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Design of dual/tri-frequency impedance transformer with ultra-high transforming ratio
In this article, the design of a new dual-band impedance transformer with ultra-high transforming ratio UHTR is presented. The closed-form expressions are derived analytically using a lossless transmission-line theory. To practically validate the proposed design concept, two examples of dual-band transformer working at smaller and larger frequency ratios are designed for different load impedance o
A performance-enhanced planar Schottky diode for Terahertz applications: an electromagnetic modeling approach
In this paper, we present the electromagnetic modeling of a performance-enhanced planar Schottky diode for applications in terahertz (THz) frequencies. We provide a systematic simulation approach for analyzing our Schottky diode based on finite element method and lumped equivalent circuit parameter extraction. Afterward, we use the developed model to investigate the effect of design parameters of
Microstrip band-pass filter with ?67 dB stop band up to 8.8 times the pass-band center frequency
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 miniaturized directional antenna for microwave breast imaging applications
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
A compact elevated CPW-fed antenna with slotted ground plane for wideband applications
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
Correlation coefficient calculations for MIMO antenna systems: a comparative study
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
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
Efficient design of axially corrugated coaxial-type multi-band horns for reflector antennas
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
Compact multi-layer -way power divider with closed-ring-shaped isolation network
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
Wide-stopband bandpass-filtering power divider with high-frequency selectivity
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