Inteligentni antenski nizovi za prostornu selekciju signala

scientific master's theses

• Author: Gordan Šišul
• Mentor: Ervin Zentner (mentor)
• Committee member: Juraj Bartolić (predsjednik povjerenstva)
• Committee member: Ervin Zentner (član povjerenstva)
• Committee member: Antun Sertić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Electrical Engineering and Computing; (Department of Communication and Space Technologies); Zagreb
• Defense date and country: 2000-11-22, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Electrical Engineering; Radio Communications
• Universal decimal classification (UDC): 621 - Mechanical engineering. Nuclear technology. Machinery

Abstract

U radu su razmotreni inteligentni antenski nizovi za prostornu selekciju signala. Prikazani su suvremeni radiokomunikacijski sustavi i utjecaj modernih tehnologija na njihove karakteristike (CDMA, adaptivni antenski nizovi). Pokazano je da adaptivni antenski sustavi koji vrše veliku prostornu selekciju signala (fokusiraju glavnu laticu na korisnika, a nule dijagrama zračenja na neželjene signale) znatno poboljšavaju svojstva sustava. Uporabom inteligentnih nizova povećava se kapacitet sustava te područje pokrivanja. Kritički su uspoređeni antenski sustavi koji rade na osnovama različitih algoritama, a također su međusobno uspoređene i metode (algoritmi) određivanja smjera dolaska signala. Detaljno je razmotren i projektiran odašiljački antenski niz s elektroničkim zakretanjem dijagrama zračenja. Osnovu njega čini upravljački sklop koji se sastoji od faznih zakretača i pojačala. Mjerenja su obavljena na svim izvedenim komponentama i cijelom sustavu. Područje rada napravljenog niza je frekvencija 1800 MHz, a niz ispravno radi i na frekvencijama ±100 MHz od centralne frekvencije. Ostvareno je pomicanje glavne latice od ±27.30. Radi poboljšavanja karakteristika sustava moguće je: a) Povećati fazne zakrete (spojiti više izvedenih faznih zakretača) i time ostvariti veći prostorni pomak glavne latice. b) Koristiti pojačala s većim rasponom pojačanja kako bi se moglo ostvariti nizove s nejednolikom raspodjelom uzbuda antena (binomni niz, Čebiševljev niz). Napravljeni sklop upotpunjuje postojeću laboratorijsku opremu.

Abstract (english)

This work is focused on smart antenna arrays with spatial signal selection. Modern radiocommunication systems are shown. The influence of the modern technologies on radiocommunication systems is also presented (CDMA, adaptive antenna arrays). It is shown that adaptive antenna arrays with spatial signal selection (the systems that focus the main lobe on user, and nulls of radiation pattern on interfering signals) considerably improve system performance. With the usage of smart antenna systems, the capacity of the system and covering area can be improved. The antenna systems based on different kind of alghoritms are compared. Several different methods for estimation of Direction-Of-Arrival are also compared.
Transmitting antenna array with electronically controlled radiation pattern is analyzed and designed. The base of this array is the control circuit constructed with phase shifters and amplifiers. Extensive measurements were done on every system component, as well as on entire system. Designed array operates at 1800 MHz with operating frequency bandwidth of 200 MHz. Achieved steering of the main lobe is ± 27.3°. System can be improved further in several ways:
a) Increased phase shifts (cascade of several phase shifters) will result with larger steering range of the main lobe.
b) The amplifiers with larger scale of gain control can be used in order to achieve array with uneven distribution of the antenna feeding signals (binome array, Chebyshev array).
Designed circuit can be used as an addition to the existing lab equipment.

• Keywords: Adaptivni antenski sustavi; algoritmi-MUSIC; R-MUSIC; ESPRIT; fazni zakretači
• Keywords (english): Smart antenna arrays; algorithms-MUSIC; R-MUSIC; ESPRIT; phase shifters
• Language: croatian
• URN:NBN: urn:nbn:hr:168:994796
• Study programme: Title: Postgraduate master programme in electrical engineering; Study programme type: university; Study level: postgraduate; Academic / professional title: Magistar znanosti elektrotehnike (Magistar znanosti elektrotehnike)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Closed access
• Created on: 2019-04-15 09:07:56