본드-와이어 안테나를 이용한 칩과 칩 사이의 RF 무선 데이터 통신

Chen, Wu-Hsin,Peroulis, Dimitrios,Jung, Byung-Hoo 한국전기전자재료학회 2010 전기전자재료 Vol.23 No.11

Co-Design of Highly Efficient Power Amplifier and High-<tex> $Q$</tex> Output Bandpass Filter

Kenle Chen,Juseop Lee,Chappell, William J.,Peroulis, Dimitrios IEEE 2013 IEEE transactions on microwave theory and techniqu Vol.61 No.11

<P>This paper reports the first co-design configuration of a power amplifier (PA) in cascade with a high- Q bandpass filter. By matching the filter's input port directly to the transistor's drain node, the conventional output matching network (OMN) of a PA is entirely eliminated. This leads to smaller size/volume, minimized loss, and enhanced overall performance. To enable this co-design method, the matching-filter synthesis theory is proposed and investigated in detail in this paper. Based on this theory, a 3% bandwidth (centered at 3.03 GHz) two-pole filter, implemented using high- Q evanescent-mode cavity resonators, is designed as the PA OMN to provide optimized fundamental and harmonic impedances for a commercial 10-W GaN transistor. Simulation and measured results show that the co-designed PA-filter module yields a desired Chybeshev filter behavior while maintaining excellent PA performance in the passband with 72% efficiency, 10-W output power, >10-dB gain, and 60-dBm output third-order intercept point. This co-designed module experimentally presents a 8% higher overall efficiency compared to a control group developed using a conventional independent PA and filter, which further validates the effectiveness of this method.</P>

Dynamic Bandpass Filter Shape and Interference Cancellation Control Utilizing Bandpass–Bandstop Filter Cascade

Tsung-Chieh Lee,Juseop Lee,Peroulis, Dimitrios Professional Technical Group on Microwace Theory a 2015 IEEE Transactions on Microwave Theory and Techniqu Vol. No.

<P>A tunable highly integrated bandpass-bandstop filter (BSF) cascade that is capable of dynamically relocating its transmission zeros arbitrarily close to its passband without causing parasitic resonances and additional mismatch loss is demonstrated in this paper. An arbitrary phase BSF that enables a compact cascade topology and an extension of the classical coupling matrix synthesis for filters terminated with a complex impedance are the key advantages of the proposed bandpass-BSF cascade. Independent and simultaneous tuning of the passband center frequency, bandwidth, and transmission zeros are possible in this topology. The proposed cascade synthesis approach is experimentally validated using commercially available lumped elements. In these implementations the transmission zeros can be placed on the skirt of the bandpass filter and can be used to create high isolation (50-dB notch 4.7% away from the passband edge), increase the selectivity of the passband, and tune the fractional bandwidth from 3% to 9% without additional mismatch loss.</P>

Vibration-Based Monitoring and Diagnosis of Dielectric Charging in RF-MEMS Switches

Jin Woo Lee,Mahapatro, A K,Peroulis, D,Raman, A IEEE 2010 Journal of microelectromechanical systems Vol.19 No.6

<P>Dielectric charging due to metal-dielectric contact is one of the major modes of failure in capacitive radio frequency microelectromechanical systems (MEMS) switches, and it leads to actuation voltage fluctuations and, eventually, to device failure. Failure prognostics for such devices require novel methods to monitor the extent and location of trapped parasitic charges on or in the dielectric layer. Motivated by the success of resonant electrostatic force microscopy for mapping local trapped charges, we present in this paper a technique that monitors the resonance frequencies of multiple eigenmodes of the bridge conductor of the switch as a means to detect parasitic charges and nonuniformities in electric fields in the switch that could arise from nonuniform parasitic charge distribution. Both theory and experiments are presented to demonstrate the technique. Moreover, its potential advantages and limitations as a new diagnostic tool for MEMS health monitoring are discussed.</P>

Initial Clinical Experience with the Endologix AFX Unibody Stent Graft System for Treating Patients with Abdominal Aortic Aneurysms: A Case Controlled Comparative Study

George N. Kouvelos,Petroula Nana,Vasilios Bouris,Michalis Peroulis,Aikaterini Drakou,Nikolaos Rousas,Athanasios Giannoukas,Miltiadis I. Matsagkas 대한혈관외과학회 2017 Vascular Specialist International Vol.33 No.1

Purpose: The newly designed unibody AFX endograft system for endovascular aortic aneurysm repair is the only graft with anatomical fixation to the aortic bifurcation in comparison to most other grafts that use the infrarenal neck as the main fixation point. The aim of this study was to assess the preliminary results of the AFX stent-graft system used with infrarenal aortic component and compare them with those obtained in patients treated with a well established endograft of the same material and pure infrarenal fixation as the Gore Excluder. Materials and Methods: A retrospective analysis of prospectively collected data from March 2014 to December 2014 identified 10 elective abdominal aortic aneurysm patients treated with the AFX endograft, in comparison to a matched group of 20 patients treated with the Excluder stent-graft. Endpoints included technical and clinical success, freedom from any secondary intervention, any type of endoleak and aneurysm related death. Results: Primary technical success was achieved in all patients and no 30-day device related complications or deaths were occurred. The two groups were similar in terms of radiation burden, contrast media, duration of the procedure, post implantation syndrome and in-hospital stay. During a median follow-up period of 23 months (range, 18-26 months) there were no differences in clinical success, freedom from reintervention and aneurysm related death. No type I endoleak was observed in either group. Five of the 6 type II endoleaks (1 in the AFX and 4 in the Excluder group) spontaneously resolved, while in only one patient (Excluder) the endoleak remained without however any change in aneurysm sac diameter (log rank=0.34). Conclusion: The initial experience with the AFX stent graft system is promising, with successful aneurysm exclusion and good short-term results. Further and larger studies are needed to fully evaluate the sort as well as the long-term results.

New Bandstop Filter Circuit Topology and Its Application to Design of a Bandstop-to-Bandpass Switchable Filter

Juseop Lee,Naglich, E. J.,Sigmarsson, H. H.,Peroulis, D.,Chappell, W. J. IEEE 2013 IEEE transactions on microwave theory and techniqu Vol.61 No.3

<P>In this paper, we show a new bandstop filter circuit topology. Unlike conventional bandstop filter circuit topologies, the new circuit topology has inter-resonator coupling structures. The presence of these inter-resonator coupling structures enables convenient switching from a bandstop to a bandpass filter. Using the new bandstop filter topology, this paper demonstrates a design of a frequency-agile bandstop-to-bandpass switchable filter. The filter is composed of tunable substrate-integrated cavity resonators and can be switched to have either a bandstop or bandpass response. Switching is achieved by turning on and off switches placed within the filter structure. A prototype of the proposed design is fabricated and the concept is verified experimentally.</P>

Intersecting Parallel-Plate Waveguide Loaded Cavities for Dual-Mode and Dual-Band Filters

Naglich, E. J.,Juseop Lee,Sigmarsson, H. H.,Peroulis, D.,Chappell, W. J. IEEE 2013 IEEE transactions on microwave theory and techniqu Vol.61 No.5

<P>Dual-mode and/or dual-band microwave filters often employ high quality factor (<I>Q</I> ), physically large, and frequency static cavity resonators or low <I>Q</I>, compact, and tunable planar resonators. While each resonator type has advantages, choosing a dual-mode and/or dual-band resonator type is often limited by these extremes. In this paper, a new dual-mode and/or dual-band resonator is shown with <I>Q</I> (360-400) that is higher than that of planar resonators while being frequency tunable (6.7% tuning range) and compact relative to standard cavity resonators. In addition, both degenerate modes of the resonator are tunable using a single actuator. The resonator is used in a single-resonator two-pole filter design and a double-resonator dual-band filter design. An analytical model is developed and design techniques are given for both designs. Measured results confirm that the proposed resonator fits between the design spaces of established dual-mode and/or dual-band resonator types and could find application in systems that require a combination of relatively high <I>Q</I>, tuning capability, and ease of integration.</P>

Appraisal of the Clinical Practice Guidelines for the Use of Antithrombotic Therapy in Elective Spinal Procedures: Do We AGREE (II)?

Ntalouka Maria P.,Brotis Alexandros G.,Angelis Fragkiskos A.,Peroulis Michail,Matsagkas Miltiadis,Fountas Kostantinos N.,Arnaoutoglou Eleni M. 대한척추외과학회 2023 Asian Spine Journal Vol.17 No.4

The perioperative management of patients medicated with antithrombotic agents who require elective spinal surgery is extremely challenging because of the increased risk of surgical bleeding and the concurrent need to minimize the thromboembolic risk. The aims of the present systematic review are to: (1) identify clinical practice guidelines (CPGs) and recommendations (CPRs) on this topic and (2) assess their methodological quality and reporting clarity. An electronic systematic search of the English Medical Literature up to January 31, 2021 was conducted using PubMed, Google Scholar, and Scopus. Two raters assessed the methodological quality and reporting clarity of the gathered CPGs and CPRs using the Appraisal of Guidelines for Research and Evaluation II (AGREE II) tool. The agreement between the two raters was assessed using Cohen’s kappa. Of the initially gathered 38 CPGs and CPRs, 16 fulfilled our eligibility criteria and were evaluated using the AGREE II instrument. The reports published by “Narouze 2018” and “Fleisher 2014” were scored as being of “high-quality” and having an adequate interrater agreement (Cohen’s kappa ≥0.60). Overall, the AGREE II domains of “clarity of presentation” and “scope and purpose” yielded the highest scores (100%), whereas the domain “stakeholder involvement” scored the lowest score (48.5%). The perioperative management of antiplatelet and anticoagulant agents in elective spine surgery may be challenging. Because of the lack of high-quality data in this field, uncertainty remains regarding the optimal practices to balance the risk of thromboembolism against that of bleeding.