Evidence map›Paper›PMID 42129245›Full record

ArticleScientific reports2026

High sensitivity differential microwave sensor based on SIW technology for measuring the permittivity and thickness of the solid materials.

Amirhosein Najafi, Sarah Poormohammad, Sajjad Azimi

Abstract read
In one paragraph

Article in Scientific reports, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

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3 · Its place in the literature

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4 · The record

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5 · Who and what money

Authors and funding

3 authors.

Amirhosein NajafiDepartment of Electrical Engineering, Urmia University, Urmia, 5756151818, Iran.
Sarah PoormohammadDepartment of Electrical Engineering, Urmia University, Urmia, 5756151818, Iran. s.poormohammad@urmia.ac.ir.
Sajjad AzimiDepartment of Electrical Engineering, Urmia University, Urmia, 5756151818, Iran.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Non-destructive evaluation of permittivity and thickness is a critical requirement in industries such as aerospace, automotive, construction, and medical engineering. This study presents a simple yet highly efficient method for characterizing the permittivity and thickness of solid materials using symmetrical Split Square Resonators (SSRs) incorporating a central via. The proposed configuration enhances electric and magnetic field confinement within the sensing area, thereby improving measurement sensitivity and spatial resolution. The sensor consists of a Substrate Integrated Waveguide (SIW) structure hosting two centrally via-loaded SSRs positioned at locations of maximum electromagnetic field intensity to achieve high sensitivity. The design operates through a combined band-pass and band-stop response: a transmission pole (TP) at 1.62 GHz and a transmission zero (TZ) at 2.95 GHz. The TZ frequency exhibits an approximately linear relationship with the permittivity and thickness of the material under test (MUT). As the MUT permittivity and thickness increase, the TZ resonance shifts from 2.95 GHz to 2.1 GHz and from 2.95 GHz to 2.48 GHz, respectively, while the TP frequency remains nearly constant. This differential behavior reduces environmental interference and enhances measurement accuracy. The sensor is fabricated using PCB technology on an RO-4003c substrate. Experimental results demonstrate high sensitivity of 3.27% for permittivity and 30.63% for thickness measurements, showing competitive performance compared to similar reported works. The overall dimensions of the sensor are 64 mm × 60 mm × 0.508 mm, corresponding to 0.0119 of the guided wavelengths.

Indexed as

Differential modeMicrowave sensorsPermittivity characterizationSubstrate integrated waveguide (SIW)Thickness measurement

Identifiers

PMID42129245
PMCPMC13542162

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