Simple, Fast, and Accurate Broadband Complex Permittivity Characterization Algorithm: Methodology and Experimental Validation from 140 GHz up to 220 GHz

Abstract

Accurate permittivity characterization has attracted a lot of attention in various areas. Resonant characterization methods are well-known for their accuracy, but they are restricted in very narrow frequency ranges, and thus, they are normally not recommended to be used for dispersive or high-loss materials. Transmission line characterization techniques are outstanding for being inexpensive, accurate, and broadband, but the algorithms are often complex to perform. This paper proposes a fast, simple, and accurate broadband permittivity characterization algorithm, which is mainly suitable for millimeter-wave applications. It combines a general line–line method and a closed-form algorithm, extracting the complex permittivity of the material under test (MUT) without the need for calculating any intermediate parameters. Validation measurements on de-ionized water in the frequency range from 140 to 220 GHz are in very good agreement with the literature data, which successfully indicates that the proposed algorithm is reliable and accurate for millimeter wave permittivity characterization.

Material Relative Permittivity Determination From the Inhomogeneous Transmission-Line Secondary Parameters

“…The equations ( 16), ( 18), (19) and (20) represent the considerable contribution and novelty developed in this paper.…”

“…The literature suggests several alternative methods in the electromagnetic area [9]- [11], classified into two groups: broadband and narrowband [12], destructive and non-destructive [13]- [15], resonant and non-resonant [16], [17], direct and indirect methods, or distributed and lumped elements [11]. Inside these two groups are found six main techniques [18]- [20] according to the application domain and the state or kind of material to be characterized [21]. These six methods are Free-space [9], [22], [23], resonant cavity [24]- [26], capacitive or parallel plates capacitor [27], inductance [11], [28], probes [29], [30], and transmission line [31]- [33].…”

Development of a Wideband Slotted Antenna Array with Low Profile and Low Sidelobe

“…Due to the easy fabrication and integration with other circuits, planar antennas, including microstrip-based [8][9][10] and substrate-integrated waveguide (SIW)based [11,12] structures, have been widely used. However, these planar antennas are obviously affected by the dielectric loss of the planar substrates at high frequencies [13,14]. To solve this problem, waveguide slot arrays with low insertion loss have been studied for achieving high-gain and low-profile engineering solutions [15][16][17][18][19].…”

Complex Permittivity Measurement of Low-Loss Anisotropic Dielectric Materials at Hundreds of Megahertz

“…Non-resonant methods are mostly based on measurements of transmitted and/or reflected electromagnetic power from a sample under test illuminated by a well-determined incident electromagnetic wave. Methods using transmission-line approaches have been developed using a coaxal cell [4,5], a rectangular waveguide [6][7][8], a partially filled waveguide [9][10][11], a coplanar waveguide [12], or a flat sample in free space [13][14][15][16][17]. Determining complex permittivity from far-field scattering patterns is another type of non-resonant method [18,19].…”