A wearable wireless inertial sensor node for body motion analysis is designed and implemented. A triaxial accelerometer, a biaxial gyroscope, and a yaw rate gyroscope are employed to sense the accelerations and angular rates of the object attached. These three ICs, a wireless mote, the power circuit, and a modified printed inverted-F antenna are integrated on a four-layer printed circuit board. To achieve the compact size for comfortable wearing, the printed antenna is deliberately designed as small as possible, while maintaining a reasonable antenna performance. The proposed inertial sensor node is also easily adaptable to applications with different power requirements because of the consideration of the periodic and moving-event wakeup in the software design. The static characteristics and Allan deviations of the implemented node are measured and analyzed. The false alarm rate of a moving detection based on Bayes rule is presented and a threshold is suggested. Finally, the raw data of several body motions are measured and those behaviors are observed apparently. The proposed inertial sensor node is compact and easily wearable; hence, it is feasible to be applied to the body motion analysis.

A Wearable Inertial Sensor Node for Body Motion Analysis

Circularly polarized superquadric dielectric resonator antenna is investigated. A single coaxial probe is used to excite circularly polarized patterns. Finite element method is used to analyze the problem. Different aspect ratios of the superquadric dielectric resonator cross section for each squareness parameter for circular polarization are calculated.

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A Single-Feed Cylindrical Superquadric Dielectric Resonator Antenna for Circular Polarization

An antenna for portable radio in which a high gain and a wide band are realized. An inverted L-shaped antenna (10) is a feeding element having one end part connected electrically with one plate surface of a circuit board (12) through a feeding point. The circuit board (12) is the substrate of circuit of a portable radio and connected with circuit components including the inverted L-shaped antenna (10). A planar antenna (14) is provided on the plate surface of the circuit board (12) opposite to the side being connected with the inverted L-shaped antenna (10) and it is a parasitic antenna having an electric length in the longitudinal direction substantially equal to one half of the wavelength of a radio wave through which the portable radio communicates. Dimensions and the mutual distances of the inverted L-shaped antenna (10), the circuit board (12), and the planar antenna (14) are adjusted to specified values, and the self impedances of the inverted L-shaped antenna (10) and the planar antenna (14) are varied along with the mutual impedance of the inverted L-shaped antenna (10) and the planar antenna (14).

Antenna for portable radio

Compact antennas for ultra wide band applications are disclosed The compact antenna may be an elliptic dipole antenna with a poise and counterpoise both having an elliptical shape A substrate may be used to support the poise and counterpoise with the substrate having a closed three-dimensional shape

Compact antennas for ultra wide band applications

An antenna that includes a first plane, a second plane spaced apart from the first plane, a first radiating surface, positioned substantially on the first plane, to act as a poise, a second radiating surface to act as a counterpoise, and an end-feed microstrip positioned on the second plane, wherein the first radiating surface and the second radiating surface are electromagnetically coupled to the end-feed microstrip.

Electromagnetically coupled end-fed elliptical dipole for ultra-wide band systems

Embodiments of a planar antenna suitable for use with a portable device for wireless communications are described. One such embodiment includes a microstrip line coupled to a radiating poise on one side of a circuit board, and a ground plane coupled to a structure on the other side of the circuit board that functions as a coplanar waveguide having an effective length of one quarter-wavelength. A further implementation includes a transformer portion configured and arranged to match the impedance of an RF signal source to the antenna driving impedance.

Patrick J. Conner

Papers

Planar antenna for wireless communications