J.M. Gomez

Analytical Field Calculation Involving Current Modes and Quadratic Phase Expressions

New analytical expressions for the computation of physical optics (PO) integrals in the analysis of scattered or radiated fields due to large objects are presented. The PO current is expanded in terms of current modes. Each current mode is defined by an exponential term whose amplitude and exponent are smooth functions. The analytical expressions are valid to compute the PO integral of modes with the exponent (phase) defined by means of quadratic functions. These expressions permit an accurate and efficient evaluation of the integrals over electrically large surfaces. Representative results showing the performance obtained are presented

Application of matrix pencil to obtain the current modes on electrically large bodies

The matrix pencil method, in combination with an interpolation using nonuniform rational bi-spline surfaces, is applied for the expansion of the induced currents on complex bodies in terms of current-modes. The approach is useful for solving electrically large problems of radiation or scattering using physical optics with one or more bounces. The techniques presented in this paper can be also useful to improve some rigorous methods

An Effective Technique for System-Level Prediction of the Radiated Emissions of Unknown Sources Inside Low-

A method for predicting electromagnetic emissions from unknown electronic devices and cables inside low-Q cavities is presented. This method is based on measurements at the unit level, equivalent source decomposition, and numerical electromagnetic simulation of the integrated system. The approach is also valid for the analysis of cables and conductors carrying electrical currents from the interior to the exterior of the measurement surface (Huygens surface) and is useful for the prediction of the electromagnetic compatibility characteristics of electronic devices located inside satellites.

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A method to predict the electromagnetic emissions from unknown electronic devices and cables at system level is presented in this paper. The method is based on measurements at the unit level, equivalent source decomposition and numerical electromagnetic simulation of the integrated system. The approach is also valid for the analysis of cables and conductors carrying electrical currents from the interior to the exterior of the measurement surface (Huygens surface) and is useful for the prediction of the electromagnetic compatibility characteristics of electronic devices inside satellites.

Cavities Using Unit-Level Measurements

Localization is an important aspect of GPS-alternative positioning systems and is of great importance for general communication areas. This paper aims to apply novel location techniques to increase the airport operational safety. These techniques would be ideal in areas where the satellite coverage or radar resolution is poor and have a clear impact on the people and goods located at these airports. We propose a novel fingerprinting localization technique using the relative ray delays due to ray-tracing effects as fingerprints instead of traditional power levels. Combined with other advanced algorithms, more precision could be obtained by these techniques resulting in improved airport operational safety in critical areas.

Effective Technique for System Level Prediction of the Radiated Emissions of Electronic Devices and Cables inside Satellites from Unit Level Measurements.

The need of incorporating into the time-domain simulation MIMICs and microwave components with frequency-dependent parameters has very importance a present design of RF and digital high-speed circuits. In this paper a new simple technique for implementing these elements in general purpose time-domain simulator, such as SPICE, will be presented. The basis of the developed technique is a generalization the Method of Characteristics and only require the knowledge of S-parameters to obtain the model, which is composed by input impedances and voltage controlled voltage sources, both frequency dependent. This model can be easily implemented in SPICE means of Analog Behavioral Modelling (ABM). The technique is validated by comparison with measurement and with conventional SPICE simulation.

New Location Techniques Based on Ray-Tracing for Increasing Airport Safety in Apron and Stand Areas

This paper presents an alternative detection method in fingerprinting technique for indoor localization and trajectory estimation based on efficient ray-tracing techniques over Wireless Local Area Networks (WLAN). Firstly, the use of radio frequency (RF) power levels and relative time delay is compared as detection method to estimate the localization of a set of mobile stations using the fingerprinting technique. The localization algorithm computes the Euclidean distance between the samples of signals received from each unknown position and each fingerprint stored in the database or radio-map obtained by using the FASPRI simulation tool. Secondly, an indoor trajectory has been simulated and tested by means of ray-tracing techniques. Experimental results shows that more precision can be obtained in the trajectory estimation by means of relative ray delay instead of RF power detection method, enabling the deploy of new applications for critical environments such as airports, where security and safety requirements are strongly involved.

A New Technique for Incorporating Microwave Circuits Into Spice from S Parameters Data

A hybrid numerical/experimental procedure for the characterization of radiated emissions from electronic devices at the system level from measurements at the unit level is presented in this work. The procedure is based on the characterization of the device in free space, the computation of equivalent currents for the equipment, followed by computation of the radiation of the device inside the satellite using the equivalent model as the source. The objective of this effort is to replace measurements at the system level to reduce cost. Related topics, such as numerical and experimental verification, electric and magnetic probe design, etc., are also described in the paper.

Fingerprinting Location Estimation and Tracking in Critical Wireless Environments Based on Accuracy Ray-Tracing Algorithms

An experimental verification of a new method for the prediction of system level radiation of electronic devices inside cavities is presented. The method starts from a unit level characterization of the equipment, a representation of the equipment by a model of equivalent currents and a further computation of the interaction of this current model with a geometrical model of the cavity. The idea is to replace a system level measurement that is very expensive for a unit level measurement plus a computation. Comparisons between the method and some measurements at system level inside a cavity satellite mock-up have been performed. The comparison proves the validity of the method for EMC applications. Moreover, the results have been analyzed to study the possibilities for the improvement of the approach.

A Systematic Approach for Radiated System-Level Verification of Unknown Sources Inside Satellites from Unit-Level Measurements

A simple technique for implementing multiconductor nonuniform transmission lines, with lossy and frequency-dependent parameters, into SPICE program is presented. The technique proposed in this paper uses the Analog Behavioral Modelling option of SPICE and only requires to know the S-parameters of the multiconductor system. So that, the transient analysis of distributed nonuniform multiconductor system can be undertaken of a straightforward and efficient way.