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1. chinaXiv:201703.00300 [pdf]

Design of X/Ku dual-band dual-linear polarization reflectarray using double parallel dipole elements

Xue, Fei; Wang, Hongjian; Yi, Min
Subjects: Geosciences >> Space Physics

Two single-layer X/Ku dual-band dual-polarization reflectarray antennas of different sizes with double parallel dipole elements are presented. Elements of the two bands are set to two orthogonal linear polarizations and placed in interlaced grid. The proposed reflectarrays operate in two frequency-bands within X-band centered at 10 GHz and Ku-band centered at 13.58 GHz. The smaller size reflectarray with elements arranged in a 13 �13 grid for X-band and in a 12 �12 grid for Ku-band is designed and simulated first. Based on the excellent dual-band performance of the small size reflectarray, then a larger size prototype has been designed, manufactured and measured. Measured results demonstrate the maximum gain of 28.54 dB with 50.93% aperture efficiency at 10 GHz and 31.06 dB with 51.34% aperture efficiency at 13.58 GHz, which show desirable dual-band dual-polarization radiation performance.

submitted time 2017-03-10 Hits2458Downloads397 Comment 0

2. chinaXiv:201703.00295 [pdf]

A broadband reflectarray using patch with slot ring on ground plane elements

Xue, Fei; Wang, Hongjian; Yi, Min; Dong, Xingchao
Subjects: Geosciences >> Space Physics

A broadband center-fed reflectarray antenna is presented in this paper. Patch with slot ring on ground plane elements are used for bandwidth improvement. It is shown that quasi-linear phase responses with broad frequency band can be achieved by such a phasing element. An 11�1 elements reflectarray is designed and simulated. The results show that the simulated gain is 23.92 dB at the center frequency of 13.58 GHz with 3-dB bandwidth of 52%, which demonstrate significant broadband operation compared with that of conventional reflectarray.

submitted time 2017-03-10 Hits1222Downloads408 Comment 0

3. chinaXiv:201703.00293 [pdf]

A new broadband reflectarray antenna using novel single-layer elements

Xue, Fei; Wang, Hongjian; Yi, Min
Subjects: Geosciences >> Space Physics

A novel single-layer reflectarray element for broadband use is proposed. Ansoft HFSS is used to analyze the reflection phase for the element. By varying the element size, a slow slope of the reflection phase curve with the phase range over 600° is achieved. A center-fed 121-element reflectarray antenna is designed using the proposed elements and a linearly polarized pyramidal horn antenna is used as the feed of the reflectarray. The simulated results show that the gain of 24.42dB at the center frequency of 13.58GHz with 3-dB gain bandwidth of 36.8% (from 11.08∼16.08GHz), demonstrating a wideband performance compared to the conventional designs.

submitted time 2017-03-10 Hits562Downloads310 Comment 0

4. chinaXiv:201703.00290 [pdf]

Deconvolution method for resolution enhancement of Dual-Frequency Polarized Scatterometer

Liu, Liling; Dong, Xiaolong; Zhu, Jintai; Zhu, Di
Subjects: Geosciences >> Space Physics

Dual-Frequency Polarized Scatterometer (DFPSCAT) is a new system utilizing Doppler beam sharpening (DBS) technology for azimuthal resolution enhancement. Considering the DBS technology is inapplicable for the middle areas of the swath, a theoretical framework of deconvolution signal processing is proposed to improve resolution. A deconvolution method of the nonlocally centralized sparse representation (NCSR) is adopted to verify its feasibility, and simulation results show that the deconvolution method have obviously better resolution enhancement and higher recovery accuracy than these of the classical scatterometer image reconstruction (SIR) method. �2016 IEEE.

submitted time 2017-03-10 Hits1516Downloads434 Comment 0

5. chinaXiv:201703.00289 [pdf]

Estimating the sea state bias of HY-2A radar altimeter by using a three-dimentional nonparametric model

Jiang, Maofei; Xu, Ke; Liu, Yalong; Wang, Lei
Subjects: Geosciences >> Space Physics

The sea state bias (SSB) has become the dominant source of error in satellite altimetry. The operational SSB correction models are two-dimensional (2-D) nonparametric models based on the wind speed (U) and the significant wave height (SWH) that can be directly measured by the altimeters. This paper estimates the sea state bias of HY-2A radar altimeter using a three-dimensional (3-D) nonparametric model based on SWH from HY-2A interim geophysical dataset records (IGDR), U and the mean wave period (MWP) from the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis project ERA-Interim. The 3-D SSB estimates can increase the explained variance by 1.72 cm2, or 1.31 cm RMS relative to the traditional 2-D SSB estimates based on U and SWH. �2016 IEEE.

submitted time 2017-03-10 Hits1167Downloads338 Comment 0

6. chinaXiv:201703.00286 [pdf]

Temperature and humidity profiles retrieving over land using clear sky measurements of microwave humidity-temperature sounder on Chinese FY-3C satellite

He, Qiurui; Wang, Zhenzhan; He, Jieying
Subjects: Geosciences >> Space Physics

An one-dimensional variational retrieval system was developed to retrieve the clear sky atmospheric temperature and humidity profiles over land using the measurements of microwave humidity-temperature sounder (MWHTS) on Chinese FY-3C satellite. The system parameters are configured by analyzing the MWHTS channel properties and the climate condition over land. The retrieval results are evaluated by root mean square error (rmse) with respect to European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis data. The validated results show that the maximum root mean square error of temperature and humidity are 2.59K and 11.87%, respectively. The retrieval results, compared with National Centers for Environmental Prediction (NCEP) 6 hour forecast profiles, show that the background profiles can affect the accuracy of retrieval profiles and FY-3C/MWHTS measurements can improve forecast precision of humidity. �2016 IEEE.

submitted time 2017-03-10 Hits3157Downloads384 Comment 0

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