Showing papers on "Band-stop filter published in 2022"

Fractional-Order Notch Filter for Grid-Connected Solar PV System With Power Quality Improvement

Abstract: In this article, we deal with the development of a fractional-order notch filter (FONF) for a grid-connected solar photovoltaic (PV) system. The developed FONF control approach is used to estimate fundamental active constituents from the distorted load currents, and hence, gating pulses for operating voltage source converter (VSC) are used in the PV system. This control approach for the grid-connected solar PV system is designed to achieve several purposes, such as feeding active power demand of the load/grid and countercurrent-related power quality issues at the common connecting point. The power quality issues taken into consideration are harmonics distortion, reactive power burden on the system, and unbalancing of connected loads. The FONF-based control proposes a modified structure of an integer-order notch filter. The integer-order filters have a limitation due to the fixed integrator and differentiator terms. In FONF, the power of integrator used in a notch filter can be modified according to the application required for obtaining the accurate response of the system. A prototype of the grid-connected solar PV system is developed in the laboratory using IGBTs based VSC and dSPACE MicroLabBox (DS-1202) to demonstrate the behavior of the FONF-based control. Simulation and experimental results are obtained for steady-state and unbalanced loads with variation in the solar irradiance. The harmonic distortions in the system are observed as per the IEEE-519 standard.

Fractional-Order Notch Filter for Grid-Connected Solar PV System With Power Quality Improvement

Abstract: In this article, we deal with the development of a fractional-order notch filter (FONF) for a grid-connected solar photovoltaic (PV) system. The developed FONF control approach is used to estimate fundamental active constituents from the distorted load currents, and hence, gating pulses for operating voltage source converter (VSC) are used in the PV system. This control approach for the grid-connected solar PV system is designed to achieve several purposes, such as feeding active power demand of the load/grid and countercurrent-related power quality issues at the common connecting point. The power quality issues taken into consideration are harmonics distortion, reactive power burden on the system, and unbalancing of connected loads. The FONF-based control proposes a modified structure of an integer-order notch filter. The integer-order filters have a limitation due to the fixed integrator and differentiator terms. In FONF, the power of integrator used in a notch filter can be modified according to the application required for obtaining the accurate response of the system. A prototype of the grid-connected solar PV system is developed in the laboratory using IGBTs based VSC and dSPACE MicroLabBox (DS-1202) to demonstrate the behavior of the FONF-based control. Simulation and experimental results are obtained for steady-state and unbalanced loads with variation in the solar irradiance. The harmonic distortions in the system are observed as per the IEEE-519 standard.

Tunable Frequency Filter Based on Twisted Bilayer Photonic Crystal Slabs

Abstract: We introduce a tunable narrow-band-stop frequency filter based on twisted bilayer photonic crystal slabs in sub-wavelength regime. A desired lineshape is achieved by introducing additional uniform slabs. The filter can operate without diffraction loss and is polarization-independent.

Pulse RFI Mitigation in Synthetic Aperture Radar Data via a Three-Step Approach: Location, Notch, and Recovery

Abstract: In complex electromagnetic environments, synthetic aperture radar (SAR) is severely affected by radio frequency interference (RFI) from other systems, such as ground-based radar, cellular networks, and global positioning systems, and this interference cannot be neglected. Pulse RFI (PRFI), a common form of RFI, can hinder SAR signal processing and image interpretation to varying degrees. The time-domain notch filtering method designed for mitigating PRFI can locate and mitigate the evident PRFI covered in SAR echo data, but it is helpless against PRFI hidden in a strong echo signal. In this article, a three-step approach is proposed to tackle the PRFI problem. In the proposed approach, the first step is to detect and locate PRFI; this is based on eigenvalue decomposition (EVD) and the short-time Fourier transform (STFT). The second step is to notch PRFI, and this is based on a time-domain notch filter. The third step is to recover the notched signal using a novel matrix completion strategy, which integrates with a robust low-rank matrix completion (LRMC) technique—i.e.,the singular value thresholding (SVT) algorithm—and a well-known Lagrange interpolation technique. Experimental results via simulated SAR data, Sentinel-1 level-0 raw data, and L-band airborne SAR raw data demonstrate the performance of the proposed approach.

Mitigating High-Frequency Resonance in MMC-HVDC Systems Using Adaptive Notch Filters

Abstract: Recently, high-frequency resonance (HFR) incidents have occurred in several MMC-HVDC projects. The resonance frequency highly depends on system conditions, making mitigation methods designed for specific scenarios ineffective once the grid condition changes. To address the issue, this paper proposes a novel HFR mitigation method based on adaptive notch filters (ANFs). The embedding positions of ANFs in the MMC control are optimally determined through impedance-based analysis. With the HFR frequency estimated by the interpolated discrete Fourier transform, the parameters of ANFs are adaptively tuned. The ANFs improve the damping performance of the captured HFR mode without affecting the dynamic characteristics at other frequencies. As a result, the HFR under varying grid conditions can be mitigated effectively. The effectiveness of the proposed method is verified through electromagnetic transient (EMT) simulations of an actual MMC-HVDC system.

Design of minimum-order allpass-based IIR multi-notch filters

Abstract: The paper investigates the design methods for the minimum-order allpass-based infinite impulse response multi-notch filters. Monotonically decreasing nature of the stable allpass filter's phase response allows the formulation of the magnitude response specifications of the allpass-based multi-notch filter as the linear equality and inequality constraints in unknown allpass filter coefficients. As not all allpass filters satisfying mentioned constraints are of the same practical interest, several design methods minimizing various cost functions are proposed. One of these methods outperforms existing design methods in terms of stability margin, while utilization of other methods can result in higher area under the passbands squared magnitude response. Proposed methods are also compared with some of the existing infinite impulse response multi-notch filter design methods, whose lower complexity counterparts are derived by means of conclusions drawn and notations introduced while deriving the proposed design methods.

Highly selective uwb bandpass filter with multi-notch characteristics using comb shaped resonator

Abstract: This paper aims to present a highly selective, compact size new ultra-wideband (UWB) bandpass filter with three sharp notches for UWB indoor applications. The fundamental geometry of the filter is based on a modified multi-mode resonator (MMR) structure which comprises an open-ended step impedance resonator (SIR) attached to an interdigitated uniform impedance resonator (UIR). Realizing a Comb-shaped resonator structure below the UIR and symmetrically extending the lower arm edge of the interdigital coupled lines, three notches are generated at 6GHz, 6.53GHz, and 8.35GHz. These notches have improved the UWB bandpass filter responses by suppressing the existing interferences in the UWB passband created by Wi-Fi 6E (6GHz), super-extended C band (6.425GHz ∼ 6.725GHz), X band satellite communications for satellite TV networks or raw satellite feeds (7.25GHz ∼ 8.395GHz). Concurrently the notched band filter has achieved superiority in other salient features concerning passband and stopband of the filter such as a high passband fractional bandwidth (115.76%), low return loss (−13.27 dB), low insertion loss (0.44 dB ∼ 0.97 dB), wide upper stopband (5.37GHz), nearly flat group delay (0.28 ns ∼ 0.45 ns), etc. The ultimate design of the UWB bandpass filter is fabricated and verified by comparing the simulated filter responses with the measured results indicating a good agreement.

Tunable bandstop filter using graphene in terahertz frequency band

Abstract: In this paper, a planar graphene-based bandstop filter is designed and simulated for the resonant frequency of 1 THz. The transmission line model of the bandstop filter is considered, which consists of open-circuited shunt stubs that are interconnected through unit elements. The bandstop filter design is carried out from the normalized low pass Chebyshev prototype. By using frequency transformation, Richard’s transformation, and Kuroda’s identity, the desired bandstop filter can be designed from the low pass prototype. The graphene layer is introduced between the conductor layer and the dielectric for supporting the propagation of plasmonic waves. The simulation results show that the desired frequency response can be obtained for the designed graphene-based bandstop filter. By varying the chemical potential of the graphene layer, the resonant frequency of the bandstop filter can be tuned over the range of 0.1 THz with the constant absolute bandwidth.

A Novel Attitude Angular Velocity Measurement Method Based on Mass Unbalance Vibration Suppression of Magnetic Bearing

Abstract: In order to eliminate the influence of synchronous harmonic current caused by mass imbalance of magnetic bearing on attitude angular velocity measurement accuracy, a notch filter which can adjust the notch depth and center frequency is proposed. Firstly, the influence of synchronous harmonic current on the measurement accuracy of magnetically suspended control and sensitive gyroscope(MSCSG) is analyzed, and then a notch filter is designed which can adjust the notch depth and center frequency, and the measurement accuracy and stability of the system after eliminating synchronous harmonic current are analyzed. Simulation results show that the proposed method can effectively suppress the unbalance vibration torque and eliminate synchronous harmonic current. Finally, the correctness and effectiveness of the proposed method are verified by experiments. Experimental results show that the proposed method can reduce the vibration torque by 50% and improve the measurement accuracy of attitude angular velocity significantly.

On-chip Brillouin notch filter on a silicon nitride ring resonator

Abstract: Noncontact Brillouin spectroscopy is a purely optical and label-free method to retrieve fundamental material viscoelastic properties. Recently, the extension to a threedimensional imaging modality has paved the way to novel exciting opportunities in the biomedical field, yet the detection of the Brillouin spectrum remains challenging as a consequence of the dominant elastic background light that typically overwhelms the inelastic Brillouin peaks. In this Letter, we demonstrate a fully integrated and ultra-compact Brillouin notch filter based on an optical ring resonator fabricated on a silicon nitride platform. Our on-chip ring resonator filter was measured to have a ∼10 dB extinction ratio and a Q factor of ∼ 1.9 · 105. The experimental results provide a proof-of-concept on the ability of the on-chip filter to attenuate the elastic background light, heralding future developments of fully integrated, ultra-compact and cost-effective Brillouin spectrometers. Characterization of the material mechanical properties is a primary task across different fields ranging from chemistry to material and life sciences. Unlike standard analytical ap1 ar X iv :2 20 1. 00 68 6v 1 [ ph ys ic s. op tic s] 3 J an 2 02 2 proaches based on the application of contact forces, Brillouin spectroscopy is purely optical and provides access to 3D mechanical properties without the need of contact nor sample labeling.1 In Brillouin spectroscopy, a narrowband monochromatic laser beam illuminates the sample and the scattered light is spectrally analyzed by a spectrometer with sub-GHz resolution.2 The frequency shift and the linewidth of the Brillouin spectral peaks arising from the light interaction with thermally-activated spontaneous acoustic waves of matter provides information about the individual elastic moduli that form the full material elastic tensor.3 The recent combination of Brillouin spectroscopy with confocal microscopy4,5 has enabled a wide variety of applications within the life sciences including the elasticity assessment of the ocular lens and cornea in-vivo,6 the 3D mechanical imaging of living cells7–10 as well as the investigation of the liquid-to-solid phase transitions of intracellular compartments.11–13 Moreover, Brillouin spectroscopy holds promises to become a diagnostic tool in clinical environments,14 where altered biomechanical properties are understood to be the primary initiators of age-linked pathologies such as keratoconus,15 cancer16,17 and atherosclerosis.18 Despite the broad range of potential applications,19 Brillouin spectroscopy remains challenging in the spontaneous regime as a consequence of the dominant elastic background light arising from both Rayleigh scattering and specular reflections. When the relative strength difference between the elastic and inelastic spectral components exceeds the contrast of the spectrometer, the Brillouin peaks are overwhelmed and cannot be detected. Multipass FabryPerot interferometers of high (∼10) spectral contrast have for long been used in Brillouin spectroscopy,20 but their relative slow scanning process imposes long (typically > 1 sec) data acquisition time that makes them not suitable for imaging. To overcome this limit, a modified non-scanning version of the solid Fabry-Perot etalon, namely a Virtually Imaged Phased Array (VIPA), has been used in Brillouin microscopy.21 Yet, its limited (∼30 dB) spectral contrast imposes complex multistage architectures that affect the system throughput efficiency and increase complexity. Extensive research has been carried out both to increase the spectral contrast of VIPA-based spectrometers and to suppress the unwanted

An Enhanced Adaptive Frequency-Locked Loop Based on Fixed-Length Transfer Delay

Abstract: The fixed-length transfer delay-based adaptive frequency-locked loop (TD-AFLL) has drawn much attention due to its concise structure and faster response speed than conventional second-order generalized integrator-based FLL. However, the application of TD-AFLL is still limited owing to the poor performance in terms of phase-angle/amplitude detection under distorted grid conditions. This paper explores an inherent input-output relationship of TD-AFLL, and a notch filter is employed to represent its filtering feature. Then a high-order filter is designed based on this notch filter, and an enhanced TD-AFLL (ETD-AFLL) with improved phase-angle/amplitude detection is further derived. The ETD-AFLL highly improves the phase-angle/amplitude detection accuracy under distorted grid conditions yet keeps the same fast response speed as TD-AFLL. In addition, the ETD-AFLL only requires a slightly additional computational cost. Experimental results are given to support the proposed ETD-AFLL.

Time-Domain Notch Filtering Method for Pulse RFI Mitigation in Synthetic Aperture Radar

Abstract: Synthetic aperture radar (SAR) often shares spectrum with other systems, such as radio, TV, cellular network, and so on, which are likely to produce radio frequency interference (RFI). Pulse RFI, which hinders SAR signal processing and image interpretation severely, is a common form of RFI and cannot be neglected. The simple and easy-to-implement frequency-domain notch filtering (FNF) method has been widely used to mitigate narrowband pulse RFIs. However, a well-known problem with abnormal sidelobe effect, which is caused by missing spectrum gaps due to the notch operation, is aroused when using FNF. In this letter, a novel time-domain notch filtering (TNF) is proposed. In the proposed method, pulse RFI occurrences are detected and notched by a simple log-ratio operator in a pulse by pulse manner. Then, missing-data iterative adaptive approach (MIAA) is performed to recover the notched signal to avoid ghosts. Experimental results via simulated and real L-band airborne SAR raw data validate the performance of the proposed method.

Fully differential fifth-order dual-notch low-pass filter for portable EEG system

Abstract: This paper presents a new fully differential fifth-order dual-notch low-pass filter based on multiple-input multiple-output operational transconductance amplifiers (MIMO OTA). This work shows that MIMO OTA-based fifth-order dual-notch filter can reduce the number of used OTAs, resulting in simplified realization and low-power consumption. The multiple-input OTA is obtained by using the multiple-input dynamic threshold MOS (DTMOS) technique without additional differential pairs. A simple common-mode feedback technique has been used; thus, fully differential OTA can be easily obtained. The proposed dual-notch low-pass filter can be applied to electroencephalogram (EEG) detection system to reject the 50 Hz powerline interference and the third harmonic 150 Hz. The proposed filter has been simulated using Cadence environment with 0.18 µm TSMC CMOS process. The power supply of 0.5 V is used and the total power consumption of the MIMO OTA is 17.5 nW. The proposed filter provides 49.7 dB dynamic range for 1% total harmonic distortion (THD) for a sine input signal of 250 mVpp at 10 Hz. At 50 Hz and 150 Hz the notch depths of attenuation are respectively −37.2 dB and −47.4 dB. The pre-layout simulation results are in good agreement with the theory.

Tunable Bandstop Filter using Graphene in Terahertz Frequency Band

Abstract: In this paper, a planar graphene-based bandstop filter is designed and simulated for the resonant frequency of 1 THz. The transmission line model of the bandstop filter is considered, which consists of open-circuited shunt stubs that are interconnected through unit elements. The bandstop filter design is carried out from the normalized low pass Chebyshev prototype. By using frequency transformation, Richard’s transformation, and Kuroda’s identity, the desired bandstop filter can be designed from the low pass prototype. The graphene layer is introduced between the conductor layer and the dielectric for supporting the propagation of plasmonic waves. The simulation results show that the desired frequency response can be obtained for the designed graphene-based bandstop filter. By varying the chemical potential of the graphene layer, the resonant frequency of the bandstop filter can be tuned over the range of 0.1 THz with the constant absolute bandwidth.

A Compact Wide Stopband Band Pass SIW Filter For K-Band Applications

Abstract: Direct coupled filters have narrow stopband due to higher order modes passband. A compact dual layer band pass filter is proposed with wide stop band. The proposed filter provides the return loss of 16.87db and insertion loss of 2.5dB at the passband frequency 20.9 GHz. The filter size is half of the conventional direct coupled filters. The stop band covers up to 40 GHz with insertion loss below 35dB. The filter has no slot which makes it immune to the EMI/EMC problems.

On-Chip Notch Filter on a Silicon Nitride Ring Resonator for Brillouin Spectroscopy

Abstract: Noncontact Brillouin spectroscopy is a purely optical and label-free method to retrieve fundamental material viscoelastic properties. Recently, the extension to a three-dimensional imaging modality has paved the way to novel exciting opportunities in the biomedical field, yet the detection of the Brillouin spectrum remains challenging as a consequence of the dominant elastic background light that typically overwhelms the inelastic Brillouin peaks. In this Letter, we demonstrate a fully integrated and ultra-compact Brillouin notch filter based on an optical ring resonator fabricated on a silicon nitride platform. Our on-chip ring resonator filter was measured to have a 10 dB extinction ratio and a Q factor of 1.9x10^5. The experimental results provide a proof-of-concept on the ability of the on-chip filter to attenuate the elastic background light, heralding future developments of fully integrated, ultra-compact and low-cost Brillouin spectrometers.

Dual Angular Tunability of 2D Ge/ZnSe Notch Filters: Analysis, Experiments, Physics

Abstract: 2D resonant gratings enable dual angular tunability by controlling the plane of incidence (POI) under linear polarization. If the POI is set to be perpendicular to the electric field vector (s‐polarization or transverse electric (TE) polarization), an excited TE mode provides spectral tuning. The orthogonally propagating transverse magnetic (TM) mode is robust in angle. Conversely, if the POI is set for p‐polarization, an excited TM mode provides the tuning. Detailed explanations of the underlying physical processes are set forth by decomposing the 2D lattice into equivalent 1D gratings using second‐order effective‐medium theory. This is shown to work extremely well even for a strongly modulated lattice with refractive‐index contrast of 3. With proper design and corresponding experiments, a widely tunable notch filter covering long‐wave infrared bands is demonstrated. Experimentally varying the incidence angle up to 16° under p‐polarization, a notch channel in TM mode tunes across a band exceeding 0.5 µm with the TE channel remaining at a constant wavelength. The interesting appearance of a resonance channel originating in diagonally propagating leaky modes is briefly examined. The analysis and experiments presented can be useful for realizing diverse 2D tunable filters while furnishing methodology for detailed understanding of the attendant near fields and mode structure.

Simultaneous Wireless Power and Data Transfer System With Full-Duplex Mode Based on Double-Side <i>LCCL</i> and Dual-Notch Filter

Abstract: The data transmission is always necessary for wireless power transfer systems, and however, the interference between power and data is the major problem for the full-duplex simultaneous wireless power and data transfer (SWPDT) system. To solve this problem, in this article, a novel SWPDT system based on the double-side LCCL and dual-notch filter is proposed. In the power transfer channel, by the double-side LCCL topology, the high impedance of power branches at the data carrier frequency reduces the power interference largely. In the data transfer channel, the dual-notch filter is utilized to separate the data carriers and realize the full-duplex communication, which could reduce the ipsilateral data interference and improve the signal-to-noise ratio (SNR). The transfer functions of data transmission are derived by the analysis on the impedance of each part. Since the interferences of power and ipsilateral data source are analyzed, the expression of SNR could be derived and the corresponding factors to improve the SNR are discussed. An optimization of data transfer channel to maximize the SNR is proposed by shifting the dual-notch filter and transformers. The experimental setup with 400-W output power and 200-kb/s data rate is conducted to verify the feasibility of the proposed SWPDT system and the correctness of the design method.

Removing Powerline Interference from EEG Signal using Optimized FIR Filters

Abstract: The Electroencephalography (EEG) is a signal representing the electrical activity of the brain and is used in the diagnosis of brain diseases. The EEG signal is weak and highly prone to noise from the powerline which generates a sinusoidal signal with the main frequency of 5060 Hz. Therefore, three harmonics of powerline noise must be removed using notch filters for a perfect diagnosis which requires three series notch filters. This paper presents a new method to design a digital notch finite impulse response (FIR) filter using a modified particle swarm optimization technique. The proposed method provides a short length, maximum stopband attenuation, and small transition width compared to different algorithms which results in removing the noise in EEG signal efficiently.

Exotic FMCW Waveform Mitigation with an Advanced Multi-Parameter Adaptive Notch Filter (MPANF)

Abstract: Adaptive notch filters (ANFs) can efficiently mitigate linear chirp signals. However, they are only a subclass of frequency-modulated continuous-wave (FMCW) waveforms. Many other FMCW signals could pose potential threats in the future. This paper evaluates several exotic FMCW waveforms and how mitigateable they are with ANFs. Furthermore, the advanced multi-parameter adaptive notch filter (MPANF) is demonstrated. In most cases, the MPANF is superior to traditional static ANFs. Several FMCW waveforms are challenging to mitigate, but most approaches indicate adequate performance. This paper demonstrates shortcomings in current mitigation techniques and provides a baseline for future-proofing global navigation satellite system (GNSS) resiliency.

Multi-Band and Frequency-Agile Chip-Based RF Photonic Filter for Ultra-Deep Interference Rejection

Abstract: Unwanted high-power and frequency-agile radio-frequency (RF) signals cause saturation and nonlinear distortions in sensitive RF receivers. RF notch filters with reconfigurable responses over multiple frequency bands are highly sought after to prevent these detrimental effects. Microwave photonic (MWP) notch filters have shown increased frequency agility compared to their electronic counterparts. However, demonstrated filter schemes focus only on single notch responses, leaving them unable to simultaneously attenuate multiple interferers over a wide frequency range. In this work, we demonstrate a high-performance chip-based MWP notch filter with three independent notches widely tunable over 20 GHz. The filter exhibits low RF passband losses of 8 dB and peak notch depth greater than 40 dB with 500 MHz spectral resolution. Specifically, each notch is formed through cascaded optical processing from on-chip, low-loss Si$_3$N$_4$ micro-resonators and Brillouin gain on an As$_2$S$_3$ photonic chip. We use this filter to demonstrate high-performance analog RF filtering by substantially attenuating multiple interferers, and show effective image rejection during RF down-conversion in a communications receiver to enable a large reduction of error vector magnitude (EVM) from 60% to 15%. Finally, we provide performance analysis and design perspectives for future photonic integration of the proposed filter subsystem.

Single and Multiple Continuous-Wave Interference Suppression Using Adaptive IIR Notch Filters Based on Direct-Form Structure in a QPSK Communication System

Abstract: The removal filter coefficients in this technique are dependent on the jammer’s power and its Instantaneous Frequency (IF) information, which can both be obtained in the time–frequency domain (adaptive filtering techniques). The dependence of the removing/reducing filter characteristics on the interference power is critical, as it allows an optimal trade-off between removal interference and the amount of self-noise generated by the filter. This trade-off is bounded by the two extreme cases of no notch filter (no self-noise) and full suppression (k1 = 1) for both low- and high-power jammer values. In this paper, a cascade second-order adaptive direct Infinite Impulse Response (IIR) Notch Filter (NF) with a gradient-based algorithm to suppress the Continuous-Wave (CW and MCW) interference is proposed for maximizing the receiver Signal-to-Noise Ratio (SNR) in a Quadrature Phase-Shift Keying (QPSK)-modulated signal. The suppression approach consists of two Adaptive IIR NFs (ANFs) based on a direct-form structure: the Hd1(z) and Hd1(z). The proposal in this work presents a low-complexity Time-Domain (TD) algorithm for controlling the update filter coefficient and notch depth. Simulation results demonstrate that the proposed approach represents an effective method for removing/reducing the impacts of CWI/MCWI, resulting in improved system performance for low- and high-power jammer values when compared with the case of full suppression (k1 = 1); furthermore, it also improves the notch filter’s output SNR for a given Jamming-to-Signal Ratio (JSR) value and Bit Error Ratio (BER) performance. For example, the SNR output of the proposed IIR NF was enhanced by 7 dB versus the case without a filter when Eb/No = 15 dB and JSR = −5 dB. The proposed method can detect and mitigate weak and strong jamming with JSR values ranging from −30 to 40 dB, and can track the hopping frequency interference. Moreover, an improved BER performance is seen as compared to the case without an IIR NF.

Analysis and Design of a CMOS LNA With Transformer-Based Integrated Notch Filter for <i>Ku</i>-Band Satellite Communications

Abstract: A transformer-based notch filter is proposed in this article. The notch filter is integrated into a three-coil transformer in the matching network. While the primary coil and the secondary coil build a magnetically coupled resonator (MCR) and transfer the in-band signal to the next stage, the tertiary coil is coupled with the primary coil to absorb the interferers. Resonating with the switched capacitors, the notch frequency can be tuned digitally. A cross-coupled pair can further enhance the quality factor of the tank and, therefore, the rejection level. A low-noise amplifier (LNA) for Ku -band satellite communication with the proposed notch filter is implemented in 65-nm CMOS to verify the theory. The LNA achieves a measured power gain of 19.5 dB at 12.2 GHz with a −3-dB bandwidth of 9.2–12.7 GHz. The LNA can achieve 13.5-dB gain suppression at 13.9 GHz. The suppression level can be enhanced by tuning the quality factor of the active notch filter, which consumes up to 0.6 mW. The noise figure (NF) is 2.3 dB at 10.6 GHz and the NF is below 2.7 dB from 9.2 to 12.7 GHz. The input return loss is better than −15 dB from 8.8 to 18.5 GHz. The LNA consumes 5.9 mW from a 1-V supply. The whole chip occupies an area of 1000 $\times 800\,\,\mu \text{m}^{2}$ .