共查询到17条相似文献,搜索用时 375 毫秒
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1W微波无线输电系统的发射端设计 总被引:2,自引:0,他引:2
介绍了一种小功率(1 W)、2.45 GHz微波无线输电系统的发射端设计。直流电平经过锁相频率合成芯片ADF4360-0转换为S波段的2.45 GHz微波信号,ADF4360-0的寄存器配置由MSP430控制;2.45 GHz微波信号经过由功放芯片ERA-5SM及ADL5606组成的驱动级功率放大器将功率放大到1 W,加上喇叭天线即组成了小功率微波输电系统的发射端。利用矩形微带整流天线接收并整流微波信号,整流后的直流电平供给负载,便形成了完整的微波无线输电系统。详细分析了设计参数与方法,并进行了仿真及验证试验。 相似文献
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2022年10月,在西安利用地基微波辐射计进行常规大气观测实验期间,发现一个频率约为25 GHz的卫星发射信号,对微波辐射计常规观测产生了明显干扰。针对该观测事实,文章首次对微波辐射计被动遥感观测卫星发射电磁波信号的可行性进行了理论分析和针对性观测实验,结果发现该卫星发射信号主要在24.4~25.6 GHz范围内,中心频率约为25 GHz,同轨道共有3颗卫星,飞行间隔约8 h,在25 GHz附近卫星发射电磁波到达微波辐射计天线口面辐射亮温超过400 K;该组卫星轨道周期为24 h,属于倾斜同步轨道卫星。进一步利用微波辐射计观测的亮温,深入分析计算得到卫星的等效辐射功率约为66.9 dBW。本次实验观测为地基微波辐射计未来避免卫星的干扰和进一步改进设计与应用积累了经验,同时也可以看出地基微波辐射计在卫星跟踪监测中有一定的应用价值。 相似文献
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通过拓展冻土介电常数模型、寒冷环境植被介电常数模型,将Matrix-Doubling算法发展为适用于寒冷环境的幼林微波辐射模型。然后利用该模型模拟寒冷环境下幼林在Ku(18.7 GHz)、Ka(36.5 GHz)波段上的亮度温度并与车载微波辐射计获得的实测亮度温度对比,进行模型验证。最后,用发展后的Matrix\|Doubling模型模拟的结果和相同环境下ω-τ模型的结果进行匹配,反演出幼林在Ku、Ka波段上的等效单散射反照率和光学厚度,为用微波遥感监测地表冻融过程中去除植被对地表微波辐射的影响提供了一种有效方法。
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综合孔径微波辐射计的技术发展及其应用展望 总被引:10,自引:3,他引:7
介绍了综合孔径微波辐射计成像的基本原理, 回顾了干涉式综合孔径技术在过去十余年间的发展历程, 较详细地介绍并分析了目前世界上已有或在研的综合孔径微波辐射计系统, 其中包括美国的ESTAR 及其2D2STAR , GeoSTAR 计划, 欧空局SMO S 计划上的主载荷MIRAS, 芬兰赫尔辛基技术大学的HUT 22D, 以及中科院空间中心研制的C 波段及X 波段综合孔径微波辐射计等。最后, 对干涉式综合孔径技术的应用前景作了简要介绍与展望。 相似文献
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A. K. SEN R. BERA M. K. SENGUPTA AJOY K. DATTA G. TARAFDER S. CHATTOPADHYAY 《International journal of remote sensing》2013,34(16):3031-3040
Abstract Radiometry at the water vapour line with a scanning antenna beam from horizon to horizon through the zenith, in the vertical plane, was shown to be useful in estimating the integrated water vapour content from the zenith angle variation of radiometric temperature. The beam scanning may be made at a rate slower than the radiometer time constant using a Dicke type radiometer. Alternatively, a fast scanning beam may be used in a total power radiometer with a synchronous detection of the radiometer output at the scanning frequency to obtain a space domain Dicke switching for the measurements. A simultaneous scanning beam with 22.235 and 31.4GHz radiometers would allow us to separate the liquid water, if any, from the integrated water vapour content. Theoretical studies of the scanning beam radiometer performance in the estimation of integrated water vapour content from radiosonde data is presented and some typical results of Dicke type scanning beam radiometers at 22.235 and 31.4 GHz are also presented in this paper. 相似文献
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A novel coplanar waveguide fed UWB antenna with quad notch band characteristics has been proposed in this work. The antenna layout is designed based on a combination of well‐known geometrical shapes: a half ellipse patch, rectangle, and triangle. The shape of the ground plane is partially tapered rectangular. The overall dimension of the antenna is 41.5 × 32 mm. The antenna uses three U‐shaped slots at the top surface to create three notched band characteristics. A split‐ring resonator is then introduced at the bottom surface of the antenna. With the integration of split‐ring resonator at the bottom surface, an additional notch band at 7.25 to 7.75 (6.7%) GHz is created in the antenna. The designed antenna has an operating impedance bandwidth (VSWR ≤2) ranges from 3.03 to 12.34 GHz except in quad frequency stop bands of 3.3 to 3.7 (11.4%), 5.15 to 5.35 (3.8%), 5.725 to 5.825 (1.7%), and 7.25 to 7.75 (6.7%) GHz. The proposed antennas are successfully designed, prototyped, and measured. The simulated and measured results are extensively studied and discussed. Correlation between the time‐domain transmitting antenna input signal and the received antenna output signal is calculated in order to ensure that the proposed antenna can be used in pulse‐communication systems. This antenna finds applications in medical imaging, military radar systems, and other common UWB applications. 相似文献
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In this article, a miniaturized fork‐shaped patch ultra‐wideband (UWB) planar wide‐slot antenna with dual band‐notched characteristics is proposed. With fork‐shaped patch, ultra‐wideband impedance matching from 3.1 to 13.2 GHz is easily achieved. Then, two novel and simple methods are applied to solve the difficulty for UWB slot antennas with fork‐shaped patch to realize band‐notched characteristics. By etching one pair of I‐shaped resonators on both branches of the fork‐shaped structure and adding a rectangular single split‐ring resonator in the rectangular openings of fork‐shaped patch, the wireless local area network (WLAN) band from 5.5 to 6.1 GHz and the International Telecommunication Union (ITU) 8 GHz band from 7.9 to 8.7 GHz are rejected, respectively. The coplanar waveguide‐fed UWB antenna is successfully designed, fabricated, and measured. The measured and simulated results show a good agreement. The antenna provides nearly stable radiation patterns, high gains and high radiation efficiency. 相似文献
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Luneburg lens antennas have been widely applied to many communication systems for their multibeam scanning and high gain characteristics. However, the large profiles of conventional Luneburg lens antennas restrict their applications. To solve these issues, an ellipsoid lens antenna fed by phased array antenna (PAA) operating at Ka‐band is proposed in this article. The profile of the ellipsoid lens is reduced by half compared to the conventional Luneburg lens, based on the transformation optics theory. The wide‐angle scanning property is obtained by optimizing the amplitude and phase distributions of the PAA, combined with the element pattern superposition principle. The proposed five‐layer ellipsoid lens antenna is able to scan up to ±45° with less than 3 dB scanning loss at 28 GHz. Finally, the lens was easily fabricated through three dimensional printing technology and computer numerical control. Experimental results are in good agreement with the numerical results, thus validating the proposed design. 相似文献
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Design of a microstrip fed printed monopole antenna for bluetooth and UWB applications with WLAN notch band characteristics 下载免费PDF全文
In this article, a microstrip fed printed dual band antenna for Bluetooth (2.4–2.484 GHz) and ultra‐wide band (UWB; 3.1–10.6 GHz) applications with wireless local area network (WLAN; 5.15–5.825 GHZ) band‐notch characteristics is proposed. The desired dual band characteristic is obtained by using a spanner shape monopole with rectangular strip radiating patch, whereas the band‐notch characteristics is created by a mushroom‐like structure. The Bluetooth and notch bands can easily be controlled by the geometric parameters of the rectangular strip and mushroom structure, respectively. The proposed antenna has been designed, fabricated, and tested. It is found that the proposed antenna yields both the Bluetooth and UWB performance in the frequency regions of 2.438 to 2.495 GHz and 3.10 to 10.66 GHz, respectively for |S11| ≤ ?10 dB with an excellent rejection band of 5.14 to 5.823 GHz to prevent WLAN signals. The experimental results provide good agreement with simulated ones. Surface current distributions are used to analyze the effects of the rectangular strip and mushroom. The designed antenna exhibits nearly omnidirectional radiation patterns, stable gain along with almost constant group delay over the desired bands. Hence, the proposed antenna is expected to be suitable for both Bluetooth and UWB applications removing the WLAN band. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:66–74, 2015. 相似文献
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A W‐band low sidelobe level offset‐fed reflectarray antenna is designed, fabricated, and measured. Compared to conventional offset‐fed reflectarray antenna, the sidelobe level of proposed one is decreased significantly when the inclination angle of reflector is half of the incident angle of the feeding. At the same time, a large‐radiation‐area element is used to obtain low sidelobe level for the offset‐fed reflectarray antenna because of its large radiating element area and low specular reflection. A 52 mm× 180 mm offset‐fed reflector antenna have been designed and measured to verify the availability. From 90 to 96 GHz, measured results show that a maximum gain of 36dBi at 93 GHz, and the peak sidelobe level of 18dBc can be obtained with the proposed architecture. 相似文献