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A compact dual-element antenna suitable for ultrawideband (UWB) MIMO operation is proposed in this work. The size of the antenna is 25 mm by 40 mm and it covers the lower UWB band of 3.15-5.15 GHz. Apart from the inherent wideband isolation obtained through the different angle and polarization characteristics in the radiation patterns of the individual elements, the gap between the two antenna ele

An antenna system is disclosed that includes two or more antennas and an impedance matching network. The antennas of the antenna system are closely separated, such as by a distance of no more than a wavelength of received signals divided by two. The impedance matching network is adapted to respond to and counteract performance degradation resulting from cross coupling between the antennas. Related

Languages differ in how events are described, but little is known about how semantics interacts with online event processing. This study targets this question examining placement events in Swedish. Swedish has three obligatory placement verbs for events where objects have support from below: sätta ’set’, ställa ’stand’, and lägga ’lay’. Swedish lacks a superordinate general term like English put (

The Radon transform and its adjoint, the back-projection operator, can both be expressed as convolutions in log-polar coordinates. Hence, fast algorithms for the application of these operators can be constructed by using FFT, if data is resampled at log-polar coordinates. Radon data is typically measured on an equally spaced grid in polar coordinates, and reconstructions are represented (as images

This work concerns efficient and reliable numerical simulations of the dynamic behaviour of a moving-boundary model for tubulin-driven axonal growth. The model is nonlinear and consists of a coupled set of a partial differential equation (PDE) and two ordinary differential equations. The PDE is defined on a computational domain with a moving boundary, which is part of the solution. Numerical simul

Recently, it has been shown that a parasitic element can be used to fully decouple closely spaced antennas. However, the decoupled antennas suffer from narrow bandwidth, as compared to the bandwidth of isolated single antennas, which is also the case for other decoupling methods, such as multiport conjugate match and neutralization line. In this paper, we investigate the potential in bandwidth enh

In this paper, we study the influence of current localization on the isolation between two antennas in a compact terminal setting. The two antennas are chosen to be a monopole and a PIFA, respectively. The degree of current localization is controlled by the permittivity value of the PIFA’s dielectric loading. Both lossless and lossy cases are simulated in order to ascertain the underlying performa

It is known that the compactness of mobile terminals complicates the design of multiple antennas, since coupling between the antennas increases when they are placed in proximity of one another. While it is possible to mitigate coupling between closely spaced antennas, a tradeoff in bandwidth is required. In this paper, we highlight ground plane excitation as an additional dimension to consider in

A simple and intuitive metric of multiplexing efficiency is proposed for evaluating the performance of MIMO antennas in the spatial multiplexing mode of operation. The metric is particularly useful for antenna engineers whose goal is to achieve the optimum antenna system design. Experimental results involving prototype mobile terminals highlight the effectiveness of our proposal.

Multiplexing efficiency is proposed as a simple and intuitive metric for characterizing multiple antenna systems in the spatial multiplexing mode of operation. Instead of comparing channel capacities of MIMO systems with different antennas, the metric offers valuable insights into the impact of antenna efficiency, efficiency imbalance and correlation on multiplexing performance. It is particularly