Design, modeling and fabrication of radio-frequency microelectromechanical switches and coplanar filters

Magdeburg, Univ., Fak. für Elektrotechnik und Informationstechnik, Diss., 2010

Compact asymmetric coplanar waveguide filter

The design and implementation of a novel asymmetric coplanar waveguide (ACPW ) band rejection filter using defected ground structure ( DGS) is presented . The proposed ACPW DGS technology provides band gap characteristics with only one cell in the lateral ground plane . The equivalent circuit model of the proposed DGS unit section is described . Measurements of ACPW DGS showed good agreement with simulation and the proposed model

Pulse Wave Propagating in Coplanar Waveguides (cPWS) on LTCC Substrates

The propagation of pulse waves in coplanar waveguides (CPWs) is investigated, and these CPWs are assumed to be fabricated on a single -layer low- temperature co-fired ceramic (LTCC) substrate. The input pulse wave can be a Gaussian pulse or a sinusoldally modulated Gaussian pulse. Based on the standard Galerkin 's method in the spectral domain, combined with fast Fourier transform (FFT), the pulse waveform and delay in CPWs are demonstrated and compared for a second plate, oriented orthogonally to the primary planar element, thus producing a crossed planar monopole (CPM), which is simpler to produce and has lower cost than a conical monopole. In this paper, further measurements have been made on this element

DESIGN AND DEVELOPMENT OF COMPACT ASYMMETRIC COPLANAR STRIP FED ANTENNAS

Antennas are indispensable component of any wireless communication device. An antenna is a transducer between the transmitter and the free space waves and vice versa. They efficiently transfer electromagnetic energy from a transmission line into free space. But the present day communication applications require compact and ultra wide band designs which cannot be catered by simple microstrip based designs. PIFAs have solved the problem to some extend, but the field of antennas needs more innovative designs In this thesis the design and development of compact planner antenna are presented. Emphasis is given to the design of the feed as well as the radiator resulting in simple compact uniplanar geometries. The Asymmetric coplanar feed used to excite the antennas is found to be a suitable choice for feeding compact antennas.The main objectives of the study are the design of compact single, dual and multi band antennas with uniplanar structure and extension of the design for practical GSM/WLAN applications and Ultra compact antennas using the above techniques and extension of the design to antennas for practical applications like RFID/DVB-H. All the above objectives are thoroughly studied. Antennas with ultra compact dimensions are obtained as a result of the study. Simple equations are provided to design antennas with the required characteristics. The design equations are verified by designing different antennas for different applications.

Development And Analysis Of A Compact Coplanar Antenna With Flared Monopole For Dual Band Applications

Department of Electronics, Cochin University of Science and Technology

Development and Analysis of a Compact Dual-Band Coplanar Antenna

The coplanar wave guide is an attractive device in microwave integrated circuits due to its uniplanar nature, ease of fabrication and low production cost. Several attempts are already done to explore the radiating modes in coplanar wave guide transmission lines. Usually coplanar wave guides are excited by an SMA connector with its centre conductor connected to the exact middle of the centre strip and the outer ground conductor to the two ground strips. The mode excited on it is purely a bound mode. The E-field distribution in the two slots are out of phase and there for cancels at the far field. This thesis addresses an attempt to excite an in phase E-field distribution in the two slots of the co planar wave guide by employing a feed asymmetry, in order to get radiation from the two large slot discontinuities of the coplanar waveguide. The omni directional distribution of the radiating energy can be achieved by widening the centre strip.The first part of the thesis deals with the investigations on the resonance phenomena of conventional coplanar waveguides at higher frequency bands. Then an offset fed open circuited coplanar waveguide supporting resonance/radiation phenomena is analyzed. Finally, a novel compact co planar antenna geometry with dual band characteristics, suitable for mobile terminal applications is designed and characterized using the inferences from the above study.

Compact asymmetric coplanar strip-fed antenna for wideband applications

An asymmetric coplanar strip-fed uniplanar antenna for wideband applications is presented. The resulting antenna offers a 2:1 VSWR bandwidth greater than 100% from 1.58 to 5.48 GHz covering the DCS/PCS/IEEE 802.11a/WiMAX bands. The antenna has an overall dimension of 44 × 35 mm2 when printed on a substrate of dielectric constant 4.4 and height 1.6 mm. The design equation is also presented in this article. The antenna exhibits good radiation characteristics and moderate gain in the entire operating band.

Design and Development of Compact Coplanar Waveguide Fed Antennas for Wireless Applications

The need of miniaturization in the present day communication industry is challenging. In the present scenario, printed antenna technology is highly suitable for wireless communication due to its low profile and other desirable radiation characteristics. Small monopole type antennas are overruled by compact small antennas for present day mobile communication applications. Coplanar waveguides (CPW) are printed on one side of a dielectric substrate. CPW have attracted the attention of antenna designers due to their excellent properties like ease of integration with ‘MMIC’, low cost, wide bandwidth, flexibility towards multiband operation, low radiation leakage and less dispersion. The requirement of omnidirectional coverage, light weight and low cost made these CPW fed antennas a good candidate for wireless applications. The main focus of the thesis is the study of coplanar waveguide transmission line. Rigorous investigations were performed on both the ground plane and signal strip of a coplanar waveguide transmission line to create effective radiation characteristics. Good amount of works have been done to transform CPW line to antenna suitable for mobile phone applications

“Design and Development of Coplanar Strip Fed Planar Antennas”

With the recent progress and rapid increase in the field of communication, the designs of antennas for small mobile terminals with enhanced radiation characteristics are acquiring great importance. Compactness, efficiency, high data rate capacity etc. are the major criteria for the new generation antennas. The challenging task of the microwave scientists and engineers is to design a compact printed radiating structure having broadband behavior along with good efficiency and enhanced gain. Printed antenna technology has received popularity among antenna scientists after the introduction of planar transmission lines in mid-seventies. When we view the antenna through a transmission line concept, the mechanism behind any electromagnetic radiator is quite simple and interesting. Any electromagnetic system with a discontinuity is radiating electromagnetic energy. The size, shape and orientation of the discontinuities control the radiation characteristics of the system such as radiation pattern, gain, polarization etc. It can be either resonant or non-resonant. This thesis deals with antennas that are developed from a class of transmission lines known as coplanar strip-CPS, a planar analogy of parallel pair transmission line. The specialty of CPS is its symmetric structure compared to other transmission lines, which makes the antenna structures developed from CPS quite simple for design and fabrication. The structural modifications on either metallic strip of CPS results in different antennas. The first part of the thesis discusses a single band and dual band design derived from open ended slot lines which are very much suitable for 2.4 and 5.2 GHz WLAN applications. The second section of the study is vectored into the development of enhanced gain dipoles. A single band dipole and a wide band enhanced gain dipole suitable for 5.2/5.8 GHZ band and imaging applications are developed and discussed. Last part of the thesis discusses the development of directional UWBs. Three different types of ultra-compact UWBs are developed and almost all the frequency domain and time domain analysis of the structures are discussed.

Compact Coplanar Waveguide Fed Ground Meandered Antenna for Wireless Application

A compact Co-Planar Waveguide (CPW) fed antenna operating at 2.4GHz with 300MHz 2:1 VSWR bandwidth is presented. Compared to a conventional quarter wavelength CPW fed monopole antenna, the aperture area reduction of the present antenna is 85%. The prototype antenna fabricated on a substrate of εr = 4.4 and thickness 1.6mm is only 22x10x1.6mm3. This much size reduction and impedance matching is achieved by adjusting the signal to ground plane separation and meandering the ground plane of a 50Ω CPW transmission line

Determination of onboard coplanar orbital maneuvers with orbits determined using GPS

In the present paper a study is made in order to find an algorithm that can calculate coplanar orbital maneuvers for an artificial satellite. The idea is to find a method that is fast enough to be combined with onboard orbit determination using GPS data collected from a receiver that is located in the satellite. After a search in the literature, three algorithms are selected to be tested. Preliminary studies show that one of them (the so called Minimum Delta-V Lambert Problem) has several advantages over the two others, both in terms of accuracy and time required for processing. So, this algorithm is implemented and tested numerically combined with the orbit determination procedure. Some adjustments are performed in this algorithm in the present paper to allow its use in real-time onboard applications. Considering the whole maneuver, first of all a simplified and compact algorithm is used to estimate in real-time and onboard the artificial satellite orbit using the GPS measurements. By using the estimated orbit as the initial one and the information of the final desired orbit (from the specification of the mission) as the final one, a coplanar bi-impulsive maneuver is calculated. This maneuver searches for the minimum fuel consumption. Two kinds of maneuvers are performed, one varying only the semi major axis and the other varying the semi major axis and the eccentricity of the orbit, simultaneously. The possibilities of restrictions in the locations to apply the impulses are included, as well as the possibility to control the relation between the processing time and the solution accuracy. Those are the two main reasons to recommend this method for use in the proposed application.

Respostas eletromagnéticas dos arranjos coplanar e coaxial em poço

Foi estudado a viabilidade de aplicação do arranjo coplanar de bobinas nas sondas de perfilagem em poço por indução eletromagnética. Paralelamente foram geradas as respostas do convencional arranjo coaxial, que é o amplamente utilizado nas sondas comerciais, com o propósito de elaborar uma análise comparativa. Através da solução analítica (meios homogêneos) e semi-analítica (meios heterogêneos) foram geradas inicialmente as respostas para modelos mais simples, tais como os do (1) meio homogêneo, isotrópico e ilimitado; (2) uma casca cilíndrica simulando a frente de invasão; (3) duas cascas cilíndricas para simular o efeito annulus; (4) uma interface plana e dois semi-espaços simulando o contato entre duas camadas espessas e (5) uma camada plano-horizontal e dois semi-espaços iguais. Apesar da simplicidade destes modelos, eles permitem uma análise detalhada dos efeitos que alguns parâmetros geoelétricos têm sobre as respostas. Aí então, aplicando ainda as condições de contorno nas fronteiras (Sommerfeld Boundary Value Problem), obtivemos as soluções semi-analíticas que nos permitiram simular as respostas em modelos relativamente mais complexos, tais como (1) zonas de transição gradacional nas frentes de invasão; (2) seqüências de camadas plano-paralelas horizontais e inclinadas; (3) seqüências laminadas que permitem simular meios anisotrópicos e (4) passagem gradacional entre duas camadas espessas. Concluimos que o arranjo coplanar de bobinas pode ser uma ferramenta auxiliar na (1) demarcação das interfaces de camadas espessas; (2) posicionamento dos reservatórios de pequenas espessuras; (3) avaliação de perfis de invasão e (4) localizar variações de condutividade azimutalmente.

Arranjos coplanar e coaxial nas sondas de perfilagem de poço: ferramentas triaxiais em reservatórios laminados

A ferramenta de indução triaxial ou multicomponente foi desenvolvida recentemente para solucionar os problemas de medição da convencional perfilagem de indução em formações anisotrópicas. Neste trabalho são apresentadas as respostas da sonda de indução triaxial em reservatórios que possuem seqüências finamente laminadas de arenito e folhelho. Reservatórios como estes apresentam a conhecida anisotropia macroscópica, portanto, os resultados demonstrarão a existência de uma resistividade horizontal e outra vertical. Devido a sonda triaxial de indução apresentar dois pares de bobinas coplanares, os quais em geral fornecem os valores de resistividade vertical, este trabalho apresenta inicialmente um estudo analítico e qualitativo das respostas obtidas pelo arranjo coplanar onde o transmissor é tratado como um dipolo. Também será apresentada a solução analítica em que a bobina transmissora é considerada como um loop de dimensão finita.