Method of Characteristic Modes Analysis and Manipulation for Antenna Design by Using Generalized Partial Element Equivalent Circuit

A method of analyzing characteristic modes (CMs) of antennas with multiple lumped LC loads is proposed based on the full-wave generalized partial element equivalent circuit (GPEEC) model. Different with traditional CMs analysis methods, this method can be integrated into an optimization algorithm. With this powerful engine, we can develop a systematic method to manipulate radiation CMs of a mobile terminal while preserving its aesthetic structure features of the industrial design. This method can reveal all possible radiation structure performances as traditional methods and even create new possible radiation modes to improve antenna performance. With the GPEEC model, a comprehensive analysis of antennas can be achieved simultaneously, including but not limited to simulating time-/frequency-domain responses, evaluating radiation efficiency contributed by the self- and mutual radiated power separately, and plotting current and field distribution. Three design examples are demonstrated, including analyzing the working mechanism of the self-curing decoupling technique for mobile terminals from the view of CMs, extending the bandwidth of an antenna in LTE-A low-frequency bands, and creating a pair of MIMO antennas in the low LTE-A bands. These examples are verified theoretically and experimentally, showing the high potential of this method in analyzing and designing antennas for mobile terminals.