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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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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Research Advances in Phased Array Antennas for Satellite Communications
摘要： Recent research advances in phased array antennas for mobile satellite communications in the State Key Laboratory of Millimeter Waves (SKLMMW) are reviewed, including the Ku-band multiple-panel phased array antenna with almost half sphere coverage, the Ka-band low cost linear phased array module for planar array applications, a single board dual polarized S-band phased array for China S-band mobile satellite communications. The development for fast phased array calibration and measurement is also introduced.
关键词： Mobile Satellite Communications,Phased Array Calibration,Phased Array
更新于2025-09-23 15:23:52
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Propagation Experiment at Ka-Band in French Guiana: First Year of Measurements
摘要： ONERA, the French Aerospace Lab, and CNES, the French Space Agency, are currently running a Ka-band propagation experiment at the Guiana Space Centre (CSG) in Kourou (French Guiana). A rain gauge and a beacon receiver able to record the 20.2 GHz beacon signal of the Amazonas 3 satellite have been deployed. The equipment is operational since January 1, 2017 and the duration of the experiment has been set to 3 years. This letter addresses some results of the first year of measurements (from January 2017 to December 2017). The annual and monthly Complementary Cumulative Distribution Functions of rainfall rate and rain attenuation are presented as well as a comparison with the rain attenuation prediction method recommended in ITU-R P.618-13.
关键词： Equatorial area,Ka-Band,Satellite communications,Propagation,Measurements
更新于2025-09-23 15:22:29
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Design and Simulation of a Slot Waveguide Array Antenna (SWAA) for Satellite Communications
摘要： One of the most used antennas today, is that of slots in waveguides. These antennas are an important type within the microwave range with various applications in electronic communications systems, radar, and satellite applications, due to its high power capacity, high efficiency, low weight, compact structure and few lateral lobes, all added together to its proven resistance to radiation, high temperatures and vibration, characteristics without which they can not be used in aerospace applications. The following lines show the design and simulation of a Slot Waveguide Array Antenna (SWAA) for satellite communications in the 30 GHz band. The antenna will be approximately 170x170 mm, constituted by 24x24 slots. It will be fed by waveguides in a lower layer connected to the radiating guides through slots. The modeling and design of the different elements that make up the power grid as T- junctions and elbows in the E and H planes were carried out.
关键词： 30 GHz band,SWAA,waveguide slots,Slot Waveguide Array Antenna,satellite communications
更新于2025-09-23 15:21:01
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DESIGN OF SUB-HARMONIC MIXER MMIC FOR EHF SATELLITE LINKS
摘要： This paper presents the design ?ow of a compact GaAs MMIC for Extremely High Frequency (EHF) satellite communications. The proposed circuit enables sub-harmonic mixing capability and integrates a LO bu?ering section, thus allowing for low frequency and low power reference signal interface. Circuit design is described in detail providing a comprehensive view of the followed theoretical approach, starting from mixer core de?nition until the complete synthesis of LO/RF/IF interfaces. In particular, the design ?ow of an innovative three-conductor Marchand balun is deeply analysed. Fabricated MMIC operates in the 43.5–50 GHz band and results in a compact layout (2.4 × 2.4 mm2) featuring a port-to-port isolation better than 25 dB with a typical conversion loss of 12 dB.
关键词： Marchand balun,sub-harmonic mixing,EHF satellite communications,GaAs MMIC,compact layout
更新于2025-09-23 15:21:01
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[IEEE 2020 IEEE International Solid- State Circuits Conference - (ISSCC) - San Francisco, CA, USA (2020.2.16-2020.2.20)] 2020 IEEE International Solid- State Circuits Conference - (ISSCC) - 19.2 A 110mK 295?μW 28nm FDSOI CMOS Quantum Integrated Circuit with a 2.8GHz Excitation and nA Current Sensing of an On-Chip Double Quantum Dot
摘要： An electromagnetic wave propagating through the ionosphere is subject to path delay and the depolarizing effect of Faraday rotation, both of which are dependent on global position and geometry. These effects introduce error and consequently reduce the range resolution of remote sensing polarimetric measurements. Satellite-to-ground communications may be adversely altered by these effects so as to inhibit signal reception. The work presented here introduces a simple vectorized model for a large-field-of-view, low-Earth-orbit, satellite system that yields Faraday rotation and path delay according to global position and geometric parameters. Comparison is made with current models, through the simulation of Faraday rotation and path delay. The presented work may extend the range over which Faraday rotation and path delay estimation are reliable. The work presented forms part of a large-field-of-view, low-Earth-orbit satellite model exploiting multiple-input multiple-output polarimetry in three dimensions.
关键词： remote sensing,Faraday rotation,ionosphere,path delay,satellite communications
更新于2025-09-23 15:19:57
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Characterization of Optical Fibers Directly Embedded on Metal using a Particle Spray based Method
摘要： The double corrugated waveguide (DCW), incorporating a row of metallic pillars on each side of the electron beam, is demonstrated as a promising slow-wave structure for millimeter wave, Ka-band, traveling wave tubes (TWTs). Different configurations, including novel bent couplers with tapered pillars, have been designed, realized, and validated by S-parameter measurements. The design and simulation of a DCW TWT demonstrated very good performance in the frequency band 32–37 GHz. The ease of fabrication and assembly make the DCW a suitable basis for a new generation of millimeter wave TWTs.
关键词： microfabrication,millimeter waves,slow-wave structures (SWSs),Double corrugated waveguide (DCW),traveling wave tubes (TWTs),satellite communications
更新于2025-09-19 17:13:59
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Photonics tech brings in the big guns [satellite optical communications]
摘要： The article discusses the transition from coaxial cables to fibre-optic interconnects in satellite communications, highlighting the benefits of photonics technologies in terms of size, weight, and power efficiency. It covers the development and qualification of fibre-optic technologies for space applications, including the first operational use of fibre-optics communications in institutional satellites and the potential for microphotonics in future satellite payloads.
关键词： space technology,microphotonics,satellite communications,photonics,fibre-optic interconnects
更新于2025-09-16 10:30:52
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[IEEE 2018 9th Advanced Satellite Multimedia Systems Conference and the 15th Signal Processing for Space Communications Workshop (ASMS/SPSC) - Berlin (2018.9.10-2018.9.12)] 2018 9th Advanced Satellite Multimedia Systems Conference and the 15th Signal Processing for Space Communications Workshop (ASMS/SPSC) - A Design Method of Cognitive Overlay Links for Satellite Communications
摘要： In this paper, we present a method to design cognitive overlay links for satellite communications, in order to allow the primary and the cognitive users to transmit concurrently while using efficiently the available power resources. By means of trellis shaping based dirty paper coding (DPC) and superposition techniques, numerous schemes are investigated in various realistic scenarios, and different trade-offs between power efficiency vs complexity are made. By simulations, we first show that we are able to design schemes where the primary user bit error rate (BER) is maintained as in the absence of the cognitive user interference. Secondly, thanks to trellis precoding and an appropriate constellation expansion, we show that the BER of the cognitive user can be made within 1dB of corresponding the Gaussian channel BER.
关键词： Trellis Precoding,Satellite Communications,Flexible Payloads,Cognitive Radio,Dirty Paper Coding,Overlay Paradigm
更新于2025-09-11 14:15:04
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Atmospheric Effects on Millimeter and Sub-millimeter (THz) Satellite Communication Paths
摘要： Satellite communications require more bandwidth due to the necessity of increasing the capacity of communication channels and bandwidth to end-users. As a result, looking for new bands is required in the electromagnetic spectrum including millimeter and sub-millimeter wavelengths. Recent technological developments made the extremely high frequencies (EHF) above 30 GHz as a candidate for wireless applications such as the fifth generation (5G) of mobile communications, high resolution radars, and remote sensing. The EHF communication systems are becoming more and more commercial, cheap, and compact. However, the fact that the atmospheric medium is not completely transparent to millimeter waves requires considerations of the frequency selective absorption and dispersion effects emerging in this band. These phenomena affect also remote sensing in the millimeter and sub-millimeter waves (the terahertz frequencies). The atmospheric effects on the propagation of millimeter and sub-millimeter wave transmission from land to satellite are discussed. It is shown that not only atmospheric absorption plays a significant role on the received signal strength but also the refraction index of the atmospheric medium. The inhomogeneous refractivity causes the beam to Bbend^ along the propagation path, and it may even Bmiss^ its destination. This phenomenon should be considered in the design of a link operating in extremely high frequencies involving highly directive antennas.
关键词： Millimeter wave propagation,Terahertz waves,Millimeter wave satellite communications
更新于2025-09-10 09:29:36