Isabelle Junqua

A Network Formulation of the Power Balance Method for High-Frequency Coupling

This paper deals with a network formulation of the power balance approach in order to estimate high frequency coupling mechanisms in complex systems. After giving the general principles of this approach found in the scientific literature, the network development of the method is presented, based on an electromagnetic topology analysis. Finally, the network formulation of this approach is applied on a simple two contiguous cylindrical structure by easily adapting a computer code initially dedicated to electromagnetic topology on cable networks.

Advanced Modeling of Crosstalk Between an Unshielded Twisted Pair Cable and an Unshielded Wire Above a Ground Plane

This paper deals with the modeling issue of the near-field coupling of an unshielded twisted-wire pair on a nearby single wire. It introduces a discussion about the appropriate modeling method for predicting the induced current on the victim wire and proposes a cost-effective approach to deal with either ideal or nonideal twisted pair. A nonideal twisted pair consists of a twisted pair whose ends are left untwisted for connection to equipment. We show that the current distribution may follow a specific spatial distribution on the nearby wire. These coupling effects are evidenced through the analysis of an equivalent circuit under the low-frequency assumption. These behaviors are illustrated for the case of both an ideal twisted pair and a nonideal twisted pair. For the latter, the ideal bifilar helix may be modeled by a simple equivalent model bifilar cable.

Field-to-Wire Coupling in an Electrically Large Cavity: A Semianalytic Solution

This paper proposes a semianalytic solution to the problem of high frequency coupling on a wire running in electrically large enclosures. This model is basically derived from the transmission-line (TL) theory in which the electromagnetic (EM) environment, represented as a random plane-wave spectrum, is characterized by its statistical parameters. The results are compared to those obtained by randomly generating elementary plane-wave samples and numerically calculating their EM coupling through a TL model.

Theoretical Approach to the Feasibility of Power-Line Communication in Aircrafts

In the domain of aeronautics, the future more electric aircraft will have to face a difficult issue related to the increasing number of wires and connectors, impacting on the weight and system reliability. A possible solution for solving at least part of this problem is to introduce power-line communication for specific applications. In this paper, the cabin lighting and communication system has been chosen as an initial scenario. Indeed, the tree-shaped architecture of the cabling is complicated enough to be representative of many other aircraft harness configurations. Channel characteristics are first determined from a propagation model based on the multiwire transmission-line theory. A software tool simulating PLC communication has been developed. By introducing the predicted channel transfer functions of different links into this software, the throughputs that can be reached, taking into account the electromagnetic constraints related to aeronautic standards, are discussed.

On the Power Dissipated by an Antenna in Transmit Mode or in Receive Mode in a Reverberation Chamber

One of the main characteristics of a reverberation chamber is its quality factor since it determines the field enhancement and the decay time of the impulse response. If a receiving antenna is placed in the room, it absorbs part of the energy which leads to a decrease of the intrinsic quality factor of the room. Such a well-known phenomenon is quantified by the quality factor of the receiving antenna, and a simple analytical formula is available in the literature. If the antenna placed in the chamber is a transmitting antenna, it also receives the waves reflected by the chamber walls and it is often supposed that its quality factor is still given by the same formula. However, it has been already outlined that the quality factor of an antenna used either in a transmitting mode or in a receiving mode is not identical, but differ by a factor of two. The objective of this contribution is to propose an analytical approach, based on the statistical properties of scattering matrices, to justify this result. Furthermore, experiments have been carried out both in the frequency domain and in the time domain to clearly point out the increase of the power dissipated in a transmit-mode antenna. Polarization effects are also studied.

HIRF Transfer Functions of a Fuselage Model: Measurements and Simulations

An entire set of high-intensity radiated field transfer functions including the main types of contemporary test methods is presented. Consequently, the applied frequency range for this task expands over many decades, from the kilohertz range up to 40 GHz. A major aim is to demonstrate the application of numerical computer modeling for such a task. Results of measurements and various solvers are compared to each other. As the activity serves also for the validation of such applications, the scenario is investigated by the use of a fuselage model with limited complexity.

Assessment of high frequency coupling in a generic object by the power balance method

This paper deals with the application of the Power Balance approach to a generic object, the GENEC, to assess high frequency coupling mechanisms. This method has been validated by measurements performed in a reverberation chamber. Finally, it will be shown how this method, once included in a global strategy, can be complementary to “Maxwell Codes” to predict high frequency constraints in a complex system.

Channel propagation emulation in mode stirred reverberating chambers

Wireless systems used in confined environment show sometimes some operating instabilities essentially due to the propagation channel. In order to predict and improve the wireless link performances, we propose to test the wireless system in a controlled propagation channel. As shown in this paper, mode stirred reverberating chambers seems to be an interesting mean able to simulate realistic and reproducible channels even with Rayleigh distributed fast fading channel. An experiment consisting in measuring Transfer Function between two antennas in multi cavities was carried out and driven by WIFI connection; results present the WIFI link integrity emulated by multipath channel propagation and controlled with simple physical cavity characteristics (Q-factor, delay spread, stirrer position, etc.).

Experimental power transfer and signal assessment of wireless communications in reverberating cavities

This paper focuses on experimental measurement of power and signal transfer of wireless communication in reverberating cavities. The experiment is based on the evaluation of a transfer function between two antennas placed inside and outside a confined reverberating environment made of several metallic cavities. Inside these cavities, a WIFI communication is used in order to control the measurement setup in order to take advantage of its simple connection with the measurement devices. Therefore the first exploitation of this experiment is directly to measure S-parameters as main parameters for characterizing this transfer functions. The second type of exploitation consists in the assessment of the integrity of the WIFI communication in such a closed and confined reverberating environment.

Reference box to control measurements of low frequency HIRF transfer functions

This paper addresses the issue of transfer function measurements inside a structure in High Intensity Radiated Fields environment (HIRF). In this context, a simple reference test object was designed and used as a set up verification device to be tested before HIRF measurement campaigns on aircraft. In order to obtain a reference measured transfer function between the incident E-field and an internal induced current this object has been calibrated in laboratory using a strip-line which enables to fully control the incident EM field. We focus, here, on the need to perfectly control the whole measurement links and test setup to ensure a sufficient level of sensitivity and reproducibility.