Microwave Properties of Low-Loss Polymers at Cryogenic Temperatures

摘要

Dielectric loss tangent and permittivity of polytetra-fuoroethylene (Teflon), high-density (HD) polyethylene, and crosslinked polystyrene (Rexolite) were measured at temperature range from 28 to 84 K and frequency of approximately 18 GHz. The material properties were determined by measurements of the resonant frequency and the Q factor of a TE_(011) mode cylindrical supercon-ducting cavity containing a sample under test. It has been demon-strated that these materials exhibit very low losses at cryogenic temperatures (2×10~(-6) for Teflon, 5×10~(-5) for HD polyethylene and 1.1×10~(-4) for Rexolite). Due to low losses, these materials can be useful in construction of various high-Q factor microwave devices for operation at cryogenic temperatures.