Reduction of Cross Polarization Level in Connected Slot Arrays using Artificial Dielectric Layers with Vertical Metallic Inclusions

The interest for phased array antennas has increased over the past years along with the need for wide bandwidth arrays. Connected arrays are becoming more prevalent as a well suited solution to achieve the desired bandwidth. In order to increase the bandwidth and the scan angle of this type of array, horizontal artificial dielectric...

Fourier Optics Field Representations for the Design of Wide Field-of-View Imagers at Sub-millimetre Wavelengths

Conformal Phased Array for DISTURB

Mankind becomes ever more reliant on wireless technology like mobile communications, navigation and radar. This development has resulted in more sensitive receivers, but this increased sensitivity also has increased the susceptibility of these receivers to interference from external sources. One of these sources that is known to disrupt...

Virtual Referee: A system to identify off- sides in Football

The off-side rule is the most complicated rule in soccer. Today, off-sides are determined with the help of referees running on the sides of the field or with the help of cameras. However, for lower league games the installation of a camera based system is very expensive. <br/><br/>This work proposes a sensor based system that can be worn by...

Vertical SiC taper with a small angle fabricated by slope transfer method

In this Letter, a slope transfer method to fabricate vertical waveguide couplers is proposed. This method utilises wet etched Si as a mask, and takes advantage of dry etching selectivity between Si and SiC, to successfully transfer the profile from the Si master into SiC. By adopting this method, a &lt;2° slope is achieved. Such a taper can...

Forward-Looking Ultra-Wideband Synthetic Array Imaging

The expansion of microwave imaging applications in various fields proposes increasingly higher requirements (including spatial resolution, dynamic range, and signal-to-noise ratio) for microwave imaging systems. To achieve high-quality imaging, microwave imaging systems generally exploit spatial-, frequency- and polarization-diversities to probe...

UWB pulse detection and TOA estimation using GLRT

In this paper, a novel statistical approach is presented for time-of-arrival (TOA) estimation based on first path (FP) pulse detection using a sub-Nyquist sampling ultra-wide band (UWB) receiver. The TOA measurement accuracy, which cannot be improved by averaging of the received signal, can be enhanced by the statistical processing of a...

A practical clock synchronization algorithm for UWB positioning systems

A clock synchronization scheme is crucial for obtaining accuracy in time-based positioning systems. Existing clock synchronization schemes are mostly based on a simplified linear clock model, which unfortunately have a poor long-term synchronization accuracy. Assuming a two-way time transfer protocol, we propose a novel clock synchronization...

A 60W Compact Highly Efficient Wideband Class-E Power Amplifier

With the rapid growth of wireless communication systems, there is more and more demand for radio frequency power amplifiers (RFPAs) in base stations to be power-efficient so as to reduce the cooling and electrical power cost. Besides the efficient requirement, wide-band working frequency and compact PCB size are also attractive for cutting more...

Creating the perfect outdoor game experience

What if you mix (indoor) gaming with outdoor play? Nowadays children spend much more time indoor instead of outside, playing with friends. Outdoor play is good for both physical as mental development of children, and this problem was the foundation of this design project. Two years ago the idea was risen by Auke Ferwerda to develop an outdoor...

Printed Antenna Elements with Attested Ultra Wide Band Array Applicability

Ultra-wideband (UWB) is a radio technology that can be used at very low energy levels, for short-range high-bandwidth communications, by using a large radio spectrum. Due to its high speed rate, this technology is nowadays one of the most promising solutions for communications. Maximum data that can be transmitted per second over a communication...

A scattering model for surface-textured thin films

We present a mathematical model that relates the surface morphology of randomly surface-textured thin films with the intensity distribution of scattered light. The model is based on the first order Born approximation [see e.g., M. Born and E. Wolf, Principles of Optics, 7th ed. (Cambridge University Press, Cambridge, England, 1999) ] and on...

WideBand PLL as a clock multiplier

In this study, the theory, design and analysis of PLL circuits are examined and a 4.9GHz ~ 5.9GHz Wideband CMOS PLL Frequency Synthesizer is designed and implemented in IBM 65nm digital-process. The objective of this thesis work is to understand the limitations in Wideband PLL systems when the application frequency range extends to multiple...

Electronic coupling of colloidal CdSe nanocrystals monitored by thin-film positron-electron momentum density methods

The effect of temperature controlled annealing on the confined valence electron states in CdSe nanocrystal arrays, deposited as thin films, was studied using two-dimensional angular correlation of annihilation radiation. A reduction in the intensity by ?35% was observed in a feature of the positron annihilation spectrum upon removal of the...

Transmission measurement of the photonic band gap of GaN photonic crystal slabs

A high-contrast-ratio (30 dB) photonic band gap in the near-infrared transmission of hole-type GaN two-dimensional photonic crystals (PhCs) is reported. These crystals are deeply etched in a 650 nm thick GaN layer grown on sapphire. A comparison of the measured spectrum with finite difference time domain simulations gives quantitative agreement...

Location of lanthanide impurity levels in the III-V semiconductor GaN

Knowledge from lanthanide spectroscopy on wide band gap (6–10?eV) inorganic compounds is used to understand and predict optical and electronic properties of the lanthanides in the III-V semiconductor GaN. For the first time the location of the 4fn ground state energy of each divalent and trivalent lanthanide ion relative to the valence and...

Evaluation of an Empirical Model to Estimate and Optimize Mechanical Properties of PECVD SiC Films

In this paper, we present a systematic investigation of the influence of the deposition parameters on the deposition rate, etch rate, and mechanical stress of SiC films prepared by plasma-enhanced chemical vapor deposition (PECVD) technique. Among the relevant deposition parameters, the SiH4 gas flow rate, the main parameter to determine the Si...