177 research outputs found
Polarimetric Radar for Automotive Applications
Current automotive radar sensors prove to be a weather robust and low-cost solution, but are suffering from low resolution and are not capable of classifying detected targets. However, for future applications like autonomous driving, such features are becoming ever increasingly important. On the basis of successful state-of-the-art applications, this work presents the first in-depth analysis and ground-breaking, novel results of polarimetric millimeter wave radars for automotive applications
1-D broadside-radiating leaky-wave antenna based on a numerically synthesized impedance surface
A newly-developed deterministic numerical technique for the automated design of metasurface antennas is applied here for the first time to the design of a 1-D printed Leaky-Wave Antenna (LWA) for broadside radiation. The surface impedance synthesis process does not require any a priori knowledge on the impedance pattern, and starts from a mask constraint on the desired far-field and practical bounds on the unit cell impedance values. The designed reactance surface for broadside radiation exhibits a non conventional patterning; this highlights the merit of using an automated design process for a design well known to be challenging for analytical methods. The antenna is physically implemented with an array of metal strips with varying gap widths and simulation results show very good agreement with the predicted performance
Beam scanning by liquid-crystal biasing in a modified SIW structure
A fixed-frequency beam-scanning 1D antenna based on Liquid Crystals (LCs) is designed for application in 2D scanning with lateral alignment. The 2D array environment imposes full decoupling of adjacent 1D antennas, which often conflicts with the LC requirement of DC biasing: the proposed design accommodates both. The LC medium is placed inside a Substrate Integrated Waveguide (SIW) modified to work as a Groove Gap Waveguide, with radiating slots etched on the upper broad wall, that radiates as a Leaky-Wave Antenna (LWA). This allows effective application of the DC bias voltage needed for tuning the LCs. At the same time, the RF field remains laterally confined, enabling the possibility to lay several antennas in parallel and achieve 2D beam scanning. The design is validated by simulation employing the actual properties of a commercial LC medium
Development and performance evaluation of a multistatic radar system
Multistatic radar systems are of emerging interest as they can exploit spatial diversity, enabling improved
performance and new applications. Their development is being fuelled by advances in enabling technologies
in such fields as communications and Digital Signal Processing (DSP). Such systems differ from
typical modern active radar systems through consisting of multiple spatially diverse transmitter and receiver
sites. Due to this spatial diversity, these systems present challenges in managing their operation as
well as in usefully combining the multiple sources of information to give an output to the radar operator.
In this work, a novel digital Commercial Off-The-Shelf (COTS) based coherent multistatic radar
system designed at University College London, named ‘NetRad’, has been developed to produce some
of the first published experimental results, investigating the challenges of operating such a system, and
determining what level of performance might be achievable. Full detail of the various stages involved
in the combination of data from the component transmitter-receiver pairs within a multistatic system is
investigated, and many of the practical issues inherent are discussed.
Simulation and subsequent experimental verification of several centralised and decentralised detection
algorithms in terms of localisation (resolution and parameter estimation) of targets was undertaken.
The computational cost of the DSP involved in multistatic data fusion is also considered. This gave a
clear demonstration of several of the benefits of multistatic radar. Resolution of multiple targets that
would have been unresolvable in a conventional monostatic system was shown. Targets were also shown
to be plotted as two-dimensional vector position and velocities from use of time delay and Doppler shift
information only. A range of targets were used including some such as walking people which were
particularly challenging due to the variability of Radar Cross Section (RCS).
Performance improvements were found to be dependant on the type of multistatic radar, method of
data fusion and target characteristics in question. It is likely that future work will look to further explore
the optimisation of multistatic radar for the various measures of performance identified and discussed in
this work
Antenna Systems
This book offers an up-to-date and comprehensive review of modern antenna systems and their applications in the fields of contemporary wireless systems. It constitutes a useful resource of new material, including stochastic versus ray tracing wireless channel modeling for 5G and V2X applications and implantable devices. Chapters discuss modern metalens antennas in microwaves, terahertz, and optical domain. Moreover, the book presents new material on antenna arrays for 5G massive MIMO beamforming. Finally, it discusses new methods, devices, and technologies to enhance the performance of antenna systems
OCM 2023 - Optical Characterization of Materials : Conference Proceedings
The state of the art in the optical characterization of materials is advancing rapidly. New insights have been gained into the theoretical foundations of this research and exciting developments have been made in practice, driven by new applications and innovative sensor technologies that are constantly evolving.
The great success of past conferences proves the necessity of a platform for presentation, discussion and evaluation of the latest research results in this interdisciplinary field
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