Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userSampling Schemes for Accurate Reconstruction and Computation of Performance Parameters of Antenna Radiation Pattern
98
0
0.0
(
0
)
Added by
Zubair Khalid
Publication date
2018
fields
Electronic Engineering
and research's language is
English
Ask ChatGPT about the research
No Arabic abstract
In practice, the finite number of samples of the spherical radiation pattern or antenna gain are taken on the sphere for both the reconstruction of the antenna radiation pattern and the computation of mobile handset performance measures such as directivity and mean effective gain (MEG). The acquisition of samples is time consuming as the measurements are required to be collected over the range of frequencies and in multiple spatial directions. It is therefore desired to have a sampling strategy that takes fewer number of samples for the accurate reconstruction of radiation pattern and incoming signal power distribution. In this work, we propose to use equiangular sampling, Gauss-Legendre sampling and optimal dimensionality sampling schemes on the sphere for the acquisition of measurements of spherical radiation pattern of the antenna for its reconstruction, analysis and evaluation of performance parameters of the antenna. By appropriately choosing the spherical harmonic degree band-limits of the gain and the power distribution model of the incoming signal, we demonstrate that the proposed sampling strategies require significantly less number of samples for the accurate evaluation of MEG than the existing methods that rely on the approximate evaluation of the surface integral on the sphere.
rate research
Read More
Internet of things (IoT) is one of main paradigms for 5G wireless systems. Due to high connection density, interference from other sources is a key problem in IoT networks. Especially, it is more difficult to find a solution to manage interference in uncoordinated networks than coordinated system. In this work, we consider 3D topology of uncoordinated IoT network and propose interference mitigation scheme with respect to 3D antenna radiation pattern. In 2D topology network, the radiation pattern of dipole antenna can be assumed as onmi-directional. We show the variance of antenna gain on dipole antenna in 3D topology, consider the simultaneous use of three orthogonal dipole antennas, and compare the system performance depending on different antenna configurations. Our simulation results show that proper altitude of IoT devices can extensively improve the system performance.
This paper explores the effects of three-dimensional (3D) antenna radiation pattern and backhaul constraint on optimal 3D path planning problem of an unmanned aerial vehicle (UAV), in interference prevalent downlink cellular networks. We consider a cellular-connected UAV that is tasked to travel between two locations within a fixed time and it can be used to improve the cellular connectivity of ground users by acting as a relay. Since the antenna gain of a cellular base station changes significantly with the UAV altitude, the UAV can increase the signal quality in its backhaul link by changing its height over the course of its mission. This problem is non-convex and thus, we explore the dynamic programming technique to solve it. We show that the 3D optimal paths can introduce significant network performance gain over the trajectories with fixed UAV heights.
Quantitative imaging in MRI usually involves acquisition and reconstruction of a series of images at multi-echo time points, which possibly requires more scan time and specific reconstruction technique compared to conventional qualitative imaging. In this work, we focus on optimizing the acquisition and reconstruction process of multi-echo gradient echo pulse sequence for quantitative susceptibility mapping as one important quantitative imaging method in MRI. A multi-echo sampling pattern optimization block extended from LOUPE-ST is proposed to optimize the k-space sampling patterns along echoes. Besides, a recurrent temporal feature fusion block is proposed and inserted into a backbone deep ADMM network to capture the signal evolution along echo time during reconstruction. Experiments show that both blocks help improve multi-echo image reconstruction performance.
We investigated the radiation pattern of an optical rod antenna and found that it had many features compared with its conventional radio-wave equivalents. After defining a parameter {Lambda} = {lambda}eff /{lambda}, which was the ratio of the effective wavelength of the rod antenna to the incident wavelength, we found that {Lambda} had a great influence on the radiation pattern. Even the radiation pattern with a higher resonant order is without side lobes and results in a sharper directivity, which provides new design flexibilities in improving the directivities of the optical antennas.
The requirement of high data-rate in the fifth generation wireless systems (5G) calls for the ultimate utilization of the wide bandwidth in the mmWave frequency band. Researchers seeking to compensate for mmWaves high path loss and to achieve both gain and directivity have proposed that mmWave multiple-input multiple-output (MIMO) systems make use of beamforming systems. Hybrid beamforming in mmWave demonstrates promising performance in achieving high gain and directivity by using phase shifters at the analog processing block. What remains a problem, however, is the actual implementation of mmWave beamforming systems; to fabricate such a system is costly and complex. With the aim of reducing such cost and complexity, this article presents actual prototypes of the lens antenna as an effective device to be used in the future 5G mmWave hybrid beamforming systems. Using a lens as a passive phase shifter enables beamforming without the heavy network of active phase shifters, while gain and directivity are achieved by the energy-focusing property of the lens. Proposed in this article are two types of lens antennas, one for static and the other for mobile usage. Their performance is evaluated using measurements and simulation data along with link-level analysis via a software defined radio (SDR) platform. Results show the promising potential of the lens antenna for its high gain and directivity, and its improved beam-switching feasibility compared to when a lens is not used. System-level evaluations reveal the significant throughput enhancement in both real indoor and outdoor environments. Moreover, the lens antennas design issues are also discussed by evaluating different lens sizes.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
