IEEE Transactions on Antennas and Propagation

A very unique phenomenon of circular patch antennas (CPA) for obtaining equal E- and H-plane co-polarization patterns, using varying substrate permittivities and ground plane sizes, is investigated in this paper. Pattern equalization is studied for the dominant and the first few higher order modes of the circular patch antenna, using different substrate permittivities (εr) for th... View full abstract»

Investigation results of a new conical-shape radiation-pattern antenna based on a hybrid technique are presented. A circular-ring patch antenna excited with the dominant mode TM02 is integrated with a monopole antenna, offering two distinct operating bands. The coupling effect of the higher-order modes of the monopole and the circular-ring patch create a third operating broad band. Usin... View full abstract»

Analysis is performed for a two-arm round spiral structure excited in phase, where the arms near the antenna center are backed by a small round disc. This spiral antenna has a frequency range where the radiation is bidirectional, having patterns symmetric with respect to the antenna plane. Subsequently, the bidirectional radiation is transformed into a unidirectional conical beam by backing the sp... View full abstract»

A class of printed antipodal drop-shaped dipole antennas for wideband wireless communication systems is presented. A suitable shaping of the feeding lines and radiating arms is adopted to achieve an operating bandwidth larger than 10 GHz useful to meet the requirements of several wireless communication standards. A thin, low permittivity dielectric substrate is used to reduce the excitation of sur... View full abstract»

The relative long wavelength of FM radio signals compared to a typical vehicle length means that a window glass-embedded FM band antenna couples strongly to vehicle structural components. Numerical simulations have been conducted to identify which key structural components in a full-size SUV have an effect on the average antenna gain patterns. In particular, it was found that the rear hatch and th... View full abstract»

The design procedure, realization and measurements of an implantable radiator for telemetry applications are presented. First, free space analysis allows the choice of the antenna typology with reduced computation time. Subsequently the antenna, inserted in a body phantom, is designed to take into account all the necessary electronic components, power supply and bio-compatible insulation so as to ... View full abstract»

We present a flexible folded slot dipole implantable antenna operating in the Industrial, Scientific, and Medical (ISM) band (2.4-2.4835 GHz) for biomedical applications. To make the designed antenna suitable for implantation, it is embedded in biocompatible Polydimethylsiloxane (PDMS). The antenna was tested by immersing it in a phantom liquid, imitating the electrical properties of the human mus... View full abstract»

A passive UHF RFID tag design is presented in the form of a transfer patch similar to a temporary tattoo that is mountable directly onto the skin surface. The transfer tag is suitable for monitoring of people over time in mission critical and secure environments. The antenna reactance is first calculated to conjugate match the measured RFID chip reactance and then full wave simulation is used to d... View full abstract»

In this paper, we explore using carbon nanotube (CNT) composite material for wideband millimeter-wave antenna applications. An accurate electromagnetic model of the composite antenna is developed using Microwave Studio for numerical analysis. Good agreement between computed and measured results is shown for both copper and CNT antennas, and their performance is compared. The CNT antenna shows stab... View full abstract»

The creation of a magnetic boundary condition into the plane of symmetry in a radiating ground plane of a portable device is proposed to enhance its radiation efficiency and bandwidth. This magnetic boundary condition is achieved by exciting the antenna through symmetrical feeding. A novel antenna consisting of a symmetrical folded dipole is presented in order to exemplify how a broad bandwidth an... View full abstract»

Low-profile antennas comprising a horizontal dipole above a high-impedance surface are analyzed. The emphasis of this paper is on the additional resonances of the radiating structure caused by surface waves propagating on the high-impedance surface. It is shown that such resonances can be favorably used for broadening the bandwidth of the antenna. The phenomenon is thoroughly modeled by exploiting... View full abstract»

With a direct integration of a field effect transistor (FET) into a C-shaped ring radiator, a novel miniaturized self-oscillating annular ring active integrated antenna is proposed and investigated in this paper. The direct integration approach provides a solid basis for the miniaturization while the slow-wave loading effect from the unstable transistor further enhances the reduction ratio. It mak... View full abstract»

This paper presents balanced-fed and fork-fed aperture-coupled patch antennas and 16-element arrays suitable for broadband millimeter-wave communications. The antennas are realized in a multi-layer organic package structure, to which RF integrated circuits can be integrated. To improve antenna bandwidth and radiation efficiency, an air cavity is used, resulting in a superstrate planar patch-antenn... View full abstract»

A three-dimensional packaging solution is introduced for wireless sensor network nodes at microwave frequencies. The package has a cubic geometry with radiating antennas on its surrounding faces. The cube which is called e-CUBE is designed in such a way that its radiation pattern resembles that of a simple dipole. The antenna is designed in a modular way and the final structure has a return loss b... View full abstract»

On-chip antennas are demanded to further lower the cost of wireless CMOS ICs. The low resistivity of silicon substrates is a major obstacle to fabricate high-gain on-chip antennas. We placed an artificial dielectric layer (ADL) between an antenna and Si substrate to improve the antenna gain. A half-wave dipole-antenna that has ADL was designed and fabricated using a CMOS-compatible process with on... View full abstract»

A compact printed filtering antenna with high band-edge gain selectivity is presented. Occupying about the same substrate area as a conventional antenna, the proposed structure not only serves as a radiator but also a second-order bandpass filter, with one filter pole provided by a Γ-shaped antenna and the other by a newly proposed coupled line resonator. High band-edge selectivity is achie... View full abstract»

The efficiency of an electrically-small antenna may be measured conveniently by placing it in a conducting Wheeler Cap. This paper presents a composite equivalent circuit that models an antenna both inside a spherical cap and also radiating into free space. The circuit is used to show how the measurements are affected by the antenna size, efficiency, and polarization (TE or TM), the cap radius, an... View full abstract»

Connected arrays constitute one of the most promising options for wideband phased arrays. Like most phased arrays, they are designed using infinite array theory. However, when finiteness is included, edge effects perturb their behavior. These effects are more severe when the arrays are designed to operate over very broad frequency ranges, since the mutual coupling between the elements facilitates ... View full abstract»

Many near-field source-localization algorithms intentionally simplifies the exact spatial geometry among the emitter and the sensors, in order to speed up the signal-processing involved. For example, the Fresnel approximation is a second order Taylor-series approximation. Such intentional approximation introduces a systemic error in the algorithm's modeling of the actual objective reality from whi... View full abstract»

The analysis of a dielectric stop band filter is performed in terms of modified dielectric frequency selective surfaces (MDFSS). In fact, an MDFSS can totally reflect the power if a plane wave impinging on it excites a leaky wave, acting thereby as a stop band filter. Its relative bandwidth is about 0.5-0.7% and it can be enlarged by cascading MDFSSs. The development of such a cascade is analyzed ... View full abstract»

A double periodic composite right/left handed transmission line (DP-CRLH TL) is proposed and analyzed based on transmission line theory. Besides the composite right/left handed property, a new leaky-wave radiation is observed at a lower frequency with narrow bandwidth. Dispersion characteristics of the structure are obtained and the cutoff frequencies are investigated by changing the ratio of indu... View full abstract»

A new type of one-dimensional leaky-wave antenna (LWA) with independent control of the beam-pointing angle and beamwidth is presented. The antenna is based on a simple structure composed of a bulk parallel-plate waveguide (PPW) loaded with two printed circuit boards (PCBs), each one consisting of an array of printed dipoles. One PCB acts as a partially reflective surface (PRS), and the other groun... View full abstract»

It is shown, using three specific examples-a series fed patch (SFP) array, a phase reversal (PR) array and a composite right/left-handed (CRLH) antenna-that one-dimensional periodic leaky-wave antennas scanning through broadside build a class of leaky-wave antennas sharing qualitatively similar and quantitatively distinct dispersion and radiation characteristics. Based on an equivalent transmissio... View full abstract»