Horn Antenna has many applications such as communication, radar, and standard reference antenna for measurement. In this research, we designed a pyramidal horn for a Circularly Polarized Synthetic Aperture Radar (CP-S...Horn Antenna has many applications such as communication, radar, and standard reference antenna for measurement. In this research, we designed a pyramidal horn for a Circularly Polarized Synthetic Aperture Radar (CP-SAR) sensor onboard a microsatellite. We utilized a 3D printer with Fused Deposition Modelling (FDM) technology for fast, low-cost, and low-weight production. Polylactide (PLA) material was used to construct 3D structures, and a copper conductive coating was painted on its surface. Gaussian distribution function was employed to create a septum polarizer profile. NPC-220 A with 1.6 thickness and 2.17 dielectric constant was used to make a microstrip monopole antenna and stripline feeding to feed the pyramidal horn to generate TE01 mode at one side of the waveguide. The design, parametric studies, and measurements are discussed in this paper. The designed antenna can achieve wide bandwidth 28% of 3 dB axial ratio, and more than 22% of s11 ≤ −10 dB in working frequency that is acceptable for CP-SAR requirement on the microsatellite.展开更多
This paper presents the development of circularly polarized microstrip antenna using Kevlar honeycomb core as the substrates for application of CP-SAR （circularly polarized synthetic aperture radar） which signal pro...This paper presents the development of circularly polarized microstrip antenna using Kevlar honeycomb core as the substrates for application of CP-SAR （circularly polarized synthetic aperture radar） which signal propagation is not affected by Faraday rotation effect in the ionosphere, as compared to linearly polarized systems especially at the L-band. The reason why Kevlar honeycomb core is used is because it is suitable for space environment in terms of lightweight and resistant to heat and shock. Measurements of the fabricated antenna were performed to confirm the simulation results. The results show good characteristics of the antennas except the axial ratio. The reason of insufficient axial ratio is assumed as fabrication error of the radiator and microstrip line.展开更多
An improved algorithm for multi-polarization reconstruction from compact polarimetry （CP） is proposed. According to two fundamental assumptions in compact polarimetric reconstruction, two improvements are proposed. ...An improved algorithm for multi-polarization reconstruction from compact polarimetry （CP） is proposed. According to two fundamental assumptions in compact polarimetric reconstruction, two improvements are proposed. Firstly, the four-component model-based decomposition algorithm is modified with a new volume scattering model. The decomposed helix scattering component is then used to deal with the non-reflection symmetry condition in compact polarimetric measurements. Using the decomposed power and considering the scattering mechanism of each component, an average relationship between copolarized and crosspolarized channels is developed over the original polarization state extrapolation model. E-SAR polarimetric data acquired over the Oberpfaffenhofen area and JPL/AIRSAR polarimetric data acquired over San Francisco are used for verification, and good reconstruction results are obtained, demonstrating the effectiveness of the proposed algorithm.展开更多
文摘Horn Antenna has many applications such as communication, radar, and standard reference antenna for measurement. In this research, we designed a pyramidal horn for a Circularly Polarized Synthetic Aperture Radar (CP-SAR) sensor onboard a microsatellite. We utilized a 3D printer with Fused Deposition Modelling (FDM) technology for fast, low-cost, and low-weight production. Polylactide (PLA) material was used to construct 3D structures, and a copper conductive coating was painted on its surface. Gaussian distribution function was employed to create a septum polarizer profile. NPC-220 A with 1.6 thickness and 2.17 dielectric constant was used to make a microstrip monopole antenna and stripline feeding to feed the pyramidal horn to generate TE01 mode at one side of the waveguide. The design, parametric studies, and measurements are discussed in this paper. The designed antenna can achieve wide bandwidth 28% of 3 dB axial ratio, and more than 22% of s11 ≤ −10 dB in working frequency that is acceptable for CP-SAR requirement on the microsatellite.
文摘This paper presents the development of circularly polarized microstrip antenna using Kevlar honeycomb core as the substrates for application of CP-SAR （circularly polarized synthetic aperture radar） which signal propagation is not affected by Faraday rotation effect in the ionosphere, as compared to linearly polarized systems especially at the L-band. The reason why Kevlar honeycomb core is used is because it is suitable for space environment in terms of lightweight and resistant to heat and shock. Measurements of the fabricated antenna were performed to confirm the simulation results. The results show good characteristics of the antennas except the axial ratio. The reason of insufficient axial ratio is assumed as fabrication error of the radiator and microstrip line.
基金supported by the National Natural Science Foundation of China(41171317)the State Key Program of the Natural Science Foundation of China(61132008)the Research Foundation of Tsinghua University
文摘An improved algorithm for multi-polarization reconstruction from compact polarimetry （CP） is proposed. According to two fundamental assumptions in compact polarimetric reconstruction, two improvements are proposed. Firstly, the four-component model-based decomposition algorithm is modified with a new volume scattering model. The decomposed helix scattering component is then used to deal with the non-reflection symmetry condition in compact polarimetric measurements. Using the decomposed power and considering the scattering mechanism of each component, an average relationship between copolarized and crosspolarized channels is developed over the original polarization state extrapolation model. E-SAR polarimetric data acquired over the Oberpfaffenhofen area and JPL/AIRSAR polarimetric data acquired over San Francisco are used for verification, and good reconstruction results are obtained, demonstrating the effectiveness of the proposed algorithm.
