Preklopna radiofrekvencijska pojačala s komplementarnim filtrima

master's thesis

• Title (english): Switchmode radiofrequency amplifiers with complimentary filters
• Author: Ante Brizić
• Mentor: Dubravko Babić (mentor)
• Committee member: Dubravko Babić (predsjednik povjerenstva)
• Committee member: Silvio Hrabar (član povjerenstva)
• Committee member: Marko Bosiljevac (član povjerenstva)
• Granter: University of Zagreb; Faculty of Electrical Engineering and Computing; Zagreb
• Defense date and country: 2019-07-02, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Computing
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Electrical Engineering

Abstract

Ovaj rad uvodi novi pristup pri korištenju konstantnih otporničkih mreža,
pobliže komplementarnih filtara u konfiguraciji dipleksera, na izlazu radiofrekvencijskih
preklopnih modulatora. Dana su teorijska razmatranja i dizajn filtara te
mjerenja napravljenih filtara s karakterističnom frekvencijom na 800 MHz i 2.5
GHz. Zaljučeno je da preklopna pojacala zaključena s komplementarnim filtrima
imaju veću i stabilniju efikasnost nego kada su zaključena samo s nisko-propusnim
filtrom. Iako povećavaju korisnost, proizvodnja ovakvih filtara predstavlja kompliciraniji
postupak naspram korištenih nisko-propusnih filtara, iz razloga što s11
parametar, za koji želimo da bude što manji moguć, ovisi o faznom neslaganju
između nisko-propusne i visoko-propusne sekcije, te u slučaju većeg neslaganja
opada, pri čemu performanse pojačala i filtra također opadaju. Kao kvalitativna
metoda za evaluaciju filtara koristi se reflektometrija u vremenskoj domeni. Korištenjem
simulacija i mjerenja putem reflektometrije potvrđeno je da diskontinuiteti
nastaju zbog faznog neslaganja između dviju filtarskih sekcija te je aproksimiran
ekvivalentni iznos diskontinuiteta.

Abstract (english)

This work introduces a novel approach in using constant resistance networks,
specially complementary filters in a diplexer configuration, on the output of a
radio-frequency switch-mode modulator. Theory concepts and design for the filters,
with a crossover frequency of 800 MHz and 2.5GHz, are considered and
the filters were assembled and measured. Based on the measurements and simulations
we concluded that switchmode RF power amplifiers terminated with
complementary filters exhibit higher and more consistent drain efficiency than
when terminated with only a low-pass filter. Despite increasing and stabilizing
the drain efficiency, the filters present a slightly more stringent assembly procedure
in comparison to the widely used low-pass filters due to the fact that the
s11 parameter, which we want to be minimal as possible, falls off due to phase
mismatch between the low-pass and high-pass section. We used time domain
reflectometry(TDR) to evaluate the quality of the filter’s assembly. Using TDR
simulations and measurements we identified the discontinuities that lower the
performance of the complementary filters.

• Keywords: Konstantne otpornicke mreže; Komplementarni Filtri; RF; RFPA; RF Pojacala Snage; RFSMPA; Preklopni Modulator; Analogni Filtar; Diplekser; Butterworthova Karakteristika; Korisnost odvoda; Reflektometrija u vremenskoj domeni; TDR
• Keywords (english): Constant Resistance Networks; Complementary Filters; RF; RFPA; RF Power Amplifier; RFSMPA; Switch-mode Modulators; Analog Filter; Diplexer; Butterworth Characteristic; Drain Efficiency; Time Domain Reflectometry; TDR
• Language: english
• URN:NBN: urn:nbn:hr:168:996007
• Study programme: Title: Electrical Engineering and Information Technology; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka elektrotehnike i informacijske tehnologije (magistar/magistra inženjer/inženjerka elektrotehnike i informacijske tehnologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Closed access
• Created on: 2020-01-07 17:02:46