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978-3-8439-1488-8, Reihe Elektrotechnik
Kompakte Ultrabreitband-Antennenkonzepte für die HF-Materialcharakterisierung und MIMO-Systeme
169 Seiten, Dissertation Universität Hannover (2013), Softcover, A5
The Ultra-Wideband technology (UWB) represents a convenient approach for high-speed, wireless communication over short distances. A combination with Multiple-Input Multiple-Output technology (MIMO) to increase the data rate for video streaming was investigated recently. Such radio systems require an increased number of antennas in the user equipment. Low cost and compact antenna integration with increased functionality can be realized on the basis of the so called Molded-Interconnect-Devices technology (MID), which enables the design of antennas and electronic circuits on three-dimensional surfaces.
This work therefore deals with the design of ultra-wideband, multiple element antennas with increased directivity and compactness using the new MID fabrication process. Especially, the four arm, logarithmic periodic antenna, which is principally convenient for ultra-wideband, multicarrier modulation methods with MIMO technique, will be optimized by exploiting three-dimensional design. The designs are intended for applications which require antenna radiation into a half sphere only. Furthermore the design and integration of a feeding network for the excitation of radiation patterns convenient for MIMO applications will be presented. Two antenna prototypes will be realized on the basis of the MID technology and verified by measurements finally.
The antenna design and the design of RF-devices in general rely on the knowledge of the RF-properties of the used materials. Since the MID technology is based on specifically materials with unknown electromagnetic properties within the microwave frequency range, these properties have to be characterized with convenient measurement techniques in the run-up of an antenna design. Three measurement techniques will be used for this purpose. Next to a resonator and a waveguide method, an antenna based free-space measurement method will be presented, which enables contact-less, temperature-dependent measurements without extensive sample preparation. The conception includes the calibration, signal processing and error analysis. Finally, a selection of materials will be measured with the three methods and the results will be tested for circuit design.