Radio frequency identification (RFID) of objects or people has become very popular in many services in industry, distribution logistics, manufacturing companies and goods flow systems. When RFID frequency rises into the microwave region, the tag antenna must be carefully designed to match the free space and to the following ASIC. In this paper, we present a novel folded dipole antenna with a very simple configuration. The required input impedance can be achieved easily by choosing suitable geometry parameters.

A folded dipole antenna for RFID

Apparatus and methods for controlling application of a substance to a substrate involve the use of a gating agent that blocks the substance from or attracts the substance to the substrate. The apparatus and methods may utilize ink jet technology to apply the gating agent directly to the substrate or to an intermediate surface. The gating agent composition includes a nonionic surfactant, and water. The gating agent composition does not contain a discernable amount of dye, pigment or other colorant agent.

Compositions compatible with jet printing and methods therefor

This paper examines the performance of the adaptive array antennas used in digital handset systems by studying the minimum mean square error (MMSE) algorithm at 2 GHz. The array is comprised of multiple quarter-wavelength monopole antennas and planar inverted-F antennas (PIFAs). By calculating the spatial correlation between two different directions, we describe how significant enhancement in the capability of reducing interference signals can be achieved, even when the handset is being held in the vicinity of a human operator in the talking position. Secondly, a computer simulation has been carried out under a flat Rayleigh fading environment with multiple cochannel interference signals, in which the average bit error rate (BER) of the handset adaptive array antenna has been characterized for the coherent detection of phase-shift keyed (PSK) signals. The performance of the handset adaptive array is compared to that of an adaptive array comprising plural parallel half-wavelength dipole antennas that are one half-wavelength apart. The performance was also evaluated with regard to the distance between the handset and the human head for different unequal median values and fading correlations of the received signals. The study has revealed that the adaptive array under consideration has substantial potential, not only to reduce the relative power of interference signals, but also to combat multipath fading of the desired signal by using the spatial diversity function of the MMSE, even in close proximity to a human operator.

Multipath performance of handset adaptive array antennas in the vicinity of a human operator

A multifunction wireless device, a method and system of identifying complexity factors and a method any system of optimizing the geometry of an antenna system using such complexity factors.

Multifunction wireless device and methods related to the design thereof

This study presents a multi-level optimization (MLO) method applied in particle swarm optimization (PSO) to solve a 3-objective optimization problem for an antenna array design consisting of two L-shaped folded monopole antennas (LFMAs) operating in the IEEE 802.11 b/g WLAN band (2400-2484 MHz). The method incorporates a simple concept whereby three sub-objective functions, representing the reflection coefficient S 11, the mutual coupling S 21, and the entire antenna volume of the LFMA array, are minimized one by one in the PSO to obtain an optimal LFMA array configuration that provides reduced size and higher antenna performance. The advantages of the proposed method, both in terms of deriving appropriate optimization results and reducing computational cost for the optimization problem, are demonstrated by comparing its performance with that of a conventional weighted aggregation (CWA) method, and a method using the concept of Pareto dominance (PD). The optimal LFMA array configuration obtained by the proposed method has a 10% resonant bandwidth ( S 11 ≤ -10 dB for 2.32-2.57 GHz), S 21 reduced to less than -15 dB in this band, and an antenna volume that was markedly decreased, to 28.5% of that of the original design.

A Multi-Level Optimization Method Using PSO for the Optimal Design of an L-Shaped Folded Monopole Antenna Array

A unique folded loop antenna for handsets has been analyzed. The folded loop antenna is constituted by the concept of integration, by which the mode increase and small sizing are achieved. It has been shown that the folded loop antenna shaped like a half-wave folded dipole has similar structure as the balanced system and so almost no unbalanced currents flow on the ground plane as well. Thus with this structure, mitigation of the antenna performance degradation due to the body effect can be made possible. Another uniqueness of this antenna lies in the use of a two-wire transmission line for the antenna element. The antenna impedance can be adjusted flexibly by changing the parameters of the transmission line. By this means, matching can be made easy without using a balun.

A folded loop antenna system for handsets

By devising the case shape and antenna placement, it is possible to provide a mobile radio terminal capable of always having a high antenna sensitivity even when the mobile radio terminal is placed in a pocket of user's clothes. In this mobile radio terminal (1), the case (2) has a plane A having a flat shape and a plane B having a protruding portion (2a) at a part of the center portion or the entire portion. An antenna element (3) is placed on the protruding portion (2a) of the plane B in parallel to the plane A. Since the plane B has a protrusion or a curved shape, when the user puts the terminal into the pocket of his/her clothes, he/she unconsciously puts the terminal with the plane A in contact with his/her body side. Accordingly, the mobile radio terminal (1) is always contained in the clothes pocket with the antenna element (3) positioned at a distance from the user's body, i.e., at the farthest position from the user's body. Consequently, the electromagnetic wave of the antenna element (3) is not affected by the user's body and the mobile radio terminal (1) can always assure a preferable antenna gain and a high antenna sensitivity.

Mobile radio terminal

This study introduces and analyzes the fundamental performance of an L-shaped built-in folded monopole antenna (LBFMA). Device performance is also compared with those of planar inverted-F antenna (PIFA) configuration. The results may be used as a first step in the antenna array design for multiple-antenna devices applied to MIMO applications.

Characteristics of L-shaped built-in folded monopole antenna for handsets

The purpose of this study is to investigate experimentally the performance of adaptive array antennas in mobile handset terminals using the RLS algorithm as the minimum mean square error (MMSE) in the 2 GHz band. Particular emphasis is placed on how well handset AAA works in a practical environment, where the user's body has an influence on performance. In this paper, two types of dual-element AAA model have been derived, Model A which is a simple model, and Model B which is a more realistic model. In Model A, for the basic study, the array is comprised of two dipole antennas placed close to a cylinder shape phantom. In Model B, for the more practical study, the array is comprised of quarter-wavelength monopole antenna and a planar inverted-F antenna (PIFA), and is placed close to a realistically shaped human phantom. By estimating the correlation between the bit error rate (BER) and the received pattern of the antenna, we describe how a significant enhancement in the ability to reduce interference signals can be achieved, even when the handset is used in proximity to a human operator in a talk situation

Experimental study of the performance of handset adaptive array antennas in the vicinity of a human operator

This paper deals with built-in folded dipole antenna (BFDA) and the built-in folded monopole antenna (BFMA) have been introduced and analyzed. Those antennas have folded dipole and monopole element, respectively. They can be built in a small volume and placed very close to the rectangular ground plane (GP), which represents a shielding plate used in the handset unit. A folded loop is essentially a two-wire transmission line, folded at about a quarter-wavelength to foam an equivalent half-wave folded dipole, and yet appears as a one-wavelength loop antenna, from which the antenna is referred to as a folded loop. In this paper, the parameters related to the feed structure are optimized in order to obtain a wider bandwidth for the BFDA system, and the fundamental performances are analyzed in both theoretically and experimentally.

Y. Koyanagi

Papers

A folded loop antenna system for handsets

Mobile radio terminal

Characteristics of L-shaped built-in folded monopole antenna for handsets

Experimental study of the performance of handset adaptive array antennas in the vicinity of a human operator

Wideband characteristics of built-in folded dipole antenna for handsets au11|^Atsushi Kajitani