Showing papers on "Band-stop filter published in 2017"

Design and Analysis of Robust Active Damping for LCL Filters Using Digital Notch Filters

Abstract: Resonant poles of LCL filters may challenge the entire system stability especially in digital-controlled pulse width modulation (PWM) inverters. In order to tackle the resonance issues, many active damping solutions have been reported. For instance, a notch filter can be employed to damp the resonance, where the notch frequency should be aligned exactly to the resonant frequency of the LCL filter. However, parameter variations of the LCL filter as well as the time delay appearing in digital control systems will induce resonance drifting, and thus break this alignment, possibly deteriorating the original damping. In this paper, the effectiveness of the notch filter-based active damping is first explored, considering the drifts of the resonant frequency. It is revealed that when the resonant frequency drifts away from its nominal value, the phase lead or lag introduced by the notch filter may make itself fail to damp the resonance. Specifically, the phase lag can make the current control stable despite of the resonant frequency drifting, when the grid current is fed back. In contrast, in the case of an inverter current feedback control, the influence of the phase lead or lag on the active damping is dependent on the actual resonant frequency. Accordingly, in this paper, the notch frequency is designed away from the nominal resonant frequency to tolerate the resonance drifting, being the proposed robust active damping. Simulations and experiments performed on a 2.2-kW three-phase grid-connected PWM inverter verify the effectiveness of the proposed design for robust active damping using digital notch filters.

DC Offset Rejection Improvement in Single-Phase SOGI-PLL Algorithms: Methods Review and Experimental Evaluation

Abstract: DC offset in the input of phase-locked loops (PLLs) is a challenging problem since it will result in fundamental frequency oscillations in the estimated phase and frequency. In this paper, a comprehensive analysis and performance evaluation of several advanced second-order generalized integrator (SOGI)-based PLL methods in enhancing the dc offset rejection capability for single-phase grid-connected power converters is presented. These methods include the cascade SOGI, modified SOGI, $\alpha \beta $ -frame delayed signal cancellation (DSC), complex coefficient filter, in-loop dq-frame DSC, notch filter, and moving average filter-based SOGI-PLL. Main characteristics and design aspects of these methods are presented. Main performance indexes, such as the setting time, frequency or phase errors are defined and these methods are systematically compared under various scenarios with both numerical and experimental results.

All-optimized integrated RF photonic notch filter

Abstract: We report a silicon nitride chip-based radio-frequency photonic notch filter with an unprecedented performance including an RF gain of 8 dB, a record-low noise figure of 15.6 dB, and a spurious-free dynamic range of 116 dB·Hz2/3, with a stop band rejection of 50 dB. This level of performance is achieved by using on-chip resonators’ unique phase responses, and thorough optimizations of the photonic link. These record results will potentially stimulate future implementations of integrated microwave photonic subsystems for real-world applications.

Parameter Design of a Novel Series-Parallel-Resonant LCL Filter for Single-Phase Half-Bridge Active Power Filters

Abstract: This paper proposes a novel high-order passive filter, i.e., series-parallel-resonant LCL (SPRLCL) filter, for single-phase half-bridge active power filters. The proposed SPRLCL filter consists of a series resonance introduced by adding a small inductor to the capacitor branch loop and a parallel resonance by paralleling a small capacitor with the gird-side inductor. Three design methods are proposed to fine tune the parameters of the SPRLCL filter. Design method I and method II enable the SPRLCL filter to attenuate more switching-frequency and double switching-frequency current harmonics than LCL or LLCL filters, while with design method III, the SPRLCL filter can be more robust against filter parameter variations. In order to achieve a better damping performance and facilitate the design of active damping control, the dominant resonance frequency of the proposed filter is set at one-third of the system sampling frequency. Based on this, a comprehensive parameter design process of the SPRLCL filter is presented, where the variation of source inductance is also considered. A proportional plus repetitive current-loop controller is designed to ensure system control stability and satisfactory harmonic compensation. Simulation and experimental results are finally presented to validate the feasibility of the theoretical analysis.

CFAR Ship Detection in Nonhomogeneous Sea Clutter Using Polarimetric SAR Data Based on the Notch Filter

Abstract: Synthetic aperture radar (SAR) ship detection is an important research topic in the field of maritime applications. The geometrical perturbation-polarimetric notch filter (GP–PNF) was recently proposed to be a promising tool and its usefulness in exploiting polarimetric SAR information for ship detection was demonstrated. The work in this paper is devoted to developing a statistical model of the filter in nonhomogeneous sea clutter to achieve constant false alarm rate (CFAR) detection based on the model. First, within the framework of a multiplicative model, the reciprocal of the gamma distribution is used to describe the texture component of sea clutter in nonhomogeneous background. As a result, a statistical model of the GP–PNF is analytically derived and found suitable for sea clutter scenes with a wide range of homogeneity. Second, we theoretically demonstrate that CFAR detection using GP–PNF is unrelated to the parameter in the original GP–PNF. Therefore, a simplified version of the GP–PNF is given. Third, the CFAR threshold of the simplified filter is mathematically derived. Experiments performed on measured L-band ALOS-PALSAR and C-band RADARSAT-2 SAR data verify the good performance of the developed statistical model and demonstrate the usefulness of the CFAR detection based on the simplified filter.

Absorptive Bandstop Filter With Prescribed Negative Group Delay and Bandwidth

Abstract: An absorptive bandstop filter is proposed and synthesized with prescribed negative group delay (NGD) and negative group delay bandwidth (NBW). It is realized with resistor-loaded coupled-line structures where the NGD can be controlled by the Q-factors of resonators. The resistor of the first section is determined for impedance matching, also providing a negative delay. A prototype is developed, following the proposed design procedure, with NGD = −6.5 ns and NBW= 105 MHz obtained. The proposed method is experimentally validated by the good agreement between the synthesized and measured results.

24.3 A high-linearity CMOS receiver achieving +44dBm IIP3 and +13dBm B 1dB for SAW-less LTE radio

Abstract: LTE-advanced wireless receivers require high-linearity up-front filtering to prevent corruption of the in-band signals by strong out-of-band (OOB) signals and self-interference from the transmitter. SAW duplexer filters are generally used for this purpose, but supporting the plethora of existing and new bands becomes troublesome with separate filters for each band. In this paper we explore the possibility of combining an isolator with on-chip filtering. However, even with 15dB isolation, the on-chip filter needs to deal with up to +10dBm TX leakage and −15dBm OOB blocking, which requires an extremely high IIP3 around +50dBm and IIP2 around +90dBm. Recently inductorless tunable N-path-filter-based receivers achieved >10dBm compression point and good IIP3 of 20 to 30dBm. In order to further improve the receiver linearity to approach the extremely high IIP3 requirement for a SAW-less receiver, a high-linearity N-path bandpass/notch filter topology and receiver architecture are proposed in this paper.

Reconfigurable Fractional-Order Filter with Electronically Controllable Slope of Attenuation, Pole Frequency and Type of Approximation

Abstract: This paper presents design of electronically reconfigurable fractional-order filter that is able to be configured to operate as fractional-order low-pass filter (FLPF) or fractional-order high-pass filter (FHPF). Its slope of attenuation between pass band and stop band, i.e., order of the filter, is electronically adjustable in the range between 1 and 2. Also, pole frequency can be electronically controlled independently with respect to other tuned parameters. Moreover, particular type of approximation can be also controlled electronically. This feature set is available both for FLPF and FHPF-type of response. Presented structure of the filter is based on well-known follow-the-leader feedback (FLF) topology adjusted in our case for utilization with just simple active elements operational transconductance amplifiers (OTAs) and adjustable current amplifiers (ACAs), both providing possibility to control its key parameter electronically. This paper explains how reconfigurable third-order FLF topology is used in order to approximate both FLPF and FHPF in concerned frequency band of interest. Design is supported by PSpice simulations for three particular values of order of the filter (1.25, 1.5, 1.75), for several values of pole frequency and for two particular types of approximation forming the shape of both the magnitude and phase response. Moreover, theoretical presumptions are successfully confirmed by laboratory measurements with prepared prototype based on behavioral modeling.

DC-Link Control Filtering Options for Torque Ripple Reduction in Low-Power Wind Turbines

Abstract: Small wind energy conversion systems (WECSs) are becoming an attractive option for distributed energy generation. WECSs use permanent-magnet synchronous generators (PMSGs) directly coupled to the wind turbine and connected to the grid through a single-phase grid-tie converter. The loading produced on the dc link is characterized by large ripple currents at twice the grid frequency. These ripple currents are reflected through the dc bus into the PMSG, causing increased heating and ripple torque. In this paper, the PMSG inverter is used to control the dc-link voltage. In order to avoid reflecting the ripple currents into the PMSG, the feedback dc-link voltage is passed through a filter. The Butterworth filters, notch filters, antiresonant filter (ARF) and moving average filter (MAF) are considered. For a fair comparison, formulas are provided to tune the filter parameters so that dc-link voltage control will achieve the selected bandwidth. The different filtering options produce different levels of torque ripple reduction. The notch filter, ARF, and MAF obtain the best results and there is a tradeoff between the filter implementation complexity, bandwidth, overshoot, and the torque ripple reduction. Simulations and experiments using a 2.5-kW PMSG turbine generator validate the proposals.

Dual-Band Microstrip Bandstop Filter With Multiple Transmission Poles Using Coupled Lines

Abstract: A novel dual-band microstrip bandstop filter with multiple poles using open/shorted coupled lines is proposed in this paper. Nine transmission poles near the two stopbands can be easily realized by conventional coupled lines and transmission lines. The two center frequencies of the dual-band bandstop filter can be adjusted flexibly by only changing the even/odd-mode of the coupled lines. The planar microstrip dual-band bandstop filter ( $\varepsilon r = 2.65$ and $h = 0.5$ mm) with nine transmission poles is designed and fabricated. High selectivity and good in-band performances can be achieved in the proposed filter.

Novel Tunable Bandstop Resonators in SIW Technology and Their Application to a Dual-Bandstop Filter with One Tunable Stopband

Abstract: Two novel tunable bandstop resonators in substrate integrated waveguide (SIW) technology are presented: a ridged SIW resonator and an open-ended coplanar waveguide (CPW) resonator that is etched into the SIW’s top metallization. The ridged SIW resonator shows a tuning range of 200 MHz at 5.54 GHz. The CPW resonator has a tuning range of 600 MHz at 3.8 GHz. The two bandstop resonators are combined to design a dual-band bandstop filter with one tunable stopband. Measured results confirm that the tunable bandstop circuits presented in this letter can be effectively used in reconfigurable SIW systems.

Mid-wave infrared narrow bandwidth guided mode resonance notch filter.

Abstract: We have designed, fabricated, and characterized a guided mode resonance notch filter operating in the technologically vital mid-wave infrared (MWIR) region of the electromagnetic spectrum. The filter provides a bandstop at λ≈4.1 μm, with a 12 dB extinction on resonance. In addition, we demonstrate a high transmission background (>80%), less than 6% transmission on resonance, and an ultra-narrow bandwidth transmission notch (10 cm-1). Our filter is optically characterized using angle- and polarization-dependent Fourier transform infrared spectroscopy, and simulated using rigorous coupled-wave analysis (RCWA) with excellent agreement between simulations and our experimental results. Using our RCWA simulations, we are able to identify the optical modes associated with the transmission dips of our filter. The presented structure offers a potential route toward narrow-band laser filters in the MWIR.

A Low-Noise Output Capacitorless Low-Dropout Regulator With a Switched-RC Bandgap Reference

Abstract: Low-noise linear regulators are critical for power supply regulation of noise-sensitive circuits, such as ADCs, phaselocked loops, and other mixed-signal/RF system-on-a-chip designs. A low-noise low-dropout (LN-LDO) regulator using switched-RC bandgap reference and a multiloop, unconditionally stable error amplifier for output capacitorless operation is presented in this paper. A sample-and-hold switched-RC filter is developed to reduce the noise of the bandgap reference and drain-side modulated current-mode chopping technique is proposed to reduce the flicker (1/f) noise of the error amplifier. A switched capacitor notch filter is utilized to filter out the residual chopping ripple of the error amplifier. Thermal noise of the current reference circuit which is significant at such low noise levels is also reduced by using a low-area penalty passive RC filter. These techniques reduce the total integrated output noise of the LDO in the 10 Hz to 100 kHz band from 95.3 μV RMS down to 14.8 μV RMS . The LDO delivers a maximum load current of 100 mA with a dropout voltage of 230 mV and a quiescent current consumption of 40 μA. It achieves a power supply rejection of 50 dB at 10 kHz for a programmable output voltage range of 1-3.3 V. Fabricated in a 0.25 μm CMOS process, the LDO core occupies an area of 0.18 mm 2 .

A Novel Cross-Feedback Notch Filter for Synchronous Vibration Suppression of an MSFW With Significant Gyroscopic Effects

Abstract: To effectively suppress the synchronous vibration torques for a magnetically suspended rotor (MSR) with significant gyroscopic effects and serious coupling dynamics, a novel cross-feedback notch filter is proposed in this paper. First, the coupled multi-input-multi-output active magnetic bearing rotor system is converted into an equivalent complex single-input single-output (SISO) system. The equivalent transformation aims at easing the controller design and extending the classical stability criterion to the complex coefficient frequency domain. Then, the principle and implementation of the proposed scheme used for synchronous vibration suppression over an entire rotational speed range is analyzed in details. The performance compared with the conventional decentralized notch filter is investigated. Moreover, the closed-loop stability, which based on the equivalent complex SISO system and complex-coefficient stability criterion is given. Experimental results on a magnetically suspended flywheel demonstrate the significant effect of the proposed method on both synchronous vibration suppression and stability preservation.

Sharp-Rejection Wideband Bandstop Filter Using Stepped Impedance Resonators

Abstract: A novel wideband bandstop filter is proposed in this paper. Using one uniform impedance resonator and two stepped impedance resonators, five transmission zeros are introduced in the stopband. Appropriate positioning of these zeros ensures the high selectivity and flat rejection level of the stopband. The bandwidth of the filter can be conveniently controlled by the characteristic impedances of the connecting lines and resonators. A complete analytic analysis is proposed to fully control the positions of transmission zeros, and the design equations and design rules for the bandstop filter are given in detail by using the lossless transmission line model. To illustrate the concept, a wideband bandstop filter with center frequency at 2 GHz and rejection level below 20 dB is fabricated. Theoretical, simulated, and measured results are found in good agreement with each other, and the measured 20-dB rejection bandwidth is as wide as 150%.

High input impedance voltage-mode universal filter and its modification as quadrature oscillator using VDDDAs

Abstract: The second order universal voltage-mode filter using voltage differencing differential difference amplifiers (VDDDAs) has been proposed It has high input impedance voltage-mode biquad filter with orthogonal tune of natural frequency and quality factor The proposed filter simultaneously provides five filter responses: low-pass ( LP ), high-pass ( HP ), band-reject ( BR ), all-pass ( AP ) and band-pass ( BP ) in the same circuit topology The natural frequency and quality factor can be tuned electronically and orthogonally dc bias current The output impedance at output nodes HP , AP and BR has low impedance which can connect to other circuit without the use of voltage buffers The proposed filter consists of three VDDDAs, one grounded resistor and two grounded capacitors This makes the proposed filter suitable for integrated circuit development With slightly modifying the proposed filter, the voltage-mode qudrature sinusoidal oscillator with low output impedance and independent control of condition of oscillation (CO) and frequency of oscillation (FO) has been achieved The results shown in this paper are from PSPICE simulation and experiment to validate the proposed circuits

Wideband Mixed-Domain Multi-Tap Finite-Impulse Response Filtering of Out-of-Band Noise Floor in Watt-Class Digital Transmitters

Abstract: A major drawback of digital transmitters (DTX) is the absence of a reconstruction filter after digital-to-analog conversion which causes the baseband quantization noise to get upconverted to radio frequency and amplified at the output of the transmitter. In high power transmitters, this upconverted noise can be so strong as to prevent their use in frequency-division duplexing systems due to receiver desensitization or impose stringent coexistence challenges. In this paper, we describe a DTX that embeds mixed-domain multi-tap finite-impulse response (FIR) filtering with programmable analog sub-sample delays within a highly linear and mismatch-resilient switched-capacitor DTX architecture. It is shown that switched-capacitor power amplifiers (SCPA) in conjunction with transformer-based power combining are ideal candidates for embedding mixed-domain FIR filtering since the near-constant source impedance of the SCPA greatly aids in linear FIR summation thereby preserving the desired noise-shaping profile. Moreover, their excellent mismatch characteristics help in ensuring precise tap weights in the FIR which enhances noise suppression. The availability of multiple taps in this architecture also allows the synthesis of FIR configurations with wide notch bandwidths (BW). Theoretical analyses of this architecture and design trade-offs related to linearity, mismatch, output power, and efficiency are discussed. The implemented 65 nm CMOS prototype exhibits a peak output power of 30.3 dBm and a peak system efficiency of 34%, and achieves a noise floor of −149 dBc/Hz over a BW of 20 MHz at an offset of 135 MHz from a 2.23 GHz carrier while transmitting a 1.4 MHz 64-QAM signal with an average output power of 22 dBm.

Tunable Cavity-Based Diplexer With Spectrum-Aware Automatic Tuning

Abstract: This paper presents, for the first time, an automatically tunable diplexer using evanescent-mode cavity filters, with spectrum-aware and interference mitigation capabilities. The diplexer consists of two second-order bandpass filters and a bandstop filter (BSF) at the receiving path. The BSF is utilized in a spectrum sensing methodology to detect potential jammers. The automatic tuning system monitors each resonator in the diplexer and biases them to accurately reach the targeted frequency accordingly. The presented diplexer presents a measured tuning range 0.75–1 GHz, with an insertion loss (IL) of less than 3.7 dB in the receive path and 2.2 dB in the transmit path and a tuning resolution of ~0.05%. The closed-feedback loop tuning time, which accounts for all mechanical and electrical time constants, is around 250 ms. The spectrum sensing capability has been experimentally demonstrated to detect a jammer. Automatic diplexer tuning results in a total jammer suppression of 30 dB with 33-MHz transmit–receive separation. Further rejection of up to ~50 dB can be achieved for higher separations. The automatic tuning control system is also analyzed for stability.

Microwave Voltage-Controlled Oscillator With Harmonic-Suppressed Stepped-Impedance-Resonator Filter

Abstract: This brief proposes a new low-phase-noise microwave voltage-controlled oscillator (VCO) with a harmonic-suppressed stepped-impedance-resonator (SIR) filter. Since the filter is synthesized by multiple resonators, it can provide a high-quality factor to improve the phase-noise performance. In addition, the harmonic-suppressed property of the filter adopted in this brief can alleviate the noise contributed from the oscillation harmonics. By applying the two techniques mentioned, the proposed VCO is designed at 2.4 GHz with a three-pole Butterworth filter, which is synthesized by the parallel transmission-line SIRs to reduce the circuit size. The proposed VCO using a three-pole filter has a measured phase noise of −147 dBc/Hz at 1-MHz offset frequency with a corresponding figure-of-merit of −203.18 dBc/Hz.

Frequency-Tunable Tri-Function Filter

Abstract: In this paper, we present a reconfigurable filter capable of having three different responses, such as bandstop, bandpass, and all-pass responses. For designing the tri-function filter, we have developed a new topology containing coupled resonators and a switch-embedded transmission line running from the input to output ports. A bandpass response can be obtained by opening the switches embedded in the transmission line. On the other hand, closing the switches produces bandstop and all-pass responses. The details of the coupling structure design satisfying three sets of the coupling coefficients for the three responses are presented. In addition, we also discuss in detail an approach for incorporating the measured parameters of the nonideal switch in our filter design. For demonstration, a frequency-tunable tri-function filter has been designed using substrate-integrated waveguide resonators. It is shown that the designed filter is able to exhibit three responses over a 1.2:1 frequency tuning range.

Partial-Update Schmidt–Kalman Filter

Abstract: The Schmidt–Kalman (or “consider” Kalman filter) has often been used to account for the uncertainty in so-called “nuisance” parameters when they are impactful to filter accuracy and consistency Us

Angle-of-Arrival Estimation of Broadband Microwave Signals Based on Microwave Photonic Filtering

Abstract: We propose and experimentally demonstrate a photonic approach to estimate the angle-of-arrival (AOA) of broadband microwave signals. Using an integrated polarization-division multiplexing Mach–Zehnder modulator and a differential group-delay module, a microwave photonic notch filter is constructed. The relative time delay in reception of the signal at two separate antenna elements can be obtained by measuring the transmission notches over the signal spectra. The AOA is calculated from the relative time delay and the antenna spacing. The experiment results show that the measurement error is less than ±0.35 ps when the relative time delay changes from −14 to 16 ps.

Harmonic disturbance attenuation in a three-pole active magnetic bearing test rig using a modified notch filter:

Abstract: This study is concerned with the problem of harmonic disturbance rejection in active magnetic bearing systems. A modified notch filter is presented to identify both constant and harmonic disturbances caused by sensor runout and mass unbalance. The proposed method can attenuate harmonic displacement and currents at the synchronous frequency and its integer multiples. The reduction of stability is a common problem in adaptive techniques because they alter the original closed-loop system. The main advantage of the proposed method is that it is possible to determine the stability margins of the system by few parameters. The negative phase shift of the modified notch filter can be tuned to achieve a desired phase margin, while the gain margin can also be adjusted separately. It is shown that the modified notch filter can be designed to suppress multiple harmonics at the same time. It is implemented on a three-pole magnetic bearing test rig to evaluate its performance. Simulation and experimental results indica...

Optical band-stop filter and multi-wavelength channel selector with plasmonic complementary aperture embedded in double-ring resonator

Abstract: A compact nanoscale wavelength band-stop filter with aperture embedded in double-ring resonator is proposed and numerically investigated by using Finite-Difference Time-Domain (FDTD) method. With a narrow aperture created between embedded double rings, the modes of the split-ring cavity can be modulated by the aperture in different manners when the parameters of the aperture are changed. Furthermore, the absorption peaks of resonator modes can be selectively inhibited by altering the positions of the aperture without changing outer size of the resonator. Based on above characteristics, a 1 × 2 multiple-contact channel selector is designed with a rotating aperture which can select the output waveguide. The proposed filter and selector have potential applications in highly integrated optical circuits.

Novel Wideband Absorptive Bandstop Filters With Good Selectivity

Abstract: This paper presents a new type of wideband absorptive bandstop filter (ABSF) design that is capable of absorbing the input power within the stopband at its Port 1. It is achieved by introducing one additional resistor to a conventional wideband stub bandstop filter. Suitable design procedures are established to facilitate the synthesis of the proposed wideband ABSFs with different filter orders and stopband bandwidths. To validate the proposed design method, microstrip ABSF design examples with a stopband center frequency $f_{0}$ of 2 GHz and 30-dB stopband bandwidths ranging from 12% to 42% are demonstrated. The measured stopband rejection at $f_{0}$ is larger than 60 dB for all design examples. In addition, good input return losses both in the passband and stopband are achieved, and the measured input return loss is better than 10 dB from dc to $2.5f_{0}$ . Larger than 90% of the input power within the stopband can thus be dissipated by the proposed ABSF. To the best of our knowledge, these are the ABSFs with the widest stopband bandwidth ever reported.

Ultra-compact air-mode photonic crystal nanobeam cavity integrated with bandstop filter for refractive index sensing.

Abstract: We propose and investigate an ultra-compact air-mode photonic crystal nanobeam cavity (PCNC) with an ultra-high quality factor-to-mode volume ratio (Q/V) by quadratically tapering the lattice space of the rectangular holes from the center to both ends while other parameters remain unchanged. By using the three-dimensional finite-difference time-domain method, an optimized geometry yields a Q of 7.2×106 and a V∼1.095(λ/nSi)3 in simulations, resulting in an ultra-high Q/V ratio of about 6.5×106(λ/nSi)−3. When the number of holes on either side is 8, the cavity possesses a high sensitivity of 252 nm/RIU (refractive index unit), a high calculated Q-factor of 1.27×105, and an ultra-small effective V of ∼0.758(λ/nSi)3 at the fundamental resonant wavelength of 1521.74 nm. Particularly, the footprint is only about 8×0.7 μm2. However, inevitably our proposed PCNC has several higher-order resonant modes in the transmission spectrum, which makes the PCNC difficult to be used for multiplexed sensing. Thus, a well-designed bandstop filter with weak sidelobes and broad bandwidth based on a photonic crystal nanobeam waveguide is created to connect with the PCNC to filter out the high-order modes. Therefore, the integrated structure presented in this work is promising for building ultra-compact lab-on-chip sensor arrays with high density and parallel-multiplexing capability.

Miniaturized Frequency Controllable Band-Stop Filter Using Coupled-Line Stub-Loaded Shorted SIR for Tri-Band Application

Abstract: Based on the coupled-line stub-loaded shorted stepped-impedance resonator (CLSLSSIR), a compact microstrip tri-band band-stop filter (TB-BSF) with controllable frequencies, stopband attenuations (SAs), and sharp transition band roll-off skirts has been presented. The proposed CLSLSSIR exhibits multimode resonant behavior and is employed to achieve tri-stopband application by applying the virtual ground effect at the attaching position. Due to the infinite input impedance effect of CLSLSSIR, as well as the resonance of $\pi $ -type network combined with two loaded CLSLSSIRs and transmission line, multiple transmission poles can be yielded to obtain high selectivity of transition band. Finally, an example TB-BSF operating at 1.57, 2.4, and 3.5 GHz with respective SAs of 18, 26.5, and 33.2 dB has been designed and fabricated.