Design Of Low-pass Filter Research Articles

Microstrip Lowpass Filter Realization Using Monic Chebyshev Polynomial

This paper presents a novel approach to microwave lowpass filter design that addresses several challenges in modern microwave systems, including size, performance, and cost. With that in mind, we propose using monic Chebyshev polynomials as the characteristic function for the filter to achieve a low passband insertion loss and maximum cutoff slope. The half-power cutoff frequency characterizes these filters, and the ripple factor is not considered a design parameter. To demonstrate the effectiveness of the monic Chebyshev approximation, a comparison is made with chained function (CF) filters designed for microwave applications. It has been shown that the monic Chebyshev filter outperforms CF filters in all applications, including microwaves.

Fine-tuning digital FIR filters with gray wolf optimization for peak performance

The design of optimum filters constitutes a fundamental aspect within the realm of signal processing applications. The process entails the calculation of ideal coefficients for a filter in order to get a passband with a flat response and an unlimited level of attenuation in the stopband. The objective of this work is to solve the FIR filter design problem and to compare the optimal solutions obtained from evolutionary algorithms. The design of optimal FIR low pass (LP), high pass (HP), and band stop (BS) filters is achieved by the utilization of nature-inspired optimization approaches, namely gray wolf optimization ,cuckoo search, particle swarm optimization, and genetic algorithm. The filters are evaluated in terms of their stop band attenuation, pass band ripples, and departure from the anticipated response. In addition, this study compares the optimization strategies applied in the context of algorithm execution time which is achievement of global optimal outcomes for the design of digital finite impulse response (FIR) filters. The results indicate that when the Gray wolf algorithm is applied to the development of a finite impulse response (FIR) filter, it produces a higher level of performance than other approaches, as supported by enhanced design precision, decreased execution time, and achievement of an optimal solution.

Design of Low Pass Filters Using a Symmetrical T-Shaped Defected Microstrip Structure

Design of Low Pass Filters Using a Symmetrical T-Shaped Defected Microstrip Structure

Design of wide stopband lowpass filter using defected ground structure

Design of wide stopband lowpass filter using defected ground structure

Design of a Microwave Quadrature Hybrid Coupler with Harmonic Suppression Using Artificial Neural Networks

In this paper, a compact and simple structure of an elliptic microstrip lowpass filter (LPF) is designed for harmonic suppression in microwave quadrature hybrid coupler (QHC) applications. A radial resonator and a rectangular resonator are used to produce an elliptic LPF. The proposed LPF is used on the outer sides of the branch line coupler, which has improved the coupler harmonic suppression. Furthermore, artificial neural networks (ANNs) are incorporated to improve the LPF design process. The LPF best structure is obtained using the proposed ANN model. The proposed LPF has a compact size, which only occupies 16.4 mm × 7.3 mm equals to 0.164 λg × 0.073 λg, has a cut frequency of 2.2 GHz, and shows a sharp transmission band with a roll-off rate of 158.3 dB/GHz. Finally, the deigned QHC operates correctly at 1 GHz, which shows high harmonic suppression ability. The proposed QHC provides wide suppression band from 2.25 GHz up to more than 14 GHz, which can effectively suppress 3rd, to 14th harmonics. The proposed coupler features desirable parameters of S11, S21, S31, and S41, with magnitude of −21 dB, −3.4 dB, −3.3 dB, and −22.5 dB, at the operating frequency. The proposed approach mitigates the complexity of the circuit fabrication, compared with the previous methods while achieved desirable performances for the proposed QHC.

Design and Implementation of Efficient IIR Low Pass Filter Based On Vedic Multiplier Algorithm

Abstract: This article presents a state-of-the-art design for a limitless impulse response (IIR) filter that can be easily reconfigured for use in real-time software. Using a vedic multiplication strategy, this work demonstrates the excellent general performance of a recursive or Infinite Impulse Response (IIR) filter. The number of repeats may be kept to a minimum and the processor's overall performance is improved by the reduction of computational delay and hardware. This research investigates the impact of different filter architectures on the development process and overall performance. To enforce and evaluate the planned filter's functionality, simulation is used across three independent platforms. The first system is MATLAB/ SIMULINK, the software package utilised to implement the IIR filter. The second strategy is called "HDL - Cosimulation," and it involves using SIMULINK's already-present tools in order to translate the formulated filter-out method into VHDL, the language used to describe very fast integrated circuits. The third approach uses Xilinx System Generator's pre-existing building components to physically realise the filter design. The method shown here allows the proposed filter to be implemented locally inside the FPGA device of interest

Realization of nth Order Wave Active Low-Pass Filter Using Differential Difference Current Conveyor

A wave active filter (WAF) based on a differential difference current conveyor (DDCC) is presented in this paper. An active filter formation depends entirely on wave quantity processing. The wave method is demonstrated for the basic wave active elements (WAEs) of active filters such as a series inductor and a shunt capacitor. The novelty of the proposed work is that the mathematical operations required to implement the wave active components, such as lossy integration-subtraction; subtraction; summation and inverter, are performed using the DDCC as an analog building block (ABB). Designing WAFs of lower to higher-order is extremely challenging, i.e., great motivation to propose a WFA using a CMOS-based DDCC for lower and higher-order low-pass Butterworth filter topologies. Additionally, the filter performances are verified through noise analysis, percentage total harmonic distortion (%THD) and Monte Carlo analysis. The proposed WFA is theoretically verified for [Formula: see text]th order low-pass Butterworth filter designs ([Formula: see text]) using DDCC-based WAEs and validated using SPICE simulations with [Formula: see text]m TSMC CMOS technology parameters for DDCC, operating on [Formula: see text][Formula: see text]V.

Spoof Surface Plasmon Polariton Based on Stepped Grooves and Its Application in Compact Low-Pass Filter Design

Spoof Surface Plasmon Polariton Based on Stepped Grooves and Its Application in Compact Low-Pass Filter Design

Minimized Group Delay FIR Low Pass Filter Design Using Modified Differential Search Algorithm

Designing a finite impulse response (FIR) filter with minimal group delay has proven to be a difficult task. Many research studies have focused on reducing pass band and stop band ripples in FIR filter design, often overlooking the optimization of group delay. While some works have considered group delay reduction, their approaches were not optimal. Consequently, the achievement of an optimal design for a filter with a low group delay value still remains a challenge. In this work, a modified differential search optimization algorithm has been used for the purpose of designing a minimal group delay FIR filter. The results obtained have been compared with the classical techniques and they turned out to be promising.

Novel Compact Lowpass Filter Using Dual-Layer Coupled Resonators

This article presents the synthesis and design of a novel compact lowpass filter (LPF) with low insertion loss and significant near-skirt selectivity. The LPF is designed based on a new structure called dual-layer coupled resonators (DLCRs) implemented with striplines embedded in air cavity, thus characterized with high quality factor and low insertion loss. To enhance band-edge selectivity and stopband attenuation, finite-position transmission zeros (TZs) are introduced with DLCRs to form pseudo-elliptical fitter functions. The equivalent circuit of DLCR is provided first, followed by detailed synthesis preconditions and procedures based on element extraction. With the elucidated synthesis process, TZs can be customized and arbitrarily placed at specified frequencies. The proposed synthesis theories are general and applicable to LPFs with arbitrary order and assigned TZs, thus providing effective guidelines for physical implementation. Besides, with smaller needed capacitances and avoided long-length high-impedance lines in TZ-producing resonant pairs, a more compact footprint is achieved with DLCRs. A 13th-order LPF with three TZs is synthesized and fabricated for navigation satellite applications, of which the good measurement results have validated the proposed theories.

Second Generation Current Controlled Current Conveyor Based Low Pass Filter Design For The Processing of EEG Signals

EEG signals are noisy signals that allow brain activity to be analyzed. In recent years, it has been seen that current conveyor-based circuits, which have many advantages such as wide bandwidth, high linearity, low power consumption, have been used instead of operational amplifiers in the analysis of these signals. In this study, a second-generation current controlled current conveyor (CCCII+) low pass filter circuit with a cut-off frequency of 100 Hz has been presented for the analysis of EEG signals. The simulation of the circuit was carried out with the Orcad pspice program. In addition, the application circuit of this low-pass filter circuit has been made and oscilloscope images have been obtained for some frequency values. AD844 IC is used as current conveyor in the application circuit. The data of epilepsy patients and normal people taken from the University of Bonn were applied to the CCCII+ low pass filter circuit and the frequency bands of these signals were examined. It has been predicted that if this CCCII+ low pass filter circuit is used in EEG measurements, it will give good results in the diagnosis of neurological diseases such as epilepsy.

Design of a Fractional Order Low-pass Filter Using a Differential Voltage Current Conveyor

In this paper, an active implementation of a differential voltage current conveyor (DVCC) based on a low-pass filter operating in the fractional order domain is presented. The transfer function for a fractional order system is dependent on the rational approximation of sα. Different methods used for calculating the rational approximation, including Carlson, Elkhazalil, and curve fitting, are evaluated here. Finally, to validate the theoretical results, a fractional order Butterworth filter is simulated in the Pspice environment using the 0.5 micrometer CMOS technology with an R-C network-based fractional order capacitor. Additionally, using the Monte Carlo analysis, the impact of current and voltage faults on DVCC response is investigated. It has been inferred that realization with a wider bandwidth is possible.

Literature Review of Low Pass Filters Based on CMOS for Biomedical Applications

Abstract: A survey of low pass filters with good linearity, low weight, and low power consumption has been done in this study .we examine the numerous low pass filter types ,their uses and design factors in this survey. we start by looking at low pass filters fundamental concepts and characteristics of their frequency response. in this study ,many low pass filter types and associated technologies are discussed. Low pass filter with low noise ,low power requirements, and low weight have been shown to be an implementing RKTG pairs in low pass filter circuits by varying the aspect ration of MOSFETs manufactured at 45nm,90nm,and 180nm technologies. this survey is valuable resource for engineers and scientists study in signal processing and communication systems since it offers a through review of low pass filters and their uses

Design and analysis of novel DGS-loaded low-pass filter with wide stopband

Abstract This article deals with design and development of a novel 7th order low-pass filter with defected ground structures for S-band applications. The proposed LPF structure was comprised of dumbbell shaped interdigital defected ground structures and open stubs as series inductor and shunt capacitor in the pass band. In addition, an equivalent circuit model was derived and optimized to achieve a 3-dB cut off frequency about 4 GHz with a reflection coefficient of better than −20 dB. Moreover, proposed low-pass filter was manufactured on a Rogers RO4003C substrate with a dielectric constant of 3.38, the dissipation factor of 0.0027. The developed LPF has a very flat pass-band with a transmission coefficient less than −0.5 dB and the measured transmission coefficient better than −18 dB in the passband (DC-3.6 GHz). Meanwhile, the prototype has a 20 dB harmonic suppression level in the frequency range from 5.54 GHz up to 43.5 GHz. Furthermore, the measured peak to peak group delay variation was less than 170 ps in the passband. The proposed filter has a very compact size of 195.3 mm2.

Bridge Static Influence Line Identification Based on Structural Dynamic Responses Under High-Speed Trains

Bridge influence lines can reflect the performance status of bridge structures and are an important tool to evaluate high-speed railway bridges. Because a high-speed train can cause large dynamic response on a bridge, it is difficult to identify the static influence line of the bridge. To extract the static bridge influence lines for bridge evaluation, this paper proposes a low-pass filter design method for static influence line identification. By maximizing the difference in bridge static and dynamic energy, the relationship between the frequency domain characteristics of the bridge dynamic response and the filter parameters is established. Based on this relationship, reasonable values of the low-pass filter parameters can be determined. After filtering the dynamic response, the quasi-static response can be effectively obtained, and the bridge static influence line can be identified through the least square regularization method. Finally, a numerical example of the vehicle–bridge interaction model is used to verify the effectiveness of the proposed method. The results show that the low-pass filter designed through the proposed principle can accurately remove the dynamic effects, and its stability and robustness are good. The research results provide a reliable method for the static influence line identification of high-speed railway bridges.

Continuous-Time Analog Filters for Audio Edge Intelligence: Review on Circuit Designs [Feature

Edge audio devices can reduce data bandwidth requirements by pre-processing input speech on the device before transmission to the cloud. As edge devices are required to ensure always-on operation, their stringent power constraints pose several design challenges and force IC designers to look for solutions that use low standby power. One promising bio-inspired approach is to combine the continuous-time analog filter channels with a small memory footprint deep neural network that is trained on edge tasks such as keyword spotting, thereby allowing all blocks to be embedded in an IC. This paper reviews the historical background of the continuous-time analog filter circuits that have been used as feature extractors for current edge audio devices. Starting from the interpretation of a basic biquad filter as a two-integrator-loop topology, we introduce the progression in the design of second-order low-pass and band-pass filters ranging from OTA-based to source-follower-based architectures. We also derive and analyze the small-signal transfer function and discuss their usage in edge audio applications.

Ladder-Type Gm -C Filters With Improved Linearity

A simple yet effective approach to improve the linearity of the transconductor-capacitor ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">G_m-C</i> ) filters is proposed without any area or power overhead. Following a generalized nodal analysis, the transconductors of classical filter topology are rewired such that their input differential voltage lies within the linear regime. The effectiveness of the proposed method is validated through the design and simulation of a fifth-order Butterworth low-pass filter (LPF) in a standard 65-nm CMOS process. The proposed filter implementation occupies 0.0164 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> (0.003 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /pole) die area and consumes 167-μW for the cut-off frequency of 1-MHz. Operating at 1-V voltage supply, it shows an in-band total harmonic distortion (THD) of –49.14 dB for 200-mV peak-to-peak 1MHz differential voltage. An in-band 3rd-order intercept point (IIP3) of 9.36 dBm is also achieved with an in-band spurious-free-dynamic range (SFDR) greater than 53-dB, all of which reflect meaningful improvements relative to the classical architecture and despite the modest linearity performance of the internal <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">G_m</i> stages.

Coaxial Low-Pass Filter Design and Manufacture

In this study, a low-pass filter with coaxial transmission lines is designed and produced. The objective for designing a coaxial low-pass filter was to utilize both low loss transmission and high breakdown voltage capability for high power microwave applications to enable the suppression of the second harmonic of the 4.4-6 GHz C-Band ( C-Band was selected as a proof of concept ) signals with minimal insertion loss. Microwave and 3D electromagnetic simulators were used in the filter design. The design was started by establishing an 11 th order Chebyshev low-pass filter prototype giving 0.05 dB ripple. Based on this prototype, a filter circuit consisting of capacitors and inductors as lumped elements was designed. The low and high impedances to be selected for the stepped impedance method, which is the basis of the transition to coaxial transmission lines, were decided and the most suitable impedances for manufacturing was determined. The filter using these impedances and designed with stepped impedance lines was transformed into the filter in which coaxial transmission lines are used. Coaxial transmission lines in the low-pass filter circuit consist of conductors with an insulating material in between. While the insulating material is selected as air in the high impedance sections of the transmission lines, it is PTFE (Polytetrafluoroethylene) with an insulating constant of 2.1 in the low impedance sections. The designed filter was manufactured. The basic properties of the manufactured filter were characterized by using RF measuring devices and compared with the designed filter. The measurements results prove that the frequency responses of the designed filter and the produced filter are very close to each other. Namely, a low-pass filter with a cutoff frequency of 6 GHz, a sharp suppression of about 45 dB at the stopband of 9 GHz and a return loss of 20 dB was designed and produced by using coaxial transmission lines. The novelty in our work can be stated that the power handling capability is increased by two techniques. The first one is that the highest transmission line radius preventing the higher order mode excitations is used to decrease the conductor loss. Teflon is covered around the low impedance lines to enhance the dielectric breakdown capability. Teflon inclusion is also used to decrease the practical low impedance level that improves the filter characteristics.

Design of Two Stage OTA based Sixth Order Butter-worth Low Pass Filter using CMOS 180nm Technology

This paper shows the design of 6th order Butter-worth low pass filter based on operational trans-conductance amplifier (OTA). The designing and simulation results are obtained using Cadence Virtuoso tool with 180nm (0.18μm) technology. The simulation results of OTA have a gain of about 97.3dB. The simulation results of butter-worth low pass filter for 1.25V supply voltage and 20μA biasing current gives -96.4mdB gain and 2.9GHz bandwidth for a frequency range of 100Hz to 10GHz. The results are presented in this paper.

Design of Modified Jacobi Microstrip Lowpass Filter for L-Band Application

In this brief, a design of microstrip lowpass filter with the 1 GHz cutoff frequency is revisited, where a class of modified Jacobi polynomials is used for the filter design. The optimization procedure for these filters includes the passband return loss minimization and the roll-off factor enhancement using the magnitude correction of the transmission coefficient. Mentioned correction is performed by introducing the multiple transmission zeros such that LC ladder prototype filter can be realized symmetrically. Three seventh degree filters for L-band applications are realized and simulated: allpole, with a single and double transmission zeros. It is shown that, among these three stepped impedance lowpass filters realizations, the filter with simple transmission zeros offers the best performance.