The patch shape of microstrip patch antenna is an important factor affecting the performance of the antenna, in order to make the microwave antenna miniaturization, high gain performance requirements, respectively, k-band operating frequency at 24GHz rectangular and circular coaxial fed microstrip antenna simulation, compare the performance and size of the circular and rectangular microstrip antenna, the dielectric substrate using Rogers 4350, the dielectric constant of 3.66, the thickness of substrate is 0.5mm. The simulation results show that the circular coaxial fed microstrip antenna operating at 24GHz is superior to the rectangular microstrip antenna in terms of size and performance, and this structure can be used in the development of small microwave sensors for the transmission and reception of microwave signals.
We present a dynamic DNA coding multi-image encryption algorithm based on integer lifting wavelet transform and compound chaos. In the encryption process, the low-frequency sub-bands of four plaintexts are extracted to get a combined image containing the multiple plaintext image information. With the help of a chaotic system, the pixel positions and pixel values of the combined image are modified by the permutation and the diffusion operations. Then we divide the image into equal-sized blocks, and the dynamic DNA coding method is used to complete the final encryption. To enhance security, we employ the RSA algorithm to protect the keys used in our encryption algorithm. Simulation results and security analysis demonstrate the robustness and the security.
Branch-cut is a classical algorithm in phase unwrapping algorithm based on path-following approach. Goldstein’s branch-cuts algorithm is prone to generate large enclosed areas and produce longer branch-cuts. Models inspired by biosystems can provide new insights into complex computing problems in the real-world. A unicellular and multi-headed slime mold, named as Physarum polycephalum, has been a research hotspot over the last few years. According to the two characteristics of Physarum: the adaptive shortest path finding and adaptive network formation, researchers combined the Hagen-Poiseuille and Kirchhoff law to establish bionic mathematical model: the maze-solving model to get shortest path between two points and multiply sources model for designing efficient network. In this paper, based on these bionic models, combined with the foraging characteristics of Physarum, a biologically inspired algorithm called Physarum Foraging Algorithm (PFA) is proposed for allocation problems of branch-cuts. Firstly, according to the distribution characteristics of residues in the interference fringes map, the residues were processed; secondly, using the bionic model to build a branch-cuts network between residues; finally, the Physarum exhibits a characteristic that the critical tubes are reserved in the process of foraging, using this unique feature to optimize the branch-cuts network, then complete reconstruction of branch-cuts. PFA cannot only significantly cut down the overall length of branch-cuts but also effectively overcome the ‘isolated island phenomenon’ in the unwrapping process. Experimental result showed that the algorithm implements optimal allocation problems of branch-cuts which greatly improves the accuracy of phase unwrapping.
Choosing a reasonable examination way is beneficial to the cultivation of high quality talents. Recently, the conventional college examination methods involve writing and oral test, which is extremely focused on academic performance and caused the separation between teachers and examinations. Optoelectronic detection technology is a specialized course with strong applicability. Therefore, we proposed a diverse form and scientific content method. It is proved that the students receive better learning effect and improve learning and engineering practice ability compared with the traditional assessment methods.
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