhood operations, are designed, and their permutations are regarded as high-layer individuals. At the same time, the three-dimensional estimation of distribution algorithm (3DEDA) is used in the high layer to learn and accumulate the information of block structures and their positions in the high-quality high-layer individuals, and then new low-layer individuals or permutations are generated by sampling the probability model in 3DEDA. Furthermore, in the low layer, an ordered series of heuristic operations presenting by each new individual generated in the high layer is regarded as a new heuristic algorithm to execute further neighborhood search in the problem’s solution space. Finally, simulations and comparisons demonstrate that HH3DEDA can effectively solve the DPFVTISP.关键词：distributed permutation flow-shop;vehicle transportation;integrated scheduling;hyper-heuristic algorithm;three-dimensional estimation of distribution algorithm;block structure5|17|1更新时间：2025-12-08
- 摘要：Human pose estimation is one of the hot research topics in the field of computer vision, but its application in traditional dance pose estimation is still in its infancy. Due to the complexity of dance pose, the strong coherence of dance movements, and difficulty in detecting of dancers＇ poses caused by serious occlusion in dance images, the traditional human pose estimation methods are difficult to accurately estimate the pose changes of dancers, thus resulting in low accuracy in estimating dance pose. We propose a hierarchical dance pose estimation method based on sequential multi-scale feature fusion. To address the problems of the drastic scale changes of the dancer pose, a keypoint estimation model based on sequential multi-scale feature fusion is constructed. Furthermore, aiming to solve the issues that the large deformation and serious occlusion of dance pose, a hierarchical pose estimation model based on the geometric relationship between human keypoints is designed to improve the accuracy of dance pose estimation. The experimental results show that the proposed method can achieve good pose estimation results on the standard human pose estimation dataset and the self-collected dance dataset.关键词：dance pose estimation;sequential multi-scale feature fusion;geometry relationship among keypoints;hierarchical pose estimation6|14|1更新时间：2025-12-08
- 摘要：For the accuracy and robustness of the blurry face image recognition in various special scenarios; this paper proposes a novel rotation delta modulation texture extraction method based on trace transform and delta modulation encoding. The method combines the communication speech coding with the image transformation technology. Firstly, the whole image is scanned by the rotating trace line based on trace transformation theory. Secondly, the sampled pixels on the trace line are encoded used delta modulation technology. The global ordered structure features are obtained in various angles. Finally, the features are trained by support vector machine for blurry face image classification and recognition. The experimental results indicate the proposed method has the better performance of blurry face image recognition under illumination fluctuations, various camera angles and image occlusions, and so on, on a variety of low-quality face image sets with different blur levels. The average recognition ratio are increased 2.18% and 2.20% compared to VGG and Sphereface methods on the face image sets with three blur levels, which indicates the proposed method has the higher accuracy and better robustness.关键词：blurry face image recognition;feature extraction;trace transformation;rotational delta modulation2|13|4更新时间：2025-12-08
- 摘要：In order to study the micro-characteristics of the electrode discharge in the spark test device in vacuum, this paper established a two-dimensional parallel plate discharge model in a vacuum environment with tungsten as the anode material and cadmium as the cathode material. We simulate the model with the PIC/MCC(Particle-In-Cell/Monte Carlo Collision) method, studies the development process of parallel plate electrode discharge under different electron emission mechanisms and the influence of space field strength, cathode surface temperature and field enhancement factor on the changes of space electrons, and obtains the field emission, thermal emission and thermal-field emission changes in the electron concentration and anode absorption current during the discharge process, as well as the spatial distribution of the electron density and electric potential, etc. The research has found that field emission is the dominant emission mechanism of micro-gap cathode electron emission. When the cathode surface temperature reaches 1040K, the boiling point of cadmium metal under the action of Joule heat, cadmium vapor will be generated, and the current density and electron concentration will gradually increase. At this time, the thermal emission will start to act on the micro-gap discharge. When the temperature is greater than the vaporization temperature of cadmium metal, the influence of the field strength will be greater than that of the temperature. When the field enhancement factor is very small, the thermal emission is almost ineffective. As the field enhancement factor continues to increase, the effect of thermal emission gradually increases, leading to a significant increase in the spatial electron concentration. The micro-gap discharge in a vacuum environment is caused by the combined effect of heat and field.关键词：field emission;micro gap;PIC/MCC;field enhancement factor;spark test device2|17|0更新时间：2025-12-08
- 摘要：In order to solve the problem of the limited number of sequences in the traditional complementary sequence sets, some scholars have proposed the concept of complete complementary code sets(CCCs) with low inter-set cross-correlation in recent years. Complete complementary code sets with low inter-set cross-correlation have perfect aperiodic auto-correlation and cross-correlation properties. As the spreading code in the multi-cell MC-CDMA communication system, CCCs can effectively eliminate intra-cell interference and suppress inter-cell interference. Two constructions of complete complementary code sets with low inter-set correlation are developed, and the resultant complementary sequence sets have the following properties: (1) each set is a complete complementary code set with parameters (N,N,N)?CCC; (2) complementary sequences from different sets have low correlation functions. Finally, an asymptotically optimal quasi-complementary sequence set is obtained when these multiple complete complementary code sets are combined .关键词：complementary sequence sets;complete complementary codes;quasi-complementary sequence sets;asymptotically optimal;inter-set cross-correlation;MC-CDMA system2|62|0更新时间：2025-12-08
- 摘要：Post quantum cryptography based on non-commutative group is a hot topic in cryptography. The order of the group ensures the difficulty of inverse operation to some extent. We mainly study the algebraic proposition of order of transitive permutation groups <g1,?g2> generated by two elements g1,?g2, give a necessary and sufficient conditions of transitive permutation group, and get a lower bound estimation of order of transitive permutation groups generated by two elements. In the process of the instantiation for generating g1,g2 which enables the order of transitive permutation groups <g1,?g2> to satisfy the corresponding lower bound value, we give a method expressing a class of special n?order cycles as the product of two n?ary permutations and a corresponding design algorithm on transitive permutation groups <g1,?g2> generated by two elements. In the end, this paper describes the application of transitive permutation group in symmetric cryptography.关键词：post quantum cryptography;finite group;transitive permutation group;order of group;element order;lower bound2|59|0更新时间：2025-12-08
- 摘要：Cache management has become a research hotspot in opportunistic networks. At present, most cache management methods are concentrated on single node. In this paper, we propose a cache sharing resource scheduling method for collaborative groups under the background of campus collaborative learning. Node activity describes the cache space utilization of mobile nodes and the enthusiasm of nodes to participate in message forwarding. Message tree describes the degree of message diffusion in the network. A linked list of delivered messages is established based on the collaboration group, and the cache space occupied by the successfully delivered messages is released in time. This method can effectively improve the node space utilization and message delivery rate, and reduce the message delivery delay. The experimental results show that, compared with the existing algorithms, the success rate of message delivery is increased by 10.53% on average, which provides a method for the sharing and utilization of group cache and the efficient scheduling of resources.关键词：collaborative learning;opportunistic network;cache scheduling;message tree;activity2|15|1更新时间：2025-12-08
PAPERS
- 摘要：In recent years, swarm intelligence, as a novel multi-disciplinary technology, has made remarkable achievements in various fields, such as shared traffic, swarm unmanned aerial vehicle system, underwater multi-agent platform, and so on, but the swarm intelligence technology combined with underwater scene is lack of systematic induction. Therefore, it is necessary to discuss and analyze the development status and trend of underwater swarm intelligence technology. This review aims to study and summarize the underwater swarm intelligence technology. It makes a complete introduction to the swarm intelligence theory, and gives the complete concept, specific algorithm and application field of swarm intelligence. And swarm intelligence technology needs to be applied to underwater scenes in order to solve a series of difficulties caused by complex marine environment. This review summarizes the research status of underwater swarm intelligence technology at home and abroad, and comments on the difficulties of underwater swarm intelligence, such as complex environment, limited communication, difficult information acquisition, insufficient system capacity and limited energy supply. In addition, aiming at these difficulties, this review analyzes the time-varying environment perception technology, underwater sensor network, collaborative navigation and positioning technology, path planning technology, underwater formation control and distributed autonomous decision-making technology combined with swarm intelligence theory, and gives the future application of underwater swarm intelligence technology in cross domain communication, multi-platform heterogeneous development trend and prospect of innovation of independent operation ability.关键词：swarm intelligence;underwater robot;intelligence control;multi-agent;autonomous underwater vehicle (AUV);particle swarm optimization;distributed system;underwater communication2|22|10更新时间：2025-12-08
- 摘要：Distributed acoustic sensor arrays have been widely employed in many applications, such as military reconnaissance, security monitoring, man-machine interaction, etc. However, the problems of clock asynchrony, frequency response mismatch and unknown node location seriously affect the performance of subsequent speech processing algorithms based on distributed acoustic sensor arrays. Therefore, scholars have been keen to study calibration methods for these three problems in recent years. This article first introduces the causes of these mismatch problems and the sequence of solving the three problems. Then, the existing methods for these three problems are reviewed. Specifically, clock synchronization methods mainly include methods based on timestamp exchange and linear phase shift in short‑time Fourier transform domain, frequency response calibration methods mainly include methods based on steering vector of sound source and adaptive filter, and node position/pose calibration methods mainly include methods based on geometric configuration among nodes and deep learning. Finally, the future research directions are provided.关键词：distributed acoustic sensor array;array mismatch;array calibration;position calibration;frequency response calibration;clock synchronization3|15|2更新时间：2025-12-08
- 摘要：The regular language inference is devoted to the study of how to derive the definition of the language from the limited information. Regular language inference is popular in information extraction, software engineering, and schema learning, etc. The learnability models of regular languages and evaluation criteria are clarified. The passive, active, and neural network‑based learning algorithms are respectively surveyed and compared from the aspects of reasoning strategies, data structures, algorithm complexity, etc, and the development trend is pointed out. Three kinds of generalization effects are analyzed. This paper points out the defects of the current researches and looks forward to future research directions.关键词：regular languages;inductive inference;regular inference;automata learning;regular expression learning;recurrent neural network (RNN)12|17|0更新时间：2025-12-08
SURVEYS AND REVIEWS
- 摘要：A method of suppressing the cross polarisation of a miniaturised circularly polarised(CP) microstrip antenna at low elevation angle is studied. A crossed slot on the radiation patch is utilised to miniaturise the proposed antenna, the antenna height is 0.777 times the wavelength, and the antenna diameter is 0.123 times the wavelength. Furthermore, the cross polarisation of the antenna at low elevation angle is analysed with different ground types, and a compact meander-line ring cavity(MLRC) ground is proposed. The cross polarisation at low elevation angle can be reduced significantly for the antenna with a compact MLRC, and the axial ratio(AR) is also improved in the whole upper-half space. The achieved height and diameter of the cavity are just 0.064 times the wavelength and 0.448 times the wavelength. The impedance bandwidth for voltage standingwave ratio（VSWR） less than 2 is 20.8%, and the CP bandwidth for AR less than 3dB is 8.5%. From the zenith to the horizontal, the cross-polarised levels are not greater than 23.2dB. The beamwidth for AR less than 3dB reaches more than 190°.关键词：circularly polarised;antenna;cross polarisation;meander-line ring cavity;low elevation angle;the CP bandwidth4|17|2更新时间：2025-12-08
CORRESPONDENCE
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