Design Of Low-pass Filter Research Articles

Comparison and Performance Evaluation of Low Pass Filter Design for various samples using Artificial Neural Network

To design any type of filters complex calculation is needed. But with the help of window method, it become simple. In this paper a Low pass filter is designed by window method with the help of Artificial Neural Network. Here, Hann window and Blackman window is used to design filter and Feed Forward Back Propagation algorithm has been taken for neural network. In this paper different data sets for cut off frequency are consider for training and testing purpose to get best results.

Sharp-Rejection, Wide and Deep Stopband Low Pass Filter Design Using Open Stubs and DGS Patterns

Sharp-Rejection, Wide and Deep Stopband Low Pass Filter Design Using Open Stubs and DGS Patterns M. Challala,∗ and M. Boulakroune University M’Hamed Bougara of Boumerdes, Institute of Electrical and Electronic Engineering, Signals and Systems Laboratory, Department of Electronics, Boumerdes, Algeria University Kasdi Merbah of Ouargla, Faculty of New Technologies of Information and Communication, Electronics and Communication Department, Ouargla, Algeria

Mitigating adjacent channel interference in vehicular communication systems

In the last few decades, dedicated wireless channels were specifically allocated to enable the development and implementation of vehicular communication systems. The two main protocol stacks, the WAVE standards proposed by the IEEE in the United States and the ETSI ITS-G5 in Europe, reserved 10MHz wide channels in the 5.9GHz spectrum band. Despite the exclusive use of these frequencies for vehicular communication purposes, there are still cross channel interference problems that have been widely reported in the literature. In order to mitigate these issues, this paper presents the design of a two-stage FIR low-pass filter, targeting the integration with a digital baseband receiver chain of a custom vehicular communications platform. The filter was tested, evaluated and optimized, with the simulation results proving the effectiveness of the proposed method and the low delay introduced in the overall operation of the receiver chain.

Development of high-stability magnet power supply

A very stable (≤10ppm) magnet power supply (MPS) is required in an accelerator to achieve acceptable beam dynamics. Many factors affect the stability of an MPS, so design of the MPS requires much attention to noise-reduction schemes and to good processing of the signals from the feedback stage. This paper describes some design considerations for an MPS installed and operated in the Pohang Accelerator Laboratory: (1) control method, (2) oversampling technology, (3) ground isolation between hardware modules and (4) low-pass filter design to reduce the switching noise and rectifier ripple components, and shows the stability of three designed devices. The MPS design considerations were verified and validated in simulations and experiments. This paper also shows the relationship between stability and measurement aperture time of digital voltage meter 3458A to measure stability of a current.

Design of LPF using suspended substrate microstrip lines as high‐Z sections for stopband extension

ABSTRACTThis article introduces the use of suspended substrate microstrip lines (SSMLs) as high‐Z sections in the design of lowpass filters (LPFs) to extend the stopband. The SSMLs are formed by etching slots on the backside of microstrip lines and placing the substrate on an aluminum base with grooves that cover these slots. The higher characteristic impedance property of SSMLs brings about not only shorter length for high‐Z lines but also a larger high‐to‐low impedance ratio, thus deepening the stopband suppression and shifting the spurious passband away. As a demonstration, a wide stopband LPF combining this structure with hammer‐shaped stubs is designed, fabricated, and measured. The 20 dB stopband is obtained from 1.45 to 11.77 GHz. Compared with reported LPFs, this shows the widest fractional bandwidth (FBW) of 156% without sacrificing other performances. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1204–1207, 2016

A Novel Non-Invasive Method for Extraction of Geometrical and Texture Features of Wood

ABSTRACTNon invasive feature detection in wood based application requires exact discrimination between geometrical edges and texture. It has been found that traditional edge detection algorithms are highly sensitive to noise and texture and produces inferior results with wood. The present work encompasses a micro level reconstruction of Palash and Rosewood by using micro X-rays CT scanner. It also encompasses a new edge detection algorithm using newly constructed Chebyshev polynomial based fractional order differentiator. Transform based method has been used for reconstruction purpose. Newly designed fractional order filter has been applied on these reconstructed images. Chebyshev polynomial based fractional order differentiator has been used for filtering operation. Quadrature Mirror Filter (QMF) concept has been used for design of high pass filter and low pass filter. Preprocessing has been performed by using this filter. Canny edge detection algorithm has been used on this preprocessed image. The algorithm has been tested on two different test cases of wood images a) Palash and b) Rosewood. The effect of relaxation coefficient has also been presented and discussed.

A convex optimization model for finding non-negative polynomials

This paper presents a convex optimization model for the problem of finding some polynomials for which certain linear combinations are non-negative polynomials. This model is then applied to solve several filter design problems. We first reformulate some low-pass filter design problems, with finite or infinite impulse response, as optimization problems over non-negative (real or complex) polynomials whose feasibility problems can be solved by applying our model. The whole optimization problems are then solved by using a combination of a bisection search procedure on an appropriate parameter and our convex optimization model to solve the feasibility problems. Some numerical examples illustrate the method.

Hybrid heuristic search method for design of digital IIR filter with conflicting objectives

The design of digital IIR filter design by using evolutionary algorithms has gained much attention in the previous years. Most of the researchers treated the design problem as a single objective optimization problem and applied the techniques for minimizing the magnitude response error. In this paper the design of filter is treated as a multi-objective problem by simultaneously minimizing the magnitude response error, linear phase response error and optimal order along with meeting the stability criterion. A hybrid heuristic search technique having differential evolution (DE) method as a global search technique and binary successive approximation based evolutionary search method as a local search technique has been proposed. Based on mean value of population, new mutation strategies have been proposed. The above proposed hybrid heuristic search technique has been applied effectively to solve the multi-parameter and multi-objective optimization problem of low-pass, high-pass, band-pass and band-stop digital IIR filter design. The obtained results reveal that the proposed technique with new proposed mutation strategies performs better than the already existing mutation strategies of DE and other algorithms applied by other researchers for the design of digital IIR filter.

Design of the adaptive log-domain low-pass filter

This paper presents the structure and realization method of the current-controlled adaptive low-pass filter which based on the design of LC ladder network. After amplifying, amplitude limiting and shaping, the input voltage signal was converted into frequency signal. Then by the broadband frequency-current conversion circuit it was converted into current signal which has a linear relationship with input frequency. The current signal was as the bias current to adjust the cut-off frequency of the log-domain low-pass filter. So that frequency of the filter can automatically track the input signal frequency. In this paper, the design principle was introduced in detail, the design formulas were derived and the circuit of adaptive second order log-domain low-pass filter was given. The filter can realize the scope of the cut-off frequency up to 30MHz. The tracking range for the input frequency is from 1MHz to 30MHz. The simulation results show the effectiveness of design method.

Design of Microstrip Lowpass-Bandpass Triplexer With High Isolation

This letter proposes a lowpass-bandpass triplexer consisting of one lowpass channel and two bandpass channels. Stepped-impedance stubs are used in the lowpass filter (LPF) design, which bring a sharp selectivity. Defected ground structures are utilized to increase the impedance of one transmission line in the lowpass section, giving improved performance. High Isolation is achieved by careful consideration of the input signal splitting structure. To illustrate the concepts, a lowpass-bandpass triplexer is designed, fabricated and measured. The cut-off frequency of the LPF is chosen to be 1 GHz. The central passband frequencies are selected to be 2.4 and 5.8 GHz. Simulated and measured results are found to be in good agreement with each other. Isolations among the three bands are better than 40 dB.

Integral-Equation Formulation for the Analysis of Capacitive Waveguide Filters Containing Dielectric and Metallic Arbitrarily Shaped Objects and Novel Applications

This paper presents an integral-equation formulation specialized for the analysis of capacitive waveguide circuits, which include arbitrarily shaped conducting and homogeneous magnetic/dielectric objects. The technique benefits from the symmetry of the structure by formulating a 2-D scattering problem with oblique angle of incidence, combined with the use of the parallel-plate Green’s functions. As practical applications, the paper proposes novel low-pass filter designs loaded or coated with dielectric and magnetic homogeneous materials. If the filter is properly designed, the use of these materials could improve the filter response, selectivity, or out-of-band performance, and power-handling capabilities. Some novel filter design implementations, showing these kinds of benefits, are presented for the first time in this paper. For validation, a commercial full-wave simulator is employed, showing the validity, accuracy, and computational efficiency of the novel software tool.

A Novel Design of a Ring Resonator Low Pass Filter

This paper presents a novel structure of low pass filter designed by using microstrip technology. The proposed filter consists of a modified ring resonator with open stubs and two input/output feed lines. Based on series of optimization and a specific design method, a compact low pass filter with good electrical performances is obtained. In order to characterize the frequency response of the proposed filter, the simulations are carried out using two different solvers (ADS Agilent and CST-MWS). Furthermore, to validate the conception approach the circuit is manufactured and measured. The experimental results shows a wide attenuation band with a good rejection level up to 6 GHz, a cutoff frequency of 2.66 GHz and a reduced insertion loss level. In addition, a good agreement between the simulation and the measured results is achieved.

The Harmonic Suppression Characteristic Analysis of a Phase-Shifting Reactor in Rectifier System

Multiple rectifier technology is an effective method to reduce the harmonic current injected from converter to the grid [1], and phase-shifting reactor (PSR) is a kind of magnetic equipment which can be used to realize the function of phase-shifting[2]-[4]. In the multiphase rectifying system, the phase-shifting property of PSR plays an important role in harmonic suppression, meanwhile, as an inductive device, its filtering property cannot be neglected. Therefore, with the purpose of evaluating the phase-shifting and filtering properties of PSR in the harmonic current suppression, three kinds of reactors with approximate harmonic suppression effect in the 6-phase rectifying system are designed, one is without phase-shifting, and the other two are with phase-shifting in different phase-shifting angle. And then, based on the Fast Fourier Transform (FFT) algorithm and the frequency sweep method, the phase-shifting and filtering properties are respectively revealed by the harmonic current spectrum diagram and the amplitude-frequency characteristic curve. Lastly, the idea to introduce the low-pass filter's design method to the design of PSR to strengthen the harmonic suppression effect is proposed.

MICROSTRIP LOW PASS FILTER DESIGNS USING DEFECTED GROUND STRUCTURE

The microwave filters play an important role in most RF/microwave applications. They are designed to remove undesired harmonics to reduce the system noise or to remove spurious mixing products. DGS slot with an interdigital shape are introduced here in two elliptic low pass filter designs. Here a fifth order low pass filter was designed, simulated and fabricated for a cut off frequency of 3GHz. Finally a prototype model were designed based on the simulation results obtained. These prototype filter designs have more than 20 dB of stop band rejection and a good return loss in the pass band. The fabricated results proved to be better than the simulation results. In the first low pas filter design the central aperture was replaced with the interdigital slot structure which improved the stop band response at the resonant frequency around 7.8 GHz. To improve the stop band rejection two interdigital structures were introduced in the bottom layer (Ground).

Electronically Tunable Current-mode High-order Ladder Low-pass Filters Based on CMOS Technology

This paper describes the design of current mode low-pass ladder filters based on CMOS technology. The filters are derived from passive RLC ladder filter proto- types using new CMOS lossy and lossless integrators. The all-pole and Elliptic approximations are used in the pro- posed low-pass filter realizations. The proposed two types of filter can be electronically tuned between 10 kHz and 100 MHz through bias current from 0.03 µA to 300 µA. The proposed filters use 1.5 V power supply with 3 mW power consumption at 300 µA bias current. The proposed filters are resistorless, use grounded capacitors and are suitable for further integration. The total harmonic distor- tion (THD) of the low-pass filters is less than 1% over the operating frequency range. PSPICE simulation results, obtained by using TSMC 0.18µm technology, confirm the presented theory.

Compact and Wide Stopband Lowpass Filter Using Open Complementary Split Ring Resonator and Defected Ground Structure

Abstract. A compact (0.16  g × 0.08  g ) and wide stop-band lowpass filter design using open complementary split ring resonator (OCSRR) and defected ground structure (DGS) is presented in this paper. Low pass filter is con-structed using two cascaded stages of OCSRR. Since the rejection bandwidth of the OCSRR is narrow, tapered dumbbell shaped DGS section is placed under the OCSRR to enhance the bandwidth. The cutoff frequency (f c ) of the proposed lowpass filter is 1.09 GHz. The rejection band-width of the filter covers the entire ultra wideband spec-trum. Hence the spurious passband suppression is achieved up to 10 f c . The designed filter has been fabri-cated and validated by experimental results. Keywords Lowpass filter, defected ground structure (DGS), open complementary split ring resonator (OCSRR) 1. Introduction On the motive of conventional filter design methods such as stepped impedance and open stub suffering from poor skirt characteristics and spurious passband, re-searchers have paid great attention over the past few years in designing a compact and sharp cutoff lowpass filters with spurious free wide stopband. Lowpass filter using different defected ground structures (DGS), photonic bandgap (PBG) structures and electromagnetic bandgap structures have been proposed in various literatures [1–9]. Sharp cutoff and low insertion loss lowpass filter using a complementary split ring resonator (CSRR) is reported in [3]. Cascaded stages of CSRR with open stub configura-tion, exhibiting sharp cutoff lowpass response are pre-sented in [4]. Planar photonic bandgap (PBG) structures involving compact microstrip resonating cell (CMCR) are utilized to design a lowpass filter with wide stopband [5]. Recently, a lowpass filter with very sharp transition band using OCSRR is demonstrated in [6]. In this paper, a new technique is proposed to reduce the size of the lowpass filter and to obtain the wide spurious free stopband. The lowpass filter is designed using open complementary split ring resonator and a tapered dumbbell shaped DGS is placed under the OCSRRs to extend the stopband. The proposed lowpass filter is smaller and outperforming the existing filters in terms of insertion loss level, roll off rate and rejection bandwidth. Figure 1 shows the schematic of OCSRR printed on the microstrip line. This structure is first proposed in [6] for designing a sharp cutoff lowpass filter with compact size. OCSRR is a negative image of the open split ring resonator. To study the frequency response characteristics of the OCSRR, this structure is designed on Rogers 5880 substrate with a dielectric constant of 2.2 and a substrate thickness of 0.381 mm and simulated using an Ansys full wave simulator.

English

English

A systematic implementation of elliptic low-pass filters using defected ground structures

For the past decade, defected ground structures (DGSs) are largely used in the implementation of low-pass filters, without a systematic approach. In this paper, a simple systematic approach for the design of elliptic low-pass filters using DGSs is proposed. An empirical model for a simple rectangular slot DGS is extracted for its equivalent circuit. Using this model, low-pass filters for various orders are designed for critical filter specifications and optimized by reducing the parasitic effects induced by DGSs. This systematic implementation of DGS-based filters achieves more than 90% of the desired filter specifications. Due to the improved slow-wave factor and power handling capacity of DGSs, the filter is more compact and reliable than the conventional filters.

High-Power Waveguide Low-Pass Filter With All-Higher-Order Mode Suppression Over a Wide-Band for Ka-Band Satellite Applications

In this letter, the design of a compact high-power waveguide low-pass filter with low insertion loss, all-higher order mode suppression, and stopband rejection up to the third harmonic, intended for Ka-band satellite applications, is presented. The method is based on step-shaped bandstop elements separated by very short (ideally of zero length) waveguide sections easily manufactured by low-cost computer-controlled milling. Matching is achieved by short input/output networks based on stubs whose heights are optimized following classical approaches. The novel filter presents a reduction in insertion loss and a remarkable increase in the high-power handling capability when compared to the classical waffle-iron filter and alternative solutions previously proposed, while the out-of-band frequency behavior remains unaltered.

An improved stopband and sharp roll off microstrip low pass filter with defected ground structures

In this paper a novel low pass filter (LPF) design procedure is proposed for electromagnetic bandgap based microstrip filters without using classical filter design approach. LPF is designed for ultra-wide stopband and sharp roll-off rate via proposed design procedure. It has been shown that finite periodic fan-shaped defected ground structures (FSDGSs) and double radial stubs (DRSs) yield broad stopband and very sharp transition band. The proposed LPF has −3 dB passband from dc to 1.49 GHz, and −20 dB broad stopband from 1.65 GHz up to 7.41 GHz. Full wave electromagnetic (EM) simulation of the proposed filter is achieved with ANSYS's High Frequency Structure Simulator (HFSS) and equivalent circuit (EC) model of the filter is proposed and verified via Applied Wave Research (AWR) software. To verify the simulations, filter is realized on ARLON AD1000 substrate, and measured with Agilent 5245A PNA-X Vector Network Analyzer. Measurement results of fabricated filter are in good agreement with EM and EC simulations.