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In this paper the classical boundary value approach employing the separation of variable technique is used to analyze the properties of elliptic dielectric resonators. In this approach, the fields inside the resonator are expanded in terms of Mathieu and modified Mathieu functions. Numerical results are given for resonant frequencies of different modes as well for field distributions inside the resonator.
A new phase shifter using Substrate Integrated Waveguide (SIW) scheme combined with a post-based technique is presented. Phase shifting is achieved by changing the diameter and the position of inductive posts inserted in the SIW substrate. Simulations were carried out using one post, and two posts. Results have shown a good agreement with the theory. To prove the concept, prototypes have been fabricated...
In this paper, a model for the analysis of a non-uniform multi-conductor transmission-line (MTL) system consisting of a bundle of twisted-wire pairs (TWPs) in the presence of electromagnetic interference (EMI) is presented. The objective of such a model is to analyze the susceptibility of TWP bundles to EMI in digital subscriber line (DSL) communication systems. In the past, crosstalk noise in TWP...
This paper addresses a two-dimensional inverse scattering numerical technique for microwave imaging for breast cancer detection. We present an accurate and efficient way to obtain the location, shapes, and dielectric properties of malignant tumors inside the body. The accuracy of the reconstructed image is achieved because the dispersion properties and spatial heterogeneous characteristics of the...
It has been previously demonstrated in optical fiber that superimposed chirped gratings can be used to implement multi-frequency transmission filters. In this paper, we propose an equivalent electrical implementation of this structure for use in microstrip technology. In an analogous fashion to an optical fiber grating, we modulate the strip-width of a 50-ohm microstrip according to the sum of two...
Ultrawideband (UWB) systems have attracted great attention in recent years with their potential to support the large data bandwidths of modern media streams. To meet these needs, early UWB antenna designs have been rediscovered and improved upon, and a new generation of UWB antenna designs is emerging. This talk will present a historical introduction to UWB antennas. The importance of learning the...
Statistical models, often calibrated by measurements offer a straightforward way to characterize a wireless channel transfer function and associated effects such as signal fading and multi-path propagation [1]. On the other hand, site-specific models, estimate channel transfer functions taking into account the important effect of such parameters as material and geometric properties of the channel...
Due to the frequency dependence of phasing mechanisms applied in planar printed reflectors, such antennas are prone to beam squint as the frequency is scanned within the operating band. A novel technique is introduced in this paper to cancel the beam squint due to frequency sweep. Another reflector is used to cancel the beam squint within the operating band. The results are compared with the beam...
The Finite-Difference Time-Domain (FDTD) technique [1] has been extensively employed in the modeling of microwave and optical structures, due to its simplicity and versatility. However, these FDTD qualities are partially compensated by the stability and numerical dispersion limitations on the choice of the cell size and the time step of the method, that render its application to complex and/or electrically...
Working with RF has been a passion of mine ever since I learned how to grab a soldering iron by the right (EM) has held my attention for the last two decades. Gradually, as I started playing with Maxwell's equations back in the “good old days,” I began wondering about this Maxwell fellow (Figure 1). Historians acknowledge him to be the most important physicist of the 19th century, the equal of Einstein...
A new multi-band microstrip patch antenna element with three folded shaped slots and two coaxial feeds is presented. The designed antenna covers frequency bands ranging from GPS (1.575 GHz) to WLAN, 5.8 GHz and new DSRC, 5.9 GHz. The antenna design has been optimized to provide desired performance in GPS (1.575) GHZ, GPRS (1.85 GHz), WLAN (2.4 GHz), WLAN (5.8 GHz), and DSRC (5.9 GHz). The antenna...
In this paper, a new compact single-layer circularly polarized microstrip patch antenna has been proposed on a relatively thin substrate to achieve three operating frequency bands centered at 1.5 GHz 2.75 GHz and 3.3GHz, respectively. To increase the bandwidths of the three operating frequency bands, multiple resonances technique was used. The simulation results show that 10-dB impedance bandwidths...
This paper presents two different schemes for aperture truncation mitigation when computing the far-field of a planar aperture field distribution. The first scheme is ad-hoc while the second is an adaptation of Papoulis' scheme. As an application, these schemes are used to improve the accuracy in computing numerically the values of the scattering coefficients for an infinite-size lossless homogeneous...
This paper reports propagation characteristics estimated from quasi-simultaneous channel measurements centered at the VHF frequencies 37.8, 57.0, and 77.5 MHz. The measurement experiments were conducted with low antenna heights (2 m) for both the base and mobile terminals and are therefore considered applicable to tactical and emergency communication scenarios. Multipath-induced time dispersion and...
Modeling of the power distribution network (PDN) and prediction of the power/ground noise or simultaneous switching noise are important topics in simulation and design of the modern electronic systems. In this paper, fast models for parallel-plate PDNs are developed by using the cylindrical wave nature of the excited noise. The models are portable to commercial circuit simulators enabling predication...
In this paper, the reflection and transmission properties of reinforced concrete are investigated by using a two-dimensional (2D) Method of Moments/Green's function (MoM/GF) model for an array of parallel circular cylinders inside a lossy dielectric slab. In doing so, a thin wire grid is used to model each thick circular cylinder subject to the “same surface area” rule of thumb. As a result, this...
Hybrid methods which combine the Moment Method (MM) with high frequency techniques such as Geometrical Theory of Diffraction (GTD) or Physical Optics (PO) have been the subject of research for many years. Ray-based hybrid methods are useful for problems involving a small object such as an antenna located in front of a large screen for which canonical asymptotic solutions are available. In the past,...
The Talbot effect has been previously examined in the millimeter-wave band. This paper presents an experimental investigation into the application of the Talbot effect to perform millimeter-wave power amplification at 30 GHz. Power splitting and combining using the Talbot effect holds the potential for very high power handling capability and efficiency.
In this paper, a new analytical method called Staircase Approximation is presented for static analysis of structures with arbitrary shapes. As an example, this method has been used to obtain the potential distribution of V Transmission Line. The complex boundary of this structure is subdivided into an arbitrary number of uniform (or non-uniform) steps, and then 2-D Laplace's equation has been solved...
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