- 标题
- 摘要
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- 实验方案
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A broadband circularly polarized monopole antenna
摘要： A compact modified C-shaped monopole antenna with broadband circular polarization is proposed, fabricated and measured. The antenna structure is simple and only consists of combined modified C-shaped radiation patch and an improved ground plane with the overall size of 25 × 25 × 1 mm3. By cutting the corner on the modified C-shaped patch and adding triangular stubs on the ground plane, the wide impedance bandwidth and axial ratio bandwidth are achieved. The design process of the antenna is given, and the circular polarization mechanism of the circularly polarized antenna is analyzed from the surface current distributions. The measured impedance bandwidth is 95.2% (4.4-12.4 GHz) with return loss better than 10 dB, and the measured 3 dB axial ratio bandwidth is 96.8% (4.42-12.72 GHz). The peak gain is above 3.0 dBi within the working band, which indicates that it is suitable for application of ultra-wideband (UWB) wireless communication systems and satellite communication systems.
关键词： axial ratio,ultra-wideband (UWB),monopole antenna,circular polarization
更新于2025-09-23 15:23:52
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Broadband simultaneously RHCP-LHCP radiating microstrip fed rectangular slot antenna for polarization diversity applications
摘要： In this article, for the first time, an antenna that can radiate LHCP and RHCP waves simultaneously is presented. The antenna enables simultaneous transmission of both right-handed (RH) and left-handed (LH) circular polarized (CP) waves separately over an elevation range from -45 to 45 degrees from the zenith. The simultaneous radiation of dual sense CP in the different spatial directions enables the antenna to act as polarization diversity transmitter. The mechanism of virtual sequential rotation of magnetic currents inside the different parts of the slot, excited with uniform phase fields results in dual CP generation. The uniform phase orthogonal fields are generated in the different parts of the slot essentially by exciting the full wavelength rectangular slot loaded with grounded stubs, symmetrically, with a shorted microstrip line. The final design of the slot antenna arrived with a rigorous parametric study on different dimensional parameters of slot and grounded stub. The measured impedance bandwidth of 22.5% centered around 7 GHz and axial ratio bandwidth of 19% is achieved. An overlapping bandwidth of 17% is achieved where both matching and AR are very good. The measured isolation between the RHCP and LHCP in the above-mentioned elevation ranges is maintained above 10 dB. The simulated and experimental results are matching very well.
关键词： right-handed CP,magnetic currents,Mobile satellite communications,axial ratio,rectangular slot,polarization diversity,left-handed CP,simultaneous dual CP
更新于2025-09-23 15:23:52
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[IEEE 2018 International Flexible Electronics Technology Conference (IFETC) - Ottawa, ON, Canada (2018.8.7-2018.8.9)] 2018 International Flexible Electronics Technology Conference (IFETC) - Circularly Polarized Microstrip Antenna on Ultrathin PET Substrate for UHF RFID Applications
摘要： Design of a circularly polarized microstrip patch antenna on an ultrathin PET substrate of 125 μm thickness is proposed for RFID applications. Screen-printed silver coating of 25 μm thickness serves as the antenna metallization. Improved feed-design and systematic optimization of the antenna overcomes the intrinsic constrains of designing microstrip antennas on extremely thin substrate. Optimally designed feed excites a nearly square patch antenna with truncated corners to achieve good impedance and radiation characteristics. The proposed antenna exhibiting 48 MHz impedance bandwidth (896 MHz to 944 MHz) and a 16 MHz AR bandwidth (907-923 MHz), can serve as a potential candidate as a low cost UHF reader antenna for RFID applications.
关键词： Microstrip Antenna,radio-frequency identification (RFID),Circular Polarization (CP),Quarter Wave Transformer,Axial Ratio (AR)
更新于2025-09-23 15:23:52
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Design of a Circularly Polarized Dielectric Resonator Antenna with Wide Bandwidth and Low Axial Ratio Values
摘要： A circularly polarized (CP) dielectric resonator antenna (DRA) with wide bandwidth and low axial ratio (AR) values is presented in this communication. The antenna consists of a stacked DRA, and it is fed by a substrate integrated waveguide (SIW) coupling slot from the bottom. The stacked DRA structure, with high permittivity dielectric strips layered on low permittivity substrate, is adopted for bandwidth and gain benefits. Here, a pair of dielectric strips rather than a single one is placed above the coupling slot with 45° inclination for generating good CP radiation, and it is elaborately designed to provide three closely coupled CP modes, constituting a wide operating bandwidth. To facilitate the application in antenna array, a cavity-backed antenna design along with a 2×2 sub-array are further presented. To verify the design, a sub-array prototype is developed and tested at Ku-band for satellite applications, showing an impedance bandwidth of 25.1%, a wide 1-dB AR bandwidth of 15.6%, and a peak gain of 15.1dBi.
关键词： substrate integrated waveguide,low axial ratio values,wide bandwidth,Dielectric resonator antenna
更新于2025-09-23 15:22:29
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[IEEE 2018 International Conference on Current Trends towards Converging Technologies (ICCTCT) - Coimbatore (2018.3.1-2018.3.3)] 2018 International Conference on Current Trends towards Converging Technologies (ICCTCT) - Broadband Circularly Polarized U-Slot Antenna for Wireless Application
摘要： The antenna presented in this paper is a broadband circularly polarized U slot antenna. The circularly polarized radiation is achieved in this paper by suspending two separated rectangular strips from the inner edge of ground and using inverted L-shaped central feeding stub. The L-shaped stub is oriented at 90 degree with respect to grounded strips. The impedance bandwidth of the antenna proposed here varies from (4.68 - 6.42 GHz) which is 31.3% and the axial ratio bandwidth (<3 dB) is from (5.15-6.45 GHz) which is 22.4% for WLAN (ranging from 5.15 to 5.85 GHz) and WIMAX (5.8GHz,5.5 GHz) applications. The antenna is left and right hand circularly polarized in Z>0 and Z<0 directions respectively. A wide notch is cut from the ground which enhances the ARBW by 51.35% in comparison to simple square shaped ground. All the results have been simulated successfully.
关键词： circular polarization (CP),axial ratio bandwidth (ARBW),slot antenna,coplanar waveguide (CPW),wireless LAN
更新于2025-09-23 15:22:29
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[IEEE 2018 International Conference on Electromagnetics in Advanced Applications (ICEAA) - Cartagena des Indias (2018.9.10-2018.9.14)] 2018 International Conference on Electromagnetics in Advanced Applications (ICEAA) - Antenna Pattern Effects in a Low Sidelobe Circularly Polarized Planar Array Due to Element Errors
摘要： Random amplitude and phase errors at the elements of a phased array antenna cause elevated sidelobe levels. Formulas for predicting the sidelobe levels based on the error statistics are well known. These same random errors also cause an error in the axial ratio of a circular polarized array. This paper presents some new expressions for the change in axial ratio as a function of the random errors.
关键词： antenna arrays,axial ratio,planar arrays,circular polarization,array errors,crossed dipoles
更新于2025-09-23 15:22:29
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The Design of Dual Circularly Polarized Series-Fed Arrays
摘要： This paper presents the design of dual circularly polarized (CP) series-fed arrays based on Sequential rotation (SR) technique with uniform radiation elements. The radiation elements and feeding network used in the array are uniform, which leads to the possibility of dual-CP radiation by series-fed SR arrays. Meanwhile, the elements radiate unequal powers due to this arrangement. The relationship between the axial ratio (AR) and four key parameters of the array is derived and thoroughly discussed. Good polarization purity and port isolation can be realized by optimizing these parameters. A dual-CP array working at 10 GHz is designed with the help of the analysis. Experimental results show that the proposed antenna has good properties.
关键词： Circularly polarized antenna,Series-Fed array,Sequential rotation,Dual circularly polarized,Antenna array,Axial ratio
更新于2025-09-23 15:21:01
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Measurement method of axial ratio using only the reflection coefficient of waveguide circular polarizer
摘要： A circularly polarized feed circuit in a primary radiator of a reflector antenna is often required to have a low axial ratio. Therefore, it is necessary to accurately evaluate the axial ratio. The left- and right-handed circular polarized components are numerically obtained from the complex coefficients measured for dual linear polarized waves. The transmission phase measurement is difficult to measure accurately, particularly at high frequencies such as Ka band. Authors proposed a method to measure the axial ratio of the circular polarization feeding circuit from the reflection coefficient only, and the proposed method has been validated by the numerical simulation.
关键词： measurement,axial ratio,circular polarization,feed circuit
更新于2025-09-23 15:19:57
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Using metasurface structures as signal polarisers in microstrip antennas
摘要： This study analyses the influence of a metasurface coupled to a rectangular microstrip antenna. The proposed metasurface converts linearly polarised electromagnetic waves into circularly polarised electromagnetic waves. The rectangular microstrip antenna is designed to operate at 2.45?GHz. The metasurface is coupled to the antenna in order to provide a structure capable of radiating circularly polarised electromagnetic waves without the need for adjustments to the antenna feed. In this analysis, the metasurface was designed from unit cells, distributed in a periodic arrangement acting as a polariser, when coupled to the upper part of the antenna. The geometry of the unit cells and their distribution in the arrangement were calculated in order to obtain an axial ratio below 3?dB in the design frequency range. Prototypes of the microstrip antenna and the metasurface were constructed to obtain experimental results and it was possible to observe a good convergence between the simulated and measured results.
关键词： metasurface,axial ratio,wireless communication,circular polarisation,microstrip antenna
更新于2025-09-10 09:29:36
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Effect of Anisotropy on Ionospheric Scintillations Observed by Synthetic Aperture Radar (Sar)
摘要： Spaced-based synthetic aperture radar (SAR) operating at low frequencies and capable of earth observation are affected by the layer of ionosphere. The interaction of the signal with the irregularity layer degrades and distorts the SAR image quality. The accurate assumption of size of the irregularities, defined by the axial ratio, in determining the effects of scintillation on the signal is critical. In the present work, the authors have compared the impact of different axial ratios on a pair of SAR images over the Indian subcontinent to estimate scintillation and ionospheric parameters. The parameters are then compared with the available ground-based measurements to determine the precise size of irregularity structure. The amplitude scintillation index, S4, estimated from the Global Positioning Satellite (GPS) receivers for two Indian stations of Tirunelveli and Rajkot are used in this study. The assumption of axial ratio value is 60:1 to estimate the parameters was found to correctly fit into the model.
关键词： SAR,ALOS-2/PALSAR-2,axial ratio,S4,CkL,scintillation
更新于2025-09-09 09:28:46