Slawomir Gruszczynski

Bio: Slawomir Gruszczynski is an academic researcher from AGH University of Science and Technology. The author has contributed to research in topics: Power dividers and directional couplers & Antenna measurement. The author has an hindex of 20, co-authored 218 publications receiving 1502 citations.

Microwave-based sensors with phthalocyanine films for acetone, ethanol and methanol detection

Abstract: The utilization of novel comb copolymer phthalocyanine (Pc) thin films as sensitive layers for microwave gas sensors at room temperature under exposure to various volatile organic compounds are presented. The microwave gas sensors are based on an interdigital capacitor fabricated in a microstrip line technique with adequate layers and dimensions. The developed sensors were tested for acetone, ethanol and methanol in the range of 0–200 ppm with special emphasis to the range of 0–25 ppm. The presented sensors will be used as a part of a microsystem for exhaled breath analysis, i.e. diabetes biomarkers detection. All the measurements are carried out at room temperature. The obtained results confirmed the possibility of utilization the microwave Pc-based sensors for exhaled acetone measurements.

Broadband Integrated $8 \times 8$ Butler Matrix Utilizing Quadrature Couplers and Schiffman Phase Shifters for Multibeam Antennas With Broadside Beam

Abstract: A novel realization of a broadband $8 \times 8$ Butler matrix having phase progressions 0°, ±45°, ±90°, ±135°, and 180° has been proposed. The presented network is composed of coupled-line 3-dB/90° directional couplers and Schiffman phase shifters that ensure its broadband amplitude and phase characteristics. The proposed solution allows for a fully planar realization without any interlayer connections, which has been achieved by both rearrangement of the matrix layout and realization of the selected crossovers as tandem connections of quadrature directional couplers. The proposed concept has been verified experimentally by the design of a Butler matrix operating within 2.5–3.5 GHz and applied in a multibeam antenna array with broadside beam.

Microstrip Antenna Arrays Fed by a Series-Parallel Slot-Coupled Feeding Network

Abstract: A novel concept of a feeding network of a microstrip antenna array composed of series-fed linear subarrays has been shown. The proposed feeding network utilizes a concept of a slot coupler, in which two microstrip lines are coupled through a slot in a common ground plane. As it has been shown, such a slot coupler provides equal-amplitude and out-of-phase output signals and, therefore, can be used for appropriate feeding (at the center) of a single linear antenna subarray that utilizes “through-element” series-feeding technique. The proposed concept of a slot coupler has been used for the design of an 8 × 8 antenna array, in which all 8 × 1 linear subarrays are series-fed, whereas all 8 linear subarrays are fed by a parallel feeding network.

Broadband Rat-Race Couplers With Coupled-Line Section and Impedance Transformers

Abstract: Design of broadband rat-race couplers with the use of a shorted coupled-line section and impedance transformers has been comprehensively investigated. A broadband rat-race coupler utilizing a shorted coupled-line section and two shorted quarter-wave long transmission lines has been modified allowing for achieving ideal isolations between two pairs of respective ports. Also it has been shown that the bandwidth of such couplers can be increased when multisection impedance transformers are applied, and that the Darlington synthesis procedure can be used for calculation of transmission-line impedances. A tabular data for rat-race couplers with up to four-section impedance transformers is given. The theoretical analysis has been verified by measurements of the manufactured broadband rat-race coupler operating within 0.8 to 2.8 GHz frequency range.

IEEE Transactions on Microwave Theory and Techniques and Antennas and Propagation Announce a Joint Special Issue on Ultra-Wideband (UWB) Technology

Abstract: Before the emergence of ultra-wideband (UWB) radios, widely used wireless communications were based on sinusoidal carriers, and impulse technologies were employed only in specific applications (e.g. radar). In 2002, the Federal Communication Commission (FCC) allowed unlicensed operation between 3.1–10.6 GHz for UWB communication, using a wideband signal format with a low EIRP level (−41.3dBm/MHz). UWB communication systems then emerged as an alternative to narrowband systems and significant effort in this area has been invested at the regulatory, commercial, and research levels.

Driver Behavior Analysis for Safe Driving: A Survey

Abstract: Driver drowsiness and distraction are two main reasons for traffic accidents and the related financial losses. Therefore, researchers have been working for more than a decade on designing driver inattention monitoring systems. As a result, several detection techniques for the detection of both drowsiness and distraction have been proposed in the literature. Some of these techniques were successfully adopted and implemented by the leading car companies. This paper discusses and provides a comprehensive insight into the well-established techniques for driver inattention monitoring and introduces the use of most recent and futuristic solutions exploiting mobile technologies such as smartphones and wearable devices. Then, a proposal is made for the active of such systems into car-to-car communication to support vehicular ad hoc network's (VANET's) primary aim of safe driving. We call this approach the dissemination of driver behavior via C2C communication. Throughout this paper, the most remarkable studies of the last five years were examined thoroughly in order to reveal the recent driver monitoring techniques and demonstrate the basic pros and cons. In addition, the studies were categorized into two groups: driver drowsiness and distraction. Then, research on the driver drowsiness was further divided into two main subgroups based on the exploitation of either visual features or nonvisual features. A comprehensive compilation, including used features, classification methods, accuracy rates, system parameters, and environmental details, was represented as tables to highlight the (dis)advantages and/or limitations of the aforementioned categories. A similar approach was also taken for the methods used for the detection of driver distraction.