Low pass filter (LPF)

This paper presents a design of compact triple-mode resonator with Defected Ground Structure. This resonator consists of a square open-loop half-wavelength resonators and a stepped impedance resonator structured in the middle which is connected to the mid

This article exhibits a filtering power divider designed with substrate integrated waveguide (SIW) technique, having the power dividing as well as filtering functionalities. In the design band-pass performance is realized by merging SIW structure having high-pass response and complementary split ring resonator (CSRRs) with parallel tank LC resonant response and the dumbbells shape defected ground structure (DGS) with high out of band rejection characteristics. The anticipated structure serves as both a power divider and a filter, it reduces both the cost and the size of the system. Structure is constructed and tested to confirm the design functionality. The measurement result shows the return loss of-25.94 dB with 3-dB fractional bandwidth of 2.85% at 14 GHz.

In this paper, a novel compact microstrip Low-Pass Filter (LPF) with sharp roll-off and ultra-wide stopband with high suppression level is presented. In the proposed filter, square-shaped resonators are used. The cutoff frequency at 3dB is 1.88GHz. The maximum insertion loss of this filter is less than 0.1dB and the return loss is also less than 16dB in the passband. In the proposed structure, the stopband extends from 2.07 to 29.5 GHz at 24dB level of suppression and is considered as an ultra-wide stopband. There is a significant relationship between simulation and fabrication results, which have justified the functionality of the proposed LFP, respectively.

In this paper, a novel compact microstrip Low-Pass Filter (LPF) with sharp roll-off and ultra-wide stopband with high suppression level is presented. In the proposed filter, square-shaped resonators are used. The cut-off frequency at 3dB is 1.88GHz. The maximum insertion loss of this filter is less than 0.1dB and the return loss is also less than 16dB in the passband. In the proposed structure, the stopband extends from 2.07 to 29.5 GHz at 24dB level of suppression and is considered as an ultra-wide stopband. There is a significant relationship between simulation and fabrication results, which have justified the functionality of the proposed LFP, respectively.

An asymmetric DGS consisting of two square headed slots connected transversely with a rectangular slot is etched in the ground plane underneath a high-low impedance microstrip line.  It provides a band-reject filtering characteristics with sharp transition. Thus, it may be modeled as m-derived filter section. Accordingly, T-type LC equivalent circuit is proposed and LC parameters are extracted. A planar composite lowpass filter is designed by image parameter method and implemented by different DGS units. A composite filter requires at least three filter sections, of which two m-derived sections and one constant k-section. In proposed scheme, one such m-derived section is directly replaced by proposed DGS unit, whose cut-off frequency is same as that of designed m-derived section. The other m-derived section implemented by proposed DGS unit divided into equivalent two L-sections which will act as a termination for impedance matching. A constant k-section has been realized by a dumbb...

Schmitt trigger (ST) circuits are widely used integrated circuit (IC) blocks with hysteretic input/output (I/O) characteristics. Like the I/O characteristics of a living neuron, STs reject noise and provide stability to systems that they are deployed in. Indeed, single-input/single-output (SISO) STs are likely candidates to be the core unit element in artificial neural networks (ANNs) due not only to their similar I/O characteristics but also to their low power consumption and small silicon footprints. This paper presents an accurate and detailed analysis and design of six widely used complementary metal-oxide-semiconductor (CMOS) SISO ST circuits. The hysteresis characteristics of these ST circuits were derived for hand calculations and compared to original design equations and simulation results. Simulations were carried out in a well-established, 0.35 μm/3.3 V, analog/mixed-signal CMOS process. Additionally, simulations were performed using a wide range of supplies and process va...

This paper consists the design studies of complementary split ring resonator (CSRR) defected ground structure (DGS) microstrip filter with low insertion loss in the passband and high rejection in stopband with a comparison of various CSRR-DGS structure has been proposed. Various parameters of microstrip filters have been studied with CSRR-DGS such as roll off rate, bandwidth, effective inductance and capacitance. On the basis of these studies, microstrip low-pass, bandpass and dual-band bandstop filters have been designed and realized with enhanced properties of filters.

This paper presents a detailed investigation utilizing a defected ground structure (DGS) to a conventional edge-coupled microstrip coupler with tight coupling level over a relatively wide frequency band. A reasonable spacing between microstrip coupled lines and stronger coupling are achieved using this technique. A 20 dB initial coupler (over a fractional bandwidth of 35% with 1dB ripple) is converted into 8 dB coupler with almost 3 times wider band by etching off a single unit cell of rectangular and meandered slot loop in the ground plane under the central part of the coupling region. Optimum DGS dimensions are related to coupler dimensions in easy to use design curves. An efficient technique for compensation of the significant unavoidable mismatch resulting from the presence of the DGS is applied and tested. Some coupler samples with different DGS are fabricated, measured, and compared with a conventional coupler counterpart to verify the simulation results and illustrate the im...

A number of methods have been proposed and implemented to improve system damping against low-frequency electromechanical oscillations in the power system. Among these, flexible ac transmission systems (FACTS) can be used to provide power oscillation damping (POD) function to the power system. The design of the POD algorithms in these devices requires estimation of the power oscillation frequency components and this is mostly achieved through the use of various filter combinations. However, these filter-based solutions are characterized by low bandwidth to extract the required signal components accurately, and this limits the dynamic performance of the FACTS controllers. Moreover, the filters are designed for specific frequencies, and a change in the system would reduce the performance of the methods. Thus, there is a need for a better estimation algorithm with fast and selective estimation of the required signal that is robust against system parameter uncertainties. In this paper, this is achieved by the use of a recursive least square algorithm that uses variable forgetting factor and a frequency adaptation mechanism. The investigated method has fast estimation in transient conditions without compromising its selectivity in steady state. The effectiveness of the proposed method is proven through simulation as well as experimental verification. Index Terms-Estimation technique, low-pass filter (LPF), lowfrequency oscillation, power oscillation damping (POD), recursive least square (RLS), variable forgetting factor. I. INTRODUCTION P OWER system disturbances such as short-circuit faults cause low-frequency electromechanical oscillations (typically in the range of 0.2-2 Hz) which are a cause of concern for secure system operation, especially in weak transmission systems [1]. The decay rate of these oscillations is mainly dependent on the damping from the generator system and on the losses in the transmission line. However, in some cases, the total damping might not be sufficient, and poorly damped oscillations can be experienced in the power system. For this reason, supplementary power oscillation damping (POD) controllers are commonly used in the power system.

The energy management strategy (EMS) or power management strategy (PMS) unit is the core of power sharing control in the hybridization of automotive drivetrains in hybrid electric vehicles (HEVs). Once a new topology and its corresponding EMS are virtually designed, they require undertaking different stages of experimental verifications toward guaranteeing their real-world applicability. The present paper focuses on a new and less-extensively studied topology of such vehicles, HEVs equipped with an electrical variable transmission (EVT) and assessed the controllability validation through hardware-in-the-loop (HiL) implementations versus model-in-the-loop (MiL) simulations. To this end, first, the corresponding modeling of the vehicle components in the presence of optimized control strategies were performed to obtain the MiL simulation results. Subsequently, an innovative versatile HiL test bench including real prototyped components of the topology was introduced and the correspondin...

The development of miniature antennas is the key requirement for radio frequency identification applications in various fields.  In this paper, a new design of a compact metamaterial microstrip antenna based CSRR resonators is proposed. The proposed metamaterial antenna has a simple structure. It is formed by a rectangular patch embedded a T-shaped slot in one side, and a two metamaterial unit cells formed by CSRR etched from the ground plane in the other side. The designed antenna is printed on an epoxy Frame Resistant 4 substrate by using CST Microwave Studio. It operates at two RFID bands around 5.8GHz and 2.45GHz. The designed antenna is fabricated by using an LPKF machine. The simulation results have been justified by measuring the parameters, respectively.

This letter presents a new circuit of the band-pass filter designed by using microstrip technology. Based on complementary split ring resonator and various series of optimization technic and a specific design method, a miniature band-pass filter with excellent electrical performances is achieved. First of all, the metamaterial unit cell is studied to obtain a desired resonant frequency and it is implemented in the ground plan in order to increase the characteristics of the bandpass behavior and decrease its operating frequencies. This proposed circuit is designed on an FR-4 substrate having a relative permittivity of 4.4 tangential losses of 0.025 and thickness of 1.6 mm. This filter is developed by using CST Microwave. The obtained features allow this filter to be used in diverse wireless applications such as IMT-E and WiMax.

A novel quarter-circle defected ground structure shape is introduced in this paper to design and implement an ultra-wide reject band low-pass filter (LPF). Moreover, an equivalent circuit model (ECM) is presented. The proposed LPF has small size and, a low insertion loss and a return loss less than-20 dB. Also, a round-20 dB suppression level ranging from 4 GHz to more than 20 GHz is achieved. The simulated results obtained by ECM and full-wave EM show good agreement with the measured ones.

A microstrip meander line with a single H-shaped Defected Ground Structure (HDGS) is employed to design a novel compact lowpass filter with sharp roll off and wide stop band. Two parametric studies were conducted to analyze the sensitivity of the HDGS position and the size effects on the filter response. The design is fabricated to have a 6 GHz cutoff frequency using Rogers TMM 10i substrate, with an area of 7.6 x 6 mm. The measured results are in a good agreement with simulation prediction. Index Terms – Defected ground structures, compact filter, lowpass filter and microstrip meander line.

This contribution presents, for the first time, the design of microwave lowpass filter with ultrawide stopband and low insertion loss based on the log-periodic zig-zag defected ground structure (DGS); the design is specifically evolved from the principle of the log-periodic line antenna and the slotline based DGS. Based on the log-periodic property, studies show that ultra-wideband suppression can be realized by increasing the flare angle or the angle subtended by each element of the slotline DGS. The developed filter therefore shows low insertion loss of 0.7 dB within the passband, sharp transition between the passband and the stopband and ultra-wide suppression band from 2.61-26.5 GHz with a 20 dB suppression level. The DGS architecture is simple and easy to realize, and the design is thus useful in many microwave applications. The fabricated prototype filter validates the study, both from simulations and from measurements.

A global image thresholding algorithm based on boundary selection is proposed for improving conventional histogram-based thresholding algorithms. An image is divided into blocks of a fixed size, and the pixel variance of each block is used for finding the boundary blocks that a bimodal histogram. Otsu's threshold value of boundary block is used to classify object blocks and background blocks. The average values of these blocks are used to determine the optimal threshold value. Experimental results show that proposed algorithm improves on conventional thresholding methods for various types of images.

In this work, a substrate integrated waveguide slot array filtering antenna for dual band applications is presented. This novel design performs the functions of both a filter and an antenna simultaneously. The main intention of this work is to design a circuit that separates the frequencies in a dual band operation. The antenna is designed as an integration of two parts; the upper part operates at 10.2 GHz while the lower part operates at 16.4 GHz. In each part, an array of five longitudinal slots is incorporated, as well as a SIW antenna with complementary split ring resonators that operate as a band pass filter at the front end. Each slot array antenna is designed for a specific frequency band, and its function depends upon its preceding band pass filter. The two band pass filters allow only signals from the frequency bands for which they are designed to their corresponding slot array antennas. This technique, along with properly spaced metal vias of the SIW antenna, prevents any leakage and hence reduces interference in dual band operation. Both the band pass filter and the antenna can be built on the same planar board. The antenna is fed through a microstrip to SIW taper transition. CST Microwave Studio software is used for optimization and simulation of the structure. The antenna was built on an RT Duroid 5880 and tested to investigate practical validation. The antenna has a bandwidth of 1.9 GHz, from 9.2 GHz to 11.1 GHz in the X-band, and 2.2 GHz, from 15.6 GHz to 16.9 GHz in the Ku band. The gain pattern is unidirectional in nature and has low side lobe levels of −24 dB and −21 dB at resonant frequencies. A noticeable difference that is greater than 20 dB between co-polarization and cross-polarization is observed. The dimensions of the antenna are 56 mm × 32 mm × 0.508 mm. There is an excellent similarity between the simulated and measured results.

A phase locked loop (PLL) is a basic element of many communication and instrumentation domain. This paper discusses the challenges in designing the low power PLL for multiple frequency output for digital applications. PLL is a key element providing clocking scheme in many electronic circuits raises the requirement of decreasing the power, with the advancement in CMOS technology. In this work, we provide review on low power PLL with good stability.

In this paper, a new Defected Ground Structure (DGS) is introduced and analyzed. The effect of the structure’s dimensions on the location of the attenuation pole and the cutoff frequency to study the frequency characteristics is investigated. In the following, a lowpass filter with 3 dB cutoff frequency at 3 GHz is designed and optimized using the proposed defected ground structure, and its frequency characteristic is reported. The designed lowpass filter is fabricated to verify the simulation process. Also, simulation results, the equivalent circuit, and the measured results with the Network Analyzer are compared.

In this thesis, modified design of band stop filters using defected ground structures have been proposed. The new proposed structures have conventional dumbbell DGS integrated with U-slot and the conventional spiral DGS integrated with U-slot both designed using microstrip lines. These structures provide high Q-factor with low insertion loss (below 1dB) in the pass band. By adding the U-slot to the conventional structures, the overall capacitance and inductance are increased which results in low resonance frequency of 1.4GHz with a notch depth of-39.13dB for dumbbell-slot when compared to 2.6 GHz with a notch depth of-32.21dB for conventional dumbbell DGS. The resonance frequency is 1.2GHz with a notch depth of-35.4 dB for spiral-slot when compared to 1.4GHz and a notch depth of-14.6dB for conventional spiral DGS. Sharp transition is achieved from pass band to stop band for the new proposed DGS while the DGS sizes remained v the same. The proposed designs were fabricated for a dielectric substrate with a dielectric constant, εr of 10. vi Dedicated to my parents and my brother vii ACKNOWLEDGEMENTS First, I would like to thank Dr.Guru Subramanyam, my advisor who has been very patient and supported me since the day I have joined University of Dayton. He had always given me the freedom to work on my own pace and my own style which made me very comfortable when I was fully loaded with other tasks. I thank him for all his support and encouragement he gave me throughout my program. I would also like to thank Dr. Sunil Kumar Khah, who was a visiting professor from India. He was the one who introduced Defected Ground Structures to me, and helped me to gain good knowledge in this topic. He also helped me with learning AWR tool and introduced me to Dustin Brown while he was leaving back to India. Dustin, who is now Dr. Brown, was really the best team member I ever had in my life. He had really helped me a lot with all kinds of problems I had when I started my thesis. He never hesitated to share his knowledge with others which was really helpful for a beginner like me when I newly joined this lab. I would also like to thank Dr. Monish Chatterjee, who is like my mentor. He always helped me boost my confidence levels whenever I felt it was necessary. I still remember my first master's class Digital Communications which was taught by him in spring 2013, during the course I viii got an opportunity to learn a lot from him. I would like to thank him for being one of my committee members. I would also like to thank Dr. Weisong Wang for being my committee member and reviewing my work and guiding me whenever I needed help. I would also like to thank Dr.Eunsung shin, Wang Shu, Hailing Yue, Kuan-Chan Pan, Ayesha Zaman for the support they gave me.

In this paper, a new Defected Ground Structure (DGS) is introduced and analyzed. The effect of the structure’s dimensions on the location of the attenuation pole and the cutoff frequency to study the frequency characteristics is investigated. In the following, a lowpass filter with 3 dB cutoff frequency at 3 GHz is designed and optimized using the proposed defected ground structure, and its frequency characteristic is reported. The designed lowpass filter is fabricated to verify the simulation process. Also, simulation results, the equivalent circuit, and the measured results with the Network Analyzer are compared.

Pre-scalar, this is considered as the most critical block in the design of frequency synthesis plays very important role, whenever we talk about high frequency operation. These blocks are used typically in PLLs for frequency synthesis. Rigorous experiments have proved that the major contribution for power dissipation in ADPLL is because of pre-scalar block. Hence it becomes very crucial to design the pre-scalar block with minimum power dissipation. In this paper we adopt a technique of using Power PC flip flop to design a divide by 16/17 pre-scalar, which consumes very minimum power. The propound circuit operates up to ~1GHz consuming very less power of 0.749mW. The output frequency is in the range of 50MHz to 60MHz. Low power divide by 16/17 pre-scalar using Power PC flip flop is proposed at 0.12 m CMOS technology using BSIM4 model at a supply of 1.2V. The circuit is schematically verified in DSCH3.8. The layout verification was carried out in Microwind2. From the simulation it was observed that very minimum power dissipation was obtained with a minimum surface area of 1875.9 m 2 .