Max Gain Research Articles

A Cavity-Backed Antenna Using SISL Technology for 77 GHz Band Application

A cavity-backed antenna based on substrate-integrated suspended line (SISL) technology is proposed for 77 GHz applications. The antenna is designed to be self-packaged using six substrate layers with embedded air cavities. Two rows of metal holes surround the core circuit to form the cavity and reduce the leaked field loss. Patches are printed in G5 and G6 layer and connected by metalized holes to form the double-side SISL with part of the substrate excavation to reduce the substrate loss. Thus, the simulation efficiency of better than 93% is achieved. Because of the cavity structure, the standing wave resonant mode can be obtained and achieve broadside radiation. A predominantly TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">710</sub> aperture field is obtained by adjusting the sizes of the backing cavity. The measured result shows that the proposed antenna has a −10 dB bandwidth from 75.6 to 81 GHz, covering 77 GHz automotive radar band and the max gain is 14.4 dBi. Based on this antenna, we design a differential-fed antenna array with a max gain of 17.5 dBi at 79 GHz.

A CMOS 24–30-GHz Low-Phase-Variation Variable Gain Amplifier Design for 5G New Radio

This letter presents a 24&#x2013;30-GHz variable gain amplifier (VGA) achieving low-phase variation in a standard RF 65-nm CMOS process. The proposed VGA employs two stages. Phase compensation during the gain variation is realized with the dynamic complementary phase variation at the first stage. The second stage is utilized to increase the gain and keep linearity. Measurement results prove that the proposed VGA achieves a continuous gain tuning range of 8.3 dB. Under this condition, low-phase variation is realized with the root-mean-square (RMS) phase error less than 3&#x00B0; from 24 to 30 GHz. Moreover, the RMS phase error is less than 2&#x00B0; at the desired 5G frequency band from 27.5 to 29.5 GHz. The peak gain is measured with 18.7 dB at 29 GHz. With the max gain setting, the measured OP_1dB and OIP₃ are 5.1 and 9.3 dBm, respectively, and the measured noise figure is from 4.6 to 6.8 dB at the frequency range from 24 to 30 GHz.

Design of Millimeter-Wave Circularly Polarized Endfire Antenna and Multibeam Antenna Array for Wireless Applications

A broadband stepped tapered slots’ endfire circularly polarized (CP) antenna and a multibeam antenna array are proposed for millimeter-wave (mmWave) applications. First, a modified tapered slot endfire antenna element is designed. Compared with the normal antipodal linearly tapered slot (ALTSA) endfire antenna, the performance of the stepped tapered slots’ antenna shows remarkable improvement, and the size of the antenna reduces effectively. The simulation and measurement results of the proposed endfire antenna show that an impedance bandwidth of 63.5% (75.1–145 GHz), an AR < 3 dB bandwidth of 50% (75.9–125.3 GHz), and a max gain of 8.8 dBic are realized, respectively. Second, to reduce fabrication and assembly requirements, a groove gap waveguide (GWG) feeding network is designed for multibeam array applications. The broadband 2 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 2 GWG network, interconnections, and transitions are designed and applied in the antenna array. Finally, a multibeam array based on the proposed endfire antenna is designed, fabricated, and measured. An impedance bandwidth up to 37.7% and a wide axial ratio bandwidth of 38.7% with a max LHCP gain of 12.8 dBic are achieved by the proposed 2 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 2 multibeam antenna array. The proposed multibeam endfire CP antenna array would be an attractive candidate for mmWave wireless applications.

Design of High-Gain Sub-THz Regenerative Amplifiers Based on Double-G max Gain Boosting Technique

This article reports the concept of a double maximum achievable gain (double- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$G_{\mathrm{ max}}$ </tex-math></inline-formula> ) core for the implementation of sub-terahertz high-gain amplifier design. The double- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$G_{\mathrm{ max}}$ </tex-math></inline-formula> core is a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$G_{\mathrm{ max}}$ </tex-math></inline-formula> core that adopts another linear, lossless, and reciprocal network that satisfies the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$G_{\mathrm{ max}}$ </tex-math></inline-formula> condition onto an even number of cascaded transistor-level <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$G_{\mathrm{ max}}$ </tex-math></inline-formula> cores. It is shown that the double- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$G_{\mathrm{ max}}$ </tex-math></inline-formula> core, due to its regenerative nature, can achieve much higher gain per stage than that of the same number of cascaded <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$G_{\mathrm{ max}}$ </tex-math></inline-formula> cores while satisfying the unconditional stability. Implemented in a 65-nm CMOS process, by adopting the proposed double- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$G_{\mathrm{ max}}$ </tex-math></inline-formula> core, 247- and 272-GHz two-stage amplifiers achieve the peak gain of 18 and 15 dB, the gain per stage of 9 and 7.5 dB, and the PAE of 4.44% and 2.37%, respectively, while dissipating 21.5 mW.

Multifold Bandwidth Improvement in Conformal Patch Antenna for Aircraft Application Using Corrugated Edge Coupling

In the high-speed Internet of Things (IOT) era, the aircraft on-board is one of the few places that lacks high speed network access. The speed of this communication link between the ground station and the aircraft is limited by the transmitting antenna power, cost, latency and available infrastructure. The Direct Air to Ground (DATG) is a much-guaranteed technique which can provide a high-speed link between the ground station and aircraft. This paper describes a novel conformal microstrip patch antenna design which provides fourfold increase in bandwidth. As the bandwidth of an antenna mounted on the fuselage of aircraft is crucial to achieve higher data rate, this antenna performance is promising and suits better for DATG application. The proposed antenna with a size of (6.81 X 7.21cm) achieves a bandwidth of ~700MHz (5.032GHz to 5.73GHz) and max Gain of 9.53dB with max radiation efficiency of 93%. As this antenna is to be mounted on the aircraft fuselage, a substrate material, RT duroid 5880 with a thickness of 0.787mm is selected to have better conformability, low loss and high gain. This paper explains the different performance metrics involved in the DATG system and derives the specification for the proposed antenna structure. Also, the detailed structural analysis with the support of parametric and Characteristic Mode Analysis (CMA) is provided to get the physical insight of the designed antenna.

Serial circulating tumor DNA (ctDNA) monitoring in metastatic colorectal cancer (mCRC) reveals dynamic profile of actionable alterations.

3572 Background: Serial ctDNA can measure dynamic changes in disease burden over time, however utility of serial profiling to detect changes in actionable alterations remains unclear. Methods: We evaluated 501 patients with ≥3 serial Guardant360 assays performed between 09/2016 and 11/2020 and compared MSI, fusion, amplification and single nucleotide variant (SNV) detection over time. This comprised 2147 assays with a median of 4 assays per patient (min 3, max 18) occurring an average of 163 days apart (+/- SD of 147 days). Maximum detected variant allele frequency in samples (maxVAF) was assessed for relation to changes in detected alterations as a surrogate for tumor volume. Results: Among 406 patients with assays assessable for MSI-status, 17 (4.2%) had MSI detected. New MSI detection on a subsequent assay always occurred with a rising maxVAF (3/3) that was also ≥0.7%, while loss of detectable MSI between assays always associated with falling maxVAFs (7/7) with 6/7 occurring when maxVAF fell below 0.4%. Fusions were noted in 9/501 (2%) patients. Among 3 patients who lost a detectable fusion, maxVAF decreased in 1 patient and changed ≤0.2% between assays in 2, while 2/3 patients with new fusions had rising maxVAFs and 1 patient had a falling maxVAF. Amplifications were detected in 242/501 patients (48%). While most genes had highly variable amplification detection between assays (9% serially detected), ERBB2 amplifications were more consistent and serially detected in 39% of detected cases (P &lt; 0.0001). New detection of amplifications occurred more commonly in cases with rising maxVAF (OR 11.70, 95% CI 7.61-18.00, P &lt; 0.0001) and loss of detectable amplifications occurred more between samples with falling maxVAF (OR 12.37, 95% CI 8.35-18.66, P &lt; 0.0001). Change in maxVAF correlated with change in number of detected amplifications (r = 0.62, P &lt; 0.0001), but only partially explained changes seen (R2= 0.39). Between serial assays, SNVs changed a median of 0 variants (IQR -1 to 1), however some patients had significant changes (max gain 21/max loss 18). Among 1646 serial time points, 454 (28%) had no change in SNVs, 674 (41%) gained SNVs, and 518 (31%) lost SNVs on subsequent assays. Gains were more common in samples with rising maxVAF (OR 7.76, 95% CI 6.18-9.73, P &lt; 0.0001) while losses were more common when maxVAF fell (OR 6.90, 95% CI 5.47-8.66, P &lt; 0.0001). The correlation between maxVAF change and SNV change was significant (r = 0.29, P &lt; 0.0001), but minimally explained SNV changes (R2= 0.086) and was a much weaker association than noted for amplification changes. Conclusions: We noted significant differences in detection of actionable alterations across serial ctDNA assays. Increased ctDNA volume (higher maxVAF) due to tumor progression may explain some variation over time, but variability also occurs outside these changes, likely reflecting clonal evolution following therapy.

Min cost improvement and max gain stability in multicriteria sorting methods on combinatorial domains

AbstractVarious multicriteria sorting methods have been proposed in the literature to assign the feasible alternatives into predefined categories. We consider here problems involving a set of totally ordered categories representing different achievement levels in the satisfaction of criteria. As in many existing methods, the assignment rule of an alternative to a category is based on the comparison of its performance vector to reference profiles defining lower bounds of the categories. Within this standard setting we address a new problem that consists in finding how to modify a given solution, within a combinatorial set of alternatives, to upgrade it in the upper category (or higher) at minimum cost. We also consider the problem of identifying the sequence of solutions that minimize the total cost while satisfying some budget constraint at every step, and the problem of determining how to modify the current solution to save money while staying in the same category. We first propose a general approach based on mixed integer (linear or quadratic) programming to solve these problems. Then, we implement this approach on various multiobjective combinatorial problems, such as multi‐agent assignment problems and multiobjective knapsack problems. Numerical tests are provided to establish the feasibility of the approach on instances of different sizes.

Study of Heterosis, Combining Ability and Parental Diversity for Seed Cotton Yield and Contributing Traits using Diallel Data in Cotton (G. hirsutum L.)

Background: Combining ability and parental diversity contributes directly to improve the heterotic potential. The experiment was aimed to study the parental diversity and its contribution to heterosis and to get an idea if parental diversity has any influence on the combining ability of the parental lines.Methods: The field testing was carried out during 2017-18 at three locations comprises, Sirsa, Bathinda and Abohar. Total eight parents were crossed in diallel manner to produce 56 combination excluding eight parental genotypes using full diallel. All the hybrids and parental lines were tested using RBD at the selected locations and the mean of these three locations data was used to study the relationship. Genetic relatedness of the parents was studied using 20 SSR markers and the distance/similarity matrix was developed using Jaccard coefficient method. Result: Genotypes showed significant (p≤0.01) differences for mean squares values for all the traits under study. F-2228, F-2164 and LH-2108 were the parents with best general combining abilities. Parental lines RS-2013 and RST were found to be the most divergent lines. The best F1 hybrids such as RST-9 x F-2164, LH-2076 x RST-9 and LH-2076 x RS-2013 comprised of diverse parents produced high heterosis for seed cotton yield. Among all the traits under study the maximum heterosis was received for seed cotton yield with a max gain of 126.8% over the mid parent.

Influence of Zinc and Ractopamine Hydrochloride Supplementation on Beef Carcass Characteristics and Quality Attributes of Aged Ribeye Steaks

ObjectivesGrowth promoting technologies such as the β agonist ractopamine hydrochloride (RAC) and nutritional practices such as increased zinc (ZN) supplementation have potential to positively impact beef cattle growth. However, the impact of these strategies (RAC and ZN) on meat quality is unclear. The objective of this experiment was to determine the extent to which ZN and RAC supplementation in the diets of finishing beef steers influence carcass characteristics and meat quality of aged longissimus steaks.Materials and MethodsCrossbred Angus steers (∼431 kg initial body weight) from a single source were fed one of four diets in GrowSafe bunks. Steers were assigned to diets based on growth potential (Gene Max gain score) and initial body weight: control (CON-NO; 30 ppm Zn (NRC requirement); n = 7), ZN supplementation (SUPZN-CON; 150 ppm ZN (60 ppm ZnSO4, 60 ppm Zn-AA); n = 7), RAC supplementation (CON-RAC 300 mg/hd/d; 30 ppm Zn; n = 6), and ZN supplementation combined with RAC supplementation (SUPZN-RAC; 150 ppm ZN (60 ppm ZnSO4, 60 ppm Zn-AA), RAC 300 mg/hd/d; n = 7). Zn treatments were fed for the entire 90 d trial. RAC supplementation occurred for the final 28 d of the feeding trial. At finishing weights (∼739 kg), steers were harvested at a commercial processing facility. Yield and quality data were collected. Whole rib sections were collected 6 d postmortem, transported to the Iowa State University Meat Lab, and fabricated into 2.54 cm thick steaks. Temperature, pH, Hunter L, a, and b values, and proximate analysis (moisture, fat and protein) were measured at 6 d postmortem on the longissimus muscle. Pairs of adjacent steaks were vacuum packaged, aged for 7, 14, 28 or 42 d, and frozen until quality evaluation. At the completion of aging and storage; purge, pH, Hunter L, a, and b values, marbling scores, cook loss, and Warner-Bratzler Shear Force (WBS) values were measured on each pair of steaks. Data were analyzed using the PROC MIXED procedure of SAS version 9.4 with fixed effect of treatment. Initial body weight was used as a covariate for hot carcass weight (HCW) analysis. HCW was used as a covariate for analysis of ribeye area, fat thickness (FT), kidney, pelvic and heart fat percentage, yield grade, and d 6 marbling score. FT was used as a covariate for d 6 pH and temperature measurements.ResultsSupplementation of Zn and RAC resulted in a greater HCW and REA with decreased fat thickness, marbling scores, and yield grades than CON-NO. Zn only supplementation had greater redness at 6 and 7 d postmortem. RAC supplementation resulted in increased WBS values at 7, 14, and 28 but no differences were observed at 42 d aging. No differences in KPH, pH, temperature, L and b value, proximate analysis and purge were determined between treatments at any d aging.ConclusionThe results demonstrate that supplementation of ZN and RAC increased carcass yield. However, RAC inclusion negatively impacted WBS values unless aged for greater than 28 d. The data reveal that WBS differences exist between treatments. The molecular explanations for these differences should be defined to understand how ZN and RAC inclusion impact tenderness development.

Device and circuit level analysis of negative capacitance hybrid CMOS: a prospect for low power/low voltage applications

In this work, a concept of negative capacitance hybrid CMOS (NCHCMOS) is presented which consists of p-NCGeOIFET (NC germanium-on-insulator FET) and n-NCSiGeOIFET (NC SiGe-on-insulator FET). Both devices have been simulated by using respective calibrated TCAD models with Landau–Khalatnikov equation. The enhanced performance of both devices due to NC effect has been shown in terms of improved barrier and subsequently reduced leakage current (by 2 orders). The max gain of Ge and SiGe NCFETs has been found to be 1.64 and 1.56 (i.e. >1) respectively which is manifested in reduced subthreshold swing values. Results have also shown that the NC of ferroelectric material attributes to very high gate capacitance which is further responsible for enormous increase in on-state current (170% in p-NCGeOIFET and 103% in n-NCSiGeOIFET). Further, to investigate the performance of these devices in low power/low voltage applications, static and transient characteristics of NCHCMOS based gates and circuit have been obtained. It has been shown that NCHCMOS gives improved circuit performance in terms of high noise margin, reduced rise and fall time, less propagation delay, and reduced power and energy dissipation as compared to HCMOS. It is also displayed that NCHCMOS exhibits very less values (approximately by an order or 2) of energy-delay-product in respect to HCMOS and provides energy efficient operation.

A compact reconfigurable slotted microstrip patch antenna using pin diode for wireless applications

A compacted (44 x 44 x 3.2 mm3) frequency reconfigurable microstrip antenna that uses electrical switching with PIN diodes is proposed for WiMAX (3500 MHz- 3910 MHz) and high frequency LTE (3500 MHz and 2600 MHz) band. The rectangular microstrip patch was at first designed to operate at the frequency of 3500 MHz as a central frequency and then reconfigured using two electrical PIN diodes placed symmetrically on slot etched at the end of the patch surface to cover further desired frequency applications. For state 1 (S1 = ON, S2 = ON), the designed antenna operates solely 3500 MHz suitable for both domestic LTE and WiMAX. For state 2 (S1 = OFF, S2 = OFF), the antenna covers further 2600 MHz for LTE and (3850 MHz – 3910 MHz) for WiMAX. The proposed antenna is designed and simulated using HFSS licensed software. Simulation results show the max gain produced by the antenna is 7.4 dBi with a radiation efficiency of 98% and a maximum bandwidth of 180 MHz.

Persistent Noise Signal in the FairfieldNodal Three‐Component 5‐Hz Geophones

Research Article| July 04, 2018 Persistent Noise Signal in the FairfieldNodal Three‐Component 5‐Hz Geophones Jamie Farrell; Jamie Farrell aDepartment of Geology and Geophysics, University of Utah, Salt Lake City, Utah 84112 U.S.A., jamie.farrell@utah.edu Search for other works by this author on: GSW Google Scholar Sin‐Mei Wu; Sin‐Mei Wu aDepartment of Geology and Geophysics, University of Utah, Salt Lake City, Utah 84112 U.S.A., jamie.farrell@utah.edu Search for other works by this author on: GSW Google Scholar Kevin M. Ward; Kevin M. Ward aDepartment of Geology and Geophysics, University of Utah, Salt Lake City, Utah 84112 U.S.A., jamie.farrell@utah.edu Search for other works by this author on: GSW Google Scholar Fan‐Chi Lin Fan‐Chi Lin aDepartment of Geology and Geophysics, University of Utah, Salt Lake City, Utah 84112 U.S.A., jamie.farrell@utah.edu Search for other works by this author on: GSW Google Scholar Author and Article Information Jamie Farrell aDepartment of Geology and Geophysics, University of Utah, Salt Lake City, Utah 84112 U.S.A., jamie.farrell@utah.edu Sin‐Mei Wu aDepartment of Geology and Geophysics, University of Utah, Salt Lake City, Utah 84112 U.S.A., jamie.farrell@utah.edu Kevin M. Ward aDepartment of Geology and Geophysics, University of Utah, Salt Lake City, Utah 84112 U.S.A., jamie.farrell@utah.edu Fan‐Chi Lin aDepartment of Geology and Geophysics, University of Utah, Salt Lake City, Utah 84112 U.S.A., jamie.farrell@utah.edu Publisher: Seismological Society of America First Online: 04 Jul 2018 Online Issn: 1938-2057 Print Issn: 0895-0695 © Seismological Society of America Seismological Research Letters (2018) 89 (5): 1609–1617. https://doi.org/10.1785/0220180073 Article history First Online: 04 Jul 2018 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Jamie Farrell, Sin‐Mei Wu, Kevin M. Ward, Fan‐Chi Lin; Persistent Noise Signal in the FairfieldNodal Three‐Component 5‐Hz Geophones. Seismological Research Letters 2018;; 89 (5): 1609–1617. doi: https://doi.org/10.1785/0220180073 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietySeismological Research Letters Search Advanced Search ABSTRACT Data from deployments of the FairfieldNodal three‐component nodes were used to analyze a persistently observed noise signal. The noise signal is most prominent in the 20‐ to 40‐Hz range but has been observed anywhere in the 10‐ to 100‐Hz range. Interestingly, the signal is affected by air temperature and moves to higher frequencies in colder temperatures. Nodes that were deployed in seismic vaults directly on flat concrete slabs do not show the noise signal, and nodes that were buried in the ground or covered in snow show a significant decrease in the noise signal. This suggests that whatever is causing this signal may be mitigated by better coupling to the ground. Spectral analysis of hydrothermal tremor in the Upper Geyser Basin, Yellowstone, suggests this noise signal can interfere with the true ground vibration and can impede the ability to accurately characterize these signals. It is our recommendation to always bury the nodes if it is possible to reduce this noise signal that can interfere with natural signals of interest in a similar frequency band. In addition, tests to better estimate the best gain setting were done, and results show that above 12 dB, the waveforms of teleseismic events on the three‐component nodes are very similar, suggesting that there is no advantage to using a gain setting higher than 18 dB for recording teleseismic events. If background noise is of interest in addition to teleseismic events, we see no adverse effects on the waveforms of teleseismic events using the max gain setting of 36 dB. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

X‐band two‐stage Doherty power amplifier based on pre‐matched GaN‐HEMTs

This study presents an X-band two-stage Doherty power amplifier (DPA) using pre-matched gallium-nitride high electron mobility transistors (GaN-HEMTs). The pre-matched GaN-HEMT includes partial matching circuits in the package using bond-wires and capacitors. To obtain broad bandwidth and low loss, the pre-matching circuits were carefully designed to have a low matching quality factor. The optimum second harmonic impedance, which was extracted from the harmonic source/load pull simulations, was applied to the pre-matching circuits for high efficiency. Using the pre-matched GaN-HEMTs, an X-band two-stage power amplifier (PA) was designed and implemented. By combining two two-stage PAs in parallel, a DPA was built. The implemented DPA exhibited a max gain of 25.5 dB and an output power from 42.5 to 45.8 dBm at the frequency band from 7.9 to 8.4 GHz. It also showed a high efficiency of 37.8% at the 6 dB back-off output power level of 39.6 dBm.

A 19 nV/ $\surd$ Hz Noise 2- $\mu \text{V}$ Offset 75- $\mu \text{A}$ Capacitive-Gain Amplifier With Switched-Capacitor ADC Driving Capability

This paper describes a capacitive-gain amplifier (CGA) with common-mode (CM) sampling (CMS) and switched-capacitor driving capability. The CMS CGA defines the amplifier CM voltage in a single auto-zero phase that significantly reduces the CM settling time. A pre-charge technique and dynamic filtering are used to allow the CGA to drive a switched-cap analog-to-digital converter (ADC) directly that relaxes the speed requirement on CGA and reduces folded noise aliases due to ADC sampling. As a result, it achieves 19-nV/ $\surd$ Hz noise density while dissipating 75 $\mu \text{A}$ . The 5 ppm/full-scale-range integral nonlinearity is achieved with programmable gain range from 1 to 128 with 2.7 to 3.6 V supply. It has 2 $\mu \text{V}$ typical offset and 0.81 ppm/°C max gain error drift. The CGA was implemented in a 0.18- $\mu \text{m}$ CMOS 1.8/3.3 V ultra low leakage technology and occupies only 0.53 mm2 die area.

Design of single-layer high-efficiency transmitting phase-gradient metasurface and high gain antenna

In this paper, based on rotation phase-gradient principle, a single-layer, high-efficiency transmitting metasurface is designed and applied to high-gain antenna. In the case of circularly polarized incident wave, the PCR (polarization conversions ratio) of the metasurface element is greater than 90% in the band of 9.11–10.48 GHz. The transmitting wave emerges an anomalous refraction when left-handed circularly polarized wave are incident perpendicularly to the 1D phase-gradient metasurface, which is composed of cycle arrangement of 6 units with step value of 30°. The simulated anomalous refraction angle is 40.1°, coincided with the theoretical design value (40.6°). For further application, the 2D focused metasurface is designed to enhance the antenna performance while the left-handed circularly polarized antenna is placed at the focus. The simulated max gain is increased by 12 dB (182%) and the half-power beamwidth is reduced by 74.6°. The measured results are coincided with the simulations, which indicates the antenna has high directivity. The designed single-layer transmission metasurface has advantages of thin thickness (only 1.5 mm), high efficiency and light weight, and will have important application prospects in polarization conversion and beam control.

Study of parametric instability in gravitational wave detectors with silicon test masses

Parametric instability is an intrinsic risk in high power laser interferometer gravitational wave detectors, in which the optical cavity modes interact with the acoustic modes of the mirrors, leading to exponential growth of the acoustic vibration. In this paper, we investigate the potential parametric instability for a proposed next generation gravitational wave detector, the LIGO Voyager blue design, with cooled silicon test masses of size 45 cm in diameter and 55 cm in thickness. It is shown that there would be about two unstable modes per test mass at an arm cavity power of 3 MW, with the highest parametric gain of ∼76. While this is less than the predicted number of unstable modes for Advanced LIGO (∼40 modes with max gain of ∼32 at the designed operating power of 830 kW), the importance of developing suitable instability suppression schemes is emphasized.

Frequency-Scanning Planar Antenna Based on Spoof Surface Plasmon Polariton

In this letter, a frequency-scanning planar antenna composed of a phase gradient metasurface and feed structure is proposed. The phase gradient metasurface can couple the wave from the feed into a spatial radiated wave whose propagation direction is manipulated by frequency as long as the feed provides a similar electromagnetic field to that of spoof surface plasmon polariton rather than exciting the spoof surface plasmon polariton. Both the simulation and measured results demonstrate the antenna works well in the frequency range from 8.9 to 9.5 GHz, that the magnitude of reflection coefficient maintains lower than −10 dB with minimum value of −20 dB, and the gain maintains at about 10 dB. The max gain direction of the antenna changes with frequency that the beam pointing angles at 8.9, 9.1, 9.3, and 9.5 GHz are −12°, −8°, −4°,and 0°, respectively.

Design of a fully integrated receiver analog baseband chain for 2.4-GHz ZigBee applications

A receiver analog baseband (ABB) chain for an integrated ZigBee (IEEE 802.15.4) transceiver is presented in this paper. The ABB is composed by a 3rd-order complex band-pass filter (BPF), a variable gain amplifier (VGA) and an analog-to-digital converter (ADC). The circuit topology of each building block has been designed complying with the IEEE 802.15.4 standard as well as featuring low power consumption and small chip size. In this work, a mixed-signal frequency auto-tuning scheme is proposed for complex BPF to accommodate the performance deterioration due to the process, voltage and temperature (PVT) variations. A novel method combined opamp- and capacitor-sharing is presented for ADC to obtain low power consumption and elimination of memory effect. The proposed ABB demonstrates 70dB dynamic range by 2dB/step, 12dBm IIP3 and 35.2nV/√Hz input referred noise. The measured SNDR and SFDR are 41.9dB and 58.7dB, respectively. Implemented in a standard 0.18-μm CMOS technology, the entire receiver ABB chain occupies an area as small as 1.5mm2 and the total power consumption is only 16mW at max gain setting from a 1.8V supply.

A Compact Wide band Printed LPDA Antenna for WLAN Applications in 5 GHz Band

A compact wide band Printed LPDA (Log Periodic Dipole Array) antenna is proposed for WLAN applications in 5-6 GHz range. The antenna having dimensions of 36.58 mm x 24.37 mm x1.6 mm is designed and simulated using HFSS 13. The prototype of proposed antenna is developed using simple FR4 substrate. The proposed antenna works well in the desired operating bandwidth from 5-6 GHz and covers dual bands of IEEE 802.11a (5.15-5.35 GHz and 5.7255.825 GHz) with VSWR effectively less than 2. The antenna shows a wide impedance bandwidth of 1.643 GHz from 4.869 GHz – 6.512 GHz, with bandwidth efficiency of 28.87 %. The antenna gain is > 6 dB throughout the operating band, with max gain of 7.6 dB at 5.6 GHz and stable radiation pattern in end fire direction. Measured results for S11 parameter are in good agreement with simulated one, which validates the proposed antenna design.

Constructing quasi-linear V̇o2 responses from nonlinear parameters

Oxygen uptake (V̇O2) kinetics have been shown to be governed by a nonlinear control system across a range of work rates. However, the linearity of the V̇O2 response to ramp incremental exercise would appear to be the result of a linear control system. This apparent contradiction could represent a balancing of changing V̇O2 kinetics parameter values across a range of work rates. To test this, six healthy men completed bouts of ramp incremental exercise at 15, 30, and 60 W/min (15R, 30R, 60R, respectively) and four bouts of an extended-step incremental exercise. V̇O2 parameter values were derived from the step exercise using two monoexponential models: one starting at time zero and encompassing the entire stage (MONO), and the other truncated to the first 5 min and allowing a time delay (5TD). The resulting parameter values were applied to an integrative model to estimate the ramp responses. As work rate increased, gain values increased (P < 0.001 for MONO and 5TD), as did mean response time (or time constant) values (MONO: P < 0.001; 5TD: P = 0.003). Up to maximal V̇O2 (V̇O(2 max)), the gains of the estimated ramp responses from both models were not different from the gains of the actual observed V̇O2 responses for 15R and 30R (15R: 11.3 ± 1.2, 11.7 ± 0.7, 10.9 ± 0.3; 30R: 10.5 ± 0.8, 11.0 ± 0.5, 10.7 ± 0.3 ml O2·min(-1)·W(-1), for actual, MONO, 5TD, respectively) but were significantly greater for 60R (8.7 ± 1.0, 9.9 ± 0.4, 10.3 ± 0.3 ml O2·min(-1)·W(-1) for actual, MONO, 5TD, respectively). Up to 80%V̇O(2 max) gain values were not significantly different for any ramp rate (P > 0.05 for all). We conclude that the apparent linearity of the V̇O2 response to ramp incremental exercise is consequent to a balancing of increasing time constant and gain parameter values.