Instruments and attachments for electronystagmography

A portable set of instruments and devices was developed which makes it possible to record spontaneous nystagmus with open and closed eyes. Rotational, caloric, position, and pressure nystagmus under any conditions may also be recorded

Phase Distribution Optimization for 1-Bit Transmitarrays with Near-Field Coupling Feeding Technique

The paper presents a consideration of the optimum initial phase distribution for 1-bit transmitarrays with near-field coupling feeding technique. The study is based on the array factor decomposition into a series of continuous aperture distributions, which naturally includes the phase quantization errors. The previously proposed virtual focus approach is compared with the optimum quadratic initial phase distribution. Both methods are found to be very similar for specific values of distribution parameters in terms of far-field performance. Some further sidelobes level improvement is proposed

Methods for Attenuating and Terminating Waves in Ridge Gap Waveguide at W_Band Carbon-Loaded Foam Carbonyl Iron Paint and Nickel Plating

Several methods for electromagnetic waves matched termination and attenuation in a ridge gap waveguide (RGW) are experimentally investigated at W-band. At these frequencies, the implementation of matched loads and attenuators is especially complicated due to small sizes of RGW design features that limits application of traditional waveguide absorbing structures (e.g., absorbing sheets and finlines, ferrite insets, carbonyl iron walls, etc.). The following three techniques are considered: (i) filling an RGW gap with a carbon-loaded foam; (ii) covering a ridge (and pins) with a carbonyl iron paint; (iii) selective nickel plating of an RGW line segment. It was found that the first method exhibits a great broadband absorbing performance and can be easily implemented in a lab environment, whereas the second method can realize a more accurate and predictable attenuating performance. Finally, nickel plating allows for designing resonant RGW terminations and is more interesting from the industrial perspective

Wideband Open-Ended Ridge Gap Waveguide Antenna Elements for 1-D and 2-D Wide-Angle Scanning Phased Arrays at 100 GHz

A new antenna element type based on the open-ended ridge gap waveguide (RGW) is proposed for beam-steering phased array applications. This element type is of a particular interest at high mm-wave frequencies (≥ 100 GHz) owing to a contactless design alleviating active beam-steering electronics integration. The key challenge addressed here is a realization of a wide fractional bandwidth and scan range with high radiation efficiency. We demonstrate a relatively simple wideband impedance matching network comprised of an aperture stepped ridge segment and a single-pin RGW section. Furthermore, the E- and H-plane grooves are added that effectively suppress antenna elements mutual coupling. Results demonstrate a wide-angle beam steering (≥ 50\ub0) over ≥ 20% fractional bandwidth at W-band with ≥ 89% radiation efficiency that significantly outperforms existing solutions at these frequencies. An experimental prototype of a 1 719 W-band array validates the proposed design concept through the embedded element pattern measurements

W-band Waveguide Antenna Elements for Wideband and Wide-Scan Array Antenna Applications For Beyond 5G

Energy-efficient and highly-compact beam-steering array antennas at W- and D-band frequencies are considered as future enabling technologies for beyond-5G applications. However, most existing solutions at these frequencies are limited to the fixed-beam and frequency-dependent beam-steering scenarios. This paper aims to fill in this knowledge gap by investigating various types of antenna elements as potential candidates for wideband and wide-scan arrays at W-band. We consider open-ended ridge and ridge gap waveguide radiating elements that could overcome the physical complexities associated with the integration of elements in large-scale electronically scanned arrays. An infinite array approach is used, where we have adopted a triangular array grid and introduced E- and H-plane grooves to the element design to enhance the scan and bandwidth performance. Cross-comparison of several simulated array designs leads to the final array elements with 25% impedance bandwidth over the scan range of \ub140\ub0 in both the E- and H-planes

Mutual Coupling Analysis of Open-Ended Ridge and Ridge Gap Waveguide Radiating Elements in an Infinite Array Environment

In this paper, we discuss mutual coupling effects in 2-D beam-steerable antenna arrays based on open-ended ridge and ridge gap waveguide radiating elements. Considering potential applications for beyond-5G systems in W-/D-band, the radiating elements are designed full-metal realizing a high radiation efficiency. Various decoupling structures based on electromagnetic soft surfaces are applied to suppress the surface waves over the array apertures. The infinite array approach is used to analyze antenna unit cells in an isosceles triangular lattice, which results in the active reflection coefficient over a scan and frequency range. The latter is used to extract the values of the mutual coupling coefficients between the elements. The analysis demonstrates the effect of decoupling structures realizing a steep drop of the mutual coupling magnitude (≤ − 20 dB) for closely-spaced array elements. This results in a wideband (≥ 20%) and wide-scan (> 50\ub0) element beam-steering performance

Reconfigurable Transmitarray with Near Field Coupling to Gap Waveguide Array Antenna for Efficient 2D Beam Steering

A novel array antenna architecture is proposed that can enable 2D (full-space) radiation pattern control and efficient beam steering. This solution is based on a fixed-beam gap wave-guide (GWG) array antenna and a reconfigurable transmitarray (TA) that are coupled in the radiative near field. An equivalent two-port network model of the coupling mechanism is presented and validated numerically. The desired TA reconfiguration capability is realized by an 8 78 array of cavity-backed patch resonator elements, where two AlGaAs PIN-diodes are integrated inside each element providing a 1-bit phase shift. The TA is implemented in an 8-layer PCB, which includes radiating elements, fixed phase-shifting inner-stripline sections, impedance matching and biasing circuitry. The combined antenna design is low-profile (~ 1.7 wavelength) owing to the small separation between two arrays (~ 0.5 wavelength), as opposed to conventional TAs illuminated by a focal source. The design procedure of the proposed architecture is outlined, and the measured and simulated results are shown to be in good agreement. These results demonstrate 23.5 — 25.2 GHz –10-dB impedance bandwidth and 23.3 — 25.3 GHz 3-dB gain bandwidth, a beam-steering range of \ub130\ub0 and \ub140\ub0 in the E- and the H-plane with the gain peak of 17.5 dBi, scan loss ≤ 3.5 dB and TA unit cell insertion loss ≤ 1.8 dB

Professor Georgiy Pedachenko: the long-awaited painting. The facts, photos, works in the book about the eminent neurosurgeon

No abstract

Millimeter-Wave Array Antenna Architectures Employing Joint Power Combining and Beam Steering for Next-Generation Backhaul Applications

We investigate the capabilities and limitations of joint power-combining and beam-steering techniques for millimeter-wave antenna applications. In this analysis, both functionalities are realized simultaneously through a power-combining and beamforming (PC-BF) network interconnecting an input array of active channels with an array of antenna elements. The first part of the paper provides a review of state-of-the-art hardware architectures of such PC-BF networks and examines their suitability for millimeter-wave applications. The architectures are grouped into two classes depending on the array embedded element patterns properties. Next, a unified PC-BF network is proposed where both functionalities are implemented in a single millimeter-wave waveguiding block. A full-wave model of such a network with 6 inputs and 7 outputs is investigated, with its application demonstrated for a W-band focal-plane array feeding a backhaul reflector antenna

Millimeter-Wave Quasi-Optical Feeds for Linear Array Antennas in Gap Waveguide Technology

A realization of the quasi-optical (QO) feed concept for linear millimeter-wave (sub-)array antennas is demonstrated in gap waveguide technology. The proposed feed architecture employs an input transition from a ridge gap waveguide (RGW) to a groove gap waveguide (GGW), a radial (H-plane sectoral) GGW section, and a transition to an output RGW array. A design decomposition approach is presented to reduce simulation complexity. Several 20-element QO feed implementations are investigated at W-band demonstrating a 20% relative bandwidth (85-105 GHz), 0.5 dB insertion loss, and a capability of an amplitude taper control within the 10-20 dB range