Jean Marie Floc'h

Planar Elliptic Broadband Antenna with Wide Range Reconfigurable Narrow Notched Bands for Multi-Standard Wireless Communication Devices

A planar elliptic broadband antenna with reconflgurable dual stop-bands performance was successfully designed and performed for multi-standard wireless communication systems. The proposed antenna consists of a broadband micro-strip fed printed monopole operating in the frequency range 0.75{ 6GHz. The notch-band characteristic was obtained by printing two Open Loop Resonators (OLRs) on the front side of the substrate close to the micro-strip feed-line. By adjusting the OLRs parameters, mono or dual band-rejection can be obtained. The passive broadband antenna was optimized to achieve narrow band rejection over the UMTS-band (around 2.1GHz) and the WiMAX-band (around 3.5GHz). The agility was produced by loading a varactor diode on each OLR. The major advantages of this structure are the high selectivity of the dismissed-bands, continuous reconflguration and wide tuning range of the notched bands. Four prototypes were realized and experimentally characterized. The measured tuning ranges corresponding to the notched bands are about 850MHz (2.25{3.1GHz) for the rejected UMTS-band and 570MHz (3.84{4.41GHz) for the WiMAX-band. Simulated and measured results are presented and discussed.

A Dual-Band Printed Dipole Antenna For IMT-2000 and 5-GHz WLAN Applications

A dual and wide-band printed dipole antenna is presented for IMT-2000 and 5.2/5.4/5.8 GHz WLAN applications. The proposed balun-fed antenna consists of a double-sided printed dipole antenna with a microstrip-fed disk-dipole printed on the top side of the substrate, and a modified annular-ring dipole and the ground plane on the bottom side. For the proposed antenna, two resonant bands are observed. The first band about 11% for the center frequency of 2.1 GHz and the second band extends from 4.1 to 88.1 GHz with a fractional bandwidth of 65%. The measured peak gains over these bands are 1.8 and 3 dBi, respectively. Details of the experimental and simulation results are presented and discussed.

Broadband UHF flexible vivaldi antenna

A novel Vivaldi flexible antenna with a -6 dB bandwidth from 150 MHz up to 900 MHz is presented. The whole antenna is realized on a 600 × 600 mm2 silicone foam substrate. In this paper we describe the design, the realization and the performances of this high gain and directive antenna. This antenna is easy to make and does not require matching network or balun.

Design of reconfigurable radiation pattern dipole antenna with director and reflector elements for telecommunication systems

A planar printed dipole antenna able to tilt its radiation pattern in different directions is proposed for wireless communication systems. Starting from a dual beam printed dipole antenna working at the 2.45 GHz ISM frequency achieved by combining two elementary dipoles back to back, and by implanting four PIN diodes on the rear side of the substrate, four configurations of directive radiation patterns are easily reached around the frequency 2.64 GHz depending on switches states. A prototype of the basic structure was realized and characterized. Simulation results of the reconfigurable radiation pattern dipole are presented and discussed.

Printed frequency reconfigurable planar inverted-F antenna for ISM applications

Frequency reconfigurable antennas present an attractive alternative to meet Cognitive Radio (CR) system requirements. In this paper, a multiband planar inverted F-antenna (PIFA) with frequency agility characteristic was designed and numerically studied for ISM applications. A varactor diode was incorporated in the corner between the radiating patch and the added floating ground plane. By applying a reverse voltage V, three resonance frequencies can be electrically controlled. Wide tuning frequency ranges were obtained; F1 can be shifted from 650 to 896 MHz, F2 from 954 to 1379 MHz and F3 from 1502 to 2457 MHz. The reference and the active antennas were manufactured and characterized. Simulations and measurements are presented and discussed.

Investigation of a Random-Fractal Antenna Based on a Natural Tree-Leaf Geometry

In this paper, we investigate a new printed antenna based on the 2D image of a fractal tree-leaf geometry by studying the effect of the irregular boundary of the proposed antenna on its radiation characteristics. Both the impedance matching properties and the radiation patterns of the antenna are studied over the frequency band 1–6 GHz. Four configurations are designed by increasing the complexity of the structure, which ranges from iteration 0 to iteration 3. The fractal properties of the proposed tree-leaf antenna are then compared to those of a conventional fractal antenna with smooth edges. Following this, the proposed antennas are fabricated and characterized experimentally. Finally, results are analyzed and discussed, and a practical application for this new type of antennas is proposed.

Capacitively Loaded Loop-Based Antennas with Reconfigurable Radiation Patterns

A class of metamaterial-inspired antennas having reconfigurable radiation patterns is proposed. They consist of a driven monopole antenna with one- and two-capacitively loaded loop (CLL), near field resonant parasitic elements. Two configurations are studied by considering the state of these CLL elements as being either open or closed configurations. Simulation results explain the design features and demonstrate that the structure can change its beam direction simply by controlling the switched states. Two prototypes with one- and two-CLL elements were fabricated and tested. The measured impedance mismatch and radiation pattern results are presented and compared to the corresponding simulated values.

Rectangular Bi-Loop Single-Feed Antenna with Polarization Agility Property for GPS and Iridium Applications

A polarization Agile printed antenna was successfully designed, prototyped and experimentally characterized for GPS and Iridium applications. Its structure is simple and consists on two radiating rectangular loops. The proposed single-feed dipole is able to toggle either between Linear Polarization (LP) and circular polarization (CP) or between two CP (Right Hand (RHCP) and Left Hand Circular Polarization (LHCP) by controlling the two PIN diodes loaded on each rectangular loop. First measurements are obtained by using copper strips instead of switches for proof of concept. The antenna radiation symmetry is maintained and good agreement is obtained between simulated and measured results.

Design of a printed elliptic reconfigurable dual band-rejected UWB micro-strip fed antenna

A printed elliptic UWB reconfigurable dual band-rejected antenna operating from 0.75 to over 6GHz was designed and performed for multi-standard telecommunication systems such as GSM 850, GSM 900, LTE, ISM 868, WiFi, WLAN, WiMAX... The main antenna consists of a very high selective UMTS (2.1 GHz) band-rejection micro-strip fed monopole. The reconfigurable discarded bands were obtained by printing two Open Loop Resonators (OLRs) on the both edge sides of the feeding line with same dimensions. By loading a varactor diode on the first OLR and an active inductor on the second one, the rejected bands become easily controllable. Hence the frequency reconfigurability is produced. Initial results are obtained by using a SMV1405 varactor diode and lumped inductors. Simulated and measured results are presented and discussed.