Nino Canales

Electromagnetic penetration studies for three different aircraft

The National Institute of Standards and Technology has completed electromagnetic penetration studies on three different aircraft for the Federal Aviation Administration. In these studies, we measured cavity coupling characteristics between antennas placed at various angular positions around an aircraft and determined the field uniformity within these cavities with antennas placed in various compartments inside the aircraft. This paper shows how penetration varies as a function of frequency, antenna type, antenna polarization, and cavity susceptibility for three different aircraft types, a commercial airline jet, a business jet, and a composite aircraft. We also report the quality factor and time decay of fields for internal coupling between two antennas placed in the aircraft at different locations.

Time-domain measurements of radiated and conducted UWB emissions

This paper summarizes results obtained from time-domain full-bandwidth emissions measurements of selected ultra wideband (UWB) transmitting devices. Brief descriptions of two NIST-developed measurement systems are provided. High-fidelity time-domain waveforms are shown, along with associated amplitude spectra for several devices. Results are shown for both conducted and radiated emissions from UWB devices.

RF Electromagnetic Penetration of the Nasa Space Shuttle Endeavour Performed with an Ultra-Wideband System

This paper summarizes a joint NIST-NASA measurement effort to thoroughly evaluate the electromagnetic penetration of the shuttle Endeavour. NASA is concerned about the effects that microwave imaging radar systems might have on critical avionics systems on its fleet of space shuttles. As part of a multifaceted effort, a portable, NIST-developed ultra-wideband measurement system was deployed at the Kennedy Space Center to evaluate electromagnetic penetration over the frequency range of 30 MHZ - 6 GHz at selected locations inside Endeavour. The measurements were performed inside a large metal hangar, which exhibited robust reverberant behavior. A combination of reverb chamber techniques and time/frequency signal processing permitted the evaluation of electromagnetic penetration at six different locations inside the orbiter.

An electric-field uniformity study of an outdoor vehicular test range

This paper describes an electric-field uniformity evaluation of an outdoor automotive antenna test range. Electric-field uniformity results are generated from accurate, full-wave electromagnetic simulations of the test range. Measured electric-field results using an ultra wideband measurement system are also presented. The simulations and measurements indicate that the turntable has a significant influence on the field uniformity.

Time-domain measurements of radiated and conducted ultrawideband emissions

This paper summarizes results obtained from time-domain full-bandwidth emissions measurements of selected ultrawideband (UWB) transmitting devices. Brief descriptions of two NIST-developed measurement systems are provided. High-fidelity time-domain waveforms are shown, along with associated amplitude spectra for several devices. Results are shown for both conducted and radiated emissions from UWB devices.

Shielding effectiveness measurements using the direct illumination technique

The authors discuss the direct illumination and reverberation chamber techniques for measuring shielding effectiveness. Using the reverberation chamber as their reference, they explain the differences between the measurements and corrections applied to the direct illumination technique.

TEM-horn antennas: a promising new technology for compliance testing

This paper discusses the advantages of using a TEM-horn antenna rather than conventional EMC antennas such as the log-periodic, hybrid, or biconical antennas. Important issues such as frequency coverage, linearity, time-resolution of events, cost, and antenna factor are also addressed.

Outdoor vehicular test range turntable impact on electric-field uniformity study

This paper describes an electric-field uniformity evaluation of an automotive manufacturerpsilas vehicular antenna range. Dipole measurements, vehicle gain measurements, ultra wideband measurements, and two independent electromagnetic simulations were performed to determine field uniformity characteristics of the antenna range. The simulations and measurements indicated that the turntable significantly influenced the sitepsilas field uniformity. It was determined that increasing the size of the metallic turntable degraded the field uniformity performance of the range. Ideally, the size of a metallic turntable should be minimized to maximize field uniformity performance.

Panoramic, ultrawideband, diagnostic imaging of test volumes

The Time-Domain, Free-Field Metrology Project at the National Institute of Standards and Technology (NIST) is developing methodologies to assess the quality and range of use (in frequency, test volume size, and test type) of EMC test facilities. Previous efforts (Johnk, R. et al., 2000; 2001) have focused on transmission tests that represented typical antenna and test artifact configurations. These tests illuminated a facility and measured the reflections from scattering objects and residual RF ringing to determine modal and basic propagation characteristics. Joint time-frequency-domain (JTFA) analysis of the measurements allow for characterization of signals in various categories, such as broad- or narrow-band scatterers, leakage, or systematic facility ringing. These directional measurements allow isolation in space and time to allow for location of facility irregularities. The initial results that are presented show scatterers intentionally placed in the Time-Domain, Free-Field Metrology Laboratory. These artifacts were imaged and identified in time, space and frequency. This panoramic, ultrawideband, reflection measurement takes a full 360/spl deg/ sweep of the facility and uses JTFA analysis tools to identify specific scatterers and other irregularities in the facility. Combinations of horizontal and vertical polarization sweeps show improved signal-to-noise ratio (SNR) and can highlight polarization sensitive events. We hope this fast testing technique, can be used as a precompliance check and determination of the RF performance of an EMC facility.