Fig. 1

Fig. 2

Fig. 3

Fig. 4
![The mean magnitude (▲) and phase (•) from the experimental EIS measurements [9] with the error bars indicating one standard deviation. The lines are the predicted counterparts from the approximate semi-analytical solution, where (–) represent a thickness of 14 μm SC and (- -) denotes a thickness of either 11 or 17 μm. These values for the thickness of SC correspond to the mean and ± one standard deviation.](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/64721f58215d2f6c89dbca62/j_joeb-2018-0006_fig_004.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=ASIA6AP2G7AKCGGZ6RE4%2F20260320%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20260320T133337Z&X-Amz-Expires=3600&X-Amz-Security-Token=IQoJb3JpZ2luX2VjEG0aDGV1LWNlbnRyYWwtMSJHMEUCICGKH0lSwy7uj1Y5UUfxeBTy0b%2F8EFFHsIciHNP9iwmKAiEA0m3GAFRNzbPTaDRQ4It8EcDFnXPIxEdwxSMwk7bcJNoquwUINhACGgw5NjMxMzQyODk5NDAiDPbZpXtsrOWqtD8j8CqYBRrXvycZmDVuZvqC2sRoM3%2FJQrEh98I1koJUxBn48gDxqufGEq8JLL9G9VK8mDaMUWSWL8kZi5b%2FXfQiVEVxbQq7E6td%2BX8UmXi%2FwOQtx213NNyP9ghDHiIZZhpJqeV20MfJArkqvl2glT6FP%2Fgt6t0LhytjOVYgT73xkNlSkzlwsGlXDniDEKjihcPcd0yWcDxNwq98tRd87kiEVpfK416vCFLgWHT6HARnrR8zlYlGW4Wn4mPugbz1dCm5sk%2FnTDMeYIZUs%2F8qrwBB%2FMN9r7SM864VGOu3pW6XxsWBfw7sZdiouxPC3BFaOq1JpQLiDMfwNzy4fLFi8cLXBnGvTAWfpsJdzvPsOTR4POABBOKYaE6BpwB1WEF9TZEdLBg3YxCRSnC4R%2BxH1HLsk5wxF1VDBNVR0%2BhJkgrE0RG6FobrcHjta%2FjkMeTfq3WrJ90bNnjH3Tt%2FQqVQ5iFngpsi3q2LtPMaHt60tbgaDi4%2FBKBqFYWtKmtQBXgOCvQ%2Bhg4%2FuT55slV24maJ3zvS%2Fk1nIA4JQYL%2FjKIvVo8lmVAt4eB7A6B4%2FONF5V%2BJik00rcJRt0ji57tJk2zvcakFaOmzBDEh%2BV1O3mZu5klH%2F9fuQva%2BYOsGeJ9S0AiUrT81eAjIkR813R3crLhe%2Fq8DqeucFG99l6K7xOuD5Bg7L6R2gCkGpFZXi9XfLabzPuAqZ29tg2ZZXMvyWrnYEfS8z2NpFtP%2F46pzLvT0LL22v4k8uc0lrMQ57osHmiE1y3S6VEPHCQ0vAIjVz7%2BTZq2h8CRlymg82VeZIRiXMpdhaS5b929d32h%2F%2BWONa%2BV1VaqRcpElbRCSXS3Gr0%2BPxaiLUkSZydjCs%2BoAHhpXuee87hOg8PFhGitwVEhIEZYwvoX1zQY6sQGBMqEVQm04%2BRRg2O7GRSbIfUa2vjNKe%2BoywaYJsQRBI3lT2Wbghl%2BM5Q0sMTgnOBhgffsOH2NNkl7yIzb2TH6m95IY0MB3m9wqsl9P2XHVw%2FBR54t%2Fkm4x%2BSdbyDdIg7jbgR4iHCRpdYUyXYyFpOVYCgGAvR%2B6tmi%2BR2XOzDjWpFG1UXK5W34dMGl2vBcYpfrHh5U9P2hLZzduxMceBhTrwKRpRJUQQ6TYM7jM8C%2FqCKw%3D&X-Amz-Signature=f7b70fd1b56df362f7e72955d86c2de0f0bb397906470d463732a600e3086077&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Fig. 5

Fig. 6

Base-case dimensions and material parameters for the 4-electrode probe and 3 skin layers (n=3, m=4)_ (The outer radius of the skin is only used in the numerical solution for verification purposes_)
| Current detection width, w1 | 1 mm | [2] |
| Ceramic width, w2, w4, w6 | 0.15, 0.15, 1.9 mm | [2] |
| Guard width, w3 | 0.3 mm | [2] |
| Secondary inject width, w5 | 0.5 mm | [2] |
| Primary inject width, w7 | 0.5 mm | [2] |
| Outer radius of the probe, R | 4.5 mm | [2] |
| Outer radius of the skin, Rskin | 20 mm | |
| Stratum corneum thickness, h3 | 14 μm | [11] |
| Viable skin thickness, h2 | 1.2 mm | [11] |
| Adipose tissue thickness, h1 | 1.2 mm | [11] |
| Inject voltage, V0 | 0.05 V | [2] |
| Depth setting, α | 0.1 | [2] |
| Electrical permittivity in vacuum, ε0 | 8.85 ×107 Fm-1 | [12] |