Accession Number:

ADA626973

Title:

Characterization of Passive Spectral Regrowth in Radio Frequency Systems

Descriptive Note:

Doctoral thesis

Corporate Author:

NORTH CAROLINA STATE UNIV AT RALEIGH DEPT OF ELECTRICAL AND COMPUTER ENGINEERING

Personal Author(s):

Report Date:

2013-01-01

Pagination or Media Count:

166.0

Abstract:

Passive spectral regrowth is the generation of nonlinear frequency content as a signal passes through a passive system. The nonlinearity may be a result of the intermodulation between individual signal components or signal components coupling to and mixing with energy in non-electromagnetic domains. Passive spectral regrowth is much weaker than regrowth in active devices due to the lack of gain, however characterization of the new spectral content is growing in importance as the sensitivity of radio-frequency RF receivers improves. Passive components at the end of an RF chain, including the antenna, can produce distortion that is difficult to remove using conventional filtering techniques. Alternatively, understanding of the nonlinear mixing may be exploited in RF sensing for unique characterization of remote or difficult-to-reach objects. To better understand passive spectral regrowth, an investigation is undertaken to experimentally and analytically characterize the nonlinear effects of spectral-regrowth-generating phenomena on an RF signal. Detection of low-level passive spectral regrowth close in frequency to a high-power stimulus signal requires extreme dynamic range measurement capability not available on commercial, o -the-shelf equipment. To enable these measurements, a high-dynamic-range nonlinear measurement system is built using analog cancellation. Automated analog cancellation with careful attention to signal path calibration and non-iterative phase calculation is key to achieving up to 140 dB of dynamic range in two-tone characterization with tones separated by at least 1 kHz.

Subject Categories:

  • Active and Passive Radar Detection and Equipment
  • Electricity and Magnetism
  • Radiofrequency Wave Propagation
  • Radio Communications

Distribution Statement:

APPROVED FOR PUBLIC RELEASE