Dalia Mohammed Nasha Elsheakh

Reconfigurable Single and Multiband Inset Feed Microstrip Patch Antenna for Wireless Communication Devices

Two novel designs for compact reconflgurable antennas are introduced for wireless communication devices. These designs solve the steering frequency problem by tracking the desired resonance frequency or by generating various operating frequency bands to be selected electronically. In the flrst design, the length of the rectangular defected ground structure (RDGS) is electrically adjusted to change the resonant frequency of the MPA. While in the second design difierent turns of spiral AMC ground plane generate frequency bands, or modes, that are selected/optimized to serve difierent communication systems simultaneously. These systems may include various combinations of bluetooth, S-band and wireless local-area network (WLAN). These designs have several advantages as the total antenna volume can be reused, and therefore the overall antenna will be compact, although, the radiation of the MPA is kept flxed without any degradation. The designs are verifled through both numerical simulations and measurement of a fabricated prototype. The results conflrm good performance of the single and multiband reconflgurable antenna designs.

Multiband Printed Metamaterial Inverted-F Antenna (IFA) for USB Applications

A printed multiband coplanar waveguide (CPW)-fed inverted-F antenna (IFA) is presented in this letter. The concept of loading a printed-IFA with composite right/left-handed (CRLH) unit cells is theoretically and experimentally investigated by using electromagnetic simulators, Advanced Design System (ADS) and High Frequency Structure Simulator (HFSS), for universal serial bus (USB) applications. The proposed USB antenna structure consists of a CPW printed-IFA with two arms loaded by two CRLH unit cells to achieve two extra operating bands in addition to the two fundamental resonant frequencies of two IFA arms. The structure is designed to operate at GSM 1.8 GHz, Bluetooth 2.4 GHz, WiMAX 3.5 GHz, and WLAN 5.2 GHz. Measured and simulated results are in good agreement with the theoretical predictions.

ULTRA-WIDE BANDWIDTH MICROSTRIP MONOPOLE ANTENNA BY USING ELECTROMAGNETIC BAND- GAP STRUCTURES

A novel compact design for ultra-wide bandwidth (UWB) planar monopole antenna is presented in this paper. The basis for achieving the UWB operation is through using semicircular microstrip monopole antenna with modifled ground plane in the form of semi circular umbrella like shape. This shape produces bandwidth ranging from 3 to 35GHz with discontinuities from 7GHz to 10GHz, from 12.5GHz to 17.5GHz and from 22GHz to 40GHz. The antenna size is reduced by 27% relative to the size of conventional rectangular monopole patch antenna. Metamaterial structures are used for further antenna performance improvement. Two types of metamaterial namely EBG and DGS are studied. First, embedding metallo EBG (EMEBG) is used to eliminate ripples in the operating band and also further reducing the antenna size by more than 30% as compared to the proposed patch. The antenna design provides an impedance bandwidth of more than 33GHz. Second, four arms spiral defected ground structure (SDGS) is used as a ground plane with four arms to further improve the antenna performance. The SAMC reduced the antenna size by more than 48% as compared to the proposed antenna patch, increased bandwidth, and decreased the cross polarization efiect. Finally, embedded EBG together with SDGS ground plane are studied to take advantages of both techniques.

Antenna Designs with Electromagnetic Band Gap Structures

The word “meta”, in Greek language, means beyond. It implies that the electromagnetic response of metamaterials (MTMs) is unachievable or unavailable in conventional materials. Many efforts have been done to search for an adequate definition for MTMs. In 2002, J.B. Pendry wrote in a conference paper: “meta-materials, materials whose permeability and permittivity derive from their structure”. Later, in 2006, C. Caloz and T. Itoh wrote: “Electromagnetic metamaterials are broadly defined as artificial effectively homogeneous electromagnetic structures with unusual properties not readily available in nature” [1]. Perhaps, a serious obstacle on the road to a universal definition for the term MTMs is the fact that researchers working with these objects do not commonly agree on their most essential characteristics. In [2] and [3], some of the problematic aspects of the non-naturality definition were raised, like the difficulty in separating classical composites from the new class of metamaterials. Another argument against the “not found in nature” property is that it unnecessary excludes impressive examples of natural media that could be called metamaterials par excellence, such as structural colors [4].

High performance compact antenna for HF radar

This paper summarizes the results of an ongoing design effort to miniaturize HF antennas for HFSWR and OTHR systems. The proposed design is based on a meander antenna described in [1]. Design modifications include a multi-element folding to increase the radiation efficiency and improve the impedance matching and also the incorporation of a back conducting plane reflector to improve the gain. Based on simulation results using the FEKO and IE3D software and experimental measurements, we were able to successfully demonstrate the anticipated advantages of the proposed prototype design.

Ultra Wide Bandwidth High Gain Vivaldi Antenna for Wireless Communications

Abstract—In this paper an ultrawide bandwidth double-layered Vivaldi antenna (DLVA) integrated in Radome housing is proposed. First the conventional Vivaldi antenna is designed with bandwidth extended from 1.8 to 6GHz at VSWR (3 : 1). Then for wider bandwidth, two slots are etched in the antenna ground plane to extend the antenna bandwidth from 1.7 to 9 GHz. For more improvement in antenna bandwidth, circular slots as electromagnetic band-gap structure (EBG) are etched to further extend the antenna bandwidth from 1.45 to 10 GHz. For gain enhancement double layers of Vivaldi antenna ground plane are designed with the same feeding line to reach 29 dBi peak. High frequency structure simulator (HFSS) ANSYS is used to design and simulate all the design steps. The proposed antenna is fabricated and measured. Finally, DLVA is integrated inside the Radome to improve the antenna gain and protect the proposed antenna from environmental factors. The antenna is fabricated and tested, and a good agreement between simulated and measured results is found.

Compact Multiband Printed IFA on Electromagnetic Band-Gap Structures Ground Plane for Wireless Applications

The fourth mobile generation requires of multistandard operating handsets of small physical size as well as has an increasing demand for higher data rates. Compact multiband printed inverted-F antennas (IFAs) for available wireless communications are proposed in this paper. A new design of a printed IFA based on a uniplanar compact EBG concept is proposed. An L-loaded printed IFA shaped over an artificial ground plane is designed as the main antenna to cover the GSM, LTE, UMTS, bluetooth, and WLAN. The multi-band is created by means of an electromagnetic band-gap (EBG) structure that is used as a ground plane. Different shapes of uniplanar EBG as ring, split ring resonator, and a spiral rather than mushroom-like structure are investigated. The proposed antenna is built on the uniplanar EBG ground plane with a size of mm2, which is suitable for most of the mobile devices.

COMPACT 3D MONOPOLE ANTENNA FOR DIFFERENT WIRELESS COMMUNICATION APPLICATIONS

A 3D compact printed monopole antenna for most of the wireless communication applications is proposed in this paper. The proposed antenna has dimensions 40 × 30 × 1.6 mm3; it is based on multi different length arms of E-shaped monopole with modified ground plane coupled with meander line. The performance of the 3D antenna is almost the same as a 2D antenna with reduction in size, and it could be fit in a wireless transceiver device. The size reduction about 25% compared to the 2D planar proposed antenna is realized on a printed circuit board to reduce the fabrication cost. The coupling between the antenna elements broadens the operating bandwidth, which includes most of the wireless commercial service bands, GSM1800/GSM1900/ UMTS/WCDMA2100 802.11b/g/LTE2600 (2690 MHz) as well as 802.11a/n (5150–5825 MHz). The antenna’s simulated and experimental results are in good agreement. It is fabricated on a low-cost FR4 substrate and measured to validate the simulation performances. Measured results display that the proposed antenna produces omnidirectional radiation pattern of −6 dB impedance bandwidth at multi operating bands and average gain of 3.5 dBi and 2 dBi for 2D and 3D, respectively over the operating band.

Microwave security system in museums (design and implementation)

The objective of this paper is to propose a competitive microwave security system that can be applied with reasonable price at museums in Egypt due to following reasons, the priceless elements in Egyptian 23 museums country wide and the lack of good recent security systems even in big ones. The system main goal is to detect valuable targets to ensure their presence in the pre-defined positions in order to protect them from stolen. The system is based on real time microwave scanning for the required space volume through transmitting RF waves at consecutive angles and detecting the back scattered waves from required objects to detect their existence at pre-specified locations.

DESIGN OF LOW SAR PLANAR MONOPOLE ANTENNA FOR MOBILE WIRELESS COMMUNICATION APPLICATIONS

Simple internal multiband monopole antenna with low SAR for most of wireless mobile communication applications is presented in this paper. The proposed antenna is an unequal arms monopole antenna with a meander strip in the other substrate side. The antenna has a simple structure and is su-ciently small in size to be easily flt on the housing of mobile or USB dongle with size 18 £ 15 £ 0:8mm 3 . The antenna is designed to operate at multi- bands to occupy most of allocated wireless communication devices by using high frequency structure simulator ver. 13 (HFSS). The proposed antenna has acceptable gain and e-ciency while providing broadside radiation pattern that covers the horizontal plane. The antenna design and experimental results are in agreement. Moreover, the speciflc absorption rate (SAR) in the human head is investigated by CST 2012 Microwave Studio Hugo Voxel Model.