Precision Permittivity Measurement for Low-Loss Thin Planar Materials Using Large Coaxial Probe from 1 to 400 MHz

Abstract

This paper focuses on the non-destructive dielectric measurement for low-loss planar materials with a thickness of less than 3 mm using a large coaxial probe with an outer diameter of 48 mm. The aperture probe calibration procedure required only to make a measurement of the half-space air and three offset shorts. The reflection coefficient for the thin material is measured using a Keysight E5071C network analyzer from 0.3 MHz to 650 MHz and then converted to a relative dielectric constant, εr and tangent loss, tan δ via closed form capacitance model and lift-off calibration process. Average measurement error of dielectric constant, Δεr is less than 6% from 1 MHz to 400 MHz and the resolution of loss tangent, tan δ measurement is capable of achieving 10−3.

Open-Ended Coaxial Probe for Effective Reconstruction of Biopsy-Excised Tissues’ Dielectric Properties

“…An in-depth analysis of the electric field's behavior under two distinct conditions, by employing metallic and dielectric coatings, demonstrated a noticeable confinement of the electric field lines, as illustrated in Figure 12a According to [41], standing waves in the coaxial line are the main cause of the radiative fringing effects in the probe aperture's plane. A fringing field occurs near the aperture of the sensor.…”

“…Hence, a phase shift between the forward wave and the reflected wave occurs and produces the standing wave inside the coaxial line [42]. According to [41], standing waves in the coaxial line are the main cause of the radiative fringing effects in the probe aperture's plane. A fringing field occurs near the aperture of the sensor.…”

Probe with a metallic bowl termination to determine the electric material parameters from variable thicknesses

“…in Therefore, each design can be presented as an electric schema, as illustrated in figure 1. That electric model is defined through a mathematical model [41,42] explained in the next section.…”

Dielectric Characterization of Ex-Vivo Breast Tissues: Differentiation of Tumor Types through Permittivity Measurements

“…This analysis of properties is fundamental for various applications, such as microwave imaging techniques for the early detection of breast cancer, as well as for treatments and diagnostics [33][34][35][36][37][38][39]. Therefore, extensive studies have been carried out for many decades to explore the multiple potential uses.…”