Compact broadband electronically controllable SIW phase shifter for 5G phased array antennas

This work presents a novel compact and broadband electronically controllable substrate integrated waveguide (SIW) phase shifter intended for beamsteering applications in antenna arrays for 5G wireless communication. The proposed phase shifter is designed to operate over a large bandwidth (26 GHz–32 GHz) with a simulated maximum insertion loss of less than 3 dB and a maximum phase difference of more than 100°+5° over the entire band. The phase shift is provided via metal posts which are switched between capacitive and inductive loading through beam-lead PIN diodes

Smrtnost od akutnih otrovanja u području Plovdiva u Bugarskoj

The severe recession in Bulgaria which followed the collapse of the totalitarian regime in 1989 had an unfavourable impact on the health status of the population. Systematic studies of acute poisoning mortality rate in the transitional period (1990-98) are scarce in the post-totalitarian Eastern European countries and are lacking in Bulgaria. This retrospective study analysed 1,150 deaths due to acute poisoning in Plovdiv Region for the period 1961-98. Acute poisoning mortality rate was moderately high in the period between 1990 and 1998 with respect to the average of 4.99 per 100,000 a year. It grew steadily during rapid socialist industrialization (1961-90) and showed a trend of slight decrease during transition (1991-1998). The decrease may largely be accounted for by the foundation of the regional toxicological centre and to a certain degree by a drop in industrial and agricultural production and exposure to hazards.Nakon pada totalitarnog režima 1989. godine, socioekonomska kriza što je zahvatila zemlju odrazila se negativno na zdravstveno stanje populacije. Sustavna praćenja akutnih otrovanja tijekom tranzicijskog razdoblja u Istočnoj Europi su oskudna, a u Bugarskoj ih nije ni bilo. U ovom se radu retrospektivno analizira 1150 slučajeva akutnih smrtnih otrovanja u području Plovdiva, i to u razdoblju 1961-1990. u vrijeme intenzivne industrijalizacije. U tom je razdoblju stopa smrtnosti od akutnih otrovanja stalno rasla dosegnuvši maksimum između 1986. i 1989., a nakon toga je počela lagano opadati. U razdoblju između 1990. i 1998. smrtnost od akutnih otrovanja iznosila je 4,99 na 100.000 stanovnika. Spomenuti trend opadanja smrtnosti pripisuje se osnivanju regionalnoga toksikološkog centra, kao i usporavanju industrijske i poljoprivredne aktivnosti s posljedicom smanjenja ekspozicije toksičnim tvarima. U smanjivanju stope smrtnosti od akutnih otrovanja posebnu ulogu imaju dobro planirane i provođene preventivne mjere

Smrtnost od akutnih otrovanja u području Plovdiva u Bugarskoj

The severe recession in Bulgaria which followed the collapse of the totalitarian regime in 1989 had an unfavourable impact on the health status of the population. Systematic studies of acute poisoning mortality rate in the transitional period (1990-98) are scarce in the post-totalitarian Eastern European countries and are lacking in Bulgaria. This retrospective study analysed 1,150 deaths due to acute poisoning in Plovdiv Region for the period 1961-98. Acute poisoning mortality rate was moderately high in the period between 1990 and 1998 with respect to the average of 4.99 per 100,000 a year. It grew steadily during rapid socialist industrialization (1961-90) and showed a trend of slight decrease during transition (1991-1998). The decrease may largely be accounted for by the foundation of the regional toxicological centre and to a certain degree by a drop in industrial and agricultural production and exposure to hazards.Nakon pada totalitarnog režima 1989. godine, socioekonomska kriza što je zahvatila zemlju odrazila se negativno na zdravstveno stanje populacije. Sustavna praćenja akutnih otrovanja tijekom tranzicijskog razdoblja u Istočnoj Europi su oskudna, a u Bugarskoj ih nije ni bilo. U ovom se radu retrospektivno analizira 1150 slučajeva akutnih smrtnih otrovanja u području Plovdiva, i to u razdoblju 1961-1990. u vrijeme intenzivne industrijalizacije. U tom je razdoblju stopa smrtnosti od akutnih otrovanja stalno rasla dosegnuvši maksimum između 1986. i 1989., a nakon toga je počela lagano opadati. U razdoblju između 1990. i 1998. smrtnost od akutnih otrovanja iznosila je 4,99 na 100.000 stanovnika. Spomenuti trend opadanja smrtnosti pripisuje se osnivanju regionalnoga toksikološkog centra, kao i usporavanju industrijske i poljoprivredne aktivnosti s posljedicom smanjenja ekspozicije toksičnim tvarima. U smanjivanju stope smrtnosti od akutnih otrovanja posebnu ulogu imaju dobro planirane i provođene preventivne mjere

Non-Invasive Millimeter-Wave Profiler for Surface Height Measurement of Photoresist Films

This work presents a low-cost non-invasive millimeter-wave surface-height measurement sensor of dielectric and polymer films on glass and quartz substrates. The surface-height profiler utilizes near-field resonance measurement technique operating at 96 GHz implemented by using a single complementary split-ring resonator (CSRR) integrated with a tailor-made WR10 rectangular waveguide. By placing a glass or quartz substrate uniformly coated with SU-8 photoresist on top of the CSRR, the thickness of the SU-8 polymer can be extracted based on the reflected and transmitted electromagnetic-wave energy interacting at the electrical boundary between the substrate and polymer film. Uniform single layers of SU-8 polymer with thicknesses from 3 to 13 μm, coated on top of glass substrate are measured and characterized. The extracted polymer-film thicknesses from the sensor in this work show an agreement of higher than 95% as compared to the commercial surface profiler instrument, while offering various advantages e.g. non-invasion, ease of measurement setup, low-cost and miniaturization

Wireless Power Transfer for Gas Pipe Inspection Robots

Wireless power transfer in metal pipes is a promising alternative to tethered exploration robots, with strong potential to enable longer operating times. Here we present experimental results, including rectification efficiency, for a prototype gas pipe inspection robot with wireless power receiver functionality

Wireless Power Transfer System for Battery-Less Sensor Nodes

For the first time, the design and implementation of a fully-integrated wireless information and power transfer system, operating at 24 GHz and enabling battery-less sensor nodes, is presented in this paper. The system consists of an RF power source, a receiver antenna array, a rectifier, and a battery-less sensor node which communicates via backscatter modulation at 868 MHz. The rectifier circuits use commercially available Schottky diodes to convert the RF power to DC with a measured efficiency of up to 35%, an improvement of ten percentage points compared with previously reported results. The rectifiers and the receive antenna arrays were jointly designed and optimised, thereby reducing the overall circuit size. The battery-less sensor transmitted data to a base station realised as a GNU Radio flow running on a bladeRF Software Defined Radio module. The whole system was tested in free-space in laboratory conditions and was capable of providing sufficient energy to the sensor node in order to enable operation and wireless communication at a distance of 0.15 metres

Low-Cost Microfabrication for MEMS Switches and Varactors

This paper presents a low-cost micro-fabrication technique for manufacturing RF MEMS switches and varactors without intensive cleanroom environments. The fabrication process entails only laser micro-structuring technique, noncleanroom micro-lithography, standard wet-bench and hot-film emboss of SU-8 and ADEX polymers. MEMS movable structures were fabricated out of 14-μm-thick Aluminum foils and suspended above coplanar-waveguide transmission lines, which were implemented on top Duroid substrates, via 5-μm-thick SU-8 dielectric anchors. Both MEMS structures and Duroid substrate were integrated using micro-patterned polymers, developed by using dry-film ADEX and SU-8 polymers, for a composite assembly. An average fabrication yield of higher than 60% was achieved, calculated from ten fabrication attempts. The RF measurement results show that the RF MEMS devices fabricated by using the novel micro-fabrication process have good figure-of-merits, at much lower overall fabrication costs, as compared to the devices fabricated by conventional cleanroom process, enabling it as a very good micro-fabrication process for cost-effective rapid prototyping of MEMS

UV-LIGA Microfabrication of 0.3 THz Double Corrugated Waveguide

A microfabrication process has been developed by using ultraviolet photolithography (UV-LIGA) with multi-layer SU-8 photoresist to create high aspect ratio Slow Wave Structures (SWS) for millimeter waves and THz vacuum electron devices. The main steps of the process will be described, applied to the fabrication of a double corrugated waveguide at 300 GHz

Higher-order mode substrate integrated waveguide cavity excitation for microstrip patch antenna arrays at 30 GHz

This paper presents a novel approach to the design and fabrication of low-cost and high-gain aperture-coupled microstrip patch antenna (AC-MPA) arrays with improved radiation pattern for millimetre-wave applications such as simultaneous wireless information and power transfer (SWIPT) and Internet-of-Things (IoT) device connectivity. A higher-order mode substrate integrated waveguide (SIW) cavity is used to feed the MPA arrays through aperture coupling. The improved design approach is introduced and discussed in detail. Simulation and experimental results for 2x2 and 4x4 arrays are presented, demonstrating excellent agreement. Key performance metrics are side-lobe levels of less than -24 dB and -29 dB in the E-plane and -22 dB and -26 dB in the H-plane and realized gain of 11 dBi and 15 dBi for the 2x2 and 4x4 arrays respectively, at a design frequency of 30 GHz

Investigation of Implantable Antennas for Exploratory Neuroscience Studies

In this paper we present a thorough and rigorous characterisation of the dielectric properties of rat skin tissue, including statistical processing. This data is used for a proof of concept study of the design, fabrication, and measurement of lightweight, flexible, and conformable microstrip patch antennas, to later enable improved chronic neuroscience research studies