Purpose: This article presents the study and simulation results of a millimeter (mm)-wave device for cancerous tissue detection. mm-Wave approach ensures cheaper equipment instead of the traditional terahertz (THz) frequency approach. A probe that could be implemented using inexpensive silicon technology is proposed, and it also permits integration of entire measuring tool for easy deployment. Skin cancer was chosen as it representŝ80% of all newly diagnosed cases and is the most common form of cancer in Australia. For an initial development and validation, due to data availability consideration in the open literature, basal cell carcinoma (BCC) was used for simulations.
Methods and results: A probe, using high-frequency signals in the upper mm-wave frequency spectrum (90-300 GHz) to maximize the lateral resolution (mm precision) and allows the detection of tumors located at up to 0.5 mm deep in the skin, is proposed. A frequency-dependent relativity permittivity and an equivalent conductivity of skins were calculated based on the double Debye parameters. For the first time, electromagnetic (EM) models were generated and used along with a high-frequency EM simulator, ANSYS HFSS, to demonstrate the sensitivity of the concept. The following two scenarios were studied: in scenario one, a BCC layer of different thicknesses (10-3000 μm) was located on the top of the normal skin and, in scenario two, the BCC was embedded in normal skin at depths from 10 to 3000 μm. Variability using ±10% of the corresponding dielectric property was also considered.
Conclusion: This study showed that the reflection coefficients vs frequency could capture useful information indicating the possible presence of BCC at mm-wave frequencies. Both magnitude and phase of the reflection coefficient were quantified, with two scenarios analyzed. It was found that a dual-band approach, 100-150 and 200-250 GHz, has the ability to highlight deviations from the normal skin.
Keywords: continuous wave; diagnostic; electromagnetics; millimeter wave; near-field; sensor.