Abstract-The feasibility of sending wireless power to a buried sensor antenna within concrete was studied. A receive patch rectenna with 75.8% conversion efficiency was designed for operation at 5.7 GHz. The received DC power at the rectenna was measured within dry and wet concrete samples with various cover thicknesses and air-gaps. For the rectenna buried within 30 mm of the concrete, the received DC power was 10.37 mW, which was about 70% of the received DC power in free-space.

A CPW-fed inductively coupled bow-tie slot antenna is introduced. The bandwidth reduction for an inductively coupled straight-dipole slot is overcome by utilizing a bow-tie slot. Antennas operating at 2.45 and 5.5 GHz are proposed that have 10 dB return loss bandwidths of 12% and 17%, respectively. Prototype antenna elements and a two-element series-fed array were fabricated and tested to validate performance.

A CPW-fed inductively coupled bow-tie slot antenna is introduced. Several geometric parameters of the antenna were varied to observe the impedance matching between the CPW-feed and the antenna. The inductively coupled CPW feeding mechanism makes the concept suitable for array applications. The bandwidth reduction for an inductively coupled straight-dipole slot is overcome by utilizing an inductively coupled bow-tie slot. Antenna models for operation at 2.45 and 5.5 GHz were constructed and return loss and radiation pattern results were obtained. The proposed antenna provides bandwidths of 8 and 13% at 2.45 and 5.5 GHz, respectively.

Structural health monitoring using embeddable wireless sensors is a promising research area. Once embedded the wireless sensor antenna must operate efficiently in order to support data communication as well as battery charging using an integrated rectifying antenna (rectenna). In this paper the characteristics of an embedded microstrip patch antenna within concrete is studied as function of the air-gap and the concrete dielectric constant and loss tangent.

Abstract-A capacitively coupled polymeric internal antenna is introduced for Bluetooth or GPS applications. Such an antenna can be easily fabricated on a flexible film substrate and attached to the inside surface of the plastic housing of a portable wireless device, such as a PDA. The proposed antenna saves critical space on the printed circuit board (PCB) and eliminates the need for a vertical contact feed. Thus manufacturing is also simplified and cost is reduced. Practical examples of utilizing such a concept for Bluetooth (2.45 GHz) and GPS (1.575 GHz) applications are provided. The antenna system requires a small coupling plate (as small as 4 by 4 mm 2 ) that can be easily surface mounted on a PCB. The solution proposed provides wideband operation satisfying Bluetooth functionality with good radiation pattern and gain.