Paweł R. Bajurko

A Broadband Absorber With a Resistive Pattern Made of Ink With Graphene Nano-Platelets

A novel type of a broadband flexible electromagnetic absorbing panel made of a resistive pattern printed on a dielectric spacer backed by a conducting surface is investigated in this paper. It is shown that an appropriate choice of the shape and sheet resistance of the pattern allows extending an absorption spectrum up to an octave and beyond, which is very competitive over alternative solutions. The pattern is made of ink with graphene nano-platelets, which allows achieving expected sheet resistance with decent repeatability, what is confirmed with measurements undertaken with the DC point probe and microwave dielectric resonator techniques. An exemplary sample of the proposed absorber is manufactured and characterized, indicating a very good agreement between theoretical study and experiments.

Time-Modulated Reconfigurable Antenna Based on Integrated S-PIN Diodes for mm-Wave Communication Systems

This paper concerns the study of the mm-wave reconfigurable antennas based on S-PIN diodes suitable for using in mm-wave communication systems. The investigated antennas were designed, fabricated, and subjected to the measurements in both steady and transient states. One selected antenna was incorporated into a wireless system to determine its suitability for operating in such a system as a time-modulated linear array. By means of appropriate switching of the antenna, multiple radio frequency (RF) chains were simulated in a receiver having only one RF chain. This allowed applying a combining technique for improving the system performance in a presence of a strong interfering signal.

Screen printed UHF antennas on flexible substrates

Printed electronics belongs to the most important developing electronics technologies. It provides new possibilities to produce low cost and large area devices. In its range several applications can be distinguished like printed batteries, OLED, biosensors, photovoltaic cells or RFID tags. In the presented investigation, antennas working in UHF frequency range were elaborated. It can be applied in the future for flexible RFID tags. To produce these antennas polymer paste with silver flakes was used. It was deposited on two flexible substrates (foil and photo paper) with screen printing techniques. After printing process surface profile, electrical and microwave parameters of performed antennas were measured using digital multimeter and network analyzer, relatively. Furthermore, a thickness of printed layers was measured.

Study of detection capability of Novelda impulse transceiver with external RF circuit

This paper reports a range of experience gained during application of Novelda impulse transceiver module in an ultra-wideband radar system. The paper describes the specific data acquisition procedure performed by the transceiver module. The external radio frequency (RF) circuit is proposed, which provides improved detection capability of the radar system. The antenna system is designed with respect to the application requirements. Some of the transceiver settings influencing the radar system performance are also discussed in details.

Null-steering in two-element time modulated linear antenna array through pulse-delay approach

This paper presents results of investigation on the radiation pattern generated with two-element Time Modulated Linear Array with single SP4T microwave switch. Utilization of SP4T switch instead of multiple SPST switches reduced an amount of power dissipated in matched loads and increased total efficiency. Due to the pulse-delay approach the null of radiation pattern has been continuously steered in a wide range of angles.

Emerging ferroelectric ceramic-polymer composites for sub-THz tunable devices

The paper presents the recent research in ferroelectric ceramic-polymer composites for sub-THz tunable devices. Developed composites are very promising group of materials due to the possibility of fabrication of materials with desired electrical and mechanical properties. Appropriate selection of components for ceramic slurry enables to obtain composites with low losses and high tunability. Using tape-casting technology and water-dispersible polymers environmentally friendly thin and flexible ferroelectric tapes can be realized. Particular emphasis is made on measurement methods of electrical properties in sub-THz range. In addition, various composites, process of fabrication and characterization of developed ferroelectric ceramic-polymer composites are discussed.

Human movement and biological functions monitoring using ultrawideband signals

The paper presents the results of investigations of human movement and biological functions monitoring using UWB and CW signals. Two types of radars operating in different frequency bands and with different bandwidths have been exploited in the measurement experiments.

Integrated Communications System for the Remote Operation of Unmanned Aerial Vehicle

The aim of the paper is to present the concept of the integrated system dedicated for communication and remote operation of the unmanned aerial vehicle (UAV). In the paper, the concept and realization of this kind of wireless communications system is presented. The system consists of two integrated solutions – unidirectional broadcast transmission of video, audio and data from UAV to the operators within the mobile command centre and two-way communication with the telemetry and control subsystem. The systems are integrated within the single chassis and placed on the UAV to ensure proper operation of the flying robot. The specific elements of the system are presented as well as main requirements and development methods are also discussed in the paper.

The ink-jet printing of microstrip lines on ferroelectric ceramic-polymer composites and its characterization in sub-THz range

In this paper the application of the ink-jet printing technology to microstrip line fabrication on tunable ferroelectric ceramic-polymer composites for devices operating at sub-terahertz range have been presented. Measurement results shown that the designed material is usable for creating structures able to tune some their electromagnetic characteristics. Relatively low temperature technology process (ink-jet printing technology) is able to deposit conductive lines on the ceramic polymer. The ink-jet printed silver microstrip lines can operate at sub-terahertz range.

Improved clutter removal for measuring wall reflectivity using the RCS technique

Absorber lining is an important part of an indoor antenna measurement chamber design. During the design phase different absorber types are selected for minimizing the expected reflection from given locations in the chamber. By the time of installation, these absorbers have already been measured as part of the production quality control. The question however arises if after installation, these absorbers still meet the requirements of the design. The free-space-VSWR measurement technique is a method to assess the overall reflectivity of the chamber at a certain location, i.e. quiet-zone reflectivity, but cannot be easily limited to measure the reflectivity of a single wall. In this work the RCS technique is revised. The reflection of the wall is measured using a quasi-monostatic RCS setup which is mounted on a linear sliding system. The linear sliding system is positioned perpendicular to the wall. After measuring at several positions the measurement results are shifted in time during post processing such that the reference target or wall add constructively and clutter or other walls destructively. Using this technique it will be shown that the reflectivity of an absorber-lined wall can be determined during installation where not all walls or floor have been covered yet.