Characterization of Dielectric Materials at WR-15 Band (50–75 GHz) Using VNA-Based Technique

Abstract

This article presents an in-depth study of a new vector network analyzer (VNA)-based electromagnetic material measurement method relying on a commercially available material characterization kit (MCK). These MCKs provide effectively a guided free-space technique with less stringent requirement on alignment compared with conventional free-space techniques. Coupled with time gating, these MCKs employ a simple calibration, composed of reflect and thru standards only, prior to taking reflection and transmission S-parameter measurements. This MCK-based method complements other conventional measurement techniques, e.g., time-domain spectroscopy (TDS) and resonant cavity, allowing fast broadband dielectric material characterization over the millimeter-and submillimeter-wave frequency ranges. In this article, a WR-15 (50-75 GHz) MCK is utilized for the measurements of S-parameters for seven types of low-loss dielectric material. Their dielectric constant and loss tangent are extracted from S-parameters and are compared against literature values. A relatively good agreement is achieved. Moreover, an investigation into the uncertainties of the extracted dielectric constant and loss tangent is performed and reported.

Material Measurements Using VNA-Based Material Characterization Kits Subject to Thru-Reflect-Line Calibration

“…The line standard based on an air gap is also demonstrated to be an effective and simple approach for implementing TRL calibration, without the need for additional components. Wang et al [16] reported on the characterization of several dielectric materials in the WR-15 band (50-75 GHz) using a MCK with default GRL calibration, and the extracted results show good agreement with published literature values after measurement uncertainties are taken into account. Here, the work is extended further, in terms of utilization of a more robust TRL calibration technique for the MCK; measurement of materials over two different waveguide bands within the range of 140-750 GHz so that a broader study is possible; and direct comparison of results from MCKs and TDS.…”

“…Wang et al [16] present an investigation into measurement uncertainties in the extracted material properties associated with MCKs, due to random errors (i.e., the samples' insertion repeatability) and systematic errors (i.e., measured S-parameters and thickness of samples). It has been found that systematic errors account for most of the overall uncertainties [16]. Here, this work is devoted to an investigation into new calibration techniques for MCKs, and so uncertainties are not discussed.…”

Benchmarking a Commercial (Sub-)THz Focal Plane Array Against a Custom-Built Millimeter-Wave Single-Pixel Camera

“…Note that, in the UK, the National Physical Laboratory (NPL) recently characterized HRS and PTFE at V-band (50 GHz to 75 GHz), using a commercial VNA and a separate material characterization kit (MCK) [31]. Within V-band, the 4 th -and 5 th -order Fabry-Pérot resonance frequencies of the 3.06 mm thick HRS sample are captured; while the 3 rdand 4 th -order are captured by the 5.99 mm thick PTFE sample.…”

“…where, the complex refractive index ̃ of the PTFE and GaAs are related to their values of dielectric constant and loss tangent by ̃= √ ′ (1 − ). Setting ̃→ 1 and 1 , 0 → 0 essentially removes the protective cover and (32) becomes (31). The simulated spectral responses for the 1 mm thick PTFE cover (red curves), 620 m thick GaAs mirror (blue curve) and their combination with a 0.5 mm air gap (black curve) is shown Fig.…”

Assessing the Impact of Data Filtering Techniques on Material Characterization at Millimeter-Wave Frequencies

“…complex S 21 or S 12 ) of the specimen. Recently, a new guided free-space method based on material characterization kits (MCKs) [11] has been developed by SWISSto12. Fig.…”