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Article
Publication date: 3 February 2020

Jin Guan, Min Gong and Bo Gao

A novel Ka-band compact parallel-coupled microstrip bandpass filter with harmonic suppression performance has been designed, implemented and tested on GaAs MMIC.

Abstract

Purpose

A novel Ka-band compact parallel-coupled microstrip bandpass filter with harmonic suppression performance has been designed, implemented and tested on GaAs MMIC.

Design/methodology/approach

This proposed filter consists of modified coupled-line units with T-shaped open-stubs.

Findings

The proposed filter with T-shaped open-stubs is valuable in performance with low loss at fundamental frequency, suppression at harmonic frequencies and small size. The simulation is based on full-wave electromagnetic analysis and the measurement is based on chip test. It shows an insertion loss below 1.2 dB, return loss better than 20 dB in the pass band and high than 28 dB suppression at harmonic frequencies.

Originality/value

This Ka-band MMIC filter with harmonic suppression is attractive for the millimeter-wave system.

Details

Circuit World, vol. 46 no. 3
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 21 September 2020

Sandhya Ramalingam, Umma Habiba Hyder Ali and Sharmeela Chenniappan

This paper aims to design a dual mode X-band substrate integrated waveguide (SIW) bandpass filter in the conventional SIW structure. A pair of back-to-back square and split ring…

Abstract

Purpose

This paper aims to design a dual mode X-band substrate integrated waveguide (SIW) bandpass filter in the conventional SIW structure. A pair of back-to-back square and split ring resonator is introduced in the single-layer SIW bandpass filter. The various coupling configurations of SIW bandpass filter using split square ring slot resonator is designed to obtain dual resonant mode in the passband. It is shown that the measured results agree with the simulated results to meet compact size, lower the transmission coefficient, better reflection coefficient, sharp sideband rejection and minimal group delay.

Design/methodology/approach

A spurious suppression of wideband response is suppressed using an open stub in the transmission line. The width and length of the stub are tuned to suppress the wideband spurs in the stopband. The measured 3 dB bandwidth is from 8.76 to 14.24 GHz with a fractional bandwidth of 48.04% at a center frequency of 11.63 GHz, 12.59 GHz. The structure is analyzed using the equivalent circuit model, and the simulated analysis is based on an advanced design system software.

Findings

This paper discusses the characteristics of resonator below the waveguide cut-off frequency with their working principles and applications. Considering the difficulties in combining the resonators with a metallic waveguide, a new guided wave structure – the SIW is designed, which is synthesized on a planar substrate with linear periodic arrays of metallized via based on the printed circuit board.

Originality/value

This study has investigated the wave propagation problem of the SIW loaded by square ring slot-loaded resonator. The electric dipole nature of the resonator has been used to achieve a forward passband in a waveguide environment. The proposed filters have numerous advantages such as high-quality factor, low insertion loss, easy to integrate with the other planar circuits and, most importantly, compact size.

Details

Circuit World, vol. 48 no. 1
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 11 May 2020

Rasime Uyguroğlu, Allaeldien Mohamed Hnesh, Muhammad Sohail and Abdullah Y. Oztoprak

This paper aims to introduce a new novel microstrip monopulse comparator system to reduce the spurious radiation from the comparator and the feed network for achieving better…

Abstract

Purpose

This paper aims to introduce a new novel microstrip monopulse comparator system to reduce the spurious radiation from the comparator and the feed network for achieving better radiation performance.

Design/methodology/approach

Two substrate layers have been used for the microstrip monopulse comparator system. The feed network and the comparator circuits are on the first substrate layer and the microstrip array antenna is on the second layer. The elements of the array antenna are novel square four-sided narrow rectangular slot antennas built on a conducting plane. A commercially available computational software, CST microwave studio, has been used for the analysis of the system.

Findings

Two substrate layers have been used for the microstrip monopulse comparator system. The feed network and the comparator circuits are on the first substrate layer and the microstrip array antenna is on the second layer. The elements of the array antenna are novel square four-sided narrow rectangular slot antennas built on a conducting plane. A commercially available computational software, CST microwave studio, has been used for the analysis of the system.

Practical implications

The system is proposed for tracking moving targets.

Originality/value

Novel slot radiators are introduced as radiating elements in this paper. The antenna arrangement shields the comparator and the feed network circuits, reducing the spurious radiation significantly.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. 39 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 20 September 2019

Jin Guan, Min Gong, Bo Gao, Yuxi Lu and Yu Lu

The purpose of this paper is to present a K-band modified hairpin bandpass filter on a planar circuit with harmonic suppression and compact size.

Abstract

Purpose

The purpose of this paper is to present a K-band modified hairpin bandpass filter on a planar circuit with harmonic suppression and compact size.

Design/methodology/approach

The inter-connect transmission lines of conventional hairpin filter are replayed by T-shaped open stub to achieve transmission zero for second harmonic. This filter is simulated and optimized by using electromagnetic simulation software and tested on-chip.

Findings

This proposed filter shows the return loss of better than −10dB, the insertion loss of better than 2 dB in pass-band and suppression of more than 40 dB at second harmonic.

Originality/value

The proposed filter can be designed on monolithic microwave integrated circuit, PCB or LTCC and it is useable for microwave and microwave and millimeter-wave systems.

Details

Circuit World, vol. 45 no. 4
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 9 July 2019

Stephen Oduro and Leul Girma Haylemariam

Corporate social responsibility (CSR) often gives a humanistic touch to the marketing activities of firms and even creates the atmosphere that businesses are reliable. Yet, little…

1303

Abstract

Purpose

Corporate social responsibility (CSR) often gives a humanistic touch to the marketing activities of firms and even creates the atmosphere that businesses are reliable. Yet, little is known about its interaction effect on the relationship between market orientation (MO) and financial and marketing performance in emerging economies. The present study aims to comparatively examine the interaction effect of CSR on the direct link between MO and financial and marketing performance in manufacturing firms in Ghana and Ethiopia.

Design/methodology/approach

The interaction effect of CSR is examined using a quantitative methodological study design. A total of 439 usable questionnaires across manufacturing firms in Ghana and Ethiopia were collected and analyzed using SEM-PLS 3.0. Analytically, the study used product indicator approach to test the interaction effect of CSR on the nexus between MO and financial and marketing performance, while PLS-multigroup analysis (PLS-MGA) was used to test the significance of the observed differences in the results among the manufacturing firms in the two countries.

Findings

Results show that MO significantly improves financial and marketing performance. However, CSR reveals both “suppression” and “spurious” effects on the direct link between MO and financial and marketing performance under varying market conditions. The relationship between MO and financial performance is weakened in Ghanaian manufacturing firms but is strengthened in Ethiopian manufacturing firms when the level of CSR is high. Results, moreover, show that the nexus between MO and marketing performance is strengthened when CSR actions are high in both Ghanaian and Ethiopian manufacturing firms. The PLS-MGA revealed that these differences in findings in the two countries are statistically significant.

Practical implications

The findings suggest that company managers and marketing practitioners can use CSR in their marketing orientation campaigns to keep high performance and to remain competitive in today’s globalized market.

Social implications

Findings illustrate that incorporation of social interests and sustainability initiatives into firms’ marketing orientation strategies can meet stakeholders’ interest and expectation.

Originality/value

This is one of the few studies that examine comparatively the interaction effect of CSR on the MO–financial and marketing performance linkage in two emerging economies. The study extends our understanding of the RBV and stakeholder theories regarding the role of CSR in firms’ marketing strategies.

Details

Sustainability Accounting, Management and Policy Journal, vol. 10 no. 3
Type: Research Article
ISSN: 2040-8021

Keywords

Article
Publication date: 1 June 1993

A. KANIEL, M. MOND and G. BEN‐DOR

Isotropic artificial dissipation is added to the Navier‐Stokes equations along with a correction term which cancels the artificial dissipation term in the limit when the mesh size…

Abstract

Isotropic artificial dissipation is added to the Navier‐Stokes equations along with a correction term which cancels the artificial dissipation term in the limit when the mesh size is zero. For a finite mesh size, the correction term replaces the artificial viscosity terms with hyperviscosity terms, i.e., with an artificial dissipation which depends on the fourth derivatives of the velocity. Hyperviscosity more effectively suppresses the higher wave number modes and has a smaller effect on the inertial modes of the flow field than does artificial viscosity. This scheme is implemented using the finite element method and therefore the required amount of dissipation is determined by analysing the discretization on a finite element. The scheme is used to simulate the flow in a driven cavity and over a backward facing step and the results are compared to existing results for these cases.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 3 no. 6
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 4 July 2016

Helmut Wernick, Patrick Hoelzl and Bernhard G. Zagar

The purpose of this paper is to present a fast and contactless measurement method to determine the spatial conductivity distribution within an intrinsically conducting polymer…

Abstract

Purpose

The purpose of this paper is to present a fast and contactless measurement method to determine the spatial conductivity distribution within an intrinsically conducting polymer, more precisely a conductive rubber sheet specimen. As a consequence of the manufacturing process and the material composition, the conductivity distribution within the sheet is assumed to be inhomogeneous.

Design/methodology/approach

The current density distribution within the conductive rubber sheet due to an excitation current is estimated from the measured magnetic field distribution. Therefore, a GMR sensor is used to spatially sample the magnetic field above the specimen. Based on the estimated current density distribution and alternatively the local power dissipation calculated from a thermal image, the conductivity distribution within the specimen is determined. For comparison a reference measurement with a classical resistivity probe is done.

Findings

The measurement results show a good agreement between the developed and the classical method. Moreover, the developed measurement method requires less time and still offers a higher spatial resolution.

Originality/value

The presented results demonstrate the potential of the developed measurement method for determining the conductivity distribution within thin and planar specimens. Furthermore, conclusions can be drawn about the material homogeneity of the used test specimen.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 35 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 1 August 2016

Kornel Ruman, Alena Pietrikova, Pavol Galajda, Igor Vehec, Tibor Rovensky and Martin Kmec

The purpose of this paper is to introduce modified in–phase and quadrature components (IQ) demodulator based on low temperature co-fired ceramics (LTCC) dielectric substrate…

140

Abstract

Purpose

The purpose of this paper is to introduce modified in–phase and quadrature components (IQ) demodulator based on low temperature co-fired ceramics (LTCC) dielectric substrate GreenTape 951PX for M-Sequence ultra-wide band (UWB) sensor system.

Design/methodology/approach

Microstrip low pass (LP) and band pass (BP) filters for UWB sensor systems with required properties (for both filters, minimum attenuation is −40dB in stopband, bandwidth of pass band is 6 to 8.5 GHz for BP filter and cutoff frequency is 2.5 GHz for LP filter) were designed, simulated, fabricated and measured using dielectric substrates Du Pont GreenTape 951 PX. The developed microstrip filters were integrated with all parts of IQ demodulator on one multilayer structure based on LTCC substrate Du Pont GreenTape 951 PX.

Findings

Both type of microstrip filters integrated in the I Q demodulator achieved better transmission characteristics in comparison with commercial available filters. It was shown that LTCC technology based on GreenTape 951PX proves good stability in gigahertz frequency and suitability for fabrication of IQ demodulator with a multilayer approach.

Originality/value

The novelty of this work lies in substituting commercially available LP and BP filters used in I Q demodulator by microstrip LP and BP filters with better performance and furthermore the I Q demodulator is fabricated based on LTCC instead of previously used PCB.

Details

Microelectronics International, vol. 33 no. 3
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 1 June 2000

A. Savini

Gives introductory remarks about chapter 1 of this group of 31 papers, from ISEF 1999 Proceedings, in the methodologies for field analysis, in the electromagnetic community…

1125

Abstract

Gives introductory remarks about chapter 1 of this group of 31 papers, from ISEF 1999 Proceedings, in the methodologies for field analysis, in the electromagnetic community. Observes that computer package implementation theory contributes to clarification. Discusses the areas covered by some of the papers ‐ such as artificial intelligence using fuzzy logic. Includes applications such as permanent magnets and looks at eddy current problems. States the finite element method is currently the most popular method used for field computation. Closes by pointing out the amalgam of topics.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 19 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 1 September 2002

Nikolaos V. Kantartzis, Theodoros K. Katsibas, Christos S. Antonopoulos and Theodoros D. Tsiboukis

A systematic, non‐orthogonal FDTD algorithm for the unified and fully dual construction of curvilinear PMLs in 3‐D lossy electromagnetic and advective acoustic problems, is…

1496

Abstract

A systematic, non‐orthogonal FDTD algorithm for the unified and fully dual construction of curvilinear PMLs in 3‐D lossy electromagnetic and advective acoustic problems, is presented in this paper. Postulating a consistent mathematical formulation, the novel methodology introduces a set of general vector parametric equations that describe wave propagation in both media and facilitate the effective treatment of the remarkably complex, arbitrarily‐aligned (non‐uniform) source or mean flow terms, particularly at low frequencies. The discretization procedure is performed via accurate higher‐order FDTD topological concepts, which along with a well‐posed variable transformation, suppress the undesired lattice dispersion and anisotropy errors. Hence, due to these additional degrees of design freedom and their optimal establishment, the new stable PMLs (split‐field or Maxwellian) accomplish a critical attenuation of the evanescent, vorticity or elastic wave families by carefully accounting for every loss mechanism. Numerical investigation reveals the superiority of the proposed technique in terms of various open‐region, waveguide and ducted‐domain simulations.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 21 no. 3
Type: Research Article
ISSN: 0332-1649

Keywords

1 – 10 of 151