Abdelheq Boukarkar

A Dual-Band Frequency-Tunable Magnetic Dipole Antenna for WiMAX/WLAN Applications

In this letter, a new dual-band frequency-tunable antenna for Worldwide Interoperability for Microwave Access (WiMAX) and Wireless Local Area Network (WLAN) is proposed. The frequency tuning is realized by the insertion of two varactor diodes into the antenna structure. At the resonant frequencies, the antenna behaves like two magnetic dipoles. The antenna is designed and fabricated. Measurements show that the antenna presents two narrow-band resonant frequencies that can be tuned separately. Either of the two bands can be tuned independently by varying the dc bias of the varactors from 0 to 30 V while keeping the other extremely stable. The antenna can cover 230 MHz of WiMAX frequency band (3.28-3.51 GHz) and 560 MHz of WLAN band (5.47-6.03 GHz). The proposed antenna has a considerable importance in wireless communications because of its planar shape, compact size, simple dc feeding network, and the frequency tuning of one band does not have any effect on the second band.

Miniaturized Single-Feed Multi-Band Patch Antennas

This communication introduces an approach for designing miniaturized single-feed multiband patch antennas. The size reduction is obtained by loading shorting metalized vias on one edge of the radiating patch, while multiband is obtained by etching inverted multiple U-shapes. A dual-band antenna with a large measured frequency ratio of 2.74 is first discussed. Then triple-band, and further quad-band antennas are, respectively, designed. The antennas have sufficient electrical small size when considering the radius of the minimum enclosing sphere to the radiating patch. A radius value of

A Tunable Dual-Fed Self-Diplexing Patch Antenna

0.09\lambda _{0}

A new reconfigurable multi-band monopole antenna for different wireless applications

is obtained for the quad-band antenna with respect to the lowest operating frequency centered at 3.04 GHz. Simulated and measured results of the antennas’ reflection coefficient and radiation patterns are provided. Good agreement between the simulation results and measurement results is achieved. The antennas’ measured peak gains and efficiencies vary from 1.43 to 3.06 dBi and 42% to 74%, respectively. Compared with other designs, the proposed antennas exhibit multiband performance by using a simple single-feed structure, realize different combinations of highly isolated frequency bands with wide tunability of frequency ratios, and have directional stable radiation patterns that are compact and of electrically small size. Indeed, they have the potential to meet the practical requirements for wireless applications.

A Miniaturized Extremely Close-Spaced Four-Element Dual-Band MIMO Antenna System With Polarization and Pattern Diversity

We propose a simple and compact design of a tunable self-diplexing patch antenna. Two U-shapes are etched on the same platform to locate the radiating patches which are excited separately using two feed ports. Metalized vias acting like metal walls are applied to reduce the antenna footprint, and to avoid coupling effects when the frequency ratio (fr) approaches 2. The tuning process is achieved by using two varactors properly inserted into the radiating structure. The operating frequencies can be tuned independently with high isolation level. Simulation and measurement results are quite consistent. Measured results show that the lower frequency band ranges from 3.9 to 4.37 GHz with measured peak gain and efficiency of 3.82 dBi–65%, while the upper band ranges from 4.63 to 5.34 GHz with peak gain of 4.48 dBi and peak efficiency of 64%. The self-diplexing antenna achieves an isolation level better than 22 and 32 dB for the lowest fr of 1.05, and the highest fr of 1.37, respectively. The radiation pattern is unidirectional and extremely stable during the frequency tuning of both bands.

A Highly Integrated Independently Tunable Triple-Band Patch Antenna

A new compact reconfigurable multi-band monopole antenna for different wireless applications is proposed. The antenna can be reconfigurable using two switches S1 and S2 modeled as perfect conductors when their states are on. The states of the switches allow the antenna to have distinct resonant frequencies. The antenna is fabricated and tested. Good agreement between simulated and measured return loss is obtained. The antenna has a simple structure, small size, and can cover several frequency bands by using just two switches; making it distinguishable and suitable for some wireless applications.