scholarly journals Design of a 335 GHz Frequency Multiplier Source Based on Two Schemes

Electronics ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 948 ◽  
Author(s):  
Jin Meng ◽  
Dehai Zhang ◽  
Guangyu Ji ◽  
Changfei Yao ◽  
Changhong Jiang ◽  
...  
Keyword(s):  
Output Power ◽  
High Power ◽  
Power Source ◽  
Terahertz Imaging ◽  
Frequency Multiplier ◽  
The Other ◽  
Two Stage ◽  
Second Stage ◽  
W Band ◽  
On Chip

Based on a W-band high-power source, two schemes are proposed to realize a 335 GHz frequency multiplier source. The first scheme involves producing a 335 GHz signal with a two-stage doubler. The first doubler adopts two-way power-combined technology and the second stage is a 335 GHz doubler using a balanced circuit to suppress the odd harmonics. The measured output power was about 17.9 and 1.5 dBm at 167.5 and 335 GHz, respectively. The other scheme involves producing a 335 GHz signal with a single-stage quadrupler built on 50 µm thick quartz circuit adopting an unbalanced structure. The advantage of the unbalanced structure is that it can provide bias to the diodes without an on-chip capacitor, which is hard to realize with discrete devices. The measured output power was about 5.8 dBm at 337 GHz when driven with 22.9 dBm. Such 335 GHz frequency multiplier sources are widely used in terahertz imaging, radiometers, and so on.

scholarly journals Design of W-Band GaN-on-Silicon Power Amplifier Using Low Impedance Lines

2021 ◽  
Vol 11 (19) ◽  
pp. 9017
Author(s):  
Jinho Jeong ◽  
Yeongmin Jang ◽  
Jongyoun Kim ◽  
Sosu Kim ◽  
Wansik Kim
Keyword(s):  
Power Density ◽  
Output Power ◽  
Power Amplifier ◽  
High Power ◽  
Common Source ◽  
High Electron ◽  
Large Signal ◽  
Power Added Efficiency ◽  
W Band ◽  
Gan On Si

In this paper, a high-power amplifier integrated circuit (IC) in gallium-nitride (GaN) on silicon (Si) technology is presented at a W-band (75–110 GHz). In order to mitigate the losses caused by relatively high loss tangent of Si substrate compared to silicon carbide (SiC), low-impedance microstrip lines (20–30 Ω) are adopted in the impedance matching networks. They allow for the impedance transformation between 50 Ω and very low impedances of the wide-gate transistors used for high power generation. Each stage is matched to produce enough power to drive the next stage. A Lange coupler is employed to combine two three-stage common source amplifiers, providing high output power and good input/output return loss. The designed power amplifier IC was fabricated in the commercially available 60 nm GaN-on-Si high electron mobility transistor (HEMT) foundry. From on-wafer probe measurements, it exhibits the output power higher than 26.5 dBm and power added efficiency (PAE) higher than 8.5% from 88 to 93 GHz with a large-signal gain > 10.5 dB. Peak output power is measured to be 28.9 dBm with a PAE of 13.3% and a gain of 9.9 dB at 90 GHz, which corresponds to the power density of 1.94 W/mm. To the best of the authors’ knowledge, this result belongs to the highest output power and power density among the reported power amplifier ICs in GaN-on-Si HEMT technologies operating at the W-band.

scholarly journals S-band hybrid amplifiers based on hydrogenated diamond FETs

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Walter Ciccognani ◽  
Sergio Colangeli ◽  
Claudio Verona ◽  
Fabio Di Pietrantonio ◽  
Domenico Cannatà ◽  
...  
Keyword(s):  
High Power ◽  
Noise Figure ◽  
Low Noise ◽  
The Other ◽  
Two Stage ◽  
Microwave Frequencies ◽  
High Power Operation ◽  
Power Operation ◽  
Two Stages ◽  
Noise Amplification

Abstract The first realizations of S-band hybrid amplifiers based on hydrogenated-diamond (H-diamond) FETs are reported. As test vehicles of the adopted H-diamond technology at microwave frequencies, two designs are proposed: one, oriented to low-noise amplification, the other, oriented to high-power operation. The two amplifying stages are so devised as to be cascaded into a two-stage amplifier. The activities performed, from the technological steps to characterization, modelling, design and realization are illustrated. Measured performance demonstrates, for the low-noise stage, a noise figure between 7 and 8 dB in the 2–2.5 GHz bandwidth, associated with a transducer gain between 5 and 8 dB. The OIP3 at 2 GHz is 21 dBm. As to the power-oriented stage, its transducer gain is 5–6 dB in the 2–2.5 GHz bandwidth. The 1-dB output compression point at 2 GHz is 20 dBm whereas the OIP3 is 33 dBm. Cascading the measured S-parameters of the two stages yields a transducer gain of 15 ± 1.2 dB in the 2–3 GHz bandwidth.

scholarly journals Symptomatic trochanteric non-union following total hip replacement treated with reattachment combined with two-stage revision surgery of the femoral stem

2019 ◽  
Vol 101 (6) ◽  
pp. e133-e135
Author(s):  
E Drampalos ◽  
L Bayam ◽  
J Oakley ◽  
M Hemmady ◽  
J Hodgkinson
Keyword(s):  
Total Hip Replacement ◽  
Hip Replacement ◽  
Posterior Approach ◽  
Femoral Stem ◽  
The Other ◽  
Artificial Joint ◽  
Two Stage ◽  
Non Union ◽  
Total Hip ◽  
Second Stage

We present a case of symptomatic trochanteric non-union following total hip replacement treated initially with a Dall-Miles grip plate. After failure of this treatment, the patient had a two-stage revision. Trochanteric non-union is one of the well-described complications after total hip replacement. It is frequently difficult to treat, while potentially causing weakness, altered gait and instability of the artificial joint. We believe that reattachment of the trochanter combined with a staged revision of the femoral stem using a posterior approach for the second stage could be a valuable technique to be added to the orthopaedic armamentarium for recurrent and symptomatic trochanteric non-unions after primary total hip replacement, particularly after failure to treat with all the other techniques described in literature.

Dynamic Modelling and Performance of a Two Stage Piezoelectric Servovalve

2016 ◽  
Author(s):  
Johan Persson ◽  
Andrew R. Plummer ◽  
Christopher R. Bowen ◽  
Phil L. Elliott
Keyword(s):  
Closed Loop ◽  
Dynamic Modelling ◽  
Flow Characteristics ◽  
The Other ◽  
Step Response ◽  
Hydraulic Fluid ◽  
Two Stage ◽  
Second Stage ◽  
And Performance ◽  
Spool Valve

This paper describes the design, simulation and testing of a piezoelectrically-actuated two stage spool valve. The first stage is a small spool controlled by a piezoelectric ring bender and the second stage is a closed loop position controlled main spool. A dynamic mathematical model of the valve has been derived. Step response tests for both the first stage and second stage are presented, and experimental second stage frequency response results are shown. The mathematical models for the amplifier, first stage and second stage spool behaviour are validated against experimental data. The second stage spool behaviour is found to be very sensitive to the first stage flow characteristics. In addition, the displacement of the hydraulic fluid by the piezoelectric ring bender, from one side of the piezoelectric ring bender to the other, had a significant impact on the valve characteristics.

scholarly journals Two-Stage Allocations and the Double $Q$-Function

10.37236/1714 ◽  
2003 ◽  
Vol 10 (1) ◽  
Author(s):  
Sergey Agievich
Keyword(s):  
The Other ◽  
Empty Cell ◽  
Two Stage ◽  
Second Stage ◽  
Th Cell ◽  
Asymptotic Expressions ◽  
Q Function

Let $m+n$ particles be thrown randomly, independently of each other into $N$ cells, using the following two-stage procedure.1. The first $m$ particles are allocated equiprobably, that is, the probability of a particle falling into any particular cell is $1/N$. Let the $i$th cell contain $m_i$ particles on completion. Then associate with this cell the probability $a_i=m_i/m$ and withdraw the particles.2. The other $n$ particles are then allocated polynomially, that is, the probability of a particle falling into the $i$th cell is $a_i$.Let $\nu=\nu(m,N)$ be the number of the first particle that falls into a non-empty cell during the second stage. We give exact and asymptotic expressions for the expectation ${\bf E}\nu$.

scholarly journals Structures lexico-syntaxiques fondées sur le verbe viser dans l’écrit scientifique. Analyse contrastive franco-polonaise

2021 ◽  
Vol 33 ◽  
pp. 1-12
Author(s):  
Katarzyna Gabrysiak
Keyword(s):  
Subject Matter ◽  
Two Dimensions ◽  
The Other ◽  
Main Body ◽  
Two Stage ◽  
Scientific Text ◽  
Syntactic Structures ◽  
Second Stage ◽  
Stage Process ◽  
The Subject

The paper offers an analysis of lexical-syntactic structures based on the verb form viser typical of a scientific text, that is a text that follows quite a stable and rigid structure. A corpus-based analysis, achieved through the use of the Scientext corpora, runs across two dimensions. The first dimension is constituted by the subject matter of the text while the other dimension concerns the relation between the author of the text and the recipient. The analysis presented is a two-stage process. At the first stage, lexical-syntactic structures are singled out. The second stage is to assign those structures to the particular parts of the text, such as Introduction, Main body, Conclusion.

Hydroxylapatite for Laryngotracheal Framework Reconstruction

1989 ◽  
Vol 98 (9) ◽  
pp. 713-717 ◽  
Author(s):  
Minoru Hirano ◽  
Tetsuji Yoshida ◽  
Shinji Sakaguchi
Keyword(s):  
The Other ◽  
Two Stage ◽  
Second Stage

Hydroxylapatite plates and rings were employed for reconstruction of the laryngotracheal framework in 12 patients. The cause of the framework defect was surgery for stenosis in nine cases and removal of malignancy in the other three. The trough method associated with a two-stage procedure was tolerated in all 12 cases. Hydroxylapatite plates or rings were used to reconstruct the framework during the second stage. The implant was well taken in all cases, without any infection or rejection. Nine of the 12 cases resulted in excellent airways.

HELPING AND SABOTAGING IN TOURNAMENTS

2005 ◽  
Vol 07 (02) ◽  
pp. 211-228 ◽  
Author(s):  
MATTHIAS KRÄKEL
Keyword(s):  
The Other ◽  
Two Stage ◽  
Second Stage ◽  
Asymmetric Equilibria ◽  
The Cost ◽  
Cost Effect

A two-stage, two-person tournament is discussed, in which each player can influence the other one at the first stage by choosing help, sabotage or no action. At the second stage, the players choose effort to win the tournament. Helping and sabotaging have two effects — they influence the likelihood of winning (likelihood effect) and they determine the equilibrium efforts and, therefore, effort costs (cost effect). Depending on the interplay of the two effects, diverse types of equilibria are possible. In particular, if the cost effect dominates the likelihood effect (i.e., both players concentrate on minimizing effort costs), two asymmetric equilibria will coexist in which one player helps his opponent, whereas the other one chooses sabotage and vice versa.

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