Naponski ugodivi kondenzator za velike signale

undergraduate thesis

• Title (english): Voltage-controlled capacitor for large signals
• Author: Mateo Brubnjak
• Mentor: Dubravko Babić (mentor)
• Committee member: Dubravko Babić (predsjednik povjerenstva)
• Committee member: Davor Bonefačić (član povjerenstva)
• Committee member: Marko Bosiljevac (član povjerenstva)
• Granter: University of Zagreb; Faculty of Electrical Engineering and Computing; Zagreb
• Defense date and country: 2019-09-02, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Computing
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Electrical Engineering

Abstract

Rad istražuje mogućnost korištenja mikrovalnih transformatora u rasponu 10-1000MHz, za svrhu smanjenja amplitude napona za elemente koji zahtijevaju konstantnu radnu točku, specifično za varaktorske diode. Varaktroske diode bi mogle biti korištene kao naponski ugodivi kondenzatori u krugovima s pojačalima visoke snage. Standardne snage (1-3W) u ovim krugovima stvaraju velike devijacije od radne točke varaktorske diode zbog čega ona postaje veliki izvor nelinearnosti.
Rad sadrži razvijeni ekvivalentni model za mikrovalne transformatore koja precizno opisuje ponašanje do prve rezonante frekvencije nakon koje transformator više nije efektrivan. Efikasna metoda za karakterizaciju istog modela koja koristi mjerenja raspršnih parametara je razvijena. Karakterizacija uključuje mjerenje induktiviteta primara i sekundara, prijenosnog omjera te parazitnog kapaciteta koji uzrokuje prvu rezonantnu frekvenciju u mjerenom s21 parametru, nakon koje transformator više nije efektivan.

Abstract (english)

The thesis explores the possibility of using micro-transformers, in the 10-1000MHz range, for the purpose of reducing voltage amplitude for components that require a constant working point, specifically varactor diodes. Varactor diodes are considered for use as voltage-controlled capacitors in tuning circuits for large signal power amplifiers. Normally this is impossible as the signal power (1-3W) in these circuits produces deviations from the varactor diode working point turning it into a large source of non-linearity.

An equivalent microwave transformer model was developed that accurately predicts behavior before the first s21 resonance frequency. An efficient method for characterization of this model was developed that uses S-parameter measurements. The method includes determining the inductance of the primary and secondary coil, coupling factor and the parasitic capacitance that causes the first resonant frequency in the measured s21 parameter, beyond which the transformer no longer functions as required.

• Keywords: transformatori; varaktorske diode; visokofrekvencijska elektronika; širokopojasna elektornika; raspršni parametri
• Keywords (english): transformers; varactor diodes; high-frequency electornics; wide-band electronics; scattering parameters
• Language: english
• URN:NBN: urn:nbn:hr:168:612126
• Study programme: Title: Electrical Engineering and Information Technology; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka elektrotehnike i informacijske tehnologije (sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka elektrotehnike i informacijske tehnologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Closed access
• Created on: 2020-01-07 17:04:27