Wideband Omnidirectional Antenna Research Articles

A Wideband Directional Microstrip Slot Antenna for On-Body Applications

Antennas are one of the main components of every wireless telecommunication system. With wideband antennas for on-body applications, there are some additional features that should be considered including radiation and physical size. In this paper, we presented a wideband omnidirectional slot antenna with a reflector element improvised under the feed line in order to minimize the impact of body on the antenna. Curiously, this reflector element allows for directionality of the antenna. In the following sections of the paper we will show that less power can penetrate body tissues in the presence of reflector elements; thus, wideband directional antennas are influenced less by human body than omindirectional antenna.

Design of Wideband Omnidirectional Two-Layer Transparent Hemispherical Dielectric Resonator Antenna

This communication investigates the wideband omnidirectional two-layer hemispherical dielectric resonator antenna (DRA), excited in its omnidirectional TM101 mode by an axial probe. For the first time, design formulas of the omnidirectional two-layer hemispherical DRA are found by using the covariance matrix adaptation evolutionary strategy (CMA-ES). The formulas are used to design a two-layer transparent hemispherical DRA which simultaneously serves as the covering of a light source. Acrylic and glass are used for the inner and outer transparent layers, respectively. ANSYS HFSS was used to simulate the DRA, and the simulation agrees reasonably well with our measurement. It was found that the transparent two-layer DRA has a measured impedance bandwidth of 31.9%, which is over two times wider than that of the single-layer TM101-mode glass DRA.

Wideband Ceiling-Mount Omnidirectional Antenna for Indoor Distributed Antenna Systems

A wideband omnidirectional antenna is presented in this letter. The proposed antenna consists of three radiators over a ground plane, a monopole composed of three patches fed by a coaxial line, a coupling patch with three shorting legs above the monopole to extend the lowest frequencies of operation, and a top-loading disk located on the top of the coupling patch for further decreasing the lowest frequencies of operation. An enhanced impedance bandwidth of 9.23:1 ranging from 650 MHz to 6 GHz with ${ S}_{11} 13.9 dB (for ${\rm SWR} \leq 1.5$ ) is achieved. The antenna meets network operator's requirements for cellular bands and has good radiation efficiency in the WiFi bands. The proposed antenna can be widely used in indoor distributed antenna systems, such as 3G, 4G LTE, and WiFi (2.4 and 5.8 GHz) bands. The antenna is simulated by ANSYS HFSS and measured in a microwave anechoic chamber. The simulated and measured results show good agreement.

NOVEL WIDEBAND OMNIDIRECTIONAL ANTENNA FOR WIRELESS APPLICATIONS

This paper presents the design of a novel wideband omnidirectional antenna with the usable bandwidth enhanced. The antenna is designed for wireless applications and proposed to operate within WLAN (2.4GHz{2.484GHz) and WiMAX (2.3GHz, 2.5GHz and 3.5GHz) frequency bands. The bandwidth is enhanced through the use of balun, while the radiation patterns remain stable. This antenna has a much wider VSWR band (47.5% for VSWR < 2) with high radiation pattern stability compared with printed dipole antennas. Details of design, simulated and experimental results of this omnidirectional antenna are presented and discussed. The measured results conflrm the validity of this design which meet the requirements of wireless applications.

Analysis and design of a wide band omnidirectional antenna

The analysis and design of an omnidirectional antenna that functions over a very broad frequency band is presented. Design guidelines for this antenna have been derived using electromagnetic analysis software. Measured results of a prototype developed according to these guidelines are presented. These results are compared to simulation results to illustrate the validity of the model used to derive the empirical design guidelines. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1352–1356, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25990

Wideband Omnidirectional and Compact Antenna for VHF/UHF Band

A wideband omnidirectional and compact (WIBOC) antenna is proposed in this letter. The antenna is constructed with a combination of an upper metallic plane with an elliptic shape, a rectangular metallic plane placed underneath, and a discone monopole antenna used as an excitator located between these metallic planes. This antenna provides broadband characteristics and omnidirectionnal radiation patterns in the azimuth plane over the whole bandwidth with a height limited to λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LF</sub> /29, where λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LF</sub> is the lowest frequency of the operating band.