A 39GHz Balanced Power Amplifier with Enhanced Linearity in 45 nm SOI CMOS

With the high data rate communication systems that come with fifth-generation (5G) mobile networks, the shift of operation to millimeter-wave frequency becomes inevitable. The expected data rate in 5G is significantly improved over 4G by utilizing the large available channel bandwidth at millimeter wave frequencies and complex data modulation schemes. With this increase in operation frequency, many new challenges arise and research efforts are made to tackle them. Among them, the phased array system is one of the hottest topics as it can be made use of to improve the link budget and overcome the path loss challenge at these frequencies. As the last circuit component in the transmitter's front-end right before the antenna, the power amplifier (PA) is one of the most crucial components with significant effects on overall system performance. Many of the traditional challenges of CMOS PA design such as output power and efficiency, are now compounded with the additional challenges that are imposed on complementary metal-oxide semiconductor (CMOS) PAs in millimeter wave phased array systems. This thesis presents a balanced power amplifier design with enhanced linearity in GlobalFoundries' 45nm silicon-on-insulator (SOI) CMOS technology. By using the balanced topology with each stage terminating with a differential 2-stacked architecture, the PA achieves saturated output power of over 21 dBm. Each of the two identical sub-PAs in the balanced topology uses 2-stage topology with driver and PA co-design method. The linearity is enhanced through careful choice of biasing point and a strategic inter-stage matching network design methodology, resulting in amplitude-to-phase distortion below 1 degree up to the output 1dB compression level of over 19 dBm. The balanced amplifier topology significantly reduces the PA performance variation over mismatched load impedance at the output, thus improving the PA performance over different antenna active impedance caused by varying phased array beam-steering angles. In addition to this, the balanced topology also optimizes the PA input and output return loss, giving a better matching than -20 dB at both input and output, and minimizing the risk of potential issues and performance degradation in the system integration phase. Lastly, the compact transformer based matching networks and quadrature hybrids reduce the chip area occupation of this PA, resulting in a compact design with competitive performance

The MDs and 95% CIs for the post-operative Hb level among patients treated with vs. without PAT.

<p>It demonstrated that post-operative Hb was significantly higher in the PAT group than in the control group.</p

Post-Operative Auto-Transfusion in Total Hip or Knee Arthroplasty: A Meta-Analysis of Randomized Controlled Trials

<div><h3>Background</h3><p>Total hip or knee arthroplasty is an elective procedure that is usually accompanied by substantial blood loss, which may lead to acute anemia. As a result, almost half of total joint arthroplasty patients receive allogeneic blood transfusions (ABT). Many studies have shown that post-operative auto-transfusion (PAT) significantly reduces the need for ABT, but other studies have questioned the efficacy of this method.</p> <h3>Methods</h3><p>The protocol for this trial and supporting CONSORT checklist are available as supporting information; see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0055073#pone.0055073.s001">Checklist S1</a>. To evaluate the efficacy of PAT, we conducted a Cochrane systematic review that combined all available data from randomized controlled trials. Data from the six included trials were pooled for analysis. We then calculated relative risks with 95% confidence intervals (CIs) for dichotomous outcomes and mean differences with 95% CIs for continuous outcomes.</p> <h3>Findings and Conclusion</h3><p>To our knowledge, this is the first meta-analysis to compare the clinical results between PAT and a control in joint replacement patients. This meta-analysis has proven that the use of a PAT reinfusion system reduced significantly the demand for ABT, the number of patients who require ABT and the cost of hospitalization after total knee and hip arthroplasty. This study, together with other previously published data, suggests that PAT drains are beneficial. Larger, sufficiently powered studies are necessary to evaluate the presumed reduction in the incidence of infection as well as DVT after joint arthroplasty with the use of PAT.</p> </div

The QUOROM diagram for review.

<p>RCT, randomized controlled trial.</p

The RRs and 95% CIs for the incidence of infection among patients treated with vs. without PAT.

<p>The result revealed no significant difference between the treatment groups.</p

Quality evaluation of included RCTs.

<p>RCTs: Randomized controlled trials; PAT: Post-operative autotransfusion group; CG: Control group; Y: Yes; UC: Unclear.</p

The MDs and 95% CIs for the volume of blood loss among patients treated with vs. without PAT.

<p>The result indicated significantly less volume of blood loss in the PAT group than in the control group.</p

The RRs and 95% CIs for the number of patients requiring at least one unit of ABT among patients treated with vs. without PAT.

<p>It indicated that RRs of patients requiring ABT in the PAT group was significantly lower than that in the control group.</p

The RRs and 95% CIs for the incidence of febrile reaction among patients treated with vs. without PAT.

<p>It indicated that the febrile reaction rate in the PAT group decreased significantly compared with the control group.</p