High PAE Research Articles

Design and optimization of spoof surface plasmon polaritons based multi-octave power amplifier using PSO algorithm

In this article, we explore how spoof surface plasmon polaritons (SSPP) theory can be applied to the design of active radio frequency (RF) power amplifiers (PAs). This work utilizes SSPP structures for the design of both input and output matching networks for a multi-octave PA. In order to perform proper impedance matching, the properties of SSPP unit structures are presented and analyzed. A description of the performance of the initial PA has been provided and discussed. Additionally, particle swarm optimization (PSO) is used to further enhance the performance of the PA circuit. In comparison with an embedded gradient method in a commercial tool, the PSO method results in a better optimization result. The fabricated PA is tested and the results indicate that in the frequency range of 0.5 GHz to 2.9 GHz, it achieves an output power of 40.4 dBm to 41.2 dBm, a power added efficiency of 60.5–65%, and an output gain exceeding 10 dB. Compared to recent work, the multi-octave PA in this work broadens bandwidth while maintaining high output power and PAE. To further verify the linearity of the SSPP-based PA, digital pre-distortion (DPD) is implemented. As a result of the DPD, the linearity of the SSPP PA was greatly enhanced.

Comprehensive Comparison of MOCVD- and LPCVD-SiNx Surface Passivation for AlGaN/GaN HEMTs for 5G RF Applications.

Passivation is commonly used to suppress current collapse in AlGaN/GaN HEMTs. However, the conventional PECV-fabricated SiNx passivation layer is incompatible with the latest process, like the "passivation-prior-to-ohmic" method. Research attention has therefore turned to high-temperature passivation schemes. In this paper, we systematically investigated the differences between the SiNx/GaN interface of two high-temperature passivation schemes, MOCVD-SiNx and LPCVD-SiNx, and investigated their effects on the ohmic contact mechanism. By characterizing the device interface using TEM, we reveal that during the process of MOCVD-SiNx, etching damage and Si diffuses into the semiconductor to form a leakage path and reduce the breakdown voltage of the AlGaN/GaN HEMTs. Moreover, N enrichment at the edge of the ohmic region of the LPCVD-SiNx device indicates that the device is more favorable for TiN formation, thus reducing the ohmic contact resistance, which is beneficial to improving the PAE of the device. Through the CW load-pull test with drain voltage VDS = 20V, LPCVD-SiNx devices obtain a high PAE of 66.35%, which is about 6% higher than MOCVD-SiNx devices. This excellent result indicates that the prospect of LPCVD-SiNx passivation devices used in 5G small terminals will be attractive.

A highly robust RF 65 nm CMOS power amplifier design using Quasi-Newton control algorithm for wireless system

This article reports a novel robust approach towards CMOS power amplifier (PA) using Quasi-newton (QN) control algorithm in 65 nm CMOS process which provides best performance parameters over redundant wide bandwidth ranging from 2.4 to 16.4 GHz frequency band. Each stage are designed and optimized using QN algorithm to get desired goals such as high linearity, small group delay variations and high PAE across the entire frequency band of interest. Moreover, pole-zeros compensation technique is adopted and derived to get better stability of the proposed PA. The simulation and measurement results of PA achieved a small signal power gain of 10.5–16.8 dB with input return loss of better than 10 dB over the frequency band of 2.4 GHz to 16.4 GHz. A small group delay variation of ±58 ps over full frequency band of operation is achieved by optimizing the design parametric analysis. It is also observed that within the frequency of 6.5 to 14.6 GHz, an excellent small group delay variation of only ±11 ps is achieved and this is due to stage-2 tuning compensation technique. It also demonstrates the achieved input power in 1 dB compression points are −3.1 to 4.3 dBm, leading to maximum power added efficiency of 36.3%, respectively. The proposed PA consumes a lower DC power of 20.5 mW under supply voltage of 1.5. In addition, Process, voltage and temperature (PVT) analysis is executed at different conditions in order to achieve a robustness of the proposed PA over the entire band of operation.

C-Band 30 W High PAE Power Amplifier MMIC with Second Harmonic Suppression for Radar Network Application.

In order to meet the application requirements of radar networks for high efficiency and high second harmonic suppression (SHS) of power amplifiers, this paper proposes a C-band 30 W power amplifier (PA) microwave monolithic integrated circuit (MMIC) based on 0.25 μm gallium nitride (GaN) high electron mobility transistor (HEMT) process. The proposed PA uses a two-stage amplifier structure to achieve high power gain. A topology with SHS is designed in the output-matching network. Besides, the large signal model load pull simulation and the harmonic control technology in the output stage are used to improve efficiency. The high-power additional efficiency (PAE) and high SHS of the PA MMIC are achieved simultaneously. In the 5-6 GHz frequency range, multiple indicator measurements of the proposed PA show that output power is over 45 dBm, the PAE is more than 57%, the SHS exceeds 45 dBc, the power gain is greater than 24 dB, which are conducted under the condition of 100 μs pulse width and 10% duty cycle. In addition, the size of the PA MMIC, including bonding pads, is 3.3 × 3.1 mm2.

Integration of peach (Prunus persica L) remnants in combination with beneficial microbes and phosphorus differ phosphorus use efficiency, agronomic efficiency and partial factor productivity in soybean Vs maize crops

Phosphorus (P) is an essential nutrient which can increase crop production, plant biomass, economic yield and profitability. The objectives of this research were to investigate the impact of peach sources (PS), beneficial-microbes and phosphorus levels on P use-efficiency (PUE), agronomic-efficiency (AE) and partial-factor productivity (PFP) in soybean and maize crops under soybean-wheat and maize-wheat cropping-systems. Peach remnants (leaves, twigs, stones and barks non-decomposed, compost and biochar) along with three P-levels (50, 75, 100 kg-ha−1) and two beneficial-microbes (PSB and Trichoderma) were used in the experiment. The results revealed that PS had significant effect on soybean and maize PUE, AE and PFP. PUE in soybean and maize were noted differ (25.6 and 28.4%) with integration of peach biochar as compared to compost and residues application. In case of P application highest PUE in soybean was recorded with 75 kg-P-ha−1(22.2%), while in maize PUE was noted with 50 kg P ha−1(33.5%). Trichoderma was promising and observed deviation in PUE for soybean (21.7%) and maize (27.8%) as compared to PSB. PAE and PFPp in soybean and maize altered with PS and highest values for AE and PFP were noted with biochar. Among the P levels, the highest PAE was recorded with 75 kg P-ha−1 in both crops, whereas PFPp in soybean was maximum with 75 kg P-ha,−1 and interestingly in maize it was noted with 50 kg-ha−1. Conclusively, PAE, PFPp and PUE were higher with biochar + Trichoderma + 75 kg P-ha−1 and can improve soybean and maize yield and productivity on sustainable basis.

A design scheme for harmonic suppression network of high efficiency class-F power amplifier

This paper presents a design scheme of class-F PA harmonic suppression network. This scheme combines the advantages of lumped parameter elements and distributed parameter elements, and makes use of the characteristics of high Q value (quality factor), large adjustability of capacitance and high reusability of the microstrip line, so that the harmonic suppression network has the advantages of them. Based on the proposed scheme, a class-F PA with a frequency of 2.4GHz and a maximum PAE of 68.86% is designed, the output power of which can reach 17.5W (42.42dBm), so as to verify the feasibility of the proposed scheme. This scheme can improve the output power of UHF (300 ~ 3000MHz) class-F PA and reduce the difficulty of circuit design under the condition of high PAE.

A Highly Efficient Ultrawideband Traveling-Wave Amplifier in InP DHBT Technology

This letter presents a 1 to >110-GHz ultrawideband traveling-wave amplifier (TWA) based on 500-nm transferred-substrate InP double-heterojunction bipolar transistor technology. The HBT cells are realized with inductive peaking at the output and match the phase delay between individual stages. The collector bias is slightly below the value for the maximum current gain. This allows a frequency-invariant high-output power characteristic with a flat group delay. The amplifier exhibits a gain of 13 dB with a measured bandwidth of 1–110 GHz and a uniform 10-dBm 1-dB compression output power with an associated maximum PAE of 8% at 110 GHz. To the best of our knowledge, this is the highest PAE and the maximum flat output power reported for such a TWA covering frequencies up to 170 GHz. The amplifier consumes only 129 mW, which is among the lowest dc power dissipations reported for the given gain–bandwidth product. Moreover, the group delay is flat across the band, which makes the TWA very useful in high-speed optical communication systems.

Phosphorus acquisition efficiency and phosphorus remobilization mediate genotype-specific differences in shoot phosphorus content in grapevine.

Crop productivity is limited by phosphorus (P) and this will probably increase in the future. Rootstocks offer a means to increase the sustainability and nutrient efficiency of agriculture. It is known that rootstocks alter petiole P concentrations in grapevine. The objective of this work was to determine which functional processes are involved in genotype-specific differences in scion P content by quantifying P uptake, P remobilization from the reserves in the cutting and P allocation within the plant in three grapevine genotypes. Cuttings of two American rootstocks and one European scion variety were grown in sand and irrigated with a nutrient solution containing either high P (0.6 mM) or low P (0 mM). The high P solution was labelled with 32P throughout the experiment. The grapevine genotypes studied show variation in the inhibition of shoot and root biomass in response to low P supply, and P supply also affected shoot, but not root, P concentrations. Genotype-specific differences in total P content were related to differences in P acquisition and utilization efficiencies (PAE and PUE, respectively). Phosphorus allocation within the plant was not affected by genotype or P supply. The rootstock genotype known to confer high petiole P content in the vineyard was associated with a high PAE under high P, and a high PUE under low P. This suggests that the petiole P concentrations in the vineyard are related to genotype-specific differences in PAE and PUE, and that these traits could be used for rootstock selection programmes in the future.

A 500–600 MHz GaN power amplifier with RC–LC stability network**Project supported by the National Key Basic Research Program of China (No. 2014CB339901).

A 500–600 MHz high-efficiency, high-power GaN power amplifier is designed and realized on the basis of the push-pull structure. The RC–LC stability network is proposed and applied to the power amplifier circuit for the first time. The RC–LC stability network can significantly reduce the high gain out the band, which eliminates the instability of the power amplifier circuit. The developed power amplifier exhibits 58.5 dBm (700 W) output power with a 17 dB gain and 85% PAE at 500–600 MHz, 300 μs, 20% duty cycle. It has the highest PAE in P-band among the products at home and abroad.

Misattributions and Potential Consequences: The Case of Child Mental Health Problems and Fetal Alcohol Spectrum Disorders.

Numerous Canadian agencies have prioritized services for people diagnosed with FAS and its broader construct FASD. This prioritization extends to prevention interventions aimed at reducing or eliminating PAE. The many difficulties identified as associated with FAS, FASD, and PAE is one of the justifications for this prioritization. Mental health symptoms and disorders are among the most commonly highlighted challenges experienced by people labelled with FAS or FASD or exposed to alcohol in utero. However, the extent of the relation between the FAS, FASD, and PAE cluster and mental health symptom and disorder clusters may be inflated secondary to at least 3 factors: diagnostic criteria overlap and etiologic assumptions, referral bias, and failure to control for confounding variables when assessing associations. Lack of awareness of these factors may lead to dissemination of misinformation, which could adversely distort the development and provision of mental health services.Diagnostic criteria for conditions falling under the FASD umbrella have been operationalized in several different guidelines. The 2005 Canadian guideline1 aimed, in part, to harmonize aspects of the 2 leading approaches at the time, that is, those of the Institute of Medicine2 and the Washington 4-digit diagnostic code.3 Guidelines typically include the complete syndrome, FAS, and require positive findings in 4 domains: problematic patterns of alcohol exposure in utero (for example, from maternal binge drinking), growth abnormalities (for example, low birth weight for gestational age), facial dysmorphology (for example, short palpebral fissures), and CNS neurodevelopment abnormalities (for example, microcephaly at birth).2 Guidelines then typically go on to describe various partial syndromes. In the case of the Canadian guideline, the following partial syndromes are included: FAS (without confirmed alcohol exposure), partial FAS, and ARND.1 Difficulties identified within children with high PAE, but who do not have classical dysmorphic manifestations, is used to support the inclusion of partial syndromes.4 However, this broadening likely contributes to problematic overlap with those children with mental health difficulties for whom PAE may be present but for whom it is not etiologic. This is particularly problematic as there is no consensus on a pathognomonic behavioural manifestation of PAE or FASD. Although some propose a unique mental health profile linked to FASD,5 such profiles are based on small clinical samples and do not appear to have been independently replicated using a nonreferred population. Nevertheless, a resulting 10-item screening tool appears to be receiving national promotion in Canada.6Concerns that weaknesses in the operationalization of partial FASD syndromes may lead to misattribution of PAE as causal for various difficulties (for example, behavioural problems) has been raised in critiques of the 2 dominant diagnostic approaches used in the field,2,3 that is, the US sources for the Canadian guidelines.7 The ARND diagnosis, within the Canadian guidelines, requires evidence of impairment in three or more of the following CNS domains: hard and soft neurologic signs; brain structure; cognition; communication; academic achievement; memory; executive functioning and abstract reasoning; attention deficit/hyperactivity; adaptive behavior, social skills, and social communication.1, p S12 However, abnormalities in 3 of the listed domains would also be commonly found in many children with various mental health disorders. PAE may not be uncommon in children with such problem clusters. However, the fraction for whom PAE is primarily etiologic is unknown, and to assume it is typically the leading etiology is highly problematic.8Complicating the picture is the inclusion of an etiologic variable, in this case PAE, in the diagnostic criteria for FASD. This is at odds with a key direction taken in psychiatry as reflected in contemporary versions of the DSM, that is, to avoid etiologic assumptions within diagnostic criteria. …

A Reactively Matched 1.0–11.5 GHz Hybrid Packaged GaN High Power Amplifier

An ultra-wideband PA using a single GaN die with resistive and reactive matching is fabricated and measured. The design includes series and shunt elements at the gate for stability and gain compensation, and uses two different substrates to obtain optimum ${\rm Z} _{0}$ ranges for the matching networks. CW measurements at 31 dBm source power show 27–48% PAE and 35.1–37.4 dBm output power from 1.0 to 11.5 GHz (168% relative bandwidth). These results demonstrate multi-watt output power and high PAE over a decade bandwidth, achieving the best results in this frequency range for a hybrid implementation.

Effect of GaN Channel Layer Thickness on DC and RF Performance of GaN HEMTs With Composite AlGaN/GaN Buffer

The effects of GaN channel layer thickness on dc and RF performance of AlGaN/GaN high-electron mobility transistors (HEMTs) with a state-of-the-art composite AlGaN/GaN (1/1 μm) buffer were systematically investigated. Although HEMTs with a thick GaN channel layer exhibit slight degraded dc and RF small-signal performance associated with short-channel effects, they demonstrate significantly enhanced OFF-state breakdown voltage and RF large-signal performance. The 1-mm HEMTs with a 150-nm-thick GaN channel layer feature a 1.4 dB higher saturated POUT and about 10% higher PAE than that with a 50-nm-thick GaN channel layer, in both Classes AB and B operation conditions. Pulse I-V characterization reveals that the buffer-related current collapse is also suppressed in the thick GaN channel sample as compared with the thin one, suggesting that a thick GaN channel layer will not only reduces the deep traps in the channel, but also reduces the electron capture probability by deep traps in the composite AlGaN/GaN buffer. The selection of a proper GaN channel layer thickness is thus of great importance to the designation of GaN-based power amplifiers for various applications.

Design of high PAE class-E power amplifier for wireless power transmission

Design of high PAE class-E power amplifier for wireless power transmission

Xylose induces the phyllosphere yeast Pseudozyma antarctica to produce a cutinase-like enzyme which efficiently degrades biodegradable plastics

There is a need to speed up the degradation of used agricultural mulch films that are made of biodegradable plastics (BPs) in the field. Treating them with BP-degrading enzymes could be a solution to this problem. A cutinase-like enzyme of yeast Pseudozyma antarctica (PaE) has wide specificity of BPs degradation, but needs to be produced efficiently. Here we report that the production of PaE by P. antarctica can be increased by using xylose as carbon source. BP-degradation activity was analyzed using a polybutylene succinate-co-adipate (PBSA) emulsion as the substrate. Strain P. antarctica GB-4(1)W was found to be the best PaE producer among the tested strains. Using a 5-L jar fermentor with xylose fed-batch cultivation, high PaE productivity could be maintained and about 21 U/ml of PaE was obtained in 120 h. This amount was 100 times higher than the amount that we obtained previously (0.21 U/ml by flask cultivation using glycerol as carbon source). Under repeated xylose fed-batch cultivation with 24 h intervals, the maximum PaE production rate (0.34 U/ml/h) was maintained and the highest PaE productivity (28,000 U/2 L/d) was repeatedly obtained for 7 intervals. The activity of filtered jar-culture (crude PaE) was stable over 12 weeks at 4°C. Commercially available BP mulch films (20 μm thickness, cut into 1-cm-squares) were completely degraded by submerging them in crude PaE (2 U/ml) at 30°C in 24 h. These results indicated that concentrated PaE can rapidly degrade the strength of BP mulch films in the field so that they do not interfere with plowing.

Phosphorus efficiency of naturalized Chilean white clover in a grazed field trial

AbstractNine naturalized white clover populations and two cultivars (Huia and Will) were evaluated at two soil phosphorus ( P ) levels (6 and 20 P mg kg−1) to characterize them for DM production and P efficiency, and to facilitate the selection of suitable genotypes to produce cultivars for P‐deficient marginal soils. The study was carried out in Chile during 2007–2010 under field grazing conditions using a randomized complete factorial block design with three replicates. The clover was grown with perennial ryegrass. Botanical composition and herbage DM production were recorded, phosphorus concentrations in soil and in clover and ryegrass herbage were determined, and P absorption (PAE) and P utilization (PUE) efficiency were calculated. Population 8‐1‐X yielded more DM under the low than under the high soil‐ P level and was the highest yielding clover in the low soil‐ P treatment. It also had the highest PAE (0·6 kg P ha−1 per mg kg−1 Olsen P) under low P availability. Dry‐matter yield of 9‐2‐X was statistically similar to 8‐1‐X and Huia at low P level; however, because of its lower P absorption, it had the highest PUE (455 kg DM ha−1 per kg ha−1 absorbed P). Furthermore, the highest yield of ryegrass occurred when grown with 8‐1‐X, and this combination gave the maximum total yield. These two populations have potential for inclusion in breeding programmes.

Contribution of phosphorus (32P) absorption and remobilization for citrus growth

Background and aims Phosphorus (P) is a mobile nutrient in the plant so growth depends on its internal remobilization and a plant’s ability to respond to its availability in the growing media. This study was conducted to evaluate the influence of P status and rootstocks on the patterns of P uptake and remobilization in orange trees. Methods Sweet orange trees on Cleopatra mandarin (CM) or Rangpur lime (RL) rootstocks were grown for nine months in nutrient solution (NS) that was either P-deficient (DNS) or was P-sufficient (SNS). After this period, half of the trees were reciprocally transferred between DNS and SNS (from D to S and S to D), while the others remained in their initial P availability. Results Trees on RL had more shoot and root growth, accumulated more P and had greater efficiency of P absorption and transport to the shoot (PAE) than those on CM. The major source of P for growth was previously stored P even with an adequate current P supply to the roots. This suggested the dominance of P remobilization over P uptake and the requirement that trees had sufficient stored P to meet P demand of new growth. Trees on CM had greater concentrations of remobilized P in new shoots than trees on RL. Conclusion Trees grafted on rootstocks less able to take up P (CM) were more dependent on the internal reserves of P for new growth than rootstocks with higher PAE (RL).

A 17–35 GHz Broadband, High Efficiency PHEMT Power Amplifier Using Synthesized Transformer Matching Technique

This paper presents a 17 GHz to 35 GHz broadband power amplifier (PA) using 0.15-μm GaAs pHEMT technology. The synthesized transformer using microstrip line matching technique is proposed in this PA design to enhance the broadband frequency response and minimize the chip size. The design procedures are also presented. A high efficiency broadband PA in commercial 0.15 μm GaAs pHEMT process with the best P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1dB</sub> of 22 dBm, P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sat</sub> of 23.5 dBm, and PAE of 40% are demonstrated to verify the design concepts. This PA has the highest PAE, smallest chip size, and wide fractional bandwidth among the broadband GaAs HEMT PAs from K to Ka band.

A 60-GHz 1-V Supply Band-Tunable Power Amplifier in 65-nm CMOS

This brief presents the design of a band-tunable 60-GHz CMOS power amplifier using 65-nm standard CMOS technology. To achieve high gain and PAE over the whole 7-GHz frequency band, this amplifier utilizes a differential band switching circuit to tune the center frequency to the channel in use, whereas high-Q transformer matching and deep-neutralized differential pairs are employed to achieve high gain and PAE in a narrow bandwidth. The amplifier achieves saturated output power of 12.3 dBm and peak PAE of 20.4% with a 1-V supply and a 63-mA current. The peak gain is 17.1 dB at 59 GHz and 16.2 dB at 53.5 GHz for the two different frequency bands, respectively.

A Fully Integrated S-Band Power Amplifier in 0.35um-SiGe BiCMOS Technology

A fully integrated S-band high efficiency power amplifier using the TSMC 0.35 um SiGe BiCMOS technology is presented. The two-stage power amplifier has been optimized for the whole S-band covering 2 GHz to 4 GHz frequency band for higher 1-dB compression point and efficiency. The input and output matching networks are designed on chip. From the simulate result, the two-stage power amplifier achieves high PAE of 28% and saturation output power of 23.3 dBm at 3 GHz, with the small signal gain of 18.7 dB. Besides, this PA realizes the PAE within the band of 2.4GHz to 4GHz exceed 25%, and the highest PAE of 30.6% at 3.4 GHz.

Design of a broadband power amplifier using an optimized feedback network

AbstractThis article presents a systematic design method for ultra broadband power amplifiers using an optimized feedback network. Based on the analysis using the network parameters for the open‐loop circuit and feedback network, a design and optimization procedure was established. To make the gain response as flat as possible throughout the broad operating frequency band, the optimized component values of the feedback network were found using an optimization program which was built based on the least‐mean‐square‐error algorithm in MATLAB. Single‐ended broadband power amplifiers were implemented to verify the optimization results for various target gains, as well as source and load impedance sets. One of the single‐ended amplifiers was selected for use as part of the push–pull power amplifier which includes broad‐band 1:1 transmission line transformers. For the operational bandwidth from 8 to 800 MHz, the ultra broad‐band push–pull power amplifier exhibited a flat gain response of ±0.331 dB from 17.2 dB, a P1dB of more than 40.5 dBm, and high PAE from 26.7 to 45 % at each P1dB point. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:2846–2851, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26372