000K utf8 1100 $c2016 1500 eng 2050 urn:nbn:de:gbv:8-diss-183519 3000 Ledig, Robert 4000 Coupling element antennas for small terminals based on the characteristic modes$hChristian-Albrechts-Universität zu Kiel [Ledig, Robert] 4030 Kiel$nChristian-Albrechts-Universität zu Kiel 4209 Future mobile communication systems use the broadband and multiple antenna technology (MIMO) to increase the spatial efficiency of the transmission channel and therefore provide higher data rates over a particular frequency range. In this thesis, the Theory of Characteristic Modes (TCM) was followed, which allows principally the use of the orthogonal chassis modes, decomposed out of the current density distribution, in order to design broadband and multiple antenna systems. A major challenge was the development of suitable coupling structures to excite several modes independently. Here, the capacitive, the inductive and the hybrid coupling concepts were discussed and compared for the selective coupling of the characteristic modes. A reconstruction of the resulting radiation patterns and the calculation of the power coefficient realized the specific coupling of the modes, the respective power budget and antenna matching as well. In particular, the results indicated a direct relationship between the characteristic modes and the low correlation of the transfer functions in multi-antenna systems. In order to show a direct coupling of the several concepts, different kind of feeding networks at the feed-point of the investigated coupling element have been developed and evaluated. Moreover, they include the power splitter and the matching networks as well. On the development of multi-band and broadband antennas, different coupling concepts for the common coupling of several modes have been investigated. This kind of excitation could be realized by using the coupling elements itself as a tuning element or by using space efficient matching networks at the feeding port. The results of this thesis reveals the utilization of the theory of characteristic modes as a synthesis tool for the design of the space efficient multi-antenna systems, as well as multi-band and broadband antennas by direct coupling of the chassis itself. 4950 https://nbn-resolving.org/urn:nbn:de:gbv:8-diss-183519$xR$3Volltext$534 4961 https://macau.uni-kiel.de/receive/diss_mods_00018351 5051 621.3 5550 antenna theory 5550 broadband antennas 5550 characteristic modes 5550 coupling element 5550 impedance matching 5550 low-volume antenna 5550 mobile antennas 5550 multiple antennas 5550 radiation