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A few years after the early investigation on ultra-wideband (UWB) wireless system, considerable research efforts have been put into the design of UWB antennas and systems for communications. These UWB antennas are essential for providing wireless wideband communications over very short distances at very low power densities. This chapter presents numerical analysis of a small slotted UWB antenna by...
This paper presents a numerical method of identifying the beam squinting optimal design parameters. It is aimed at eradicating the arbitrary method of selection of phi, (φ) thetaT(θT) and phiT(φT) which improves the overall production process. Arbitrary selection of design parameters for beam squinting method which has been identified to solve the inherent return loss problems associated with the...
The Radial Line Slot Array (RLSA) antennas become more popular due to its good characteristics such as low profile, low cost, aesthetically pleasing, ease of installation and simple structure. Many researchers have contributed to the development of RLSA antennas. This antenna started with the name of annular slot antenna designed by Kelly and Goebel in 1960's. In 1980's, the researchers from Japan...
This paper investigated the capability of Electromagnetic band gap (EBG) in reducing the backlobe of the microstrip patch antenna array. Four different size of EBG have been simulated and the radiation patterns are presented. The results show that if only one slot of antenna is inserted into the structure, (3mm×6mm) EBG produced the best back lobe reduction that is from −10.24db to −17.67dB. If the...
A dual-band B-shaped monopole antenna for MIMO application is presented. The proposed antenna consists of B-shaped element which operates at dual band frequencies of 2.45GHz and 5.8GHz. The prototype has been fabricated and when tested, the impedance bandwidths are 29.9% and 33.8% for 2.45GHz and 5.8GHz, respectively. Good agreement between the measurement and simulation results in term of return...
A microstrip-fed broadband printed monopole antenna covering 1.7 – 6.0 GHz is miniaturized using half-cut technique, and arranged in pair for uplink/downlink microwave-photonic access point. This paper discusses the effect of the miniaturization to S11 and radiation pattern of individual antenna, and also the best choice of antenna pair, ground-plane type, and total width of the access point.
Current indoor location determination systems require an offline training phase in order to build a radio map that contains a list of radio fingerprints at known locations. The process of building this radio map is usually a time-consuming and requires an intensive work where the accuracy of these systems depends on various factors such as the number of collected radio fingerprints and the time in...
This paper presents dual band 4 ×4 Butler Matrix beam forming network integrated with antenna array operating at WLAN systems, 2.45GHz and 5.8GHz bands. Array antenna connected to a beam forming network can produce the desired multilobe radiation pattern. A signal fed in one port of Butler Matrix is divided into equal parts thus generate certain phase and equal amplitude which determine the beam direction...
This paper presents a small printed ultra wideband (UWB) antenna with a coupled slot. This proposed antenna uses coupled L and U slots to broaden the bandwidth. A truncated ground plane is designed to control the antenna's impedance matching. Both slots were designed by investigating the behaviour of the current distribution of the patch antenna. It is shown that by proper design of the slot width...
The demand for ultra wideband (UWB) communications is rapidly increasing due to the need to support more users and to provide more information with higher data rates. With appropriate technical standards, UWB devices can operate using spectrum occupied by existing radio services without causing interference, thereby permitting scarce spectrum resources to be used more efficiently. This paper presents...
Orthogonal frequency division multiple access (OFDMA) is a multi-carrier transmission technique that has been recently recognized as an excellent method for high speed bi-directional wireless data communication and it is one of the strong candidates as multiple access technique for the next generation of downlink receivers In this paper we aim to investigate the effect of fading channel on the performance...
At WRC-07, the frequency band 3500 MHz has been allotted for the next generation of mobile International Mobile Telecommunication-Advanced (IMT-Advanced). Meanwhile this band is already in used by fixed services which means that harmful interference probability may be transpired. In this paper, a new coexistence method between the aforementioned services in various geographical deployment areas (dense...
This paper tries to present a new form of adaptive modulation which has the ability of using the high order modulation schemes such as 256-QAM and 128-QAM at low SNR values such as 2, 4 and 8 dB in order to enhance the data rate without degrading the SER performance especially at low SNR values. This new form of adaptive modulation is combined together with the power control and the PAPR clipping...
The coexistence and intersystem interference coordination between systems is difficult to be achieved and relies on many technical factors. In this paper, intersystem interference scenarios such as co-channel, zero-guard band, and adjacent channel will be analyzed to determine the coexistence coordination requirements between IMT-advanced and fixed services. These coordination requirements in terms...
3500 MHz fixed wireless access system is a point-to-multipoint (P-MP) wireless technology providing broadband services. In this paper, P-MP fixed cellular service network structure such as Local Multipoint Distribution (LMDS) service is proposed to share same network area and frequency band (3400-3600 MHz) with the fourth generation of mobile (IMT-Advanced) represented by mobile Worldwide Interoperability...
In this paper, experimental data was demonstrated the concepts of reconfigurable number of elements that produced broad beam and narrow beam radiating pattern characteristic. Using modified WPD in the antenna structure, produced better performance in term of return loss characteristic. This research has taken advantage of the flexibility of the number of element technique by applying it to the problem...
Channel characterization and state information play important role in the realization of optimal performance in communication systems. In mobile communication systems, the channel is realistically nonstationary and is often modeled equivalently as time-frequency integral operator with finite supports in time and frequency, employing the Fourier kernel and fixed window as the analyzing functions which...
Active photonic antenna (APhA) designed for 2.4 GHz communication in downlink side is proposed. The APhA consists of photodiode, RF amplifier and band pass filter (BPF) in small package, integrated with RF antenna. The APhA design is simulated using optical communication simulation software at varied fiber length and free space loss (FSL). Performance improvement over passive photonic antenna (PPhA)...
Due to its low propagation loss, large bandwidth, and competitive cost, optical fiber become one of the best solution for the backhaul. However, new fiber network deployment is still very expensive in outdoor and rural environment. This paper proposes and evaluates design of 5.8 GHz photonic antenna in a radio over fiber system for point-to-point applications. Simulation result shows that the proposed...
This paper is divided into two parts. The first part presents the study of smart antenna beamforming where a single beam is shaped by weighting and summing the antenna outputs. In order to calculate the weight of the array elements, the conventional beam-former (known as delay and sum) has been chosen. Matlab software is used to calculate the weights, and to obtain the array factor of 8 elements linear...
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