Analysis and Two-Dimensional Modeling of Directional Coupler Based on Two Coplanar Lines

This chapter is dedicated to physical modeling and numerical characterization of directional coupler based on two coplanar lines using the general theory of coupled lines. The modeling in this chapter is two-dimensional due to the chosen numerical method (MOMs), for that purpose the analysis is divided into steps, we started by analyzing and modeling a micro-coplanar line in the quasi-TEM approximation using Green’s functions and the integral equation method then we conclude by using the telegraphist equations and the results of the first step to modeling a couple of micro-coplanar lines

Ultra-broadband high efficiency mode converter

In this paper we develop a small-sized mode converter with high performance, high conversion efficiency and instantaneous bandwidth as high as 55%. This mode converter transforms energy from the TM01 first high-order mode towards the fundamental TE11 circular waveguide mode. The proposed structure increases the free spurious operating bandwidth in comparison with the existing results in literature. An X/Ku-bands experiment prototype unit was designed, ensuring practical return losses better than 28 dB and insertion losses less than 0.1 dB (conversion efficiency > 98.8%) within the entire frequency bandwidth ranging from 9.25 GHz to 16.25 GHz. The presented architecture offers useful features such as very wide bandwidth, small size, easy achievement as well as excellent performance, which makes it very suitable for High-power microwave (HPM) sources that generate the TM01 circular waveguide mode. In these cases the TE11 mode is needed since it has a convergent radiation pattern able to drive conventional antennas. Moreover, this compact concept is fully scalable to any millimeter frequency band

A miniature microstrip patch antenna array with defected ground structure

The aim of this work is to miniaturize a microstrip patch antenna array resonating at 10 GHz. It presents an improved method of size reduction of a microstrip antenna array with circular polarisation using Defected Ground Structure (DGS) which is used to perform serious LC resonance property in certain frequency. By integrating Defected Ground Structure elements, the resonance frequency was shifted from 10 GHz to 7.5 GHz. The proposed structure of DGS is incorporated in the ground plane of our array antenna. Prototype of the antenna was fabricated with FR4 substrate and tested. The simulation and measurement results were in good agreement

Reducing side lobes of antenna array by the binomial method

This paper explores optimization and synthesis of linear, which prints antennas arrays. The developed synthesis bases on an optimization binomial method. The objective of this paper is to adapt the binomial method to reduce the side lobe level. The application of this formalism gives terrific results

Applying B-Spline Biorthogonal Wavelet Basis Functions to the Method of Moments in Solving Poisson equation

The aim of this paper is to introduce the application of B-spline biorthogonal wavelet with various orders (number of vanishing moments) in Electrostatic problems and making improvement in the moment method development. Due to the order of wavelet, the impedance matrix resulting in this problem is sparsified by wavelet, and consequently, the solution can be obtained rapidly. To illustrate these concepts, the two-body problem of parallel square conducting plates is presented. To demonstrate the effectiveness and accuracy of the proposed technique, numerical results for charge density potential, capacity, and error relative for different order of B-spline biorthogonal wavelets and dielectric constant are presented. Results are compared to the previous work done and published, excellent results are obtained

Influence de variation de la distance de séparation entre les antennes Patch

Ce travail présente l’influence de variation de la distance de séparation entre deux antennes patch rectangulaire

A Novel Cpw Low Cost Lowpass Filter Integrating Periodic Structures

In this work, we propose a novel design of a planar CPW lowpass “LPF” filter based on the use of periodic structures. The periodic cells are formed from a rectangular slot repeated periodically. The originality of this work is to develop a new LPF structure which is simple, low cost for fabrication and easy to associate with others microwave planar circuits. The proposed and validated LPF is a compact planar filter structure. The final circuit is simulated and optimized by using two electromagnetic solvers, ADS (Advanced Design System) and HFSS (High Frequency Structural Simulator). After many series of optimization we have validated the final circuit into simulation by using optimization methods integrated into the both solvers, taking into account a high density of meshing in order to cover the whole circuit. The fabricated LPF circuit shows good agreement between simulation and measurement results in term of matching input impedance and insertion loss with a cutoff frequency of 1.25GHz. The entire area of the proposed LPF is 35x31 mm2

Design and implementation of a technology planar 4x4 butler matrix for networks application

In this paper, switched beam smart antenna systems are investigated to improve the performance of wireless networks. The microstrip technology of antenna arrays with Butler matrix topology as a beam-former is used to implement the switched beam smart antenna system. The optimum design of a 4x4 planar Butler matrix array, operating at 5.6 GHz for WLAN applications. System’s design and optimization was based on computer simulations

Miniaturized microstrip patch antenna with defected ground structure

The aim of this work is to miniaturize a microstrip patch antenna resonating at 3 GHz. For this purpose, defected ground structure (DGS) has been employed to shift the resonance frequency of an initial microstrip antenna from 5.7 GHz to 3 GHz by disturbing the antenna's current distribution. The proposed DGS is incorporated in the ground plane under the patch antenna to improve its performances. Finally, a miniaturization up to 50%, with respect to the conventional microstrip antenna, is successfully accomplished. A prototype of the antenna was fabricated with the FR4 substrate and tested. The measurements results were in good agreement with simulation results

Diseño de un amplificador de alta eficiencia clase-E @ 2GHz

Class-E power amplifiers have 100% theoretical efficiency, due to switched-mode operation. This concept has traditionally been applied to VHF and UHF frequency ranges. In this paper we propose its application to microwave frequencies, designing and characterizing a class-E power amplifier at 2 GHz based on a HEMT solid state device and microstrip technology