Analysis and design of defected ground structure for EMC improvement in mixed-signal transceiver modules

In this research, the return path discontinuity (RPD), located under the power amplifier (PA) substrate, of X-band transceiver module (Base), mounted on a four-layer printed circuit board (PCB), is investigated to improve the signal integrity by reducing the difference in the reference potential. This study is performed by initially employing the wirebond method, through the assessment of both numbers and sizes of bondwires by advanced design system (ADS). Six bondwires of 25 µm are added, producing an improvement of 6.82 dB for the reflection coefficient and 1.19 dB for the isolation and insertion loss. For further improvement, spiral shape defected ground structure (DGS) is implemented in the inner ground layer (layer 2) without using bond wires. The DGS simulation results illustrate an improvement of 3 dB for S11 and 0.6 dB for S12. To improve the electromagnetic compatibility (EMC), the authors propose combination and integration of both wirebond and DGS methods, called wirebond–DGS method, which results in an improvement of 11.86 dB for S11, 1.34 dB for S12 and S21, and 12.03 dB for S22. Finally, the wirebond–DGS RF module was fabricated and the measurement results exhibit an improvement of 8.07 dB for S11 and 9.39 dB for S22 in comparison with the fabricated Base module. In addition, 0.53 dB improvement for both S12 and S21 is also achieved

Approximate synthesis formulas for microstrip line with aperture in ground plane

Approximate closed-form expressions for the propagation characteristics of a microstrip line with a symmetrical aperture in its ground plane are reported in this article. Well-known expressions for the characteristic impedance of a regular microstrip line have been modified to incorporate the effect of this aperture. The accuracy of these expressions for various values of substrate thickness, permittivity and line width has been studied in detail by fullwave simulations. This has been further verified by measurements. These expressions are easier to compute and find immense use in the design of broadband filters, tight couplers, power dividers, transformers, delay lines, and matching circuits. A broadband filter with aperture in ground plane is demonstrated in this article. (c) 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2012

High directivity DGS-based coupler

This paper reports a new design of microstrip directional coupler with high directivity. This directional coupler uses corrugated coupled lines and floating conductor in the ground plane of microstrip to enhance coupling. Based on this structure, directional coupler having 4.4% bandwidth has been designed at 4500 MHz with 10 dB coupling and 35 dB directivity. The designed directional coupler has been fabricated and tested for the validity of the design. Measured results are presented in this paper

Achieving Personalized Privacy and Compromised Conspiracy in Location Proof Updating System

Abstract- An alibi is a form of defense used in criminal procedure wherein the accused attempts to prove that he or she was in some other place at the time the alleged offense was committed. Today’s location-sensitive service relies on user’s mobile device to determine the current location. This allows malicious users to access a restricted resource or provide bogus alibis by cheating on their locations. To address this issue, we propose A Privacy-Preserving Location proof Updating System in which collocated Bluetooth enabled mobile devices mutually generate location proofs and send updates to a location proof server. Periodically changed pseudonyms are used by the mobile devices to protect from the untrusted location proof server. In order to defend against colluding attacks, we also present betweeness ranking-based and correlation clustering-based approaches for outlier detection. APPLAUS can be implemented with existing network infrastructure, and can be easily deployed in Bluetooth enabled mobile devices with little computation or power cost. Extensive experimental results show that APPLAUS can effectively provide location proofs, significantly preserve the source location privacy, and effectively detect colluding attacks In addition We propose two in-network aggregate location anonymization algorithms, namely, resource-and quality-aware algorithms. Both algorithms require the sensor nodes to collaborate with each other to blur their sensing areas into cloaked areas, such that each cloaked area contains at least k persons to constitute a k-anonymous cloaked area This helps the system to enable and provide high-quality location monitoring services for system users, while preserving personal location privacy. Index Terms- Wireless sensor networks (WSN), source location, privacy, pseudonyms, colluding attacks. 1

Analysis And Design Of Two Layered Ultra Wide Band Filter

Design of an Ultra Wide Band (UWB) filter over 3.1 GHz to 10.6 GHz using broad side coupled and spur lines in microstrip medium suitable for UWB communications has been presented in this paper. Parameters of broad side coupled lines have been appropriately chosen to achieve ultra wide band response. Spur lines have been incorporated at the input and output feed lines of the filter to improve the stop band rejection characteristics of the filter. Filter has been analyzed based on circuit models and full wave simulations. Experimental results of the filter designed using the proposed structure has been verified against the results obtained from circuit models and full wave simulations. The results match satisfactorily. Stop band rejection of better than 20 dB was obtained over the frequencies of 13 GHz to 18.2 GHz. Overall size of the filter is 40 x 18 x 0.787 mm(3)

Förebyggning av utbrändhet på organisatorisk nivå

The workplace is for many associated with joy and commitment, for others it is associated with fatigue, inadequacy and cynicism that is explained as the three dimensions of burnout. A general view of burnout is that it is an individual problem that many companies ignore, because a preventive task does not generate immediate profits. This has been a growing problem for years. Burnout costs not only money but also time and knowledge. Unfortunately, the popular belief is that "If it ain’t broke, don’t fix it." Organizations that think this way are sacrificing future benefits for short-term gains. A company that chooses to turn its expertise to work preventively against burnout results in a more dedicated staff, whether they're going to burn out or not. A dedicated staff will perform better at work. The purpose of this study is to investigate what actions the management of a company can take to prevent and deal with burnout. Empirical evidence has been gathered through interviews with an HR specialist and an interview with Torbjörn Henriksson, psychologist and CEO of Arbus. The basis for the theory and interview comes from the theories of preventive work against mental illness and burnout, and Aaron Antonovsky theories of sense of coherence. According to the theory and empirical work that requires a committed and dedicated leadership that includes staff in the process of improvement towards the prevention of burnout. Keywords for a successful preventive work have proven to be communication, training of staff and management, communion, justice, respect and recovery time from stress.Arbetsplatsen är för många förknippad med glädje och engagemang, för andra är det förknippat med utmattning, otillräcklighet och cynism som förklaras som de tre dimensionerna av utbrändhet. En allmän bild av utbrändhet är att det är ett individuellt problem som flera företag blundar för, då ett preventivt arbete inte genererar omedelbar ekonomisk vinst. Detta har varit ett växande problem under många år. Utbrändhet kostar inte bara pengar, utan även tid och kunskap. Tyvärr är den folkliga uppfattningen att ”om det inte finns någonting som är brutet så finns det ingenting att laga”. Organisationer som tänker på detta sätt offrar framtida fördelar mot kortsiktiga vinster. Ett företag som väljer att rikta sin kunskap för att arbeta preventivt mot utbrändhet kommer till följd av det få mer engagerad personal, oavsett om de är på väg att bli utbrända eller inte. En engagerad personal kommer prestera bättre på arbetsplatsen. Syftet med detta arbete är att undersöka vad ledningen hos ett företag kan göra för att förebygga och hantera utbrändhet. Genom intervjuer med en HR-specialist inom arbetsmiljö och hälsa samt en intervju med Torbjörn Henriksson, psykolog och VD för Arbus, har empiri samlats. Underlaget för teori och intervju kommer främst från teorier om preventivt arbete mot psykisk ohälsa och utbrändhet samt Aron Antonovsky teorier om känsla av sammanhang. Det framgår av teori och empiri att det krävs en engagerad och dedikerad ledning som inkluderar personalen i förbättringsarbetet mot att förebygga utbrändhet. Nyckelord för ett lyckat preventivt arbete har visat sig vara kommunikation, utbildning av personal och ledning, gemenskap, rättvisa, respekt och återhämtning från stress

A multi-layer ultra wide band power splitter

This paper presents analysis and design of multilayer ultra wide band (UWB) power splitter suitable for wireless communications. An UWB power splitter is designed in suspended substrate stripline medium. The quarter wave transformer in the conventional Wilkinson power divider is replaced by broadside coupled lines to achieve tight coupling for broadband operation. The UWB power splitter is analyzed using circuit models of coupled lines and full wave simulator. Experimental results of 3dB power splitter designed using the proposed structure have been verified against the results from circuit simulation and full wave simulation. The return loss is better than 12 dB across the band 3.1GHz to 10.6GHz. Size of the power splitter is 30mm× 20mm×6.38mm

Broadband Equal Power Divider

Abstract This paper presents the design of broadband two way equal power divider in microstrip medium with defected ground structure suitable for broadband communication systems. Quarter wave broadside coupled lines are used in the place of conventional transformers widely used in the popular Wilkinson power dividers. The proposed power divider structure takes the advantage of top and bottom layers of the microstrip medium to create broadside coupled line configuration using defected ground plane. The floating conductor in the bottom layer plays a critical role in achieving the band select characteristics. Experimental results of two way equal power divider designed using the proposed structure has been verified against the full wave simulations. The isolation between the paths is more than 20dB and the return loss at each port is better than 15dB across the desired band of 3GHz to 8GHz

Design of compact low pass filter with wide stop band using tri-section stepped impedance resonator

This paper reports the design of a compact low pass filter (LPF) with wide stop band region using trisection stepped impedance resonators in microstrip medium. Experimental results of a low pass filter designed at 1 GHz have been compared against the analytical and EM simulation results for the validation of the design. Results are satisfactorily matching each other. The maximum insertion of the measured filter is 0.2 dB and minimum return loss is 13.5 dB over the pass band. The stop band rejection is better than 20 dB from 1.5 GHz to 4.2 GHz and hence wide stop band performance is achieved. Overall size of the filter is 30 mm x 20 mm x 0.78 mm which is 0.1 lambda x 0.066 lambda. x 0.0026 lambda at 1 GHz. (C) 2011 Elsevier GmbH. All rights reserved

Dual band(WLAN & WiMAX) suppressed harmonic microstrip filter with perturbed ground

Design of a dual band pass filter employing microstrip line with defected ground is presented in this paper. A dual band filter at 2.45GHz and 3.5GHz (covering WLAN and WiMAX) with 6% bandwidth has been designed at each frequency. Apertures in ground plane were used to improve the stop band rejection characteristics and coupling levels in the filter. Measured results of the experimental filter were compared against the simulation results for the purpose of validation