Dual Notch Filter Research Articles

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

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 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LCCL</i> and dual-notch filter is proposed. In the power transfer channel, by the double-side <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LCCL</i> 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.

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

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.

Fully Adaptive Multiband Bandstop Filtering Sections and Their Application to Multifunctional Components

An original RF design approach for the realization of fully reconfigurable planar multiband bandstop filters (BSFs) is reported. The engineered RF filtering topology allows independent control of its stopbands in terms of center frequency and bandwidth. It exploits the in-series cascade of $ {K}$ spectrally agile $ {N}$ -notch filtering cells that are connected through $ {K-1}$ static impedance inverters to realize an $ {N}$ -band filtering transfer function with $ {K}$ th-order stopbands. Each of these multinotch cells is formed by $ {N}$ tunable resonators—center-frequency control—that interact with the same nonresonating node by means of different variable couplings—bandwidth control. Additional features of this tune-all multiband BSF architecture when compared with related prior-art devices are: 1) scalability to the synthesis of an arbitrary number of stopbands; 2) notch-spectral-merging capability into wider eliminated bands of the same order, which equivalently allows the intrinsic control, i.e., without RF switches, of the amount of active rejected bands; and 3) smaller physical size. The coupling-matrix modeling of the conceived multiband BSF scheme is presented. Moreover, its cointegration with other RF analog-processing actions in multifunctional components, such as bandpass filtering and power division, is investigated. For experimental-validation purposes, three UHF-band mechanically reconfigurable microstrip prototypes are developed and tested. They correspond to a dual-notch filter, a wideband bandpass filter with embedded notches in its tunable passband, and a Wilkinson-type power divider with inserted stopbands for dynamic multi-interference mitigation.

Rotational circular split ring resonator array loaded CPW for dual notch and wide bandstop applications

ABSTRACTA compact design of a wide bandstop and dual notch filter using an array of circular split ring resonators (SRR) on a coplanar waveguide is proposed in this article. The band rejection is determined by the resonance frequencies of the loaded SRRs. The resonance frequencies of the SRRs are optimized by gradual angular rotation of the inner rings of the SRRs. The dual notch is achieved with dual SRR pairs with two different angular orientations of (0°–60° and 0°–90°). A wideband rejection is achieved by an array of eight pairs of SRRs with gradually changing angular orientation from 0° to 90°. Good agreement is achieved between the simulated and the measured results. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1204–1209, 2015

Development of UWB Bandpass Filter with Two NotchBands to Reject IEEE 802.11a/b Services

This paper presents an Ultra-Wideband (UWB) bandpass filter with two notched bands for avoiding interference between the UWB radio system and the existing radio systems. This novel UWB dual notch filter is based on microstrip structure which consists of ring resonator and interdigital coupling. The dual notched bands operation is implemented by integrating folded stubs in the inter-digital coupled microstrip conductors. The structure generates two distinct resonant frequencies to stop 2.4 GHz and 5 GHz Wireless Local Area Network (WLAN) services. The resonance of each stub introduces a narrow rejection band in the UWB passband which then results in dual notched bands. The notched band can be shifted to any other desired frequency by tuning the length of the stub. Simulation, design, fabrication and measurement of the proposed UWB bandpass filter with notched bands are carried out strictly following the FCC's spectrum mask. The filter demonstrated both excellent ultra-wide bandwidth (from 1.8 GHz to 7.8 GHz) and rejection performance of -41 dB at 2.6 GHz and -24 dB at 5.3 GHz. The designed filter is successfully simulated using electromagnetic simulator, IE3D. The overall size of the developed filter with the above features is 6 mm (length) x 39.2 mm (height) x 1.6 mm (height). The measured insertion loss and group delay of the developed filter over the desired passband is at acceptable level.