The performance of measurement-based simple models for the x-band complex permittivity of 370 ohms/sq. Kapton XC
- Los Alamos National Laboratory
- SDSMT
The X-band complex permittivity of a commercially-available, carbon loaded, polyamide film is measured. Simple though approximate models are obtained which are shown to be necessary and suitable for analytic or computational modeling of thin absorbing structures realized with the thin lossy film. The utility of each model is tested against experimental results for thin high-impedance surface (HIS) enhanced Salisbury absorbers, enhanced in the sense that the HIS augmented absorber is much thinner than a conventional Salisbury absorber. Kapton XC(reg.) is a commercially-available, carbon-loaded polyamide film manufactured by Dupont(reg.). Though these films are exceptionally durable and available in a range of surface resistivities, their effective permittivity is complex valued and, therefore, their sheet impedance is frequency dependent as is typical of carbon-loaded dielectrics. We have measured the X-band complex permittivity of Kapton XC(reg.) with a manufacture's quoted direct current (DC) sheet resistivity of approximately 370 {Omega}/sq. and thicknesses of 40.0 {mu}m. This study showed the need for relatively precise knowledge of the real part of a carbon particulate loaded, lossy thin film's permittivity in order to accurately engineer the reflection coefficient of high-impedance surface enhanced electromagnetic absorbers. Specifically, simple, approximate models can be obtained for the X-band complex pennittivity of commercially available, carbon loaded, 370 {Omega}/sq., Kapton XC(reg.) thin film. These simple, approximate models can be used in the analytic modeling of high-impedance surface enhanced X-band absorbers or computational modeling of other possibly more complicated absorbing structures which are composed, in part, of 370 {Omega}/sq. Kapton XC(reg.) and designed to operate within the X-band. Finally, the results of this study illustrate the need for simgle models for calculating the complex permittivity spectra of 370 {Omega}/sq. Kapton XC(reg.) over a relatively broad bandwidth (1-20 GHz) to facilitate accurate analytical and computational modeling.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC52-06NA25396
- OSTI ID:
- 956504
- Report Number(s):
- LA-UR-09-00226; LA-UR-09-226; TRN: US201014%%1873
- Resource Relation:
- Conference: IEEE International Symposium on Antennas and Propagation ; June 1, 2009 ; North Charleston, SC, USA
- Country of Publication:
- United States
- Language:
- English
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