Upotreba nefosterovskog negativnog kondenzatora u strukturama za subvalno tuneliranje i raspršenje elektromagnetske energije

master's thesis

• Title (english): Application of negative capacitor in structure for subwavelength tunneling and scattering of electromagnetic energy
• Author: Petar Kolar
• Mentor: Silvio Hrabar (mentor)
• Committee member: Silvio Hrabar (predsjednik povjerenstva)
• Committee member: Juraj Bartolić (član povjerenstva)
• Committee member: Zvonimir Šipuš (član povjerenstva)
• Granter: University of Zagreb; Faculty of Electrical Engineering and Computing; Zagreb
• Defense date and country: 2015-07-09, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Electrical Engineering

Abstract

Efekt subvalnog tuneliranja javlja se prilikom rasprostiranja elektromagnetskog vala kroz otvor puno manji od valne duljine elektromagnetskog vala. Efekt tuneliranja se u ovom radu postiže smanjenjem relativne permitivnosti sredstva u otvoru na vrijednost manju od 1. Opisani su razni načini efektivnog smanjenja permitivnosti koji koriste princip umjetnih materijala (metamaterijala). Analiziran je problem uskopojasnosti efekta subvalnog tuneliranja prilikom korištenja efekta rezonancije s pasivnim elementima te je ponuđeno rješenje navedenog problema korištenjem aktivnih elemenata (tzv. nefosterovskih elemenata).
Tuneliranje je ispitano na prijenosnoj liniji s metalnom preprekom i nefosterovskim elementom. Kao nefosterovski element korišten je negativni kondenzator u radiofrekvencijskom opsegu frekvencija temeljen na ultra-brzom operacijskom pojačalu. Prikazan je način projektiranja negativnog kondenzatora, simulacija pomoću simulatora električnih krugova i punovalna simulacija elektromagnetskog dijela. Izrađen je prototip negativnog kondenzatora u radiofrekvencijskom opsegu 10 MHz do 500 MHz, ugrađen u prijenosnu liniju i načinjen niz mjerenja za demonstraciju efekta tuneliranja te su rezultati uspoređeni sa simulacijom.

Abstract (english)

The subwavelength tunneling effect is created while electromagnetic wave propagates through a subwavelength aperture within a metallic screen. In this Diploma Thesis, the subwavelength tunneling effect has been achieved by lowering down a relative permittivity of a medium inside the subwavelength aperture to a value lower than 1. Various possibilities of effective lowering of permittivity by using a principle of artificial materials (metamaterials) have been described. Also, the problem of narrowband behaviour of the subwavelength tunneling effect, by using a principle of passive resonance, has been described. Furthermore, the solution of the tunneling problem by using the active (so-called non-Foster) elements has been proposed.
The tunneling effect has been measured by using a transmission line blocked by a metallic obstacle loaded with a non-Foster element. The non-Foster element used in this Thesis is a negative capacitor based on ultra-fast op-amp, operating in RF range. The negative capacitor design has been shown, as well as both electric-circuit simulation and full-wave electromagnetic simulation. The negative capacitor prototype, operating in a frequency range 10 MHz - 500 MHz has been constructed and embedded into a transmission line. A set of measurements has been performed in order to demonstrate the subwavelength tunneling effect. All the measurement results have been compared to those from numerical simulations.

• Keywords: metamaterijali; subvalno tuneliranje; nefosterovski element; negativni; kondenzator
• Keywords (english): metamaterials; subwavelength tunneling; non-Foster element; negative capacitor
• Language: croatian
• URN:NBN: urn:nbn:hr:168:600723
• Study programme: Title: Information and Communication Technology; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka informacijske i komunikacijske tehnologije (magistar/magistra inženjer/inženjerka informacijske i komunikacijske tehnologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Closed access
• Created on: 2018-02-06 09:42:53