Complex dielectric measurements and analysis of brain tissues in the radio and microwave frequencies

• Published in: IEEE transactions on microwave theory and techniques 1997-10, Vol.45 (10), p.1730-1741
• Main Authors: Jian-Zhong Bao, Shin-Tsu Lu, Hurt, W.D.
• Format: Article
• Language: English
• Subjects: Biological system modeling; Brain modeling; Coaxial components; Computer aided analysis; Dielectric measurements; Electromagnetic modeling; Electromagnetic scattering; Electromagnetic waves; Frequency response; In vitro; Microwave frequencies; Microwaves; Permittivity measurement; Probes; Temperature distribution; Tissue
• ISSN: 0018-9480; 1557-9670
• DOI: 10.1109/22.641720

We present in-vitro complex dielectric measurements of gray and white matter of rat brains in the frequency range between 45 MHz and 26.5 GHz at body and room temperatures using the open-ended coaxial probe technique with an HP8510B network analyzer. The measurement data exhibited two separated dispersions, and were analyzed by means of a complex nonlinear least-squares technique. We suggest two empirical models to describe the experimental data: one containing two Cole-Cole functions was applied to the data from this paper, and another including one Havriliak-Negami and one Cole-Cole function was utilized to a combination of past and present literature data in a wider frequency range from 100 kHz to 26.5 GHz. The adoption of previously published data at the frequencies below 45 MHz increases the valid frequency range of the model.