In this paper, an indoor repeater antenna with high isolation for WCDMA application is proposed. The designed repeater has very small separation of 20 mm between the donor and server antennas. The antenna has two resonance frequencies to cover the WCDMA band from 1.92 GHz to 2.17 GHz. The fabricated antenna has VSWR below 1.5, gain over 8 dBi, and isolation between server and donor antennas less than -80 dB in the WCDMA band.

A composite patch array antenna with built-in polarizer has been developed to reduce road clutter noise by 20 dB for 76 GHz automotive radars. A polarizer is placed in front of Tx and Rx patch arrays within their reactive near-field region to suppress cross-polarized sidelobe radiation from their feeding lines while maintaining a low-profile characteristic with 4 mm thickness. Additional metal-lined absorbers within the composite antenna structure, while terminating cross-polarized waves undesirably excited by the patch arrays, also serve as miniature clutter plates to further reduce sidelobes toward the road surface. The resultant composite antenna achieved sidelobe levels of -45 dB, a 20 dB improvement over standard patch arrays, at elevation angles close to 90.

This paper proposes a new circuit-fed 2-D amplifying array architecture using the multi-ported aperture-coupled patch antennas. The power distribution achieved by this array is formed by stacking three kinds of basic cells repeatedly. Each cell, which serves as a radiator and also a power relay, has a multi-ported patch antenna and one or two amplifiers. The signal transmission coefficient of the cell from the input port to the output port is designed with a power level of 0 dB and a phase of 360. An X-band 4 3 element array with uniform amplitude distribution is demonstrated. The measured results, such as the antenna gain and the radiation patterns, agree very well with the predicted ones, due to the precision design of the basic cells. The measured gain of the antenna array is 27.7 dBiA at the frequency of 10.4 GHz on the H-plane, with a half-power beamwidth of 14 in the H-plane and 16 in the E-plane.

For the digital watermarking patchwork algorithm originally given by Bender et al., this paper proposes two improvements applicable to audio watermarking. First, the watermark embedding strength is psychoacoustically adapted, using the Bark frequency scale. Second, whereas previous approaches leave the samples that do not correspond to the data untouched, in this paper, these are modified to reduce the probability of misdetection, a method called full index embedding. In simulations, the proposed combination of these two proposed methods has higher resistance to a variety of attacks than prior algorithms.

As one of the technologies for the retrieval of desired contents over large-scale networks, multi-agent systems are receiving much attention. Since there are too many contents on the network to search them all exhaustively, some applications on multi-agent systems have time constraints, that is, they must obtain a result by a given deadline. To find better results for such applications, it is important for the agents to complete their tasks on as many nodes as possible by the deadline. However, most existing agent systems using round robin scheduling disciplines do not take time constraints into account. Therefore, agents are likely to miss their deadlines on many nodes. In this paper, we propose an efficient agent-dispatching method for time-constrained applications. This method decides creation and migration of a clone agent according to the estimated value of the number of agents that would have completed their tasks by the deadline. The results of our performance evaluation show that the proposed method increases the number of agents that complete their tasks.

This letter reports a high-performance Ka-band equilateral triangular microstrip patch (ETMP) antenna suspended on a thin dielectric membrane. The membrane is released using a silicon bulk-micromachining technique. A set of closed-form expressions to calculate the resonant frequency of the proposed antenna on the micromachined substrate is also presented. The measured performance of the antenna structure is verified using the finite element method (FEM) based Agilent High Frequency Structure Simulator (version 5.5). The fabricated antenna exhibited a wide -10 dB return loss bandwidth of 1.2 GHz at 35.4 GHz. The measured antenna cross-polarization level is less than -15 dB in both the E- and H-planes.

Due to the demand of dual-band modern wireless communications, this paper presents a dual-band patch antenna for IEEE802.11 a and g wireless local area network (WLAN) system. The antenna has bidirectional patterns that can be switched by an RF switch to select the feeding probe positions. The 2.4 GHz and 5.2 GHz patches are stacked on a ground plane and are matched to the RF switch by open stubs. Analysis and design are illustrated and throughput improvement is demonstrated in an indoor environment.

In this study, a wideband 3/4 elliptical ring patch operating millimeter wave band is proposed. Using this structure, the patch antenna is designed for circular polarization and wide-band operation at about 32.1-40 GHz for millimeter wave communication. Simulated and measured results for main parameters such as voltage standing wave ratio (VSWR), impedance bandwidth, axial ratio, radiation patterns and gains are also discussed. The study shows that modeling of such antennas, with simplicity in designing and feeding, can well meet the requirements of millimeter-wave wireless communication systems.

In this paper, small sized arrays with a few elements are investigated. The antenna diameter is assumed to be less than 3λo. The focus of this paper is to compare the gain characteristics of a triangle arrangement with these of a uniform arrangement. The method of moments is used to calculating the gain characteristics. It is shown that the triangle arrangement is not always sufficient to obtain maximum gain for a small-sized antenna with only a few elements. Also, the type of antenna element used greatly influences the required number of elements and the element configuration.

In this paper, the authors propose a circularly polarized printed antenna combining a slot array antenna and a patch antenna, with dual-band operation. The proposed antenna has good isolation performance, is compact, and has simple configuration. This antenna is composed of two parts, a patch antenna (for Rx) on the top, and a slot array antenna (for Tx) on the bottom, respectively. The element layout is such that the lower radiation element is not hidden by the upper one for wide observation angle. Hence, both radiation elements can naturally radiate the targeted polarization. Both slot array and patch antenna are fed by electromagnetically coupled microstrip line feed. With such a configuration, it is possible to efficiently obtain good isolation characteristics for both frequency bands. Furthermore, this antenna can be easily composed and it is not necessary to use any feeding pin or via hole. The target of this antenna is mobile communications applications such as mobile satellite communications, base-station of wireless LAN, etc. Here, the design techniques are discussed and the numerical and experimental analyses are presented.

An electrooptic near-field mapping system based on a gain-switched distributed feedback (DFB) pulsed laser and a CdTe electrooptic crystal was used for characterizing stationary and transient near-field patterns of conventional and uniplanar compact photonic band gap (UC-PBG) patch antennas. Effect of the UC-PBG structure on reduction in surface waves in the UC-PBG patch antenna was experimentally verified by comparing stationary and transient near-field measurement of the conventional and UC-PBG patch antennas.

Two compact and low loss dual-mode filters are proposed by using degenerate modes of slotted triangular microstrip patch resonators. The geometrical size and radiation loss of the triangular patch are reduced simultaneously by loading both horizontal and vertical slots. The resonant frequencies of two degenerate modes can be easily controlled by varying the dimensions and positions of the slots. A two-pole dual-mode filter operating at 3.94 GHz with a fractional bandwidth of 4.3% is designed, fabricated, and measured. The measured results verify well the theoretical predictions.

In this paper, we propose multicast technique in order to reduce the required network bandwidth by n times, by merging the adjacent multicasts depending on the number of HENs (Head-End-Nodes) n that request the same video. Allowing new clients to immediately join an existing multicast through patching improves the efficiency of the multicast and offers services without any initial latency. A client might have to download data through two channels simultaneously, one for multicast and the other for patching. Each video stream is divided into blocks which are the same size of multicast grouping interval Im. Blocks then are evenly distributed into different HENs according to their popularity and the order of requests. Only when the playback time exceeds the amount of cached video data, server generates new multicast channel. Since the interval of multicast can be dynamically expanded according to the popularity of videos, it can be reduced the server's workload and the network bandwidth. We adopt the cache replacement strategy as LFU (Least-Frequently-Used) for popular videos, LRU (Least-Recently-Used) for unpopular videos, and the method for replacing the first block of video last to reduce end-to-end latency. We perform simulations to compare its performance with that of conventional multicast. From simulation results, we confirm that the proposed multicast technique offers substantially better performance.

This investigation proposed a novel dual-mode circular patch bandpass filter (BPF) with enhanced stopband performance. The novelty of the proposed structure is to use a pair of square etched areas acting as a perturbation element on the circular patch resonator such that two split modes are coupled and the filter structure can be reduced. The coupling coefficients of two split modes are obtained. To improve the stopband performance, a pairs of H-shaped defected ground structure (DGS) cells are used below the input/output port to suppress the spurious response of the proposed BPF. The equivalent circuit of the DGS cell is discussed and the relations between bandstop characteristic and the suitable DGS dimensions are also investigated. The proposed BPF is demonstrated with a central frequency fo = 2.2 GHz, a 3-dB fractional bandwidth of 8% and a wider stopband of -35 dB from 2.5 to 6 GHz. Measured results of experimental filter have good agreement with the theoretical simulated results.

A magnetic field probe consisting of a LiNbO3 optical waveguide modulator and a loop antenna element was developed to enable accurate measurement of magnetic near-fields in the gigahertz range. The invasiveness of the probe was assessed by using it to measure the magnetic field distribution above a patch antenna operating at 2.49 GHz. The measurements were compared with those obtained using a shielded loop probe. The experimental results obtained using the probe were also compared with simulation results obtained using a finite-difference time-domain (FDTD) method. The overall results indicated that the optical waveguide probe was capable of accurately measuring magnetic near-fields with low disturbance of the measured fields.

An aperture-coupled patch antenna on a modified-shape groundplane is proposed in this paper. It is applicable to the H-plane array without perpendicular feed structure. Availability of the depth-area under antenna-substrate is effectively improved by using radiation from the T-shaped element, while the advantage of aperture-coupled antenna in suppressing the spurious-feed-network radiation remains effective. Basic characteristics of the antenna are investigated through the numerical examination by using FDTD-method. As a result, the increased bandwidth is also obtained, which is observed as dual-resonance characteristics due to the T-shaped element and the aperture-fed patch. A H-plane array of the proposed element incorporating a probe-fed patch antenna is also presented to show an potential as a polarization diversity antenna.

We proposed 3D-mesh watermarking using CEGI distribution that has robustness against mesh simplification, cropping, vertex randomization, and rotation and which does not need the original model for detection the watermark. The proposed algorithm embeds the watermark bits into the normal vector direction of meshes that are mapped into the cells that have the large magnitude of complex weight in patch CEGIs. The watermark can be detected based on the known center point of each patch and the rank table of the cell in each patch instead of original model. Experimental results verified that the proposed algorithm has robustness against the attacks.

This paper discusses the design, fabrication, and measurement of four L-shaped-slot microstrip patch antenna for HiperLan2. The prototype consists of four L-shaped slots. To obtain suitable bandwidth, the form layer is inserted between the ground plane and substrate. The design considers various important factors that include the four L-slot's length, width, position, air-gap height, and feed-point position. Once these factors are optimized, a four L-shaped slot microstrip patch antenna is fabricated and measured. The measured results of the fabricated four L-shaped slot antenna are as follows: resonant frequency is 5.35 GHz, bandwidth is approximately 8.1% (VSWR < 2.0), and gain is 8-9 dBi. The experimental far-field patterns are stable across the pass band. The 3 dB bandwidth in Elevation and Azimuth are 69and 62, respectively.

In this study, a multiple U-shaped slot microstrip patch antenna for application to the 5 GHz band is designed and fabricated. To obtain sufficient bandwidth in the operating band, foam is inserted between the substrate and ground plane, the type of form is styrofoam, the coaxial probe source is used, and the position of the probe shift is adjusted from the center to the left. The measured result (5.02-5.955 GHz) of the fabricated antenna satisfies the conditions of VSWR < 2.0 in 5 GHz band (5.15-5.35 GHz, 5.47-5.725 GHz, 5.725-5.825 GHz), gain of 3.88-9.28 dBi, and broad radiation pattern.

This paper describes the choke-loaded patch array antenna for use in the IMT-2000 repeater systems. The choke structure of the 4-element array is designed by means of an electromagnetic analysis. A high front-to-back (FB) ratio is required for suppressing mutual coupling in order to stop the oscillation caused by the interference waves between a transmitting and receiving antenna. The suppression of the FB ratio by a choke is limited in the case of the 16-element array because its side lobe level is large. In this paper, we examine the effect of suppressing the mutual coupling using a binomial array.