Archivo Digital UPM: No conditions. Results ordered -Date Deposited. 2019-11-12T07:57:30ZEPrintshttp://oa.upm.es/style/images/logo-archivo-digital.pnghttp://oa.upm.es/2019-04-01T16:55:51Z2019-04-01T16:55:51Zhttp://oa.upm.es/id/eprint/54495This item is in the repository with the URL: http://oa.upm.es/id/eprint/544952019-04-01T16:55:51ZFlat reflectarray that generates adjacent beams by discriminating in dual circular polarizationOne planar 18x18 cm2 reflectarray prototype, capable of generating adjacent pencil beams with orthogonal circular polarizations (CP) in Ka-band (19.2-20.2GHz), has been designed, manufactured and measured as a proof-of-concept to demonstrate the possibility of beam separation in dual CP applications. The prototype exhibits main beams pointing at elevation angles of 16.7° and 21.3° for left-hand CP and righthand CP respectively. A 1.5dB gain variation and 66efficiency is achieved in the frequency band 19.2-20.2GHz for a design center frequency of 19.7 GHz. These results will be useful for future work involving the design of multi-spot dual CP and dual band planar reflectarrays.Rafael Florencio DíazJosé Antonio Encinar GarcinuñoRafael R. BoixMariano Barba GeaGiovanni Toso2019-03-04T17:54:02Z2019-04-24T11:23:32Zhttp://oa.upm.es/id/eprint/53671This item is in the repository with the URL: http://oa.upm.es/id/eprint/536712019-03-04T17:54:02ZReflectarray to generate four adjacent beams per feed for multi-spot satellite antennasThis contribution describes a design concept of a reflectarray antenna to produce four adjacent beams per feed through the simultaneous use of polarization and frequency discrimination. The feed position is computed to produce two adjacent beams in different frequencies accounting for the beam squint effect, which ensures a minimum phase variation between the phase distributions at the two frequencies. The other two beams in orthogonal polarization are generated by implementing in the reflectarray a different phase-shift for each polarization. This contribution presents the design, manufacturing and measurement of a 43-cm demonstrator that operates at transmit frequencies in Ka-band. The proposed concept can be suitable for multiple spot beam satellites in Ka-band, enabling a reduction in the number of antennas and feeds needed to provide the multi-spot coverage.Daniel Martínez de RiojaEduardo Martínez de RiojaJose Antonio Encinar GarcinuñoRafael Florencio DíazGiovanni Toso2019-03-04T17:37:38Z2019-04-24T11:20:39Zhttp://oa.upm.es/id/eprint/53680This item is in the repository with the URL: http://oa.upm.es/id/eprint/536802019-03-04T17:37:38ZDual-polarization reflectarray in Ku-band based on two layers of dipole arrays for a transmit–receive satellite antenna with South American coverageA 1.1-m reflectarray antenna has been designed, manufactured and tested to fulfil the requirements of a satellite antenna in Ku-band that provides South American coverage in Tx and Rx. The reflectarray cells consist of four dipoles for each polarization in two dielectric layers, selected because of their simplicity and high performance. The dipole dimensions are optimized in all the reflectarray cells to accomplish the prescribed radiation patterns, by iteratively calling an analysis routine based on method of moments in spectral domain and local periodicity. The measured radiation patterns of the manufactured antenna have been satisfactorily compared with simulations and with a 3-layer reflectarray previously designed, manufactured and tested for the same mission.Jose Antonio Encinar GarcinuñoRafael Florencio DíazManuel Arrebola BaenaMiguel Alejandro Salas NateraMariano Barba GeaJuan Enrique Page de la VegaRafael R. BoixGiovanni Toso2018-03-06T16:09:53Z2018-03-06T16:09:53Zhttp://oa.upm.es/id/eprint/49525This item is in the repository with the URL: http://oa.upm.es/id/eprint/495252018-03-06T16:09:53ZApplication of bifocal concept to dual reflectarray configurations for multi-beam satellite antennas in Ka-bandThis contribution describes the design of a multi-beam dual reflectarray antenna for operation in transmission in Ka-band (20 GHz). The bifocal design concept has been used to obtain an improved performance for the off-axis beams with respect to the single focused antenna. The required phase-shift distributions are initially obtained with the reflectarrays in parallel planes, and then adjusted to compensate the tilting of both reflectarrays in the final Cassegrain configuration. The simulated radiation patterns in the elevation and azimuth orthogonal planes have been calculated for the two beams generated by the focuses, and then the multi-beam performance of the antenna has been evaluated.Eduardo María Martínez de Rioja del NidoJosé Antonio Encinar GarcinuñoAntonio Pino GarcíaBorja González ValdésCarolina Tienda HerreroSean V. HumGiovanni Toso2018-02-13T15:52:28Z2018-02-13T15:52:28Zhttp://oa.upm.es/id/eprint/49121This item is in the repository with the URL: http://oa.upm.es/id/eprint/491212018-02-13T15:52:28ZDual-polarization reflectarray in Ku-band Based on
two layers of dipole-arrays for a transmit-receive
satellite antenna with south american coverageA 1.1-m reflectarray antenna has been designed, manufactured and tested to fulfil the requirements of a satellite antenna in Ku-band that provides South American coverage in Tx and Rx. The reflectarray cells consist of four dipoles for each polarization in two dielectric layers, which were selected because of their simplicity and high performance. The dipole dimensions are optimized in all the reflectarray cells to accomplish the prescribed radiation patterns, by iteratively calling an analysis routine based on MoM-SD and local periodicity. The measured radiation patterns of the manufactured antenna have been satisfactorily compared with simulations and with a 3-layer reflectarray previously designed for the same mission.José Antonio Encinar GarcinuñoRafael Florencio DíazManuel Arrebola BaenaMiguel Alejandro Salas NateraM. BarbaRafael R. BoixGiovanni Toso2018-02-06T17:12:36Z2018-02-06T17:12:36Zhttp://oa.upm.es/id/eprint/49122This item is in the repository with the URL: http://oa.upm.es/id/eprint/491222018-02-06T17:12:36ZEnhanced MoM for the analysis of multilayered periodic structures containing dipoles with application to the design of reflectarray antennasThe spectral domain Method of Moments (MoM) is customarily used in the analysis of multilayered periodic structures. In this paper a hybrid MoM is introduced for the analysis of multilayered periodic structures containing sets of dipoles at two metallization levels. In the hybrid MoM the matrix entries involving basis functions of dipoles at different metallization levels are computed in the spectral domain. However, the matrix entries involving basis functions at the same metallization level are computed in the spatial domain. The implemented hybrid MoM is applied to the design of multilayered reflectarray antennas made of dipoles under the local periodicity assumption. Thanks to the use of interpolated expressions for the periodic spatial Green's functions in terms of both coordinates and incidence angles, the CPU time required by the hybrid MoM in the design of the antennas is around twenty times faster than that required by the spectral domain MoM.Rafael Florencio DíazRafael R. BoixJosé Antonio Encinar GarcinuñoGiovanni Toso2018-01-29T16:58:19Z2018-01-29T16:58:19Zhttp://oa.upm.es/id/eprint/49119This item is in the repository with the URL: http://oa.upm.es/id/eprint/491192018-01-29T16:58:19ZCross-polar reduction in reflectarray antennas by means of element rotationA cross-polar reduction technique for dual polarization reflectarray antennas is proposed. This technique is based on the determination of the rotation angle of each reflectarray element that minimizes the cross-polar components of the electric and magnetic fields reflected by that particular element in each polarization under local periodicity assumption. The results obtained with the cross-polar reduction technique have been validated by comparison with results provided by the commercial software CST. The technique has been applied to the reduction of the cross-polarization radiated by a dual polarization transmit-receive reflectarray antenna. The results obtained after cross-polar reduction show minimum values of cross-polar discrimination of 35 dB for one polarization and 40 dB for the orthogonal polarization, both in the Tx and Rx-bands.Rafael Florencio DíazJosé Antonio Encinar GarcinuñoRafael R. BoixGerardo Pérez PalominoGiovanni Toso2018-01-20T09:46:29Z2019-05-31T07:42:06Zhttp://oa.upm.es/id/eprint/49084This item is in the repository with the URL: http://oa.upm.es/id/eprint/490842018-01-20T09:46:29ZOptimized periodic MoM for the analisis and design of dual polarization multilayered reflectarray antennas made of dipolesA hybrid version of the Method of Moments (MoM) is applied to the analysis of the scattering of plane waves by periodic multilayered structures containing dipoles at two metallization levels. The MoM matrix entries involving basis functions (BFs) at different metallization levels are computed in the spectral domain as double infinite summations with fast exponential convergence. The MoM matrix entries involving BFs at the same metallization level are computed in the spatial domain as double integrals, which require low-order quadrature rules. The integrands are cross correlations between BFs times multilayered periodic Green?s functions (MPGFs). The cross correlations between BFs are obtained in terms of elliptic integrals of first and second kind. Also, the MPGFs are accurately interpolated in 4-D in terms of both the spatial variables and the angles of incidence. The hybrid MoM proposed is used in the design of dual polarization reflectarray antennas under the local periodicity assumption. Thanks to the 4-D interpolation of the MPGFs, which minimizes the total number of MPGFs that have to be computed per reflectarray element, the proposed hybrid MoM is shown to be around 15 times faster than the standard spectral domain MoM in the design of the antennas.Rafael Florencio DíazRafael Rodríguez BoixJosé Antonio Encinar GarcinuñoGiovanni Toso2016-06-25T09:39:47Z2019-06-06T13:39:58Zhttp://oa.upm.es/id/eprint/41031This item is in the repository with the URL: http://oa.upm.es/id/eprint/410312016-06-25T09:39:47ZReflectarray antennas for dual polarization and broadband telecom satellite applicationsA reflectarray antenna with improved performance is proposed to operate in dual-polarization and transmit-receive frequencies in Ku-band for broadcast satellite applications. The reflectarray element contains two orthogonal sets of four coplanar parallel dipoles printed on two surfaces, each set combining lateral and broadside coupling. A 40-cm prototype has been designed, manufactured, and tested. The lengths of the coupled dipoles in the reflectarray cells have been optimized to produce a collimated beam in dual polarization in the transmit and receive bands. The measured radiation patterns confirm the high performance of the antenna in terms of bandwidth (27%), low losses, and low levels of cross polarization. Some preliminary simulations at 11.95 GHz for a 1.2-m antenna with South American coverage are presented to show the potential of the proposed antenna for spaceborne antennas in Ku-band.Rafael Florencio DíazJosé Antonio Encinar GarcinuñoRafael R. BoixVicente LosadaGiovanni Toso2016-06-14T18:39:06Z2016-06-14T18:39:06Zhttp://oa.upm.es/id/eprint/41029This item is in the repository with the URL: http://oa.upm.es/id/eprint/410292016-06-14T18:39:06ZA Transportable Reflectarray Antenna for Satellite Ku-band Emergency CommunicationsThe design of a Ku-band reconfigurable reflectarray antenna for emergency satellite communications is presented. Bidirectional high data rate satellite links are needed in emergency conditions where other telecommunication infrastructures are not available. In order to operate in this type of scenario, an antenna should be deployable, transportable, and easily repointable. The need of an automatic and fast satellite location and pointing system leads to a completely electronic reconfigurable antenna. The operative bandwidth is from 10.7 to 12.5 GHz for reception and from 14 up to 14.5 GHz for transmission (30% of relative bandwidth). The selected antenna architecture is based on a dual reflectarray system comprising a passive subreflectarray and an active main reflectarray made of reconfigurable 1-bit elementary cells based on PIN diodes.Simone MontoriFabrizio CacciamaniRoberto Vincenti GattiRoberto SorrentinoGuido AristaCarolina TiendaJosé Antonio Encinar GarcinuñoGiovanni Toso