Abstract-The new definition of arbitrary isolation between antennas is proposed according to the microwave network theory. The multilevel fast multipole algorithm (MLFMA) with the near-field preconditioner is implemented to predict the isolation between multiple antennas on electrically large platforms over a wide frequency range. Experimental results show that the isolation defined in this paper is more practical than the traditional one. Finally the radiation pattern and the isolation results for the ultra-shortwave antennas mounted on full-scale models such as an aircraft and a ship are obtained and discussed, which can give significant instructions to the platform-mounted antennas design.

No abstract

No abstract

Abstract-A peculiarity of counter-propagating energy-flows in nonlinear left-handed metamaterials (LHMs) is investigated for the case when the frequency of fundamental wave is in the negativeindex range and second-harmonic wave is in the positive-index range. Based on the electromagnetic theory, the comparisons of Manly-Rowe relations for nonlinear materials and process of secondharmonic generation under phase-matching condition in LHMs and RHMs are shown separately. That a surface of nonlinear left-handed metamaterials operates as an effective mirror which reflects the energy in form of second harmonics is demonstrated. Numerical results of fundamental and second-harmonic field intensity distributions are in agreement with theoretical results.

Free positioning of receivers is one of the key requirements for many wireless power transfer (WPT) applications, necessary from the end-user point of view. However, realization of stable and effective wireless power transfer for freely positioned receivers is technically challenging because of the need of complex control and tuning circuits. In this paper, we propose a concept of power channeling via an array of repeaters that enables self-tuning of multi-transmitter WPT systems without any sensing or control elements. The proposed WPT system consists of uncoupled transmitters and uncoupled repeaters which form independent power transfer channels. The proposed self-tuning WPT system is capable of maintaining stable output power with constant high efficiency regardless of the receiver position. Namely, our numerical and experimental results for a four-transmitter WPT system in form of a linear array show the efficiency 94.5 ± 2% for any position of the receiver within 20 mm range. INDEX TERMS Wireless power transfer, overlapping coils, multiple transmitter coils, free positioning.