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Focal ratio degradation (FRD), the decrease of light’s focal ratio between the input into an optical fiber and the output, is important to characterize for astronomical spectrographs due to its effects on throughput and the point spread function. However, while FRD is a function of many fiber properties such as stresses, microbending, and surface imperfections, angular misalignments between the incoming light and the face of the fiber also affect the light profile and complicate this measurement. A compact experimental setup and a model separating FRD from angular misalignment was applied to a fiber subjected to varying stresses or angular misalignments to determine the magnitude of these effects. The FRD was then determined for a fiber in a fiber positioner that will be used in the Subaru Prime Focus Spectrograph (PFS). The analysis we carried out for the PFS positioner suggests that effects of angular misalignment dominate and no significant FRD increase due to stress should occur.
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Coil Distance and Angle Misalignment Effects on the Mutual Inductance for 13.56 MHz WRAP Sensors
In the new era of smart and connected health, new technologies are needed for unobtrusive and seamless monitoring of physiological signals at real life settings. In this grand challenge, we are developing a novel technology called Wireless Resistive Analog Passive (WRAP) sensors. WRAP sensors utilizes printed spiral coil (PSC) inductive link whose sensitivity directly depends on the mutual inductance between primary and secondary coils and it changes due to the physical misalignment. We have previously reported COMSOL simulation results for distance and angular misalignments. In this paper we report experimental results of distance and angular misalignments and compare them to analytical and simulation results for distance. The experimental and analytical results are in good agreement while the simulation results are loosely correlated. For the angular misalignment, the experimental results follow similar trend as simulation results, however analytical results shows disagreement. This work is expected to aid in optimization of PSC for WRAP sensors.
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- Award ID(s):
- 1637250
- PAR ID:
- 10065828
- Date Published:
- Journal Name:
- National Radio Science Meeting
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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