Nonactive antenna compensation for fixed-array microwave imaging : Part I : Model development

• Published in: IEEE transactions on medical imaging Vol. 18; no. 6; pp. 496 - 507
• Main Authors: PAULSEN, K. D, MEANEY, P. M
• Format: Journal Article
• Language: English
• Published: New York, NY Institute of Electrical and Electronics Engineers 01.06.1999
• Subjects: Algorithms; Antenna arrays; Biological and medical sciences; Data acquisition; Diagnostic Imaging - instrumentation; Electric impedance; Humans; Image Processing, Computer-Assisted; Image reconstruction; Investigative techniques, diagnostic techniques (general aspects); Mathematical models; Medical sciences; Microwaves; Miscellaneous. Technology; Pathology. Cytology. Biochemistry. Spectrometry. Miscellaneous investigative techniques; Phantoms, Imaging; Sensor data fusion; Near field; Image quality; Microwave; Distortion; Passive circuit; Technique; Boundary condition; Compensating network; Image reconstruction; Antenna; Test object
• ISSN: 0278-0062; 1558-254X
• DOI: 10.1109/42.781015

Fixed-array microwave imaging with multisensor data acquisition can suffer from nonactive antenna element interactions which cause distortions in the measurements. In Part I of a two-part paper, we develop a nonactive antenna compensation model for incorporation in model-based near-field microwave image reconstruction methods. The model treats the nonactive members of the antenna array as impedance boundary conditions applied over a cylindrical surface of finite radius providing two parameters, the effective antenna radius and impedance factor, which can be determined empirically from measured data. Results show that the effective radius and impedance factor provide improved fits to experimental data in homogeneous phantoms where measurements are obtained with and without the presence of the nonactive antenna elements. Once deduced, these parameters are incorporated into the nonactive antenna compensation model and lead to systematic data-model match improvements in heterogeneous phantoms. While the improvements afforded by the nonactive antenna model are small on a per measurement basis, they are not insignificant. As shown in Part II, inclusion of this new model for nonactive antenna compensation produces significantly higher quality image reconstructions from measurements obtained with a fixed-array data acquisition system over the frequency band 500-900 MHz.