@phdthesis{,
    author = {Goncharova, Iuliia},
    title = {Compact Microwave Antennas and Antenna Combinations for Terrestrial and Satellite Services on Vehicles},
    editor = {},
    booktitle = {},
    series = {},
    journal = {},
    address = {},
    publisher = {},
    edition = {},
    year = {2019},
    isbn = {},
    volume = {},
    number =  {},
    pages = {},
    url = {},
    doi = {},
    keywords = {cellular communication, navigation, GNSS, SDARS, satellite radio, antenna, antenna combination},
    abstract = {Recent developments in cellular communication - like elaboration of Long Term Evolution (LTE) standard - allow large data rates up to 3 Gb/s in down link and connectivity of modern people even while driving. However, a renewal of base-station and at end-user equipment is certainly needed for using the advantages of the LTE service. Thus, along with other hard-ware changes, a user-end shall contain at least wo broadband antennas since this standard implies Multiple-In-Multiple-Out technique (MIMO) and carrier aggregation. Last years show a trend of hiding the increased number of vehicular antennas as much as possible by placing them either upon a roof underneath a shark-fin cover or integrated in car's body. However for even complicated systems, there is a strictly limited mounting space, therefore car antennas must be very compact while providing the required radiation properties. A dense placement in multiple-antenna modules poses an additional obstacle – mutual coupling between aerials. It is especially critical in that modules which contain transmitting antennas for cellular communication and sensitive aerials for satellite reception. All these challenges and developments have motivated to research a new wideband compact  antenna for the LTE communication on car. The investigation was conducted in different operation scenarios: in a stand-alone case, in a 2x2 MIMOmodule and in combinations with receiving radiators for other services like terrestrial radio, navigation and satellite broadcast. The researched aerial for LTE (so called 3-D or «Nefer»-antenna) consists of two structures, which are joined together at an excitation point. Due to the independence of the antenna's parts one from another, this 3-D radiator reaches demanded impedance and radiation properties within LTE low, middle and upper bands covering the frequencies of the currently-available cellular communication. In a 2x2 MIMO module, the 3-D radiators of this dual-band principle enable stable connection to the LTE-800-MHz network with enough mean throughput of 24 Mbit/s (state on 2012) which was  measured during the drive-test in live network. Since a typical antenna module for a personal vehicle includes several radiators for distinct services, the 3-D aerial (single and in 2x2 MIMO-system as well) has been combined and carefully investigated in several modules with aerials for satellite radio and navigation made according to the scarabaeus concept. In these combinations, 3-D radiators for cell-phone service are well-decoupled from antennas for satellite signal reception. Decoupling can be even improved by means of band-rejection filters for the critical frequencies and by optimization of filtering properties of the antennas for satellite services as it is shown in the thesis. In the researched combinations, the Nefer-antennas keep their omnidirectional pattern with only slight deviations and reach sufficient impedance matching to 50-Ohm line. Thus, the thesis proposes a high-efficient compact and reliable solution for LTE service on a personal vehicle which can even be used in complicated multiple-antenna modules. Alongside with the main topic on antennas for cellular communication, some researches on scarabaeus aerials for satellite reception were conducted. These investigations were required because of the recent improvements in navigation – like opening of the GPS-L2C band for civil use and development of interoperable L1Csingal – and due to the strengthened requirements on decoupling from terrestrial interferers. These researches are reflected in the thesis too.},
    note = {},
    
    school = {Universität der Bundeswehr München},
    
}