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Showing papers on "Electronic filter published in 2018"


Proceedings ArticleDOI
01 Jun 2018
TL;DR: In this paper, the effect of high dv/dt on the filter and the effectiveness of the proposed solution are validated using simulation and experimental data is also provided to validate the proposed concept.
Abstract: For high power medium voltage (MV) grid connected applications LCL filter proves to be an attractive solution to filter out the current harmonics when compared to $L$ or LC filters. The inductance requirement reduces drastically to meet the same Total Harmonic Distortion (THD) standards for grid connections for LC L filters compared to $L$ filter which makes the system dynamics much faster. The increasing use of Silicon Carbide (SiC) based power devices for MV applications has made the effects of the parasitic elements in the filter more prominent, due to the high dv / dt experienced by the passive filter elements during device switching transients. This paper addresses the issues associated with the high dv / dt experienced by the LC L filters for SiC-based MV applications. In order to study these effects, the parasitic elements of the inductor are modeled and analyzed. A suitable solution is proposed to improve the overall system performance. The effect of high dv / dt on the filter and the effectiveness of the proposed solution are validated using simulation. Experimental data is also provided to validate the proposed concept.

29 citations


Journal ArticleDOI
TL;DR: The simulation results show that the studied filters can be ranked from the best to worst as triple-tuned, damped double- Tuned, double- tuned, C-type and single-tuning ones in terms of their performance on the transformer’s loading capability improvement.

28 citations


Journal ArticleDOI
TL;DR: In this article, a new OTRA-based multifunction Inverse filter configuration is presented which is capable of realizing low pass, high pass and band pass filters using only two OTRAs and five to six passive elements.
Abstract: A new OTRA-based multifunction Inverse filter configuration is presented which is capable of realizing low pass, high pass and band pass filters using only two OTRAs and five to six passive elements. To the best knowledge of the authors, any inverse filter configuration using OTRAs has not been reported in the literature earlier. The effect of the major parasitics of the OTRAs and their effect on the performance filter have been investigated and measured through simulation results and Monte-Carlo analysis. The workability of the proposed circuits has been confirmed by SPICE simulations using CMOS-based-OTRA realizable in 0.18 µm CMOS technology. The proposed circuits are the only ones which provide simultaneously the following features: use of reasonable number of active elements (only 2), realizability of all the three basic filter functions, employment of all virtually grounded resistors and capacitors and tunability of all filter parameters (except gain factor, H_0 for inverse high pass). The centre/cut-off frequency of the various filter circuits lying in the vicinity of 1 MHz have been found to be realizable, which has been verified through SPICE simulation results and have been found to be in good agreement with the theoretical results.

26 citations


Journal ArticleDOI
TL;DR: As further modification to the proposed approach, the possibility of realising pole–zero symmetry is presented, which makes the new proposed tuning method useful for both existing and future designs.
Abstract: An approach of tuning first-order filters is proposed in this study. The proposed approach is based on employing feedback in first-order filter circuits, wherein a scaled output is combined with the input signal, so as to facilitate easy tuning of filter parameters. Various options of tuning the filter parameters are explored by employing feedback from low-pass, high-pass or all-pass outputs. The approach enables easy tuning of filter parameters by varying the gain of an external amplifier, without adjusting the passive elements comprising the filter core. A new current-mode filter circuit is further proposed, which employs a recently introduced active element, namely an extra-X current conveyor. The new approach is used in the designed first-order filter circuit. The new proposed circuit benefits by employing only a grounded capacitor, exhibits low-input and high-output impedances. The approach of tuning filter parameters through external means, without disturbing filter core, and the new proposed circuit are verified through simulations with promising results. As further modification to the proposed approach, the possibility of realising pole–zero symmetry is presented, which makes the new proposed tuning method useful for both existing and future designs.

24 citations


Proceedings ArticleDOI
28 Mar 2018
TL;DR: In this paper, a two level pulse width modulation (PWM) generator and a filter circuit has been proposed for reduction of total harmonic distortion or THD of current and voltage outputs of the three phase voltage source inverter.
Abstract: This paper presents modeling of a gate pulse triggered three phase 180° voltage source inverter or VSI model supplying nonlinear loads with its output voltage and current waveforms. A two level pulse width modulation or PWM generator and a filter circuit has been proposed here for reduction of total harmonic distortion or THD of current and voltage outputs of the three phase voltage source inverter. In this PWM generator the modulating signal is compared with a high frequency triangular carrier wave. The PWM technique used here is sinusoidal pulse width modulation or SPWM technique. With the application of SPWM and filter the performance of the VSI will be analyzed using MATLAB SMULINK and FFT toolbox. As a result reduction of THD can be seen in the VSI model in both current and voltage output.

20 citations


Journal ArticleDOI
TL;DR: In this paper, a microwave planar negative resistance oscillator with higher frequency stability and lower phase noise (PN) is introduced for sensing applications, where a split-ring resonator is used as sensing element at 2.4 GHz and is used for microfluidic concentration sensing of high lossy solution of water in ethanol.
Abstract: A microwave planar negative resistance oscillator with higher frequency stability and lower phase noise (PN) is introduced for sensing applications. Split-ring resonator is used as sensing element at 2.4 GHz and is used for microfluidic concentration sensing of high lossy solution of water in ethanol. Stabilizing the frequency response with the use of active filter leads to 14-times enhancement in the limit of detection, from 7% (passive filter) to 0.5% (active filter), while the linearity of the sensor is preserved; the sensing range is then increased. Nearly 13-dBc/Hz improvement in the measured PN, in great agreement with theory, also verifies the frequency domain stability of the oscillator.

18 citations


Journal ArticleDOI
TL;DR: A circuit health estimation method was developed using a kernel-based machine-learning technique that exploits features that are extracted from responses of circuit-comprising components exhibiting parametric faults, instead of the component-level parameters.
Abstract: Degradation of electronic components is typically accompanied by a deviation in their electrical parameters from their initial values, which can ultimately lead to parametric faults in electronic circuits. Existing approaches to predict parametric faults emphasize identifying monotonically deviating parameters and modeling their progression over time. However, in practical applications, where the components are integrated into a complex electronic circuit assembly, product, or system, it is generally not feasible to monitor component-level parameters. To address this problem, a circuit health estimation method was developed using a kernel-based machine-learning technique. This method exploits features that are extracted from responses of circuit-comprising components exhibiting parametric faults, instead of the component-level parameters. The method was evaluated using data from simulation experiments on a benchmark Sallen–Key filter circuit and a dc–dc converter system.

17 citations


Journal ArticleDOI
TL;DR: This paper presents the implementation of a bandpass filter tuning circuit solely based on noise observation for a continuous-time (CT) delta–sigma modulator gyroscope readout system that minimizes the angular rate noise floor.
Abstract: This paper presents the implementation of a bandpass filter tuning circuit solely based on noise observation for a continuous-time (CT) delta–sigma modulator gyroscope readout system. By evaluating the noise at the electronic filter input, a filter frequency deviation of less than 50 Hz or approximately 0.5% of the gyroscope’s drive resonance frequency is achieved, which minimizes the angular rate noise floor. The automatic tuning works in the background during normal angular rate readout with input signals up to the full scale, over a temperature range of 115 °C, and with interference signals of up to −27.2 dBFS. The power (27 $\mu \text{W}$ ) and area (0.06 mm2) overhead to the overall system is less than 2%. The overall CT readout system achieves a noise floor of 0.002 °/s/ $\sqrt {\mathrm {Hz}}$ and a bias instability of 0.9 °/h while consuming only 1.71 mW.

15 citations


Journal ArticleDOI
TL;DR: The novel topology of DVR using semi-Z-source inverter is proved to be a better solution to the full-bridge inverter-based DVR.
Abstract: A novel topology of single-phase dynamic voltage restorer (DVR) is proposed to compensate the load voltage during voltage sag and voltage swell events. The semi-Z-source converter is utilised in its inverter operating mode for this proposed topology. The reduction in the number of active switches in the inverter and also in the current conduction path without compromising the output voltage range is the merit of the semi-Z-source inverter-based DVR against the commonly used full-bridge inverter-based DVR. The load voltage contains harmonics within the permissible limits when the compensation is performed by the semi-Z-source inverter-based DVR. The need for the filter circuit is eliminated; hence, the magnitude difference and the phase shift in the inverter output voltage due to the filter circuit are not present in the semi-Z-source inverter-based DVR. The proposed topology is cheap compared to the full-bridge inverter-based DVR topology. The simulations performed in MATLAB/Simulink environment are presented to validate the performance of the proposed topology. A comparison between the semi-Z-source inverter-based DVR and full-bridge inverter-based DVR is presented in this paper. The novel topology of DVR using semi-Z-source inverter is proved to be a better solution to the full-bridge inverter-based DVR.

15 citations


Journal ArticleDOI
TL;DR: A comprehensive overview of all reactive power-sharing approaches among multiple passive filter arms and a new method of multiple-arm passive filter design based on the crow search algorithm to minimize the total harmonic current distortion (THDI) as an objective function for an industrial plant are presented.

15 citations


Journal ArticleDOI
TL;DR: The main contribution of this work is to reduce the total harmonic distortion (THD) by using a passive filter and to enhance the output voltages by adopting a multicarrier pulse width modulation (MCPWM).
Abstract: In this paper, a three-phase multilevel cascaded H-bridge inverter is developed for injecting renewable power energy into the grid through a filter. The main contribution of this work is to reduce the total harmonic distortion (THD) by using a passive filter and to enhance the output voltages by adopting a multicarrier pulse width modulation (MCPWM). The simulation results affirm a good performance of the proposed multicarrier PWM control using a three-phase five-level inverter. The proposed inverter is tested as well as the THD and the spectral analysis of the output voltage are calculated using Simulink/Matlab software.

Journal ArticleDOI
TL;DR: A differential evolution (DE) algorithm with a new mutation strategy, named as average DE (ADE), is introduced for analog active filter design, which minimizes the total design error of the state variable filter (SVF) for the optimal selection of component values.
Abstract: Component selection in electronic circuit design is an important issue to achieve a targeted performance and quality level. Particularly in filter circuits, changes in gain and phase response of the circuit are directly dependent on the component values of the filter. Therefore, the selection of component values must be done carefully. In this article, a differential evolution (DE) algorithm with a new mutation strategy, named as average DE (ADE), is introduced for analog active filter design. The ADE algorithm minimizes the total design error of the state variable filter (SVF) for the optimal selection of component values. Simulation results indicate that the proposed algorithm reduces the design error when compared to other methods.

Journal ArticleDOI
TL;DR: Electromagnetic interference (EMI) modeling techniques for different function units in a VFD system, including induction motors, motor bearings, and rectifier-inverters, are reviewed and evaluated in terms of applied frequency range, model parameterization, and model accuracy.
Abstract: Electromagnetic interference (EMI) causes electromechanical damage to the motors and degrades the reliability of variable-frequency drive (VFD) systems. Unlike fundamental frequency components in motor drive systems, high-frequency EMI noise, coupled with the parasitic parameters of the trough system, are difficult to analyze and reduce. In this article, EMI modeling techniques for different function units in a VFD system, including induction motors, motor bearings, and rectifier-inverters, are reviewed and evaluated in terms of applied frequency range, model parameterization, and model accuracy. The EMI models for the motors are categorized based on modeling techniques and model topologies. Motor bearing and shaft models are also reviewed, and techniques that are used to eliminate bearing current are evaluated. Modeling techniques for conventional rectifier-inverter systems are also summarized. EMI noise suppression techniques, including passive filter, Wheatstone bridge balance, active filter, and optimized modulation, are reviewed and compared based on the VFD system models.

Proceedings ArticleDOI
01 Oct 2018
TL;DR: In this paper, a novel topology to obtain 3 port non-reciprocal propagation in a magnetless medium is presented, where a modulation frequency of 15 MHz guarantees 10 dB of non-reward contrast at 870 MHz by modulating a SAW filter with a switched capacitor network.
Abstract: A novel topology to obtain 3 port nonreciprocal propagation in a magnetless medium is here presented. A modulation frequency of 15 MHz guarantees 10 dB of nonreciprocal contrast at 870 MHz by modulating a SAW filter with a switched capacitor network. An unprecedented 40dBc first order Inter Modulation Distortion (IMD) is achieved thanks to unique features of RF acoustic filters, obtaining a Linear Periodically Time Variant (LPTV) circuit behaving as a quasi-LTI circuit.

Journal ArticleDOI
TL;DR: In this paper, the effects caused by a new hexagonal defect groundplane (DGS) structure when it is applied to a rectangular microstrip antenna and studies its effectiveness to suppress higher-order modes.
Abstract: This study analyses the effects caused by a new hexagonal defect ground-plane (DGS) structure when it is applied to a rectangular microstrip antenna and studies its effectiveness to suppress higher-order modes. To improve the rejection characteristics of the analysed DGS, a genetic algorithm was used to optimise its parameters. Controlling higher-order modes of the fundamental operating frequency was successfully demonstrated, and the experimental results showed that optimising the hexagonal DGS could enhance the S 11 parameter of the fundamental mode while simultaneously suppressing or further attenuating higher-order modes. Such results are particularly important once DGS is applied for self-immunity of antennas against harmonic radiations by avoiding the use of a filter circuit.

Proceedings ArticleDOI
01 Jul 2018
TL;DR: This work involves the modeling and stability analysis of Feedback Voltage Sense Current Cancellation Active EMI Filters and type of applications that benefit from using voltage sensing over current sensing for is identified.
Abstract: Passive EMI filters occupy significant volume in a power converter. Active EMI Filters (AEF) are a means to reduce the volume of passive filter components. It is essential to identify the boundaries within which the AEF could be designed and the possible volume reduction that is achievable. This work involves the modeling and stability analysis of Feedback Voltage Sense Current Cancellation (VSCC) Active EMI Filters. Type of applications that benefit from using voltage sensing over current sensing for is identified. An example of a non-PFC AC-DC converter is considered. Noise sensing networks comprising high voltage capacitors and high pass filter networks are designed for sensing noise. The overall filter implementation is modeled, and stability analysis is carried out. Suitable compensation networks are designed to make the filter viable. Major bottlenecks that limit the maximum attenuation are identified and general guidelines for the application of Feedback VSCC topology are proposed.

Journal ArticleDOI
TL;DR: Simulations prove that the described HFDT can effectively reduce specific harmonic currents with IFI-based filters and the successful suppression of harmonics is demonstrated and discussed based on field-test measurements.
Abstract: This study analyses and evaluates the feasibility of a harmonic filtering distribution transformer (HFDT) for a harmonic reduction in low-voltage distribution networks With this new-type transformer, power quality of the distribution systems can be improved by preventing the low-voltage-side harmonic currents from penetrating the higher voltage side As the physical size of available space in prefabricated substations is strictly limited, necessary low space occupying filtering techniques are needed Therefore, an HFDT with integrated filtering inductors (IFIs) capable of being implemented in regular air-insulated prefabricated substations is proposed Two sets of passive filters configured by IFIs and external capacitors are employed for harmonic filtering Two methods for estimating the inductance parameter are provided One is the dimension-based method and the other is the reduced-order inductance matrix method The relevant harmonic reduction analysis is based on simulations with a field–circuit coupling model, which consists of a three-dimensional finite-element electromagnetic model of an HFDT with IFIs and a corresponding electric circuit of a simplified distribution network These simulations prove that the described HFDT can effectively reduce specific harmonic currents with IFI-based filters Finally, the successful suppression of harmonics is demonstrated and discussed based on field-test measurements

Journal ArticleDOI
TL;DR: A new current mode single-input-multiple-output nth order universal filter circuit that offers some important features such as resistor less realization, no passive component matching constraints, low sensitivity, electronic tunability and active-C realization is presented.
Abstract: This article presents a new current mode single-input-multiple-output nth order universal filter. The proposed circuit employs (n + 1) number multiple output second generation current conveyors and n number grounded capacitors only. Presented circuits can realize current mode low pass, high pass, band pass, notch and all pass responses simultaneously at different high output impedance terminals. The current mode filter circuit provides low input impedance by selecting the proper value of bias current and also has high output impedance, which is suitable for cascading. The circuit offers some important features such as resistor less realization, no passive component matching constraints, low sensitivity, electronic tunability and active-C realization. The functionality of the proposed filter circuit is tested with the PSPICE simulation, which is found to agree well with the proposed theory.

Patent
Changjoon Park1
05 Mar 2018
TL;DR: In this paper, a switching circuit includes at least one Surface Acoustic Wave (SAW) filter, a Single-Pole n Throw (SPnT) switch connected to an input port of each of the SAW filters, and a DualPole N Throw (DPnT)-switch connected to the output of each SAW filter.
Abstract: A switching circuit is provided. The switching circuit includes at least one Surface Acoustic Wave (SAW) filter, a Single-Pole n Throw (SPnT) switch connected to an input port of each of the at least one SAW filter, and a Dual-Pole n Throw (DPnT) switch connected to an output port of each of the at least one SAW filter.

Book ChapterDOI
01 Jan 2018
TL;DR: In this paper, the physical realization of microwave filters is discussed, showing how one can combine filter circuit models with electromagnetic (EM) simulation tools to determine the filter physical dimensions, and how to translate the coupling matrix elements to physical dimensions using a dielectric resonator filter as an example.
Abstract: This chapter addresses the physical realization of microwave filters illustrating how one can combine filter circuit models with electromagnetic (EM) simulation tools to determine the filter physical dimensions. Numerical examples are given in this chapter to demonstrate, step by step, the application of the approach to the design of dielectric resonator, waveguide, and microstrip filters. The chapter presents electric wall and magnetic wall symmetry analysis for the calculation of interresonator coupling. It also considers the design of the four‐pole Chebyshev inductive iris‐coupled waveguide filter. The chapter demonstrates the use of a synthesis approach to translate the coupling matrix elements to physical dimensions using a dielectric resonator filter as an example. Practical filter designers may find the materials given in this chapter very useful to come up with a reasonably good initial design for Chebyshev filters.

Journal ArticleDOI
TL;DR: The object of this paper is to develop an inverter which is used for variable speed drives with increase in output voltage by eliminating transformer and filter circuit.
Abstract: Z-source based multilevel inverters are the recent topologies as they have boosting ability and near sinusoidal output waveforms. This paper proposes different inverter topologies such as Z-source multilevel inverter and quasi Z-source multilevel inverter. This paper also deals with switched inductor and improved switched inductor topologies with quasi Z-network. The proposed switched inductor system reduces the voltage stresses caused by capacitors, power devices and diodes. In addition to multilevel inverter advantages, the proposed configuration employs Z-source inverter advantages. The Z-source inverter as compared to the traditional inverter is less costly, less complex, more efficient and more reliable. The performance of the proposed configurations is analysed by varying passive elements in impedance network and is simulated in MATLAB/SIMULINK. Phase disposition (PD) pulse width modulation (PWM) technique is applied on the proposed configurations and performance parameters are measured by the fast Fourier transform FFT analysis. The object of this paper is to develop an inverter which is used for variable speed drives with increase in output voltage by eliminating transformer and filter circuit. The performance is checked with standared parameter of the inverter.

Journal ArticleDOI
01 Feb 2018
TL;DR: From the simulation results, it is seen that single-tuned passive filter can reduce the harmonics of the current 82.23% harmonic that wants to be reduced and also can reduce other orders harmonics between 7% to 8%.
Abstract: The using of non-linear loads generated by industrial machines may result inconsistent harmonics that do not reach the IEEE 519 - 1992 standards. This study discusses the use of single-tuned passive filters in reducing harmonics in the plastics processing industry. The system modeling using matlab / simulink simulation resulted in total harmonic distortion (THD) of 15.55%, can be reduced to 4.77% harmonics in accordance with IEEE 519 - 1992 standards. From the simulation results also seen that single-tuned passive filter can reduce the harmonics of the current 82.23% harmonic that wants to be reduced and also can reduce other orders harmonics between 7% to 8%.

Journal ArticleDOI
TL;DR: It is shown that the required linearity of wideband SAW-less receivers is surprisingly higher than what has been commonly assumed, and that blockers located at the frequencies of the local oscillator harmonics can significantly increase the noise floor of the receiver.
Abstract: The required linearity of wideband receivers for applications, such as software-defined radio in the absence of input surface-acoustic wave (SAW) filters, is studied. It is shown that the required linearity of wideband SAW-less receivers is surprisingly higher than what has been commonly assumed. For these receivers, although the out-of-band blockers can reduce the compression point of the receiver, they can also potentially generate interferers that appear in the desired frequency band, resulting in higher noise floor and signal corruption. The required out-of-band IIP2 and IIP3 of low-noise amplifier (LNA) and mixer for single and concurrent applications are analytically derived. The required wideband SAW-less receiver phase noise is also studied, and it is shown that blockers located at the frequencies of the local oscillator harmonics can significantly increase the noise floor of the receiver. The effects of input and intermediate filters on the above applications along with the conditions under which they help to alleviate the limitations of LNA and mixer are defined. The validity of the models and subsequent derivations is verified by actual measurements using a wideband SAW-less receiver.

Journal ArticleDOI
19 Nov 2018-Energies
TL;DR: In this article, a new method for minimizing current spikes appearing during brushless DC motors start-up or sudden set point changes is proposed, which is based on controlling the MOSFET gates of the motor driver using R-C filters.
Abstract: Due to their high efficiency and low cost of maintenance, brushless DC motors (BLDCMs) with trapezoidal electromotive forces (back-EMFs), have become widely used in various applications such as aerospace, electric vehicles, industrial uses, and robotics. However, they suffer from large current ripples and current spikes. In this paper, a new method for minimizing current spikes appearing during BLDCM start-up or sudden set point changes is proposed. The method is based on controlling the MOSFET gates of the motor driver using R-C filters. These filters are placed between the PWM control signal generator and the MOSFET gates to smooth these control signals. The analysis of the proposed method showed that the R-C filter usage affects the BLDCM steady-state performances. To overcome this limitation, the R-C filter circuit was activated only during current spikes detection. The effectiveness of the proposed method was analytically analyzed and then validated through simulation and experimental tests. The obtained results allowed a reduction of 13% in current spikes amplitude.

Proceedings ArticleDOI
01 Feb 2018
TL;DR: The effective parameters on filter performance is extracted and by means of NSGAII an optimum filter design is presented and result shows proper performance of the algorithm and improved system behavior.
Abstract: Output passive filter is one of the inseparable parts of 400 Hz inverters. It is common to use LC filter between the inverter and load for switching harmonic elimination. Since performance and cost of the system is totally affected by the filter design, an optimum filter design will lead to an optimized system. In this paper the effective parameters on filter performance is extracted and by means of NSGAII an optimum filter design is presented. Achieved result shows proper performance of the algorithm and improved system behavior.

Proceedings ArticleDOI
01 Nov 2018
TL;DR: In this article, a ladder type SAW filter for LTE Band 42 was designed and fabricated, which achieved very low insertion loss of 1.7 dB max in the passband of 3.5+/-0.1 GHz.
Abstract: Regarding higher frequency above 3 GHz, up until now BAW filters have been believed to be better solution than SAW filters due to their increase of electrodes resistance. This paper describes a new high performance SAW filter surpassing BAW, with 3.5 GHz center frequency employing I.H.P. SAW technology which is new type SAW structure with high Q factor. Experimental studies for one-port resonators in 3.6 GHz show very high Bode-Q max of 2500 and optimum aperture lengths of IDTs. Using the results, a ladder type filter for LTE Band 42 was designed and fabricated. Very low insertion loss of 1.7 dB max has been achieved in the passband of $\mathbf{3.5+/-0.1 \ GHz}$:. Steeper skirt characteristics and adequate attenuation have been also realized.

Journal ArticleDOI
TL;DR: An effective algorithm that hybridizes the Genetic Al algorithm to form a Hybrid Genetic Algorithm (HGA) and the use of Tabu Search (TS) for the analog active filter component selection is presented and compared to other reported state-of-the-art algorithms.
Abstract: Analog filters are circuits that process electrical signals on a frequency-dependent basis. Analog filter circuits can be implemented using resistors, capacitors and inductors and they can also be implemented with only resistors and capacitors with the use of active circuit equipments. The selection of optimum component values is difficult because of the number of possible filter combinations. This paper presents an effective algorithm that hybridizes the Genetic Algorithm (GA) to form a Hybrid Genetic Algorithm (HGA) and proposes the use of Tabu Search (TS) for the analog active filter component selection. The GA has a powerful global searching ability and so is used to perform exploitation and because TS also has good local searching ability, it too is applied to perform exploitation. Thus, the proposed HGA will have very good searching ability. In this study, a band-pass Sallen-Key filter circuit was used, and the filter component values were found using HGA with LabVIEW. The results are compared to other reported state-of-the-art algorithms, such as the artificial bee colony (ABC) and differential evaluation (DE) to demonstrate the effectiveness and efficiency of the developed method. It can be said that the developed LabVIEW based HGA gives satisfactory results with regard to amplitude response, the minimum fitness values and the computational time.

Patent
14 Dec 2018
TL;DR: In this paper, a broadband dual-polarization base station filter antenna unit without an external filter circuit and an array thereof is presented. But the antenna unit is arranged in the middle of the reflector and the antenna comprises an oscillator arm, a balun and two parasitic metal rings.
Abstract: The invention discloses a broadband dual-polarization base station filter antenna unit without an external filter circuit and an array thereof. The antenna unit is arranged in the middle of the reflector. The antenna comprises an oscillator arm, a balun and two parasitic metal rings. The vibrator arm is provided with a microstrip line branch, is connected through the balun, and is fed through thebalun, and the balun is provided with a feeder line. The upper part and the lower part of the vibrator arm are respectively provided with parasitic metal rings. The antenna unit has the characteristics of compact and simple structure. The invention realizes good out-of-band rejection effect and has good frequency selectivity without cascading filter, thus avoiding filter insertion loss. The invention realizes high polarization isolation, and realizes stable pattern in wide frequency band at the same time.

Patent
01 Feb 2018
TL;DR: In this paper, a programmable programmable amplifier includes an amplifier, an input capacitor, a feedback circuit, and a high-pass filter circuit, where the first switches are configured to be selectively switched on for activating at least one feedback capacitor to adjust a gain of the amplifier.
Abstract: A programmable amplifier includes an amplifier, an input capacitor, a feedback circuit, and a high-pass filter circuit. The amplifier has an input coupled to the input capacitor for receiving an input signal. The feedback circuit includes multiple feedback capacitors of differing capacitance values that are each selectively coupled between the output of the amplifier and the input of the amplifier using multiple first switches. The high-pass filter circuit includes multiple switched capacitors of differing capacitance values that are each selectively coupled between the amplifier output and a ground node using multiple second switches. The first switches are configured to be selectively switched on for activating at least one feedback capacitor to adjust a gain of the amplifier, while the second switches are configured to be selectively switched at a first and second phase of a clock signal to adjust a high-pass cutoff frequency of the amplifier independently of how the gain is adjusted.

Proceedings ArticleDOI
C. Kirkendall1, Brice Ivira1
01 Oct 2018
TL;DR: In this article, a finite element based method for rapid simulation of filter response under high power was proposed to capture the effect of heat flow within the filter die as well as its path through the PCB to thermal ground.
Abstract: The increasingly stringent power requirements imposed on BAW filter technologies has made coupling between thermal and piezoelectric physics relevant to the design process. Existing lumped filter models do not account for the effect of a 3D temperature distribution over each resonator. Here we report a new finite element based method for rapid simulation of filter response under high power that captures the effect of heat flow within the filter die as well as its path through the PCB to thermal ground.