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Magneto-elasto-electric (ME) coupling heterostructures, consisting of piezoelectric layers bonded to magnetostrictive ones, provide for a new class of electromagnetic emitter materials on which a portable (area ~ 16 cm2) very low frequency (VLF) transmitter technology could be developed. The proposed ME transmitter functions as follows: (a) a piezoelectric layer is first driven by alternating current AC electric voltage at its electromechanical resonance (EMR) frequency, (b) subsequently, this EMR excites the magnetostrictive layers, giving rise to magnetization change, (c) in turn, the magnetization oscillations result in oscillating magnetic fields. By Maxwell’s equations, a corresponding electric field, is also generated, leading to electromagnetic field propagation. Our hybrid piezoelectric-magnetostrictive transformer can take an input electric voltage that may include modulation-signal over a carrier frequency and transmit via oscillating magnetic field or flux change. The prototype measurements reveal a magnetic dipole like near field, demonstrating its transmission capabilities. Furthermore, the developed prototype showed a 104 times higher efficiency over a small-circular loop of the same area, exhibiting its superiority over the class of traditional small antennas.

A class of popular linearly polarized slotted antennas are compared with respect to their RF mechanism, radiation mechanism, impedance matching, and cross polarization characteristics for wireless communication frequency band 1.9–2.4 GHz.It is found that C‐shaped and double C‐shaped patch antennas, even though miniaturized, suffer from narrow bandwidth and high cross polarization level, due to its orientation of slot. U‐slotted and E‐shaped patch antennas show high bandwidth with minor penalty in size and cross polarization level. In order to understand the effect of slot on the radiation in these antennas, a novel strategy of looking at the near‐field of these antennas has been presented. These near‐field plots are analyzed to explain certain far‐field radiation characteristics in these antennas such as‐ cross‐pol level. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1746–1757, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26894

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In this paper, a compact and low-profile proximity-fed textile-based antenna with robust performance and improved bandwidth is proposed for body-area network (BAN) applications. The employed proximity-fed antenna differs from traditional wearable antennas in the sense that it not only exhibits improved bandwidth but also a reduced footprint. The proposed antenna also possesses an extreme robustness when subject to structural deformation and human body loading effects. In addition, the impact of the uncertainty in the dielectric constant (a characteristic associated with most textile material systems) is investigated for the first time. Experimental results show that the proposed proximity-fed antenna outperforms wearable antennas that employ more conventional feeding methodologies. The antenna was fabricated using two different flexible textile-based material systems (i.e., one printed and one embroidered). The advantages and disadvantages of each fabrication approach are discussed. The proposed antenna is characterized in free-space and on a human body, yielding robust performance in both cases. INDEX TERMS Antenna, textile antennas, embroidered, screen printing, wearable application.