Ultra-wide band (UWB) is a wireless technology deployed for transmitting data at high rates over short distances. Similar to Wi-Fi and Bluetooth, UWB is a radio frequency (RF) technology that operates via radio waves. To remove minor... more
This paper shows with simple setup and analysis that given the constraint of transmit power, receiver noise and a limited bandwidth, the capacity of the channel grows with the number of parallel transmissions from the transmitting... more
In this study the effect of temperature on the optimum fiber length for maximum gain of Erbium doped almino-germanosilicate, aluminum oxide and yattria-silicate glass, with fixed pump power. The optimum length depends strongly on the... more
In multi-antenna system, the correlations between the receiver antennas degrades the systems performance. In this paper, we propose a spatial decorrelation receiving technique in frequency-selective SIMO channels. A spatial-to-modal... more
Rate-distortion theory is considered for the Shannon cipher system (SCS). The admissible region of cryptogram rate R, key rate R k , legitimate receiver's distortion D, and wiretapper's uncertainty h is determined for the SCS with a noisy... more
The paper presents the propagation analysis of ultrawideband Gaussian signal in an automated collaborative warehouse environment where human and robots communicate to ensure that mutual collisions do not occur. The warehouse racks are... more
We consider the fast Rayleigh fading wiretap channel, over which a legitimate transmitter wishes to have secure communication with a legitimate receiver in the presence of an eavesdropper. We consider an average power constraint on the... more
A tree fractal antenna, for UWB applications with micro-strip feed is presented. By adopting the proposed patch, much wider impedance band width is achieved and by increasing the fractal iteration new resonances are seen. The antenna... more
Ultra-Wideband (UWB) is a radio transmission scheme that uses extremely low power pulses of radio energy spread across a wide spectrum of frequencies. UWB has several advantages over conventional continuous wave radio communications... more
An efficient method to fabricate transparent glass ceramic fibers containing in-situ grown Yb 3 þ doped oxide nano-particles based on yttria-alumino-silicate glass is presented. These large-mode area Yb 3 þ doped fibers having a core... more
This paper investigates the impact of channel bandwidth on fading in wireless channels using indoor measurements. The variation of channel energy over a local region is examined for narrowband, wideband and ultrawideband (UWB) channels,... more
An overview of the propagation characteristics of ultrawideband (UWB) indoor radio channels is presented with an emphasis on the spatio-temporal channel properties. Extensive measurement results are provided and practical considerations... more
A typical ultrawideband (UWB) antenna acts as a space-frequency filter. As a result, the UWB signal transmitted or received by such an antenna undergoes joint angular-spectral distortion, and consequently the system suffers serious... more
Ultrawideband (UWB) systems offer high spatiotemporal resolution and are therefore well suited to sensor localization applications. In this paper, we consider the use of UWB signals for positioning and ranging based on fingerprinting... more
In this paper, the relation between small-scale fade depth and channel bandwidth in an indoor environment is investigated. The fade depth, a measure of the signal power variability over a local region in space, is evaluated for... more
A two dimensional numerical model of an optically gated GaAs MESFET with non uniform channel doping has been developed. This is done to characterize the device as a photo detector. First photo induced voltage (V op) at the Schottky gate... more
with respect to the angle of arrival of incident wave and the fact that several times greater values of the peak intensity can be achieved. Narrowband receivers exploiting these effects may potentially have improved sensitivity and... more
In this manuscript, a simple synthesis method of single square loop frequency selective surface (SSLFSS) is discussed, which may find the suitable application in the fast analysis and fabrication of the frequency-selective surface. The... more
An innovative wireless sensor network (WSN) based on Ultra-Wide Band (UWB) technology for 3D accurate superficial monitoring of ground deformations, as landslides and subsidence, is proposed. The system has been designed and developed as... more
Channel measurements are reported for an emulated indoor MIMO-UWB system. The emulated system represents a ceiling-mounted access-point with two identical UWB, horizontally-polarized, antennas and a portable terminal for desk-top use with... more
An innovative wireless sensor network (WSN) based on Ultra-Wide Band (UWB) technology for 3D accurate superficial monitoring of ground deformations, as landslides and subsidence, is proposed. The system has been designed and developed as... more
In this paper, a novel low-profile bandstop Frequency Selective Surface (FSS) is proposed for Wireless Local Area Networks (WLAN) Applications. The unit cell of the proposed FSS consists of a modification in a square patch element by the... more
In this paper, a single-layer bandstop Frequency Selective Surface (FSS) is proposed for Wireless Local Area Networks (WLAN) Applications. The unit cell of the proposed FSS consists of a modification in a square patch element by the... more
A typical ultrawideband (UWB) antenna acts as a space-frequency filter. As a result, the UWB signal transmitted or received by such an antenna undergoes joint angular-spectral distortion, and consequently the system suffers serious... more
Orthogonal static or fixed links with polarization multiplexing can be formed by using dual polarized antennas with a low cross coupling from one polarization to the other. This is limited by the level of achievable polarization purity of... more
Dual-resonant double square ring elements are applied to the design of a four-layer transmitarray operating at 30 GHz. The design procedure is described and results of a 7.5%-1 dB gain bandwidth and 47% radiation efficiency are reported.
Accurate positioning systems can be realized via ultra-wideband signals due to their high time resolution. In this article, position estimation is studied for UWB systems. After a brief introduction to UWB signals and their positioning... more
An easily assembled three-dimensional bandpass frequency-selective structure (FSS) is proposed, which exhibits quasi-elliptical bandpass filtering performance with two transmission poles in the passband and wide out-of-band rejection with... more
Radio sensing is a rapidly emerging research field. It focuses on designing an integrated communication system that can also perform localization and radar functionalities sharing the same transmit signals and potentially the same... more
This paper presents a hexagonal shape defected ground structure (DGS) implemented on two element triangular patch microstrip antenna array. The radiation performance of the antenna is characterized by varying the geometry and dimension of... more
AbstractThis paper demonstrates the performance of Ultra Wideband (UWB) systems in the Stochastic Tapped Delay Line (STDL) model of the UWB channel with RAKE receiver. System models are based on Direct Sequence Code Division Multiple... more
The effect of fading and interference effects can be combated with equalizer for a MIMO system. MIMO systems exploit the multipath propagation in rich scattering environment using multiple transmit and receive antennas to increase the... more
We evaluate the performance of a dual-polarized wideband antenna in terms of polarization-MIMO in Random-LOS for two different modes of operation: 2 and 4-port excited mode. The 2-port mode was obtained by differential excitation of two... more
A new polarization rotator based on a recently proposed 3-D frequency selective structure (FSS) is designed. The rotation is an added function to the band-reject FSS, which is built using an array of parallel plate waveguides. The device... more
The paper presents the propagation analysis of ultrawideband Gaussian signal in an automated collaborative warehouse environment where human and robots communicate to ensure that mutual collisions do not occur. The warehouse racks are... more
Roundtrip Time-of-arrival (ToA) measurements employing ultra-wideband (UWB) signals can provide high-precision ranging information. However, the accuracy is degraded by multiuser interference (MUI), in particular in the presence of... more
A mobile 4x4 multiple input multiple output (MIMO) system containing dual polarized patch antennas is used to perform wireless measurement campaigns on nonline of sight (NLOS) channels in an indoor office setting. The MIMO system uses... more
The RE-co-doped silica optical fibers emitting in the eye-safe spectral range are still attractive for new applications like LIDAR, pollution monitoring, navigation, and free-space optical communication. High gain and beam quality of... more
In Antenna Technology, Electromagnetic Band Gap (EBG) structures are one of the mostly used structures to improve gain of antenna, suppress surface waves and band notching. In UWB frequency spectrum more number of small frequency bands... more
This paper analyzes integrated components for ultra-broadband millimeter-wave wireless transmitters enabling the 5 G objective to increase the wireless data rates 10× to 100×. We have pursued the photonic-based approach to generate the... more
A novel concise Rupee shaped micro strip patch antenna with CPW (Co-planar Waveguide Feed) is designed, which is used for Multiple Input Multiple Output (MIMO) systems. The described two element MIMO system reproduces at a dual band of... more
Due to inherent advantages of high speed transmission, immunity towards multipath and low cost, ultra wide band (UWB) has become the key technology for the next generation of wireless communication systems. This paper addresses the... more
Ultra-wideband (UWB) also known as digital pulse wireless is a wireless technology for transmitting large amount of digital data over a wide spectrum frequency bands with low power over short distances. Ultra-wideband systems cannot only... more
It is well established that the performance of communication systems is improved when deploying multiple antennas at one or both of the transmit/receive sides; and the amount of the gained improvement depends on the level of multipath... more
A spherical shape ultra-wideband antenna is a microstrip patch antenna whose emitted signal bandwidth exceeds the lesser of 500 MHz. One of the major issues hindering the ultrawideband antennas is poor diversity factors, poor voltage... more
with respect to the angle of arrival of incident wave and the fact that several times greater values of the peak intensity can be achieved. Narrowband receivers exploiting these effects may potentially have improved sensitivity and... more
We present technological building blocks and concepts under study which could ease the build-up of future THz remote sensing and communication systems. Critical issues regarding such systems mainly rely on the availability of sensitive... more
We present in this paper indoor measurements at 2.45 GHz of a tripole antenna pair and investigate typical channel characteristics that include the antenna elements. Each of the two antenna arrays consists of three orthogonal co-located... more
The goal of this paper is to present a design technique that optimizes the transmission phase distribution of triple-layer transmitarray antennas. It aims to reduce the effects of the lossy elements with low transmission coefficients on... more
In this study, the movement of mobile robots on a certain path by preserving their formation and with a leader-follower was examined. Knowing the initial and final positions and orientations of the leader robot, the cubic polynomial was... more