International Journal

Step-impedance resonators and step-impedance capacitor coupling pads are introduced to microstrip band-pass filters to suppress spurious stop-band responses up to the ninth order, thereby providing a very wide stop band. Combined with improvements in existing suppression techniques, the overall suppression in one of the filters, with 1 GHz center frequency and 42% bandwidth, is ?54 dB, up to 8.9 G

A novel compact directional antenna with improved gain is proposed for microwave breast imaging (MBI) applications. The radiating fins are modified by etching several slots to make the antenna compact and enhance antenna performance in terms of bandwidth, gain, efficiency, and directivity. Several parameters are studied and optimized to frequency from 3.1 to 6.5 GHz, which is typically used in the

In this paper, a miniaturized elevated-coplanar-waveguide-fed antenna with a slotted ground plane is proposed. This antenna has a compact size of 25 mm × 25 mm × 1.6 mm where the ground plane is reduced by etching a trapezoidal slot along with two extended slits. A ?10 dB wide-impedance bandwidth of 126% ranging from 2.8 to 12.4 GHz is achieved for the proposed antenna. The proposed antenna is suc

The correlation coefficient () is an important metric for the evaluation of multiple-input?multiple-output (MIMO) antenna systems because it describes the relationship between the channels in a particular propagation environment. Highly correlated channels will degrade the MIMO system performance. Various methods to calculate are analyzed in this work using three different types of antennas with

A novel uniplanar wideband magneto-electric dipole antenna element is proposed in this paper. The proposed antenna is composed of the conventional bow-tie radiation patch as an electric dipole, a semi-circular loop, which works as a magnetic dipole, a coplanar ground plane, two directors with different lengths for enhancing gain, and a microstrip-to-coplanar stripline transition balun. The designe

A highly efficient design procedure for dielectric-loading multi-band coaxial-type feed antennas is proposed in this paper. Cylindrical modal matching method is employed for generalized scattering matrix calculation inside the feed, while spherical wave expansion is adopted for the feed aperture discontinuity in consideration of the outer shape. Closed-form scattering matrices with respect to diff

A compact multi-layer N-way power-dividing structure with good isolation and output return loss performance is proposed. The isolation network is circularly distributed that constitutes a closed ring-shaped architecture. The equivalent circuit model is given and the [S] matrix is developed to analyse and design the power-dividing structure. Finally, a six-way power divider centered at 2.1 GHz is d

A wide-stopband bandpass-filtering power divider with high-frequency selectivity has been proposed in this paper. The input and output feeding lines and eight 1/4 wavelength resonators are used to realize the signal transmission. In order to obtain good frequency selectivity, source-load coupling transmission path is used to generate transmission zeros near the passband. A four-way power divider w

In this paper, we designed and developed a novel internal compact printed loop antenna for WWAN/WLAN/ISM/LTE smartphone applications. The proposed antenna is composed of a meander loop antenna and a capacitively coupled feeding line. It has a planar structure, with an overall dimension of 120 × 60 mm, the antenna portion occupying a size of 20 × 60 mm, which makes it suitable for practical smartph

An axially slotted cylinder coated with two different types of inhomogeneous coating layers is considered. These inhomogeneous coatings have decreasing permittivity profiles. The effects of various parameters of these coatings upon the gain pattern have been investigated using numerical simulations. It is studied that the gain at certain observation angles can be enhanced or diminished by controll