Design and Measurements of a Quasi-isotropic UWB Planar Antenna

ISSN 1874-4761This paper summarizes the design and measurements of a quasi-isotropic printed UWB antenna, with the analysis of its performances through defined figures of merit. State of the art and review of some recent patents give us the opportunity to exploit some empirical considerations about the shape and the methodology of conception. A simple structure is simulated by means of CST Microwave Studio to show the possibility of fulfilling, at a defined level, UWB antenna requirements such as matching, fidelity and quasi-isotropy of the radiation pattern with a simple micro-strip design and a standard technology. The design of this antenna is based on considerations about bulbous and bended traveling wave antennas. Results of its characterization in anechoic chamber are quantified in terms of amplitude and phase variation, in order to illustrate the level of dispersion for the different directions. The article presents some promising patents on quasi-isotropic UWB antenna

Robust antenna diagnostics method using equivalent elemental dipoles and the spherical wave expansion

International audienceA robust method for antenna diagnostics that can provide the reconstruction of the aperture field from spherical near- or far-field measurements, is presented. This method is based on the equivalence principle which consists in the rewriting of the spherical wave expansion of the radiated field in terms of infinitesimal electric and magnetic dipoles distributed over the antenna main surface. This method presents the advantage of being very stable and extremely robust beside the measurement noise. Synthesized data (simulated antenna) used with different level of noise will show the viability of this technique for antenna diagnostics purpose

A New Criterion to Jointly Design the Antenna and Optimize the Communication Capacity in IR-UWB.

International audienceThis paper presents the impact of the antenna design over the capacity of a IR-UWB system in a Multi-User Interference environment. A new antenna design is proposed and it is showed using a new performance criterion that for this design, the communication capacity given by the Sholtz's pulse [13] might be reached using some other types of pulses

Numerical and experimental assessment of a phase retrieval technique applied to planar near field distribution for wide band application

International audienceThe work presented in the following is devoted to the characterization of an harmonic source in a wide band of frequencies [0.5, 20 GHz] from the knowledge of the amplitude-only electric fields at near field measurement distance. Such a problem leads to the development of a “phase reconstruction” algorithm. In that paper a classical propagation/retro-propagation scheme has been applied. This is the first step of a study concerning the characterization of electromagnetic pulsed source from phaseless measurement techniques in near field conditions. The algorithm has been tested and validated using numerical and experimental data acquired at different frequencies and in different configurations

The use of infinitesimal dipoles and the spherical wave expansion for planar antennas modeling

International audienceIn this paper, a method to derive an equivalent radiation model for planar antennas is presented. This method uses the spherical near-field (NF) data (measured or computed) to ascertain an equivalent set of infinitesimal dipoles placed over the main antenna surface. The spherical wave expansion (SWE) of the NF data is written in terms of infinitesimal dipoles using a transition matrix. This matrix expresses the linear relations between the spherical wave coefficients of the antenna and the spherical wave coefficients of each dipole. Once the excitation of each dipole is known, the field at any angle and distance from the antenna is rapidly calculated even inside the minimum sphere. Computations with EM simulation data of an antenna array illustrate the reliability of the method

Aperture antenna modelling by a finite number of elemental dipoles from truncated spherical field measurement: Experimental investigation

International audienceA method to determine a distribution of a finite number of elementary dipoles that reproduce the radiation behaviour of the antenna under test (AUT) from truncated spherical field measurements is proposed. It is based on the substitution of the actual antenna by a finite number of equivalent infinitesimal dipoles (electric and magnetic), distributed over the antenna aperture. This equivalent set of elementary dipoles is optimized using the transmission coefficient involving the spherical wave expansion of the measured field and using an appropriate matching method. Once the current excitation of each dipole is known, the radiated field of the antenna at different distances can be rapidly determined. The reliability and the accuracy of the method are shown using experimental data issued from the measurement of an X-band horn antenna, in two different measurement setups

A cavity-backed dual polarized array of connected spiral antennas

978-1-4673-0461-0International audienceA connected array of spiral antennas with dual polarization and backed by a cavity is presented. A 5-elements array is measured using a simple, yet efficient, feeding technique. A low profile cavity is used to make the radiation unidirectional. First measurements show a good agreement between simulations and measurement

An "F-gain" antenna for UWB-RFID

ISSN: 1937-8718International audienceThis paper presents an UWB antenna concept adapted for a potential application of RFID in a severe multi-paths environment for European regulation (UWB-LDR 6 - 8.5 GHz). The UWB provides theoretically the signal integrity and designing the UWB antenna is compatible with low size, cost and low complexity consideration. Under the hypothesis of using the same antenna at both transmitting or receiving states, the 1/f2 effect of free space attenuation can be minimised by a pre-emphasis included in the antenna design, that is to say an "f-gain" antennas at both transmitting (Tx) and receiving (Rx) parts. As a result, the printed antennas described are neither constant aperture nor constant gain typ

A wideband antenna for P-band airborne SAR applications

International audienc