Abstract-It has been shown recently that the use of modified assigned material parameters (MAMPs) within the finite-difference time-domain (FDTD) method provides a systematic, readily extensible, accurate, and efficient approach to the electromagnetic analysis of microstrip structures. In this paper, it is shown that this technique can also be applied with equal effect to lossless and lossy coaxial lines, wires in a lossy medium such as earthing grids, and more complex structures which include coaxial feeds and shorting posts. The modified parameters are calculated directly from the known asymptotic fields near the wire and do not rely on the concept of "equivalent radius." Results are given which show equal or superior performance compared to those obtained using other methods but with the added advantage of flexibility and rigor.

A novel pattern and polarization reconfigurable wearable slot antenna suitable for smart glasses is proposed. The antenna is designed and fabricated on glass and reconfiguration is realized using four PIN diodes. It operates in the 2.4 GHz Industrial, Scientific and Medical Band. It consists of an equilateral L-shaped slot fed by a single coplanar waveguide feed. The slot is manipulated with switches to generate two modes of operation. Each mode corresponds to one of the two states of the switches which result in different L-shaped slots with unequal legs creating patterns that are polarized in perpendicular to each other. The antenna has been shown to perform well near the human body using numerical and physical phantoms. The correlation between the two modes is calculated to be less than 0.04 with 41% and 56% on-body efficiency for each mode. The Specific Absorption Rate is shown to be well below the limit specified in the European Standards through simulations.INDEX TERMS Antenna radiation pattern, glass, slot antenna, wireless body sensor network.

Modern body-centric communication systems require good link quality. Antenna performance is of primary importance when meeting this requirement. This paper contributes a method suited to the difficult task of quantifying antenna performance in a body-centric communications system. In a case study, a planar wrist wearable antenna, which provides radiation pattern switching across the 2.4GHz operating band through an innovative technique that does not require an additional switching mechanism, is benchmarked against a monopole and a patch antenna in a residential setting. The performance of the antenna, and subsequently the benefits of the pattern switching technique, are successfully quantified. The holistic method includes both antenna measurements and channel simulation with ray-tracing. Results are verified against real world measurements.

In order to take full advantage of the benefits to be obtained by using MIMO techniques for mobile communications, it is necessary to use an antenna array which is both compact and also has low mutual coupling between ports. Generally these requirements are conflicting and to achieve them simultaneously is the subject of much research. In this paper a novel design for a two element Cavity Backed Slot (CBS) array is described which has a measured mutual coupling of less than-15dB despite an element spacing of only λ λ λ λ/6. This is achieved by adding a simple and easily manufactured meandering trombone structure to an existing CBS array which carries a portion of the input signal to the feed of the neighbouring element. Measured and simulated results are presented for the behaviour of the antenna and predictions are presented for the achievable channel capacity in several realistic scenarios.