Current Issue : January - March Volume : 2020 Issue Number : 1 Articles : 5 Articles
A novel, cedar-shaped, coplanar waveguide-fed frequency reconfigurable antenna is\nproposed. The presented antenna uses low-cost FR4 substrate with a thickness of 1.6 mm. Four PIN\ndiodes are inserted on the antenna surface to variate the current distribution and alter the resonant\nfrequencies with different combinations of switches. The proposed antenna is fabricated and\nmeasured for all states, and a good agreement is seen between measured and simulated results.\nThis antenna resonates within the range of 2 GHz to 10 GHz, covering the major wireless applications\nof aviation service, wireless local area network (WLAN), worldwide interoperability for microwave\naccess (WiMAX), long distance radio telecommunications, and X-band satellite communication.\nThe proposed antenna works resourcefully with reasonable gain, significant bandwidth, directivity,\nand reflection coefficient. The proposed multiband reconfigurable antenna will pave the way\nfor future wireless communications including WLAN, WiMAX, and possibly fifth-generation\n(5G) communication....
In this paper, a wideband slot antenna element and its array with stereoscopic differentially fed structures are proposed for the\nradar system. Firstly, a series of slots and a stereoscopic differentially fed structure are designed for the antenna element, which\nmakes it possess a wide bandwidth, stable radiation characteristics, and rather high gain. Moreover, the stereoscopic feeding\nstructure can firmly support the antennaâ??s radiation structure and reduce the influence of feeding connectors on radiating\nperformance. Secondly, a 4 * 4 array is designed using the proposed antenna element. And a hierarchical feeding network is\ndesigned for the array on the basis of the stereoscopic differentially fed structure. For validation, the antenna element and 4 * 4\narray are both fabricated and measured: (1) the measured - 10 dB impedance bandwidth of the antenna element is 62%\n(6.8-12.9 GHz) and the gain within the entire band is 5-9.7 dBi and (2) the measured - 10 dB impedance bandwidth of the array is\napproximately 50% (7 to 12 GHz) with its gain being 14-19.75 dBi within the entire band. Notably, measured results agree well\nwith simulations and show great advantages over other similar antennas on bandwidth and gain....
The millimeter-wave (mmWave) antenna array plays an important role in the excellent\nperformance of wireless sensors networks (WSN) or unmanned aerial vehicle (UAV) clusters.\nHowever, the array elements are easily damaged in its harsh working environment but hard to\nbe repaired or exchanged timely, resulting in a serious decline in the beamforming performance.\nThus, accurate self-diagnosis of the failed elements is of great importance. In previous studies,\nthere are still significant difficulties for large-scale arrays under extremely low SNR. In this paper,\na diagnosis algorithm with low complexity and high reliability for the failed elements is proposed,\nwhich is based on a joint decision of communication signal and sensing echoes. Compared with the\nprevious studies, the complexity of the algorithm is reduced by the construction of low-dimensional\nfeature vectors for classification, the decoupling of the degree of arrival (DOA) estimation and the\nfailed pattern diagnosis, with the help of the sub-array division. Simulation results show that, under\nan ultra-low SNR of -12.5 dB for communication signals and -16 dB for sensing echoes, an accurate\nself-diagnosis with a block error rate lower than 8% can be realized. The study in this paper will\neffectively promote the long-term and reliable operation of the mmWave antenna array in WSN, UAV\nclusters and other similar fields....
We propose a convex optimization approach for an array synthesis pattern to enhance\nthe electromagnetic field in the gap region of a dielectric bow-tie antenna. This method allows the\ninduction of the desired antenna modes by exploiting the concurrent excitation of the structure with\nplane waves with different propagation directions and complex amplitudes. By engineering the\nexcitation coefficients of the array, different modes are excited in the bow-tie antenna and the radiation\npattern of the generated second harmonic (SH) field is modified accordingly. Using our approach,\nwe demonstrate both the feasibility of performing synthesis of the SH radiation pattern in dielectric\nantennas and the possibility of developing innovative sensing applications in photonics....
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