Current Issue : October - December Volume : 2020 Issue Number : 4 Articles : 5 Articles
A wideband circularly polarized (CP) antenna is presented to achieve enhanced impedance, axial ratio (AR), and gain bandwidths.\nThe antenna consists of two circular patches, a split-ring microstrip line with six probes, and a circular ground plane. By using\nthese six probes which are placed in sequence on the split-ring microstrip line, the operating bandwidth of the proposed antenna is\nincreased. The characteristic mode method is used to analyze different modes of the antenna and reveal the mechanism of\nextending the 3-dB AR bandwidth. Measured results show that the proposed antenna obtains an impedance bandwidth of......................
We propose a novel array antenna with high aperture efficiency by employing an array\nelement operating in a high-order mode to improve the transmission efficiency of wireless power\ntransmission applications. The proposed array element, operating at a frequency of 5.8 GHz, consists of\na square patch with four metallic shorting pins, an extended cavity, and a high dielectric superstrate.\nThe four metallic shorting pins derive the high-order operation, which can enhance the bore-sight\ngain, resulting in the high aperture efficiency of the array. The extended cavity structure can help\nfurther improvement the aperture efficiency and minimize the mutual coupling strength between\nadjacent elements. The proposed antenna element is extended......................
In order to realize the miniaturization of quasi-Yagi antenna array, an antenna array with split-ring resonators (SRRs) based on\ntwo 7 units quasi-Yagi elements is designed in this paper. The radiation performance of the quasi-Yagi antenna array degrades\nsignificantly when array element spacing is reduced. After embedding SRRs on both sides of the miniaturized dielectric substrate\nsurface, the S parameters and gain of array are significantly better than the array without SRRs, and the adjustable wave beam\nenergy is also enhanced effectively. It indicates that the proposed antenna array with SRRs has good directional radiation\nperformance under the miniaturize process at the operation frequency of 2.45 GHz, which could be widely applied in the fields of\nsmart rail transportation and wireless power transfer....
The design of multiband microstrip rectenna for radio frequency energy harvesting\napplications is presented in this paper. The designed antenna has\ngood performance in the GSM-900/1800, WiFi and WLAN bands. In addition,\nthe rectifier circuit is designed at multi resonant frequencies to collect\nthe largest amount of RF ambient power from different RF sources. The developed\nantenna is matched with the rectifier at four desired frequencies using\nseveral rectifier branches to collect the largest of RF power. The proposed\nrectenna is printed on FR4 substrate with modified ground plane to achieve\nsuitable impedance bandwidth. The proposed antenna consists of elliptical\nradiating plane with stubs and stepped modified ground plane. The rectenna\nresonates at quad frequency bands at (GSM 900/1800, WiFi band and WLAN\nbands) with rectifier power conversion efficiency up to 56.4% at 0 dBm input\npower using the HSMS-2850 Schottky diode. The efficiency is more enhanced\nby using SMS-7630-061 Schottky diode which is characterized by a low junction\ncapacitance and a low threshold voltage to achieve higher conversion efficiency\nup to 71.1% at the same 0 dBm input power for the same resonating\nfrequency band....
Polarized smart antenna array has attracted considerable interest due to its capacity of matched reception or interference\nsuppression for active sensing systems. Existing literature does not take full advantage of the combination of polarization isolation\nand smart antennas and only focuses on uniform linear array (ULA). In this paper, an innovative synthesis two-dimensional\nbeampattern method with a null that has cross-polarization for polarized planar arrays is proposed in the first stage. This method\naims to further enhance the capability of interference suppression whose optimization problem can be solved by second-order\nconic programming. In the second stage, a new sparse array-optimized method for the polarized antenna array is proposed to\nreduce the high cost caused by the planar array that is composed of polarized dipole antennas. Numerical examples are provided to\ndemonstrate the advantages of the proposed approach over state-of-the-art methods....
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