Lumped Element RF Low Pass Filter with 20 dB Improved Suppression at the Center Frequency of an RF Injection Network for Conductive Emission Testing

Author(s):  
Ali Attaran ◽  
William B. Handler ◽  
Blaine A. Chronik
2018 ◽  
Vol 876 ◽  
pp. 133-137
Author(s):  
Ping Cheng Chen ◽  
Chung Long Pan ◽  
J.D. Huang ◽  
S.H. Hong

A design and simulation for low pass microstrip line filter with defected ground structure has been researched, the main purpose is with the simplest method to design an ideal low pass filter. In this paper, simulated soft (Ansoft HFSS V.6.0) used to be simulated the frequency response under different geometric shape of DGS. The results show good performance of a low pass filter with DGS. Final, a low pass filter with DGS design and fabricated, The properties are shown as flow: center-frequency: 7.28G, S21:-47dB, cut-off frequency: 5.88GHz.


2013 ◽  
Vol 273 ◽  
pp. 371-374
Author(s):  
Bao Ping Li ◽  
Yan Liang Zhang

Due to the frequency response periodicity of distributed transmission line, microstrip band-pass filter usually produces parasitic pass-band and outputs harmonics away from the center frequency of main pass-band. Based on the study of rectangular ring defected ground structure, a 5-order microstrip LPF(low-pass filter) was designed using the single-pole band-stop and slow-wave characteristics of the rectangular ring DGS(Defected Ground Structure) and SISS(Step-Impedance Shunt Stub) structure. Compared with traditional LPF, this LPF presents the advantages of compact size, low insertion loss, broad stop-band and high steep. It also validates the requirements of miniaturization and high performance for filters.


Author(s):  
Darine Kaddour ◽  
Jean-Daniel Arnould ◽  
Philippe Ferrari

In this paper, a miniaturized bandpass filter for ultra-wide-band applications is proposed. It is based on the embedding of high-pass structures in a low-pass filter. A semi-lumped technology combining surface-mounted capacitors and transmission lines has been used. The filter design rules have been carried out. Furthermore, two filters having a 3-dB fractional bandwidth of 142 and 150%, centered at 0.77 and 1 GHz, respectively, have been realized for a proof of concept. Measured characteristics, in good agreement with simulations, show attractive properties of return loss (|S11| <−18 dB), insertion loss (<0.3 dB), and a maximum group delay and group delay variation of 2 and 1.3 ns, respectively. A distributed filter based on the same low-pass/high-pass approach has been also realized and measured for comparison. The size reduction reaches 85% for the semi-lumped filter, and its selectivity is improved with a shape factor of 1.3:1 instead of 1.5:1. The semi-lumped filter's drawback is related to a smaller rejection bandwidth compared to the distributed one. To improve the high-frequency stopband, an original technique for spurious responses suppression based on capacitively loaded stubs has been proposed. Even if the performances do not reach that obtained for the distributed approach, with this technique spurious responses are pushed until eight times the center frequency. A sensitivity study vs. critical parameters has also been carried out, showing the robustness of the design.


2015 ◽  
Vol 743 ◽  
pp. 233-238 ◽  
Author(s):  
Qi Yuan Zhu ◽  
Xiang Li Meng

Microstrip filter has extensive application in microwave circuit and communication system in the future. We take lumped components low-pass filter as the prototype and employ the Richards transformation and the Kuroda rule to change the low pass prototype into a bandstop filter. By using ADS (Advanced Design System) method we design a microstrip stub bandstop filter, whose center frequency, range of frequency and relative width are respectively 4GHz, 3GHz ~ 5GHz and 8%. And then we further optimize the parameters to get the circuit design layout. It is shown that all indexes reach the design requirements and the method possesses the features such as short period and high reliability.


2020 ◽  
Author(s):  
Jana Van Canneyt ◽  
Jan Wouters ◽  
Tom Francart

AbstractObjective‘F0 tracking’ is a novel method that investigates the neural processing of the fundamental frequency of the voice (f0) in continuous speech. Through linear modelling, a feature that reflects the stimulus f0 is predicted from the EEG data. Then, the neural response strength is evaluated through the correlation between the predicted and actual f0 feature. The aim of this study was to improve upon this ‘f0 tracking’ method by optimizing the f0 feature.ApproachSpecifically, we aimed to design a feature that approximates the expected EEG responses to the f0. We hypothesized that this would improve neural tracking results, because the more similar the feature and the neural response are, the easier it will be to reconstruct the one from the other. Two techniques were explored: a phenomenological model to simulate neural processing in the auditory periphery and a low-pass filter to approximate the effect of more central processing on the f0 response. Since these optimizations target different aspects of the auditory system, they were also applied in a cumulative fashion.ResultsResults obtained from EEG evoked by a Flemish story in 34 subjects indicated that both the use of the auditory model and the addition of the low-pass filter significantly improved the correlations between the actual and reconstructed feature. The combination of both strategies almost doubled the mean correlation over subjects, from 0.78 to 0.13. Moreover, canonical correlation analysis with the modelled feature revealed two distinct processes contributing to the f0 response: one driven by the compound activity of auditory nerve fibers with center frequency up to 8 kHz and one driven predominantly by the auditory nerve fibers with center frequency below 1 kHz.SignificanceThe optimized f0 features developed in this study enhance the analysis of f0-tracking responses and facilitate future research and applications.


2015 ◽  
Vol 754-755 ◽  
pp. 581-590
Author(s):  
Hui Fang Liew ◽  
Syed Idris Syed Hassan ◽  
Mohd Fareq bin Abd Malek ◽  
Yufridin Wahab ◽  
Melaty Amirruddin ◽  
...  

This paper presents the design technique of a compact composite microstrip filter operating at ultra high frequency (UHF) band and its fabrication using micro-electro mechanical system MEMS technology. The fringing compensation method is applied into the design of the microstrip line transformation from lumped element. The filter lumped circuits and microstrip line circuit were designed and simulated using Advanced Design Software (ADS) and fabricated on silicon substrates to obtain the best filter characteristic based on S-parameter. The measured and simulated results have achieved a good agreement within the frequency of interest. This shows that the fringing compensation method of transforming lumped element into microstrip line is able to solve the conventional design of complexity size of circuit of composite low pass filter (LPF) into microstrip line. The proposed filter design can replace the conventional filters in wireless communication as they offer better performance at lower cost in the RF microwave communication applications.


Radio frequency (RF) and microwave filters characterize a class of electronic filter, intended to function on signals in the frequency range between megahertz to gigahertz. A Lumped element RF filters is a passive device whose size across any dimension is much smaller than the operating wavelength so that there is minimal change in phase of waveform between the input and output connections. RF filters can also be designed using distributed elements in which all the inductors and the capacitors are replaced by the open and short circuit stubs. This paper concentrates on an analysis and design of low pass filter with the help of only lumped elements and a high pass filter with both lumped and distributed elements.


1998 ◽  
Vol 8 (3) ◽  
pp. 141-143 ◽  
Author(s):  
Shau-Gang Mao ◽  
Hwann-Kaeo Chiou ◽  
Chun Hsiung Chen

Frequenz ◽  
2018 ◽  
Vol 72 (11-12) ◽  
pp. 517-521
Author(s):  
Guoan Wu ◽  
Siyuan Dong ◽  
Qinfen Xu

Abstract A compact filtering Wilkinson power divider with harmonic suppression based on lumped components is presented in this paper. The new divider uses two 5th-order elliptic-function low-pass filters to replace the quarter wavelength microstrip lines of the conventional Wilkinson power divider. The structure combines the power divider and the filter into a complete device. By integrating elliptic low-pass filters with the power divider, the proposed structure can suppress harmonics due to the filter’s band-notched characteristic. The power divider demonstrates a measured suppression of 37.1 dB for the second harmonic, 36.6 dB for the third harmonic, 38.6 dB for the fourth harmonic respectively. The harmonic suppression is higher than 20 dB from 2.75 to 7.035 GHz. Furthermore, lumped components are utilized to achieve improvement on size reduction. Compared with the conventional divider, the proposed structure effectively reduces the size by 77 %. The insertion loss is 3.2 dB at the center frequency (1.45GHz).


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