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Article
Publication date: 16 April 2020

Revathi Ganesan and Radha Sankararajan

The purpose of this paper is to propose a miniaturized tri-band bandstop filter that finds application in a modern dense communication system where size and multi-band…

Abstract

Purpose

The purpose of this paper is to propose a miniaturized tri-band bandstop filter that finds application in a modern dense communication system where size and multi-band plays a vital role.

Design/methodology/approach

In this paper, the authors propose a miniaturized tri-band microstrip bandstop filter which combines the conventional bandstop filter and spur microstrip line structures such that this design achieves tri-band operation at 1.8 GHz and 3 GHz. The overall length of the microstrip filter is found to reduce from 126 to 45 mm because of introduction of spur lines and via-hole grounding. The addition of spur lines replaces two resonators, introduces two additional resonant frequencies and enhances the −6 dB bandwidth of the center frequency by 14 %.The addition of via-holes in each resonator reduces its length into half of its original length, thereby reducing filter size.

Findings

Resonance occurs at three different frequencies 1.8, 2.4 and 3 GHz. The filter size reduces from 126 to 45 mm, and the −6 dB rejection bandwidth of center frequency improves by 14 %.

Originality/value

The overall filter size is reduced by 65% and it resonates at three different frequencies 1.8, 2.4 and 3 GHz with an improved bandwidth of 10 % around the center frequency.

Details

Circuit World, vol. 46 no. 4
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 13 September 2011

Francisco J. Clemente‐Fernández, Juan Monzó‐Cabrera, Juan L. Pedreño‐Molina, Antonio J. Lozano‐Guerrero and Alejandro Díaz‐Morcillo

The purpose of this paper is to analyze the limitations of conventional reactive and resistive filters employed in the open ports of microwave‐heating applicators, in…

Abstract

Purpose

The purpose of this paper is to analyze the limitations of conventional reactive and resistive filters employed in the open ports of microwave‐heating applicators, in order to know the limits of these filters as a function of the permittivity of the inner materials.

Design/methodology/approach

CST Studio Suite™ commercial electromagnetic software has been employed to simulate the behaviour of singly and doubly corrugated reactive filters. Additionally, several configurations for resistive filters implemented with water are assessed. Optimization procedures based on genetic algorithms have been used by modifying some geometric parameters of the filters in order to obtain the best possible bandstop response.

Findings

Results show the serious limitations of these filters depending on the electric permittivity of the inner materials.

Practical implications

These limitations restrict the type of the materials that can be processed, so there is a need for new structures which solve these problems.

Originality/value

Although extensively used in many applications, there are few works that analyze the behaviour of these filters as a function of the geometric parameters or the sample permittivity, and therefore this influence needs to be studied.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 30 no. 5
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 1 June 1973

The 2120 frequency analyser is a constant percentage bandwith analyser for use in the frequency range 2Hz to 20kHz with provision for the connection of external filters

Abstract

The 2120 frequency analyser is a constant percentage bandwith analyser for use in the frequency range 2Hz to 20kHz with provision for the connection of external filters extending the range to 180kHz. It consists of a measuring amplifier combined with a built‐in active RC filter complex which is continuously variable and can be switched into four basic modes. It can be used as a constant relative band‐width filter having four selectable bandwidths of 1 per cent, 3 per cent, 10 per cent and 1/3 Octave; as a tunable bandstop filter which will suppress any chosen frequency more than 60dB, suppression at 0·5fo and 2fo being less than 1dB; as a tunable high pass filter, or as a tunable low pass filter.

Details

Aircraft Engineering and Aerospace Technology, vol. 45 no. 6
Type: Research Article
ISSN: 0002-2667

Article
Publication date: 19 May 2020

Christos Salis, Nikolaos V. Kantartzis and Theodoros Zygiridis

The fabrication of electromagnetic (EM) components may induce randomness in several design parameters. In such cases, an uncertainty assessment is of high importance, as…

Abstract

Purpose

The fabrication of electromagnetic (EM) components may induce randomness in several design parameters. In such cases, an uncertainty assessment is of high importance, as simulating the performance of those devices via deterministic approaches may lead to a misinterpretation of the extracted outcomes. This paper aims to present a novel heuristic for the sparse representation of the polynomial chaos (PC) expansion of the output of interest, aiming at calculating the involved coefficients with a small computational cost.

Design/methodology/approach

This paper presents a novel heuristic that aims to develop a sparse PC technique based on anisotropic index sets. Specifically, this study’s approach generates those indices by using the mean elementary effect of each input. Accurate outcomes are extracted in low computational times, by constructing design of experiments (DoE) which satisfy the D-optimality criterion.

Findings

The method proposed in this study is tested on three test problems; the first one involves a transmission line that exhibits several random dielectrics, while the second and the third cases examine the effects of various random design parameters to the transmission coefficient of microwave filters. Comparisons with the Monte Carlo technique and other PC approaches prove that accurate outcomes are obtained in a smaller computational cost, thus the efficiency of the PC scheme is enhanced.

Originality/value

This paper introduces a new sparse PC technique based on anisotropic indices. The proposed method manages to accurately extract the expansion coefficients by locating D-optimal DoE.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. 39 no. 3
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 1 June 2004

L. Unsworth

The problem of determining a rational function whose magnitude characteristic approximates some arbitrary functions of frequency in an equiripple sense is discussed. A…

Abstract

The problem of determining a rational function whose magnitude characteristic approximates some arbitrary functions of frequency in an equiripple sense is discussed. A novel method that provides a rational all‐pole equiripple approximation to any arbitrary magnitude response in the frequency domain is described. The technique is applied to a typical example that serves to illustrate the effectiveness of the method.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 23 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

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: 12 November 2019

Kanchana D., Radha Sankararajan, Sreeja B.S. and Manikandan E.

A novel low profile frequency selective surface (FSS) with a band-stop response at 10 GHz is demonstrated. The purpose of this designed FSS structure is to reject the…

Abstract

Purpose

A novel low profile frequency selective surface (FSS) with a band-stop response at 10 GHz is demonstrated. The purpose of this designed FSS structure is to reject the X-band (8-12 GHz) for the application of shielding. The proposed FSS structure having the unit cell dimension of 8 × 8 mm2, the miniaturization of the FSS unit cell in terms of λ0 is 0.266 λ0 × 0.266 λ0, where λ0 is free space wavelength. The designed FSS provides 4 GHz bandwidth with insertion loss of 15 dB. The transverse electric (TE) and transverse magnetic (TM) modes of the proposed design are same because of polarization independent characteristics and hold the angularly stable frequency response for both TE and TM mode polarization. Both the simulation and measurement results are in good agreement to each other.

Design/methodology/approach

The proposed FSS design contains square-shaped PEC material, which is placed on the substrate and the shape of the circle and rectangle is etched over the PEC material. The PEC material of the patch dimension is 0.0175 mm. The substrate used for the proposed design is FR4 lossy with the thickness of 0.8 mm and permittivity εr = 4.3 having a loss tangent of 0.02.

Findings

To find a new design and miniaturized FSS structure is discussed.

Originality/value

100%

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…

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: 25 January 2021

Preeti Pannu and Devendra Kumar Sharma

This paper aims to design a most demanding low profile and compact ultra-wide band (UWB) antenna system for various wireless applications. The performance (in terms of…

59

Abstract

Purpose

This paper aims to design a most demanding low profile and compact ultra-wide band (UWB) antenna system for various wireless applications. The performance (in terms of data rate) of UWB system is improved by using multiple-input-multiple-output (MIMO) technology with it. Owing to the overlap of other existing licensed bands with that of UWB, electromagnetic signals can interfere. So, notched band UWB MIMO antenna system reported here which is highly compact, bandwidth efficient, superior data rate and high inter-element isolation comparatively to other reported designs.

Design/methodology/approach

A 49 × 49 × 1.6 mm3 quad-port UWB MIMO antenna with specific bandwidth elimination property is designed. The proposed planar MIMO configuration comprises unique four identical “Cordate-shaped” monopole radiators fed by 2.3-mm thick microstrip-lines. The radiators are located right-angled to each other to enhance inter-element isolation. Further, a different approach of slitted-substrate is applied to minimize the overall size and mutual coupling of the MIMO antenna, as a substitute of decoupling and matching structures. The defected ground structure is used to obtain −10 dB impedance bandwidth in entire UWB band, without compromising with the lower cut-off frequency response. Further, to eliminate the undesired resonant band (WLAN at 5.5 GHz) from UWB, a rounded split ring resonator is introduced in monopole patch.

Findings

In the entire operating band of 2.8 to 11 GHz, isolation among elements is more than 24 dB, envelope correlation coefficient less than 0.002, diversity gain greater than 9.99 dB and TARC less than −7 dB are obtained at all 4-ports.

Research limitations/implications

The measured parameters of the fabricated prototype antenna on FR4 substrate are found in good agreement with the simulated results. The small variation in software results and hardware results are observed due to hardware design limitations.

Practical implications

The proposed design may be used for any wireless application following in the range of UWB.

Originality/value

It can be shown from graphs of measured parameters of the fabricated prototype antenna. They found to be in good agreement with the simulated results.

Details

World Journal of Engineering, vol. 18 no. 3
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 1 January 1992

Allen‐Bradley recently announced a new addition to the company's CVIM vision input module offering. The Allen‐Bradley optical character recognition package, OCR‐PAK…

Abstract

Allen‐Bradley recently announced a new addition to the company's CVIM vision input module offering. The Allen‐Bradley optical character recognition package, OCR‐PAK, allows the CVIM module to read character strings within an image for product identification.

Details

Sensor Review, vol. 12 no. 1
Type: Research Article
ISSN: 0260-2288

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