Isolating Bandpass Filters Using Time-Modulated Resonators

2020 ◽  
Author(s):  
Xiaohu Wu ◽  
Xiaoguang Liu ◽  
Mark Hickle ◽  
Dimitrios Peroulis ◽  
Juan Sebastian Gomez-Diaz ◽  
...  
Keyword(s):  
Frequency Conversion ◽  
Modulation Depth ◽  
Modulation Frequency ◽  
Center Frequency ◽  
Reverse Direction ◽  
Analysis Method ◽  
Low Loss ◽  
Lumped Element ◽  
Reverse Isolation ◽  
First Time

In this paper, we demonstrate, for the first time, an isolating bandpass filter with low-loss forward transmission and high reverse isolation by modulating its constituent resonators. To understand the operating principle behind the device, we develop a spectral domain analysis method and show that the same-frequency nonreciprocity is a result of the nonreciprocal frequency conversion to the intermodulation (IM) frequencies by the time-varying resonators. With appropriate modulation frequency, modulation depth, and phase delay, the signal power at the IM frequencies is converted back to the RF frequency and adds up constructively to form a low-loss forward passband, whereas they add up destructively in the reverse direction to create the isolation. To validate the theory, a lumped-element three-pole 0.04-dB ripple isolating filter with a center frequency of 200 MHz and a ripple bandwidth of 30 MHz is designed, simulated, and measured. When modulated with a sinusoidal frequency of 30 MHz, a modulation index of 0.25, and an incremental phase difference of 45°, the filter achieves a forward insertion loss of 1.5 dB and a reverse isolation of 20 dB. The measured nonmodulated and modulated results agree very well with the simulations. Such nonreciprocal filters may find applications in wideband simultaneous transmit and receive radio front ends.

scholarly journals Isolating Bandpass Filters Using Time-Modulated Resonators

2020 ◽  
Author(s):  
Xiaohu Wu ◽  
Xiaoguang Liu ◽  
Mark Hickle ◽  
Dimitrios Peroulis ◽  
Juan Sebastian Gomez-Diaz ◽  
...  
Keyword(s):  
Frequency Conversion ◽  
Modulation Depth ◽  
Modulation Frequency ◽  
Center Frequency ◽  
Reverse Direction ◽  
Analysis Method ◽  
Low Loss ◽  
Lumped Element ◽  
Reverse Isolation ◽  
First Time

In this paper, we demonstrate, for the first time, an isolating bandpass filter with low-loss forward transmission and high reverse isolation by modulating its constituent resonators. To understand the operating principle behind the device, we develop a spectral domain analysis method and show that the same-frequency nonreciprocity is a result of the nonreciprocal frequency conversion to the intermodulation (IM) frequencies by the time-varying resonators. With appropriate modulation frequency, modulation depth, and phase delay, the signal power at the IM frequencies is converted back to the RF frequency and adds up constructively to form a low-loss forward passband, whereas they add up destructively in the reverse direction to create the isolation. To validate the theory, a lumped-element three-pole 0.04-dB ripple isolating filter with a center frequency of 200 MHz and a ripple bandwidth of 30 MHz is designed, simulated, and measured. When modulated with a sinusoidal frequency of 30 MHz, a modulation index of 0.25, and an incremental phase difference of 45°, the filter achieves a forward insertion loss of 1.5 dB and a reverse isolation of 20 dB. The measured nonmodulated and modulated results agree very well with the simulations. Such nonreciprocal filters may find applications in wideband simultaneous transmit and receive radio front ends.

scholarly journals Analysis method of the cavitation vibration signals in poppet valve based on EEMD

2021 ◽  
Vol 13 (2) ◽  
pp. 168781402199811
Author(s):  
Beibei Li ◽  
Qiao Zhao ◽  
Huaiyi Li ◽  
Xiumei Liu ◽  
Jichao Ma ◽  
...  
Keyword(s):  
Ensemble Empirical Mode Decomposition ◽  
Center Frequency ◽  
Analysis Method ◽  
Vibration Signals ◽  
Poppet Valve ◽  
Mode Decomposition ◽  
Marginal Spectrum ◽  
Cavitation Intensity ◽  
Eemd Method ◽  
Peak Value

To study the vibration characteristics of the poppet valve induced by cavitation, the signal analysis method based on the ensemble empirical mode decomposition (EEMD) method was studied experimentally. The component induced by cavitation was separated from the vibration signals through the EEMD method. The results show that the IMF2 component has the largest amplitude and energy of all components. The root mean square (RMS) value, peak value of marginal spectrum, and center frequency of marginal spectrum of the IMF2 component were studied in detail. The RMS value and the peak value of the marginal spectrum decrease with a decrease of cavitation intensity. The center frequency of marginal spectrum is between 12 kHz and 20 kHz, and the center frequency first increases and then decreases with a decrease of cavitation intensity. The change rate of the center frequency also decreases with an increase of inlet pressure.

Healthcare and Terrorism: The Lebanese Experience

2021 ◽  
pp. 1-4
Author(s):  
Nooreddine Iskandar ◽  
Tatiana Rahbany ◽  
Ali Shokor
Keyword(s):  
Public Health ◽  
Qualitative Study ◽  
Thematic Analysis ◽  
Terrorist Attacks ◽  
Analysis Method ◽  
Structured Interviews ◽  
Security Issues ◽  
The Face ◽  
The Common ◽  
First Time

Abstract Background: Due to the common instability caused by political and security issues, Lebanese hospitals have experienced acts of terrorism multiple times. The most recent Beirut Explosion even forced several hospitals to cease operations for the first time in decades—but studies show the preparedness levels for such attacks in similar countries are low. Objective: The aim of this study is to explore the experience of Lebanese hospitals with terrorist attacks. Methods: This qualitative study used semi-structured interviews with various stakeholders to assess their experience with terrorist bombings. Data was analyzed using the thematic analysis method. Results: The researchers found that Lebanese hospitals vary greatly in their structures and procedures. Those differences are a function of 3 contextual factors: location, culture, and accreditation status. Hospitals found near ‘dangerous zones’ were more likely to be aware and to have better response to such events. A severe lack of communication, unity of command, and collaboration between stakeholders has made the process fragmented. Conclusion: The researchers recommend a larger role for the Ministry of Public Health (MOPH) in this process, and the creation of a platform where Lebanese organizations can share their experiences to improve preparedness and resilience of the Lebanese healthcare system in the face of terrorism.

scholarly journals Distribution characteristics of typical geological relics in the Western Sichuan Plateau

2020 ◽  
Vol 12 (1) ◽  
pp. 307-323
Author(s):  
Qizhong Wang ◽  
Zhongquan Li ◽  
Yuan Yin ◽  
Shuang Yang ◽  
Wei Long ◽  
...  
Keyword(s):  
Geological Heritage ◽  
Tibet Plateau ◽  
Analysis Method ◽  
Western Sichuan ◽  
Distribution Rules ◽  
Index Analysis ◽  
External Forces ◽  
Qinghai Tibet Plateau ◽  
First Time ◽  
Tectonic Movements

AbstractThe Western Sichuan Plateau (WSP), located in the eastern margin of the Qinghai–Tibet Plateau, is the most strongly deformed region of the continental crust in China. Frequent tectonic movements shape the unique topography and landform of the WSP and have also produced abundant geological heritage resources. Based on the existing geological heritage survey data in Sichuan Province, the nearest index analysis method of employing a regional spatial point model was used to reveal the distribution rules and the genetic mechanism of typical geological relics in the WSP for the first time. Results indicate that the formation and distribution of geological relics in the WSP are generally controlled by tectonic movement and supplemented by the comprehensive action of external forces such as flowing water. Their distribution shows a condensed spatial distribution pattern and extends along the strike of a fault zone and river strike strip. Finally, based on the characteristics of geological relics in the WSP, some suggestions on the protection and development of regional geological relics were put forward.

scholarly journals Neural Rate and Timing Cues for Detection and Discrimination of Amplitude-Modulated Tones in the Awake Rabbit Inferior Colliculus

2007 ◽  
Vol 97 (1) ◽  
pp. 522-539 ◽  
Author(s):  
Paul C. Nelson ◽  
Laurel H. Carney
Keyword(s):  
Inferior Colliculus ◽  
Dynamic Range ◽  
Modulation Depth ◽  
Average Rate ◽  
Modulation Frequency ◽  
Detection Threshold ◽  
Depth Functions ◽  
Depth Discrimination ◽  
High Modulation ◽  
Envelope Processing

Neural responses to amplitude-modulated (AM) tones in the unanesthetized rabbit inferior colliculus (IC) were studied in an effort to establish explicit relationships between physiological and psychophysical measures of temporal envelope processing. Specifically, responses to variations in modulation depth ( m) at the cell’s best modulation frequency, with and without modulation maskers, were quantified in terms of average rate and synchronization to the envelope over the entire perceptual dynamic range of depths. Statistically significant variations in the metrics were used to define neural AM detection and discrimination thresholds. Synchrony emerged at modulation depths comparable with psychophysical AM detection sensitivities in some neurons, whereas the lowest rate-based neural thresholds could not account for psychoacoustical thresholds. The majority of rate thresholds (85%) were −10 dB or higher (in 20 log m), and 16% of the population exhibited no systematic dependence of average rate on m. Neural thresholds for AM detection did not decrease systematically at higher SPLs (as observed psychophysically): thresholds remained constant or increased with level for most cells tested at multiple sound-pressure levels (SPLs). At depths higher than the rate-based detection threshold, some rate modulation-depth functions were sufficiently steep with respect to the across-trial variability of the rate to predict depth discrimination thresholds as low as 1 dB (comparable with the psychophysics). Synchrony, on the other hand, did not vary systematically with m in many cells at high modulation depths. A simple computational model was extended to reproduce several features of the modulation frequency and depth dependence of both transient and sustained pure-tone responders.

Solitary wave solution of nonlinear Bogoyavlenskii system by variational analysis method

2021 ◽  
Author(s):  
KangLe Wang
Keyword(s):  
Solitary Wave ◽  
Variational Analysis ◽  
Solitary Wave Solution ◽  
Solitary Wave Solutions ◽  
Analysis Method ◽  
Soliton Theory ◽  
Practical Applications ◽  
The Road ◽  
Wave Solutions ◽  
First Time

In this work, the Bogoyavlenskii system (BS) and fractal BS are investigated by variational method for the first time. An efficient and simple scheme is proposed to seek their exact solitary wave solutions, which is called variational analysis method. The novel scheme requires only two steps, making it much attractive in practical applications, and a good result is obtained. This paper cleans up the road to the exact solitions, and it sheds a new light on the soliton theory. Finally, the physical properties of solitary wave solutions obtained are analyzed by some simulation figures.

A Low Loss Fully Embedded Stripline Parallel Coupled BPF for Applications using the 60 GHz Band

2011 ◽  
Vol 2011 (CICMT) ◽  
pp. 000050-000053
Author(s):  
Alexander Schulz ◽  
Sven Rentsch ◽  
Lei Xia ◽  
Robert Mueller ◽  
Jens Mueller
Keyword(s):  
Return Loss ◽  
Bandpass Filter ◽  
Coplanar Waveguide ◽  
Center Frequency ◽  
60 Ghz ◽  
Low Loss ◽  
Wireless Applications ◽  
High Data ◽  
V Band ◽  
Waveguide Transmission

This paper presents a low loss fully embedded bandpass filter (BPF) using low temperature co-fired ceramic (LTCC) for multilayer System-in-Package (SiP) and Multi-Chip-Module (MCM) applications, e.g. wireless applications for the unlicensed 60 GHz band. The measured insertion loss was 1.5 dB at the center frequency 58 GHz, and a return loss of less than −10 dB was achieved, including two grounded coplanar waveguide transmission line (CPWg) to stripline transitions. The four layers BPF has a 3 dB bandwidth of about 11 GHz which supplies e.g. broadband and high data rate applications. The whole BPF requires a substrate area of 5.6 × 2.1 × 0.42 mm3 with transitions and a shielding via fence. This BPF suits well for V-band applications in a LTCC package because of the compact dimensions and the good performance.

scholarly journals High-κ polymers of intrinsic microporosity: a new class of high temperature and low loss dielectrics for printed electronics

2020 ◽  
Vol 7 (2) ◽  
pp. 592-597 ◽  
Author(s):  
Zhongbo Zhang ◽  
Jifu Zheng ◽  
Kasun Premasiri ◽  
Man-Hin Kwok ◽  
Qiong Li ◽  
...  
Keyword(s):  
High Temperature ◽  
Gate Dielectric ◽  
Printed Electronics ◽  
Low Loss ◽  
New Class ◽  
Polymers Of Intrinsic Microporosity ◽  
First Time ◽  
Intrinsic Microporosity

For the first time, sulfonylated polymers of intrinsic microporosity (PIMs) are exploited for high-κ, high-temperature, and low-loss gate dielectric applications.

Design, Fabrication and Test of Modified Septum Antennas for Satellite Telecommunication

Frequenz ◽  
2018 ◽  
Vol 72 (7-8) ◽  
pp. 301-313 ◽  
Author(s):  
Mohammad Fazaelifar ◽  
Shahrokh Jam ◽  
Raheleh Basiri ◽  
H. Reza Azadi
Keyword(s):  
Axial Ratio ◽  
Beam Width ◽  
Center Frequency ◽  
Low Loss ◽  
Ground Station ◽  
Large Bandwidth ◽  
Low Weight ◽  
Measurement Results ◽  
Novel Design ◽  
Better Than

Abstract In this paper at first, the ordinary septum polarizer has been designed and used for parabolic reflector feed in Ground station antenna. Next, a novel design of modified septum polarizer with wider beam-width is proposed for satellite antenna. Compactness, low weight, large bandwidth, high TX/RX isolation, low axial ratio as well as low loss are the advantages of the septum polarizer. The designed antenna has high purity circular polarization ( $\left| {AR} \right| \le 1.6dB$ ) and low return loss. The frequency bandwidth of the antenna is about 27 % in the center frequency 11 GHz and the TX/RX isolation is better than 32 dB. Finally the septum polarizer, modified septum polarizer and reflector are fabricated and tested and there were good agreement between simulation and measurement results.

Neural Processing of Amplitude-Modulated Sounds

2004 ◽  
Vol 84 (2) ◽  
pp. 541-577 ◽  
Author(s):  
P. X. JORIS ◽  
C. E. SCHREINER ◽  
A. REES
Keyword(s):  
Modulation Depth ◽  
Average Rate ◽  
Modulation Frequency ◽  
Limited Range ◽  
Neural Processing ◽  
Neural Responses ◽  
Critical Stimulus ◽  
Stimulus Attribute ◽  
Neural Architecture ◽  
Physiological Properties

Joris, P. X., C. E. Schreiner, and A. Rees. Neural Processing of Amplitude-Modulated Sounds. Physiol Rev 84: 541–577, 2004; 10.1152/physrev.00029.2003.—Amplitude modulation (AM) is a temporal feature of most natural acoustic signals. A long psychophysical tradition has shown that AM is important in a variety of perceptual tasks, over a range of time scales. Technical possibilities in stimulus synthesis have reinvigorated this field and brought the modulation dimension back into focus. We address the question whether specialized neural mechanisms exist to extract AM information, and thus whether consideration of the modulation domain is essential in understanding the neural architecture of the auditory system. The available evidence suggests that this is the case. Peripheral neural structures not only transmit envelope information in the form of neural activity synchronized to the modulation waveform but are often tuned so that they only respond over a limited range of modulation frequencies. Ascendingthe auditory neuraxis, AM tuning persists but increasingly takes the form of tuning in average firing rate, rather than synchronization, to modulation frequency. There is a decrease in the highest modulation frequencies that influence the neural response, either in average rate or synchronization, as one records at higher and higher levels along the neuraxis. In parallel, there is an increasing tolerance of modulation tuning for other stimulus parameters such as sound pressure level, modulation depth, and type of carrier. At several anatomical levels, consideration of modulation response properties assists the prediction of neural responses to complex natural stimuli. Finally, some evidence exists for a topographic ordering of neurons according to modulation tuning. The picture that emerges is that temporal modulations are a critical stimulus attribute that assists us in the detection, discrimination, identification, parsing, and localization of acoustic sources and that this wide-ranging role is reflected in dedicated physiological properties at different anatomical levels.

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