Symmetric coplanar waveguide sensor loaded with interdigital capacitor for permittivity characterization

Abstract

This article presents the developing of interdigital capacitor (IDC) based symmetric coplanar waveguide (CPW) sensor to characterize the complex permittivity of unknown dielectric sheets. The symmetric structure is realized by using two identical 3 dB CPW dividers where each branch is loaded with an IDC unit. The proposed method is designed using three, five, and seven fingers of the IDC unit, and the measurement sensitivity is analyzed accordingly. The permittivity of tested samples is extracted by the genetic algorithm. To validate the robust sensing performance of the proposed method, simulation and experimental tests are performed and analyzed, and the accuracy is compared with published values. The proposed method gives the maximum error of 3.42%. With the feature of high-sensitivity, the proposed sensor can be used as an excellent candidate for determining the permittivity of materials in microwave frequencies.K E Y W O R D S coplanar waveguide, high sensitivity, interdigital capacitor, permittivity extraction, symmetric sensor

A Dielectric Loaded Resonator for the Measurement of the Complex Permittivity of Dielectric Substrates

“…In this way, with a single material, we obtained samples with effective dielectric permittivity 1.7 < ε ′ r < 3.1 and 0.02 < ε ′′ r < 0.06 [27]. The new configuration of the DR shown in this paper is experimentally validated through the comparison of εr measurements obtained on the same materials with the well-known split ring resonator (SRR) method [28]- [32]. In particular the SRR used for this validation is tuned at ∼ 2.2 GHz.…”

Design and test of an inkjet-printed microwave interdigital capacitor on flexible Kapton substrate

“…The proposed IDC is meant to be used for sensing applications and, in this case, spurious resonances are desirable since they may be exploited as trackers [31]. In the literature, IDCs and, in general, planar resonators have been employed for sensing purposes and they exhibited good performance when used in the frequency range between 1 GHz and 5 GHz [32][33][34][35][36]. For this reason, the proposed IDC is designed to operate on this frequency band.…”

Magneto-Dielectric Composites Characterization Using Resonant Sensor and Neural Network Modeling

“…A DDITIVE manufacturing has spurred interest in developing next-generation RF/microwave devices, like antennas [1], [2], filters [3], [4], or phase shifters [5], [6], with a focus on innovative materials like magneto-dielectrics (MD). To characterize MD materials and extract permittivity (ε) and permeability (µ) values, various methods involving waveguides [7], [8], [9], microstrip transmission lines, and resonant structures like split-ring resonators (SRR) have been employed [10], [11], [12], [13], [14]. However, these approaches face limitations in characterizing MD materials with non-zero complex permeability, and often use separate polynomial expressions for ε and µ, neglecting their intrinsic correlation.…”