Artem V. Boriskin

Enhancing Exposure Efficiency and Uniformity Using a Choke Ring Antenna: Application to Bioelectromagnetic Studies at 60 GHz

An effective solution for increasing the exposure uniformity and efficiency of biological samples in in vitro bioelectromagnetic experiments at 60 GHz is proposed by introducing a novel choke ring antenna (CRA). The CRA is optimized to provide a uniform exposure of samples, whose dimensions are equivalent to those of a standard 35-mm Petri dish, positioned close to the antenna aperture, i.e., 10–20 wavelengths. The antenna prototype is fabricated in metallized foam. The realized exposure efficiency of the sample exceeds 55% (if estimated for an exposure uniformity better than

Two-Shell Radially Symmetric Dielectric Lenses as Low-Cost Analogs of the Luneburg Lens

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Lens-Corrected Axis-Symmetrical Shaped Horn Antenna in Metallized Foam With Improved Bandwidth

0.5 dB). To validate the numerical results, the field intensity profiles on the surface of a high-water-content phantom have been experimentally obtained using a high-resolution infrared camera. Compared to the standard open-ended waveguide and horn antennas, typically used for millimeter-wave dosimetry, a twofold advantage of the proposed CRA is demonstrated, namely, the improvement of the exposure efficiency by a factor of 1.5 to 2 with a simultaneous reduction of the exposure distance by a factor of 8–2, respectively, depending on the type of the reference antenna. These advantages make the proposed CRA an excellent candidate for 60-GHz short-range exposure systems for in vitro bioelectromagnetic studies.

Contactless Microstrip Transition for Flexible Microfluidic Circuits and Antennas

This communication provides guidelines for the design of two-shell radially symmetric dielectric lenses with collimating capabilities compatible with those of the classical Luneburg lens. Unlike earlier publications, it is demonstrated that such a lens can be designed using any standard low permittivity dielectric materials, provided the optimal shell thickness is selected. The lens characteristics are studied in 2-D formulation using exact series representation. A detailed description is given for lenses with radius of 10 λ0 and core made of Rexolite. The design recommendations are then generalized for lenses with radii of 5 to 15 λ0 and cores made of Teflon, Fused Silica and Quartz. Finally, a chart defining the optimal shell thickness for lenses made of two arbitrary dielectric materials is provided. Validity of the recommendations for design of 2-D and 3-D radially symmetric lenses is proven by comparison with optimal designs reported by other authors.

Improvement of the Scanning Performance of the Extended Hemispherical Integrated Lens Antenna Using a Double Lens Focusing System

A lens-corrected smooth-walled axis-symmetrical dielectric-loaded horn antenna is designed and characterized in Ka-band using the bodies of revolution finite-difference time domain (BoR-FDTD) technique and genetic algorithm. The joint optimization of the horn and dielectric loading profiles enables us to develop a horn with a very good gain performance achieved in a frequency range of about 18%. Compared to earlier results, the bandwidth improvement exceeds a factor two. A lightweight prototype is fabricated in metallized foam. A very good agreement between the numerical and measured data is obtained.

Beam-Forming Capabilities of Waveguide Feeds Assisted by Corrugated Flanges

This letter presents an ultrawideband contactless microstrip-to-microstrip transition connecting a conventional surface line with an embedded microfluidic line composed of a room-temperature liquid metal. The operational bandwidth of the transition spreads from about 0.8 to 7.9 GHz, which corresponds to the fractional bandwidth of ~ 165%. A detailed parametric study is reported for the transition geometrical parameters and substrate curvature. The performance of the transition is validated successfully via prototyping. The liquid metal used is galinstan, and the substrate is made of PDMS.

Annular Cavity Horn Antenna Provides a Fivefold Increase of the Power Density in BEM Experiments in the 60-GHz Band

We demonstrate that an integrated lens antenna (ILA) with a double lens (DL) focusing system can provide simultaneously a high broadside directivity and a low scan loss over a wide angular range. The proposed DL ILA system consists of a hemispherical substrate lens and a planoconvex objective lens. A prototype of a high-gain DL ILA with lenses made of a low permittivity dielectric material is fabricated and characterized in the frequency range of 75-79 GHz. The realized scan loss in terms of gain within a ±30° field of view is <;1.1 dB in both planes. The performance of the DL ILA is compared with that of two hemispherical ILAs designed to provide the best broadside directivity and the lowest scan loss, respectively.

Advanced modeling of choke ring antennas for mm-wave applications

The physical mechanisms behind the formation of shaped-beam radiation patterns by flat horns (i.e., open ended waveguide feeds with finite-size corrugated flanges) are studied in a rigorous manner using the singular integral equation (SIE) approach. The problem is considered for TM polarization in the two-dimensional (2-D) formulation. First, dispersion curves of periodic grating are presented and used to analyze the modes supported by the waveguide flanges. This includes the surface wave, stopband, and leaky-wave regimes. The modes corresponding to the poles on the bottom “nonphysical” Riemann sheets are also considered. Finally, various types of radiation patterns produced by flat horns with gratings operating in different regimes are illustrated with an emphasis on generating sectoral beams being of interest for many practical applications. The results are validated via comparison with full-wave three-dimensional (3-D) analysis.

Inset-fed liquid metal patch antenna

This letter presents a circular horn antenna with annular cavity (CHAAC) optimized for in vitro bioelectromagnetic (BEM) studies in the 60-GHz band. The antenna produces an axisymmetric shaped-beam radiation pattern with the half-power beamwidth of about 70° that enables a highly uniform exposure of biological samples positioned close to the antenna aperture. The comparison to standard waveguide feeds reveals the significant advantages (in terms of the exposure uniformity and incident power density) offered by the CHAAC for BEM experiments at millimeter (mm-) waves. In such a way, a new application area for this class of antennas is demonstrated.