Configurations of Splitter/Combiner Microstrip Sections Loaded with Stepped Impedance Resonators (SIRs) for Sensing Applications

Abstract

In this paper, several configurations of splitter/combiner microstrip sections loaded with stepped impedance resonators (SIRs) are analyzed. Such structures are useful as sensors and comparators, and the main aim of the paper is to show that the proposed configurations are useful for the optimization of sensitivity and discrimination. Specifically, for comparison purposes, i.e., to determine anomalies, abnormalities or defects of a sample under test (SUT) in comparison to a reference sample, it is shown that up to three samples can be simultaneously tested. Simple models of the proposed structures are presented, and these models are validated through electromagnetic simulation and experiment. Finally, the principle of operation is validated through a proof-of-concept demonstrator.

A Review of Sensing Strategies for Microwave Sensors Based on Metamaterial-Inspired Resonators: Dielectric Characterization, Displacement, and Angular Velocity Measurements for Health Diagnosis, Telecommunication, and Space Applications

“…However, if the resonators are separated enough, coupling no longer arises. Alternatively, a divider/combiner configuration, where each transmission line branch is loaded with a resonant element, can be considered [30,36]. In this case, coupling is prevented, but, in general, the two notches for the asymmetric configuration are related to an interference phenomenon.…”

Extremely Sensitive Microwave Sensor for Evaluation of Dielectric Characteristics of Low-Permittivity Materials

“…The main advantages of SRR-and CSRR-based sensors are the small size with high sensitivity, lower cost with robustness, and high precision. The performance of the planar microwave sensor depends on the resonating structure as well as the hosting transmission line [43][44][45][46][47][48].…”

“…Sensors 2020, 20, 1916 2 of 17 In [43], an SRR with a resonance frequency of 0.87 GHz is used to design a differential sensor with a size of 0.1λ g 2 for liquid characterization and an average sensitivity of 0.91% is achieved. In [44] a stepped impedance resonator (SIR) loaded with a microstrip transmission line is used to design a differential sensor with a size of 0.046 λ g 2 for comparison of three samples simultaneously, and an average sensitivity of 1.81% is achieved. In [45], a CSRR with resonance frequency of 1.7 GHz is utilized to design a differential sensor with a size of 0.098 λ g 2 for dielectric characterization and the average sensitivity of 1.96% is achieved.…”

Multi-Negative Index Band Metamaterial-Inspired Microfluidic Sensors

“…The sensing capability and efficiency are directly influenced by the correlation between the MTM structures and the fluidic channel. To differentiate the sensing performance, symmetry properties in transmission line loaded with one or more MTM structures need to be considered to avoid the lack of coupling due to the complete cancellation between electric and magnetic fields [6,[37][38][39][40]. All the MTM structures implemented for microfluidic microwave sensors are either a split ring resonator (SRR), a complementary SRR (CSRR), an open SRR (OSRR), or a splitring-cross resonator (SRCR) [1, 2-4, 7, 8, 10-13, 15-20, 22], which are typical magnetic resonators first introduced as negative permeability MTMs [41].…”