Theoretical investigations of scattering from plastic foams

Plonus, M. A.

doi:10.1109/tap.1965.1138379

Cited by 18 publications

(10 citation statements)

References 8 publications

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“…Furthermore, the well-established PCB-related methods such as the ring resonator [3]- [5] are not directly applicable to foams since a ring cannot be easily printed on a foam material. Early data on scattering-based foam measurements as well as two simple theory models have been discussed by Plonus [6] and Knott [7]. Knott's model for lowdensity foam samples was confirmed by recent measurements reported in [8].…”

Section: Suspended Ring Resonator For Dielectric Constant Measurementmentioning

confidence: 79%

Suspended Ring Resonator for Dielectric Constant Measurement of Foams

Waldron

Makarov

Biederman

et al. 2006

IEEE Microw. Wireless Compon. Lett.

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The present study introduces a microstrip-based resonant device that is specifically intended for measurements of polymer foam permittivity at frequencies of 1 to 10 GHz. The device utilizes the standard microstrip ring resonator. However, the ring and the ground plane/feed network are physically located in separate planes, enabling the placement of an arbitrary sample of material to be measured in the substrate of the ring resonator. A transmission line model is developed and tested in order to predict the frequency response of the circuit. Experimental data is reported and compared with theory. The measurements indicate a high potential resolution of the method.

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Section: Suspended Ring Resonator For Dielectric Constant Measurementmentioning

confidence: 79%

Suspended Ring Resonator for Dielectric Constant Measurement of Foams

Waldron

Makarov

Biederman

et al. 2006

IEEE Microw. Wireless Compon. Lett.

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show abstract

“…The new pressed foam density is given by: (5) Secondly, as mentioned in [10], knowing the volume ratio, we can calculate the effective relative dielectric constant of pressed foam by (6): (6) Where V g and V p are the volume of gas and polymer. In the reference [10], Plonus finds the volume ratio of gas to base polymer in the foam as a function of foam density and uses this to determine the dielectric constant of the foam.…”

Section: A Some Instances Of the Foams Usedmentioning

confidence: 99%

“…In the reference [10], Plonus finds the volume ratio of gas to base polymer in the foam as a function of foam density and uses this to determine the dielectric constant of the foam. The equation (7) gives the volume of gas to volume of the base polymer ratio in considered foam knowing the density of base polymer (ρ p ) and gas (ρ g ).…”

Section: A Some Instances Of the Foams Usedmentioning

confidence: 99%

Technological Process to Control the Foam Dielectric Constant Application to Microwave Components and Antennas

Bor

Lafond

Merlet

et al. 2014

IEEE Trans. Compon., Packag. Manufact. Technol.

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Abstract-A technological process to control the foam dielectric constant, an important issue for the design of microwave components and antennas, is described. For that purpose, the use of different commercial foam materials has been considered. This kind of foam substrate is made of original material (PVC, resin, …) into which gas is injected. So the dielectric constant of such foam is close to 1. It can be increased by expelling the gas out of the foam material. The authors are presenting the technological process used to expel the gas by pressing a foam slab at relatively low temperature (90°C). Thanks to this technological process, the dielectric constant variation can be controlled by the ratio between the initial and final slab thickness. It holds a great interest for the design of microwave antennas and circuits. Indeed, the dielectric constant inside gradient index lenses (Luneburg, Maxwell fish-eye and Fresnel lenses) must follow a particular law to obtain the desired radiation capabilities. Results of materials characterization are presented to validate the technological process. Foam based antennas and components are also shown to illustrate the interest of the process.Index Terms-Foam material, controlled dielectric constant.

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“…It is further possible to predict the dielectric constant of a sample. For that purpose, two theoretical methods are used: Knott [9] and Plonus [10]. By knowing the density of the combination of core materials (all components of the foam except air) and its permittivity, the authors are able to calculate the permittivity of a pressed foam sample.…”

Section: B Pressing Processmentioning

confidence: 99%

Creation of a gradient index structure inside foam material - Microwave application for a lens antenna at 60 GHz

Bor

Lafond

Himdi

2014

2014 IEEE MTT-S International Microwave Symposium (IMS2014)

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International audience— Creating a gradient index into a dielectric structure is a major issue nowadays for the design of microwave components and antennas, especially for inhomogeneous lenses as Luneburg, Fresnel and Maxwell Fish-eye. The use of a foam material and a simple technological process can allow this. Because a foam material is composed of air bubbles, and core materials (resin, PVC, …), removing the air will increase the density of the foam and so increase its dielectric constant. The authors present a simple technological process to expel the air from a piece of foam in order to increase the permittivity of the foam. This is then applied to the design of a Luneburg lens antenna at 60 GHz

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Theoretical investigations of scattering from plastic foams

Cited by 18 publications

References 8 publications

Suspended Ring Resonator for Dielectric Constant Measurement of Foams

Suspended Ring Resonator for Dielectric Constant Measurement of Foams

Technological Process to Control the Foam Dielectric Constant Application to Microwave Components and Antennas

Creation of a gradient index structure inside foam material - Microwave application for a lens antenna at 60 GHz

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