Modern small satellites (MSS) are revolutionizing the space industry. They can drastically reduce mission cost, and make access to more affordable. The relationship between a modern satellite ldquoconventionalrdquo large is similar that compact laptop work-station computer. This paper gives an overview of antenna technologies for applications in satellites. First, introduction their structures presented. followed by description technical challenges designs satellites, interactions Specific...

The development of a circularly-polarized compact high-gain antenna to be used for the European Student Earth Orbiter small satellite mission is described. realized stacking two coaxial shorted annular patches and placing top one at half wavelength from lower one. At variance other similar configurations proposed in past, presented this paper has several important features which can extremely useful application space environment. In particular, it easily fabricated employing suspended...

An aperture-coupled reflectarray element giving a full phase tuning range with single varactor diode is proposed in this paper for pattern reconfigurability applications. The agility achieved by proper optimization of the line, thus providing an alternate inductive/capacitive effect able to avoid use two diodes, usually adopted similar existing configurations. active structure design demonstrative prototype 3 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML"...

This paper presents a study on reconfigurable transmit-array (TA) antennas based multilayer tunable elements. The proposed configuration can be referred to as antenna–filter antenna (MAFA) and it viewed an extension of the antenna-filter concept. It consists multiple layers cascaded form spatially distributed bandpass filter. Phase agility is achieved by tuning resonant frequency each layer. main objective this introduce new design technique for MAFA TA antennas. As will shown, key feature...

A dual-band dual-linear polarization reflectarray configuration is developed for future 5G cellular applications. single layer unit cell including two pairs of miniaturized fractal patches designed to operate at distinct frequencies within the Ka-band (27/32 GHz), in a dual-polarization mode. An in-depth analysis behavior carried out, demonstrate total independence between frequency bands and polarizations. The proposed offers very simply thin structure, small sizes, low losses, while...

Since the Global Positioning System (GPS) was launched, significant progress has been made in GPS receiver technology but multipath error remains an unsolved problem. As solutions based on signal processing are not adequate, most effective approach to discriminate between direct and waves is specify new more restrictive criteria design of receiving antenna. An innovative low profile, lightweight dual band (L1+L2) radiator with a high multipath-rejection capability presented. The proposed...

A novel hybrid procedure is proposed in this paper for far-field reconstruction from phaseless near-field data. basically interferometric approach adopted to retrieve the phase amplitude-only measurements, which are collected by a simple microstrip circuit used conjunction with two identical probes moving on scanning surface. certain number of sets complex data obtained, apart constant phase-shifts be computed, one each set. nonredundant representation based introduction reduced field then...

The application of varactor diodes as phase-shifting devices in reflectarrays has received considerable attention because it represents a low-cost and low-complexity solution for the creation scanning antennas with continuous phase tuning. main issues related to design varactor-loaded are difficulty correct characterization unit cell, limited range achievable by changing polarization voltage device. contribution presented this communication attempts cover both these aspects. In particular,...

Magnetic nanoparticles (MNP) enhanced microwave imaging could provide an effective approach for early stage diagnosis of breast cancer, if encouraging results coming from accurate and realistic numerical studies are confirmed by experimental proof concept framework. To this end, ad hoc laboratory setup has been designed built up to verify the possibility detecting low signal scattered MNP when embedded into a simplified but phantom. This paper describes developed measurement first run...

A Minkowski fractal geometry is proposed in this letter as miniaturized absorber cell suitable for multipath phenomena mitigation within the European RFID UHF band. The structure analyzed through combined use of an equivalent transmission line model and method-of-moments-based full-wave simulations. Very high miniaturization capabilities (about 50% with respect to standard configurations) are demonstrated 868 MHz unit cell, characterized by absorptivity more than 99%, a good angular...

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> This letter presents a new type of planar electromagnetic band-gap (EBG) surface composed short-circuited microstrips densely coupled with each other through interlocked branch stubs. With respect to conventional mushroom surface, this structure exhibits better space-wave decoupling performance due the soft nature surface. surfaces, like shorted strip already introduced in literature, present...

The Universal Software Radio Peripheral USRP NI2920, a software defined transceiver so far mainly used in Defined applications, is adopted this work to design high resolution L-Band Radar system. enhanced available bandwidth, due the Gigabit Ethernet interface, exploited obtain higher slant-range with respect existing implementations. A specific LabVIEW application, performing radar operations, discussed, and successful validations are presented demonstrate accurate target detection...

Fractal geometries are appealing in all applications where miniaturization capabilities required, ranging from antennas to frequency selective surfaces (FSS) design. Recently, some fractal patches configurations, giving low losses, reduced size, and quite good phase ranges, have been proposed for the design of reflectarray unit cells. This paper reviews existing fractal-based reflectarrays, highlighting their benefits limitations. Furthermore, a comprehensive analysis an innovative cell,...

A transformation procedure directly computing the antenna far-field pattern from near-field samples acquired on a planar spiral is proposed in this paper. The convolution property of radiation integral exploited to efficiently perform evaluation by taking advantages Fast Fourier Transform, without need any intermediate interpolation process. Validations circular arrays elementary dipoles are presented show effectiveness method.

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A reconfigurable aperture-coupled reflectarray element offering a continuous tuning of the reflection phase is presented. single varactor load demonstrated to be sufficient for full range. Experimental validations are reported measured an X-band element.

A dual-layer active reflectarray configuration is proposed for broad-band beam-steering and/or frequency-tunable applications. unit cell composed by two stacked fixed-size rectangular patches, properly loaded with a single varactor diode, designed to realize the dynamic phase tuning mechanism. The approach offers wider bandwidths, respect existing varactor-based cells, and quite good frequency reconfigurability features, as demanded several radar or satellite communication An X-band...

An L1 Global Positioning System (GPS) antenna with improved multipath-rejection capability is presented. The realized a shorted annular elliptical patch (SAEP). Some of the characteristics SAEP are presented briefly and detailed account design given. Measured results discussed.

A new approach for beam steering in reflectarray applications is introduced this paper. The progressive phase distribution achieved by loading each microstrip patch element with a varactor diode on the radiating edge. In following, scattering characteristics of single loaded antenna will be presented. As proof concept, capability five elements linear has been experimentally investigated.

An extensive analysis is performed on the aperture-coupled reflectarray configuration to highlight and quantify bandwidth enhancement due use of reduced inter-element spacings. Bandwidth extension directly evaluated phase curves relative reflection coefficient against frequency for different lengths tuning line. The operating range computed with proposed approach numerically validated gain patterns synthesized reflectarrays a strong broadband behavior demonstrated moderate aperture...

A hybrid array configuration suitable for wideband millimeter-wave applications is presented in this work. The proposed structure based on the use of circular waveguide elements electromagnetically coupled trough apertures to a stripline distribution network. adopted excitation mechanism avoids transition components generally reducing overall antenna efficiency. Simulated and measured results Ka-band prototype are discussed prove radiation behavior.

An improved synthesis procedure is presented in this letter for the design of waveguide slot arrays directly integrated on substrate exciting microstrip line. To take into account smallness height, standard shunt-admittance model usually adopted single radiating properly modified an T-network model. Accordingly to choice, a two-step developed accurately determine slots' parameters. Experimental validations are discussed 8-GHz linear array with <formula formulatype="inline"...

Abstract. A big challenge in terms or landslide risk mitigation is represented by increasing the resiliency of society exposed to risk. Among possible strategies with which reach this goal, there implementation early warning systems. This paper describes a procedure improve activities areas affected high risk, such as those classified critical infrastructures for their central role society. research part project LEWIS (Landslides Early Warning Integrated System): An System Landslide...

A hybrid approach for phaseless imaging of dielectric targets is proposed in this letter. two-probe measurement strategy with the related phase-retrieval method adopted conjunction an inversion procedure based on inexact-Newton to give efficient and low-cost setup, avoiding need multiple acquisition surfaces. preliminary experimental validation real input data presented.