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“The Laboratory of Electromagnetics and Acoustics (LEMA) at EPFL-Switzerland, has always had an vocational European attitude. Since the late seventies, LEMA embarked on a series of European projects in collaboration with European institutional (EU-EC, ESA, European Science Foundation…) and industrial partners. These activities resulted not only in significant advances in antenna research but also...
Mobile phones are being required to operate with increasingly more communication protocols. Since simultaneous operation of several services is required, this leads to a greater number of antennas. Further, the introduction of Long Term Evolution (LTE) makes it mandatory to accommodate two antennas for Multiple Input Multiple Output (MIMO) operation. However, despite the increase in the number of...
The measurement of the radiation and matching performance of millimeter-wave antennas is a very challenging task. As a single 60 GHz antenna has usually a size of few millimeters, the feeding scheme cannot be as simple as a connector: a microelectronic probe is definitely the preferred feeding technique. The measurement setup we present has been derived from a classical microelectronic probe measurement...
Stacking method is used to enhance the 3 dB axial ratio and impedance bandwidth of the circularly polarized cylindrical dielectric resonator antennas excited by an external tape helix. In this method, a dielectric cylinder with lower permittivity than the basement cylindrical dielectric resonator is placed concentrically on top of the basement cylinder. The new configuration offers an axial ratio...
This paper presents a dual-band single layer printed reflectarray antenna with closely separated frequency bands centered at 12 and 14 GHz. The novel unit cell, with which the antenna has been designed, consists of a printed cross-dipole and a split ring element mounted on the same substrate, providing the antenna with dual polarization capability at both bands. The antenna is composed of 17 × 17...
This paper presents a low-cost beam-switching method for circularly-polarised (CP) patch antenna. By fabricating a switchable single feed circular patch antenna over a properly designed electronically tuneable high impedance ground plane, its radiation pattern can be steered. The feeding network in this design is also simplified. To demonstrate the concept, an antenna prototype with right hand circular...
In this paper we present an analysis of the behaviour of a 2.4 GHz Low Noise Amplifier (LNA) for Wireless Body Area Network (WBAN) applications facing antennadetuning issue. An amplifier with ultra-low power, low voltage, and with reduced component count is prototyped to validate simulation results, then the behaviour is analyzed through simulations based on data measured on real users. The analysis...
A novel dual band circularly polarized (CP) microstrip patch antenna for wireless power transmission (WPT) at 5.1 GHz and 5.5 GHz is proposed. In particular, we are designed to be able to services for 5.1 GHz wireless local area network (WLAN) in wireless battery charging at 5.5 GHz. The designed antenna has the two shorted diagonal slots in the square patch. As a result, this paper presents possibility...
A probe-fed printed folded monopole antenna for WLAN applications is presented. The antenna operates at 2.45 GHz and 5.8 GHz, is compact and has omni-directional characteristics in both bands. A parametric study of key geometrical parameters is reported.
In this paper, an effective approach based on dielectric overlay is proposed to reduce the specific absorption rate SAR values of strip-line RF coils [2] for 7 Tesla magnetic resonance imaging MRI and to avoid skin burn in ultra-high field MRI. Results show (40–12) % reduction of SAR values when substrates of (10.2–2) dielectric constants have been used.
This paper reports a study of the influence on the fidelity factor due to loading an Ultra Wideband monopole with a pair of dielectric substrate pads. The fidelity factor was calculated, with and without loading, using the simulated transmitted and received pulses in three points in the azimuth plane. Results show that this dielectric loading technique does not cause significant pulse distortion....
A circularly polarized elliptical dielectric resonator antenna (EDRA) has been studied theoretically and experimentally when a single conformal strip is employed for excitation. The antenna has been analyzed using a rigorous moment method model in conjunction with the volume-surface-integral-equation (VSIE). The results have been compared to those obtained from measurements with good agreement.
Plasmonic antenna is capable of replacing an array antenna producing directive high gain beam at a desired direction by structuring the metal surface with certain patterns, having characteristic dimensions on a scale much smaller than the wavelength of the microwave. Excitation of localized surface plasmon modes on structured metal surface strongly localized the microwave. This enables the metal surface...
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