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Performance characteristics of Electrically Small Antennas are limited by fundamental physics. Using Non-Foster elements into antennas structures appears like an opportunity to overshoot those limits. In this paper, a Negative Impedance Converter circuit is designed for antenna applications at 868 MHz. These active circuits, that produce Non-Foster negative capacitance or inductance, are known as...
Performance characteristics of passive electrically small antennas are limited by fundamental physics. Using active elements into antenna structures appears like an opportunity to overshoot those limits. Non-Foster elements are classically used in matching networks for electrically small antennas in order to increase their impedance matching bandwidth. In this paper, Non-Foster elements are proposed...
Antenna impedance measurements are usually performed with a coaxial cable connected to the RF input port. For miniature or very integrated antennae, the presence of a coaxial cable can alter drastically the impedance and radiation behaviors. In this paper a new broadband measurement method based on RF/optical transceivers device which avoid the coaxial cable disturbance is presented. A validation...
This paper deals with a 3D low-profile 6-sector antenna system designed for home networking MIMO applications in the 5GHz band. The designed system utilizes the proposed new concept of folded end-fire Vivaldi antenna. It is made up of several low-cost FR4-based substrates, six of which are placed vertically around a common central axis and inserted between two horizontal circular substrates, all featuring...
An ultra-miniature single access antenna has been designed, simulated and realized on FR4 substrate, covering the full UHF band with a second order radiation pattern diversity. The important antenna size reduction (sizes <λ0/34.6 at the lowest frequency) has been obtained by combining two technologies: 1- the twisted slot antenna and 2- the use of tunable components for both frequency and...
In this article a very compact antenna system allowing simultaneous activation of a pre-defined number of sectors is presented. The design approach is based on using multiple retro-directive arrays co-localized in the near field of feeding sources. Parametric study in the 5 GHz WiFi frequency band of such an antenna system shows a very compact design of a 4-sectors antenna system with typically 10...
This paper introduces an ultra-miniature UHF antenna. The design combines different technologies to reduce the size:(meta-material inspired shape, use of a magneto-dielectric material as antenna support, use of an active component and a passive matching network for frequency tuning and impedance matching over the whole UHF band.) This antenna has been simulated and measured on nomad type terminal...
In this paper results of a parametric study showing the advantages of using magneto-dielectric materials, in comparison with pure dielectrics, as substrate support for miniature printed antenna, are presented. Further to the reported widening of the frequency bandwidth, it is shown that for a given antenna size and resonant frequency, almost fixed by the refractive index n √rHrΠ of the material, increasing...
This paper introduces a new ultra-wideband (UWB) printed circular dipole antenna having a filtering feature for rejecting the Wi-Fi band (4.9-5.9 GHz). UWB regulation in Europe [1] and Japan require the rejection or the avoidance of the 5 GHz Wi-Fi frequency band, but due to the very wide frequency band used by UWB technology, it is also particularly exposed to other systems disturbances. Some experiments...
Compact 2.4 GHz WiFi printed antennas based on a ldquotwistedrdquo slot approach have been designed and integrated on a board taking into account isolation requirements with an existing DECT module (1.9 GHz) for simultaneous WiFi and DECT operations. The obtained isolation between WiFi and DECT antennas of 30 dB has been ensured thanks to quarter wavelength slot stubs and a proper positioning of the...
An USB key like digital Terrestrial TV receiver with built in antenna diversity is designed, realized and tested. It allows a free to air reception of Digital Terrestrial TV on a PC or a laptop. The housing of the compact receiver is used as part of antennas. The design is optimized to cover the whole UHF European frequency bandwidth (470MHz- 862MHz) with good antenna efficiency taking into account...
This paper describes different measurements schemes for UWB antenna characterization in frequency domain as well as in time domain. The antenna measurements are well known in frequency domain, but the UWB technology introduces new requirements, especially in the time domain and then different measurement methods are necessaries. The time domain characteristics could be obtained through direct method...
A built-in antenna for a USB key like digital terrestrial TV receiver allowing free to air reception of digital terrestrial TV on a computer PC has been designed, realized and tested. The housing of the compact receiver is used as part of the antenna. The antenna design is optimized so that it covers the whole UHF frequency bandwidth with good radiation efficiency, while its size is imposed by the...
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