Start Date

2016 12:00 AM

Description

Manufacturers of rubber articles seek to control the porosity level after cure to a target level to deliver the desired characteristics. A nondestructive means to measure the porosity is desirable for efficiency. Wideband millimeter wave reflectometry measurements, along with a robust synthetic aperture radar (SAR) imaging algorithm, results in production of high-resolution 3D images capable of nondestructive inspection of such products using relatively compact instruments [1]-[2]. SAR imaging at millimeter wave frequencies has demonstrated great efficacy for detecting relatively large voids inside rubber composites mainly due to the high contrast (9 to 1) between rubber and air dielectric permittivities. To this end, several 1”-thick rubber blocks with small localized embedded porosities were inspected to investigate the efficacy of the method for porosity detection. Localized porosity was introduced by placing small Styrofoam pieces and water droplets between rubber layers prior to curing the block. The blocks were raster scanned at Ka-band (26.5 – 40 GHz) and V-band (50 – 75 GHz) frequencies to generate wideband raw data. The SAR algorithm produces 3D images using these wideband holographic data which is then can be displayed at a 2D slice at any depth within the object. A complete description of the technique and several imaging examples will be presented along with a discussion of the results.

Language

en

File Format

application/pdf

Share

COinS
 
Jan 1st, 12:00 AM

Millimeter Wave SAR Imaging for the Detection of Porosity in Rubber Products

Manufacturers of rubber articles seek to control the porosity level after cure to a target level to deliver the desired characteristics. A nondestructive means to measure the porosity is desirable for efficiency. Wideband millimeter wave reflectometry measurements, along with a robust synthetic aperture radar (SAR) imaging algorithm, results in production of high-resolution 3D images capable of nondestructive inspection of such products using relatively compact instruments [1]-[2]. SAR imaging at millimeter wave frequencies has demonstrated great efficacy for detecting relatively large voids inside rubber composites mainly due to the high contrast (9 to 1) between rubber and air dielectric permittivities. To this end, several 1”-thick rubber blocks with small localized embedded porosities were inspected to investigate the efficacy of the method for porosity detection. Localized porosity was introduced by placing small Styrofoam pieces and water droplets between rubber layers prior to curing the block. The blocks were raster scanned at Ka-band (26.5 – 40 GHz) and V-band (50 – 75 GHz) frequencies to generate wideband raw data. The SAR algorithm produces 3D images using these wideband holographic data which is then can be displayed at a 2D slice at any depth within the object. A complete description of the technique and several imaging examples will be presented along with a discussion of the results.