Year: 2015
Type: article
Abstract: We show that simple radio-frequency (RF) interferometers can have slow-wave positive group delay (PGD) or negative group delay (NGD), as well as superluminal propagation (SP) regions, due to a destructive interference process. These properties are easily tunable, which makes RF interferometers unique among systems that have NGD and SP regimes. A two-stage interferometer arrangement, which includes a first stage interferometer in the material-under-test path of a second stage, has significantly improved sensitivity in comparison with a one-stage reference interferometer. With a power divider based first stage and at its maximum NGD frequency, the frequency sensitivity improvement is as high as 7 times. With a quadrature based first stage, the sensitivity is increased by as much as 20 times. Sensitivity improvements are also observed at PGD and SP frequency regions.
Source: Applied Physics Letters
DOI: 10.1063/1.4934622
Authors: Jeffrey Osterberg, Pingshan Wang
Institution: Clemson University
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2205351740