Directional antennas can be useful in significantly increasing the capacity of wireless ad hoc networks. With directional antennas, independent communications between nodes can occur in parallel, even if the nodes are within range of each other. However, mutual interference by simultaneous transmissions limits the maximum number of such concurrent communications. Furthermore, it poses bounds on...

This paper deals with a method of the radiation pattern determination of the directional antennas. The method combining both the functional minimization method and the Fourier iterative algorithm is based on the phaseless near-field measurement on two plane surfaces. The method is used for a reconstruction of the phase distribution on the aperture of the measured antenna, and for the determinat...

An investigation into the effect of ground slot in a microstrip antenna is presented. Initially, a planar inverted-F antenna dedicated for 2.45 GHz WLAN lower band is designed. Its rectangular ground plane is then introduced with slots to excite new magnetic resonance for 5.2/5.8 GHz WLAN upper band. The slots are optimized by tuning their three different configuration parameters which are the ...

This paper addresses the problem of energy-efficient and power aware data routing strategies within the ad hoc networks using directional antennas and considers the battery power of each node as an important criteria while determining the route for data packet transmission. Energy depletion of nodes in ad hoc networks is one of the prime concerns for their sustained operation. Conventional rout...

In this paper, dimensioning of Universal Mobile Telecommunication Systems (UMTS) Radio Access Method (RAN) has been performed with respect to varying antenna gain of NodeB and sectorization of site layout of network sites. Three different site layouts have been configured to estimate the number of sites required to cover the deployment area. In the first site layout, Single Omni directional ant...

In this paper, a novel design for coplanar waveguide antenna is developed which, consists of two U-shaped slots. The antenna is named Clip. The antenna is designed at central frequency of 2.4 GHZ with input impedance of 50Ω. The antenna dimensions represent 72% size reduction than conventional microstrip rectangular patch antenna. The measured antenna bandwidth is about 11% while its gain is ab...

In this paper we propose a Directional Antenna Medium Access (DAMA) protocol that takes advantage of the benefits offered by directional antennas and is best suited for sparsely distributed networks. A large portion of DAMA has been inspired by the IEEE 802.11 MAC, with major enhancements including a new neighbor discovery scheme, and an optimized circular directional transmission of RTS and CT...

Antenna 3D pattern measurement can be a tedious and time consuming task even for antennas with manageable sizes inside anechoic chambers. Performing onsite measurements by scanning the whole 4π [sr] solid angle around the antenna under test (AUT) is more complicated. In this paper, with the aim of minimum duration of flight, a test scenario using unmanned aerial vehicles (UAV) is proposed. A pr...

A uniformly spaced comb taper slot antenna array is proposed for directional ultra-wideband (UWB) applications. The UWB array consists of four identical comb taper slot antennas, a mutistage with four-way microstrip UWB power divider, and four identical coaxial cable lines. A maximum gain of 15.5dBi within the band is obtained when the element separation is properly selected. The uniform spacin...

It was shown by numerous authors that the characterization of RFID (radio-frequency identification) transponder antennas that are favored to be small, have low gain, and show a strongly reactive input impedance, is far from trivial. We propose a method that utilizes a small, highly-stable, battery-driven signal source to generate the transmit signal directly at the antenna. The signal source is...