The bandwidth limitations of resonant, electrically small antennas that fully occupy a spherical volume are well defined by the inverse of the Chu-limit or the lower bound on quality factor. Recently, Gustafsson et al developed lower bounds for the Q of antennas of arbitrary shape. We have previously described antenna designs fully occupying a spherical volume and a cylindrical volume that exhi...

A 3-D beam scanning antenna array design is proposed that gives a whole 3-D spherical coverage and also suitable for various radar and body-worn devices in the Body Area Networks applications. The Array Factor (AF) of the proposed antenna is derived and its various parameters like directivity, Half Power Beam Width (HPBW) and Side Lobe Level (SLL) are calculated by varying the size of the propo...

A full-vectorial integral equation method is presented for calculating near fields and far fields generated by sources in the presence of general finite-sized dielectric structures with cylindrical symmetry. The method is relevant for modeling of a class of antenna designs and some optical components with cylindrical symmetry, e.g., vertical-cavity surface-emitting lasers, microdisk lasers, and...

Suitably shaped metal nanostructures acts as resonant optical antennas that efficiently collect light an confine it to a sub wavelength volume which has been modified by using the dielectric resonators working at optical frequencies. In radio frequencies and microwaves a category of antenna known as dielectric resonator antenna (DRA), whose radiant element is dielectric resonator (DR). In this ...

In this paper we suggest a cylindrical array, which utilizes signal cancellation and sparse element spacing. The array has narrow beamwidth and low sidelobe level. The beamwidth is about 12° for a 35 element array having -20 dB sidelobe level. Omnidirectional coverage area is obtained by a combination of commutation and phasing. The array has less elements and smaller size than a respective arr...

This paper presents an experimental Phased Array Antenna System operating at 10 GHz. Geometry of the antenna array is cylindrical. Antenna element excitation phases are adjusted at the intermediate frequency stage. Antenna element excitation amplitudes are taken to be constant. A least squares technique is used for phase computation and radiation pattern synthesis. The obtained radiation patter...

This paper presents a top-hat sleeve monopole antenna for ultra-wideband (UWB) applications. The proposed antenna comprises a stem, a dielectric coat, and a top hat sleeve. A modal expansion technique used in cylindrical coordinate system is applied to study the impedance and radiation characteristics of the antenna. Influences of varying parameters of the antenna on impedance matching and radi...