Title :
Design of multi-antenna feeding for MIMO terminals based on characteristic modes
Author :
Miers, Zachary ; Hui Li ; Buon Kiong Lau
Author_Institution :
Dept. of Electr. & Inf. Technol., Lund Univ., Lund, Sweden
Abstract :
Conventional antennas in single-antenna terminals that resonate at frequencies lower than 1 GHz usually rely on the chassis as the main radiator. To effectively exploit chassis excitation for MIMO terminals, each of the multiple antennas is required to excite one distinct chassis mode. However, in today´s terminals, there is typically only one chassis mode that can radiate efficiently at frequencies below 1 GHz. Fortunately, it has been shown that minor modifications in the chassis structure can cause more than one mode to resonate at these frequencies. Nevertheless, proper antenna feeding methods are needed to practically tap into these modes. In this paper, we propose a general technique to feed orthogonal chassis modes of a given conducting structure using the theory of characteristic modes. By separating a radiating structure into individual modal currents, the near field radiating properties are exploited for capacitive or inductive feeding without significant coupling to other orthogonal modes of radiation. As a proof of concept, we apply the technique to feed a modified terminal chassis that has two significant characteristic modes at 0.89 GHz.
Keywords :
MIMO communication; UHF antennas; antenna feeds; antenna radiation patterns; MIMO terminals; antenna feeding methods; capacitive feeding; characteristic modes theory; chassis excitation; conducting structure; distinct chassis mode; frequency 0.89 GHz; inductive feeding; main radiator; modified terminal chassis; multiantenna feeding; near field radiating properties; orthogonal chassis modes; orthogonal modes; radiating structure; single-antenna terminals; Antenna feeds; Couplings; MIMO; Mobile antennas; Resonant frequency;
Conference_Titel :
Antennas and Propagation Society International Symposium (APSURSI), 2013 IEEE
Conference_Location :
Orlando, FL
Print_ISBN :
978-1-4673-5315-1
DOI :
10.1109/APS.2013.6710752