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Physical-based rain attenuation prediction models conventionally assume a deterministic dependence of rain cell size on rainfall rate and uniaxial structure. This study examined the impact of these assumptions on attenuation predictions. In comparison with model predictions that apply an exponential distribution of cell sizes, the deterministic models exhibited a small cell size effect in which the...
In the late 1990's Professor Per-Simon Kildal got the idea that reverberation chambers could be used for characterizing small antennas and mobile devices. Many thought the idea was crazy but he was persistent and worked hard to realize his dream to build a small chamber that could be used by the wireless industry. This paper gives a short history of the research at Chalmers and the creation of the...
This paper presents an analysis of the polarisation characteristics for the channel in dynamic off-body communications, and an empirical channel model, based on measurements performed at 2.45 GHz in an office environment. Body presence and propagation conditions have a strong influence on signal depolarisation. The model assumes three components for the total path loss: mean path loss, represented...
The evaluation of performance represents a critical activity to ensure the quality standards of electromagnetic test labs. Intra- and inter-laboratory measurement campaigns are used for that purpose. However, problems arise when a low number of participants take part in the comparison. We present several intercomparison examples and the difficulties that appear in the data analysis.
One-port reflection calibration is a widely used technique for RF and microwave VNA measurements in a broad range of applications including on-wafer chip testing, production testing, and microwave imaging. Recent developments in the field of antenna tuning components lead to advanced, highly stable MEMS-based variable capacitors. In this study we present the use of an antenna tuning integrated circuit...
In this paper, the problem of NFC/RFID technology frontend performance verification is addressed. To make this technology succeeded, it is necessary to test conformance, acceptance, compliance, consistency and interoperability of NFC/contactless infrastructure. Industry bodies such as EMVCo is developing and maintaining programs to ensure device conformance, acceptance, compliance, consistency, and...
Polynomial chaos expansions are used to analyze the propagation of uncertainties on array parameters in Angle-of-Arrival estimation performed by the MUSIC algorithm.
In this paper the results of integrated antenna measurements are analyzed to identify the main reflection locations when measuring with wafer probes. Two different approaches are described and the measurement results for two different probe designs are shown. First, the main reflection center on the wafer probe is determined by analyzing the measured far field radiation pattern at 160 GHz. The second...
In this paper leakage-free contactless flange adapters for mm-wave frequencies are presented. The adapters are compatible with standard rectangular waveguide flanges, covering the whole operational bandwidth of those. They are placed in between standard waveguides in order to avoid leakage at the joints between flange surfaces. Unlike standard flanges, the adapters are contactless, i.e., they do not...
This paper proposes a new algorithm for estimating the relative attitude between two unmanned aerial vehicles based on multiple-input multiple-output radio frequency transmissions between the two aircraft. The method is able to estimate all three Euler angles required to describe the relative attitude, in contrast to prior methods that place severe limits on what can be estimated. Initial simulations...
In the paper a new form of universal polynomial chaos expansion, which was introduced in [1], is applied to numerical stochastic simulations of ultra-wideband electromagnetic wave propagation. It is assumed that stochastic parameters of a propagation scenario follow a Gauss distribution. The final coefficients of an expansion are analytical functions of a mean and a standard deviation of a stochastic...
In the present paper, a preliminary study for the development of a portable setup suitable for in vivo measurements of tissue dielectric properties is presented. The setup consists of a hand-held spectrum analyzer, equipped with a tracking generator to operate as a vector network analyzer, and an in-house software for the post-processing of measured parameters. The proposed setup was optimized to...
Several geometrical modalities of representing electromagnetic (EM) field quantities are reviewed. The shortcomings arising from the representation as local vector functions are examined. Alternative geometrical frameworks that are capable to more accurately model the physics of the EM field are discussed. The study is intended to bring conceptual clarifications and to present incentives for including...
The efficient calculation of the Lattice Sums (LSs) for evaluating the free-space periodic Green's function (PGF) of an infinite phased array of line sources is addressed here and is extended for the first time to leaky waves. The method is based on the Graf's addition theorem for the 0-th order Hankel function that leads to an expansion in terms of Bessel functions of the relevant PGF. The coefficients...
We propose a stable and accurate method for the numerical calculation of Prolate Spheroidal Wave Functions (PSWFs) having circular support in both the spatial and spectral domains. Such PSWFs are used to represent the aperture field of circularly shaped aperture antennas and expoited in a Near-Field/Far-Field transformation algorithm. The results show how the quality of the reconstructions can profit...
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