As part of the European Space Agency (ESA) studies new instrument for Earth observation, design a synthetic aperture radar (SAR) architecture based on overlapped array antennas was launched last year. The objective activity is to develop test unit reflector SAR antenna fed by an organized in subarrays, supporting novel multichannel wide-swath architectures, and exploiting multiple beams both azimuth range/elevation directions. In letter, hybrid analog/digital beamforming reception with...

Large deployable reflector based multi-channel antenna systems are a key component of next generation SAR missions as they allow implementing multi-beam imaging capabilities and provide an efficient way to overcome the classical resolution-coverage trade-off, covering wide swaths with high azimuth resolution. The presented work shows design multichannel L-band system architecture on different feeders concepts capable map 400 km ground swath 5 meter spatial resolution in dual polarization....

This article addresses the noise behaviour (noise temperature and figure) of some passive microwave multiport circuits. The analysis method is based on noise-wave formulation. With exception attenuator case, which used as a reference, circuit elements considered are lossless devices, in sense that neither conductive nor dielectric losses accounted for. shows that, when connected to matched loads their ports, these multiports circuits lose nature scattering matrix not unitary; therefore, they...

Abstract This paper presents a theoretical analysis of the effect beam scanning and amplitude tapering on cross‐pol level sequentially rotated linear arrays composed circularly polarized patch antenna elements. Arrays eight elements are considered to illustrate analysis. Several sequential phase distributions analyzed in terms cancellation over field view. These arrangements location maximum peak levels their values. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 343–350, 2001.

This paper provides a wrap-up of some the activities undertaken by SMOS L1 team to fine tune instrument calibration and modeling that eventually has resulted into full-polarimetric measurement image reconstruction enhanced performance.

Abstract A new method to determine antenna efficiency, based on the Wheeler cap technique, is presented. It uses ratio between measured Q factors of shielded and free‐space impedances as a measure radiation efficiency. The reflection coefficient fitted an analytical function from which unloaded can be determined. particularized microstrip patch antennas illustrated with simulated results. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 132–142, 2004; Published online in...

This paper presents the effect of interaction between switch and antenna parameters on cross-polarization a dual polarization switching antenna. It is shown that isolated combines with isolation giving place to degradation purity combined Analytical expressions for combination in switched element are given. Simulations pattern measurements presented. © 2007 Wiley Periodicals, Inc. Int J RF Microwave CAE, 2007.

This paper summarizes the initial phase of study antenna element for a future SMOS radiometer mission. The shows main requirements, potential candidates and design constraints that drive selection candidate. A major difference with respect to current mission is new should alias free spacing. An overview preliminary performances selected candidate shown.

ESA's Soil Moisture and Ocean Salinity (SMOS) mission, is providing L-band observations of the Earth surface since November 2009. In preparation a future ESA involved in several technological activities intended to develop components for an advanced radiometer mission. this context paper presents current design status antenna element that constitutes first stage receiver unit populates aperture synthesis instrument.

Two broadband stacked configurations, composed of a printed annular ring as driver and parasitic circular disk with without superstrate have been presented. A maximum bandwidth 380 MHz has obtained for both them by experimental optimization the design parameters involved (spacer height, size feed location). Radiation patterns shown at central edge frequencies, average crosspolar components better than 17dB. The antennas are studied within context cellular radio systems. >

The microwave imaging radiometer using aperture synthesis (MIRAS) (M. Martin-Neira et al., November 1997) is the single payload of SMOS (soil moisture and ocean salinity) mission by European Space Agency (ESA). MIRAS performance was successfully tested during spring 2007 prime contractor, EADS-CASA Espacio Spain, at ESA premises in ESTEC, Netherlands. currently Thales, Alenia Space, Cannes (France), for integration with satellite platform: http://www.esa.int/esaLP/LPsmos.html. MIRAS-SMOS...

The effect of different sequential phase distributions on the cross-polar performances a linear array sequentially fed circularly polarized (CP) patch antenna elements is analyzed. Using as an example eight elements, peak locations and their maximum value are computed, it shown that which do not provide symmetry in excitation give minimum values. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 25: 387–390, 2000.

MIRAS (Microwave Imaging Radiometer with Aperture Synthesis) is a microwave radiometer to measure Ocean Salinity and Soil Moisture (SMOS). Both parameters have strong scientific interest in understanding the water cycle behaviour. measurements are based on sensitivity changes dielectric constant due humidity salinity content. synthesis allows one obtain good spatial resolution radiometric thinned antenna. SMOS mission (MIRAS) has been selected within Earth Observation programme of ESA for...

An improved and compact design of an antenna system for full coverage up to 15 degrees elevation is presented. This consists a pair antennas in microstrip technology (patch ring), photoetched concentrically the same substrate. A circuit placed on rear face. Its bandwidth, typical radiators, makes it suitable land-mobile communications. interesting characteristic this its versatility supplying different requirements including positioning receiving output, if desired. The problems experimental...

The design of a leaky-wave antenna array in the L-band is presented. has been developed to feed large reflector that part SAR system for Earth observation. basic element differentially fed patch excites leaky modes resonant cavity defined by metasurface. performance 3x3 sub-array studied and presented this paper, as well individual element. Important aspects affect overall are discussed together with measured results fabricated prototype.

The design of the feeding system for focal array in OLAF (Over-Lapped Sub-Array Fed) antenna SAR Instrument at L-Band is presented. proposed consists a circular patch with balanced excitation all it embedded ground plane which connected to lower by some shorting pins, reducing mutual coupling neighbour radiating elements array. has been implemented 180° hybrid using differential input port. Dual polarization achieved two hybrids within same layer. stringent requirements system, namely low...

The electrical architecture of a multibeam hybrid Synthetic Aperture Radar system is presented. SAR Instrument analogue-digital multichannel radar intended to provide high resolution and wide swath coverage. To achieve that the composed large oversize reflector fed by CORPS (Coherently Radiating Periodic Structure) feedarray. corresponds distributed semiactive digital configuration extends along feedarray length. paper presents main characteristics OLAF SAR.