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In this work, a novel wideband microstrip modified slotted U-shaped printed monopole antenna operating from 3 to 20 GHz for super-wideband applications is proposed. To have an effect on the enhancement of bandwidth and to get better impedance matching over the frequency band, three modifications are introduced, the first one is to print two symmetric triangular shaped slots in the radiating element and the second one is to modify the partial rectangular ground plane to be defected ground plane by slotting three triangular structures. The third modification is to embed a circular slot in the center of the patch for integrating the entire FCC band (3.1–10.6 GHz) in the super wide band antenna. Both CST Microwave Studio and Ansoft HFSS 3-D EM solver were used for the simulation analysis of antennas while measurements after fabrication are performed by applying ZVB 20—vector network analyzer 20 MHz–20 GHz. The average maximum gain of the antenna is 5.72 dB with good radiation patterns. The antennas have only been measured up to 20 GHz (the upper frequency limit of the laboratory vector network analyzer device), simulations results both in CST and HFSS shows satisfactory design's performance up to 40 GHz. So as this antenna is a candidate to fulfils the future UWB spectrum requirements in a very wide band. A good agreement between the measured and simulated results is achieved in term of return loss in the measured band (up to 20 GHz). [ABSTRACT FROM AUTHOR]

Circular disc monopole antennas are investigated for current and future ultrawideband (UWB) applications. The studied antennas are compact and of small size (25 mm\,\times\,35 mm\,\times\,0.83 mm) with a 50-\Omega feed line and offer a very simple geometry suitable for low cost fabrication and straightforward printed circuit board integration. More specifically, the impedance matching of the classic printed circular disc UWB monopole is improved by introducing transitions between the microstrip feed line and the printed disc. Two particular designs are examined using a dual and single microstrip transition. By using this simple antenna matching technique, respective impedance bandwidths (\vert S11\vert < -10 dB) from 2.5 to 11.7 GHz and 3.5 to 31.9 GHz are obtained. Results are also compared to a classic UWB monopole with no such matching network transitions. Measured and simulated reflection coefficient curves are provided along with beam patterns, gain and group delay values as a function of frequency. The transient behavior of the studied antennas is also examined in the time domain. [ABSTRACT FROM AUTHOR]

In this article, we present a novel circular disc antenna for current and future ultrawideband (UWB) applications. The proposed antenna has a small size of 30 mm × 35 mm, a simple geometry, and the excitation is launched through a 50-Ω microstrip feed line. The impedance matching of the proposed antenna is improved by introducing a second microstrip line between the feed line and the circular patch. A prototype of the proposed antenna has been fabricated and its performances are measured. The obtained results show that the proposed antenna operates on UWB frequency range from 2.7 to 28.8 GHz. Measured radiation patterns and simulated gain and radiation efficiency of the proposed antenna are presented and discussed. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1130–1133, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24261 [ABSTRACT FROM AUTHOR]

In this paper, a novel UHF RFID Tag antenna for automotive tire is presented. The antenna shape and size are reduced by using a meander line. To ensure a proper impedance matching between the antenna and the microchip, especially when antenna is immersed in dielectric medium, a simple approach is presented. The square-load is added at the both ends of antenna tag in order to improve the bandwidth aspect. The tag has a reduced size: 40mm*13.5mm*0.018mm. Hence, it can be embedded in automotive tire. The tag provides the low profile and low cost fabrication. The simulated results show that our approach is helpful to achieve impedance matching process. Moreover, the proposed antenna has omnidirectional radiation patterns and a good gain that satisfy maximum power transmitting in RFID communication once tag is embedded in rubber material. [ABSTRACT FROM AUTHOR]