High Gain 130GHz Frequency Doubler with Colpitts Output Buffer Delivering Pout up to 8dBm with 6% PAE in 55nm SiGe BiCMOS

A mmWave frequency doubler in a SiGe BiCMOS technology is presented. The core of the circuit comprises a push-push pair, for second-harmonic generation, and a stacked common-collector Colpitts oscillator which works as a common-base injection-locked amplifier to boost the conversion gain and output power. The class-C operation of the transistor in the Colpitts buffer leads to a pulsed current shape with enhanced second-harmonic content. As a result, the power conversion gain of the frequency doubler is increased by up to 10dB, compared to the push-push pair alone. Moreover, the common-collector configuration keeps separate the oscillator tank from the load, allowing independent optimization of the harmonic conversion efficiency and the load impedance for maximum power delivery. Realized in a SiGe BiCMOS technology with 330GHz fmax, the proposed frequency doubler delivers Pout up to 8dBm at 130GHz with 13dB conversion gain and 6.3% Power Added Efficiency. A Figure of Merit is proposed to benchmark frequency doublers and the presented chip shows up to 3 times improvement compared to previously reported designs in the same frequency range

E-Band Frequency Sextupler With >35 dB Harmonics Rejection Over 20 GHz Bandwidth in 55 nm BiCMOS

A frequency multiplier by six (sextupler) for local oscillation (LO) generation in E-band is presented. It comprises a tripler, a doubler, and an output buffer. A detailed analysis is proposed to discuss the optimal order of the multiplication stages to minimize the unwanted harmonics of the input. Moreover, novel circuit topologies for the tripler and doubler are introduced. The tripler core is devised to reproduce the transcharacteristic of a third-order polynomial that ideally generates only the third harmonic of a sinusoidal input signal. By leveraging an envelope detector for adaptive biasing, the circuit maintains excellent suppression of the driving signal and unwanted harmonics over wide variations of the input power. The proposed topology improves output signal purity and current conversion efficiency against classical triplers based on the transistors biased in class C. The cascaded frequency doubler is based on a novel push-push configuration that provides a differential output and excellent odd-order harmonic rejection due to an enhanced robustness to amplitude and phase unbalances of the driving signal. The sextupler is fabricated in a 55-nm SiGe-BiCMOS technology. Driven with a 0-dBm input signal and consuming 63.1 mW of dc power, it delivers ${P_{{out}}}$ up to 5.6 dBm at 72 GHz. ${P_{{out}}}$ is above 0 dBm over 20-GHz bandwidth (BW), while undesired harmonics of the input are suppressed by more than 35 dB. Compared to previously reported millimeter-wave frequency multipliers, the sextupler demonstrates improved harmonic rejection, conversion gain, and efficiency, without compromising the operation BW and output power

40GHz Frequency Tripler with High Fundamental and Harmonics Rejection in 55nm SiGe-BiCMOS

This paper presents a novel frequency tripler circuit topology which yields a remarkable improvement on the suppression of the driving signal frequency at the output,compared to conventional designs exploiting transistors in class-C. The active core of the circuit approximates the transfer characteristic of a third-order polynomial that ideally produces only a third-harmonic of the input signal. Implemented in a 55nm SiGe-BiCMOS technology and consuming 13.6mA from 1.7V,the tripler demonstrates ~40dB suppression of the input signal and its 5th harmonic over 16% factional bandwidth and robustness to power variation of the driving signal over a 15dB range

Influence of pH on chloride binding isotherms for cement paste and its components

In this paper, chloride (Cl−) binding isotherms are developed for cement hydration compounds, specifically, calcium-silicate-hydrates (CSH) and AFm phases including mono-sulfate aluminate, hydroxy-AFm, monocarbonate-AFm, and hemicarbonate-AFm, in simulated concrete pore solutions to account for the effect of pH and the presence of other ions. pH and the presence of other ions have a strong influence on the Cl− binding capacity of cement compounds, which have not been taken into consideration in previous research. A novel experimental technique is developed to characterize the binding capacity from very low (1 mM) to very high concentrations (5 M). To overcome the existing challenges of measuring both low and high Cl− concentrations without significant dilution and in the presence of SO42− and OH− ions, a potentiometric method was used. The amorphous CSH in the hydrated cement paste; thus, the heterogeneity of the hydrated components of the cement paste was also quantified and accounted for in this study.The funding for this research was provided partly by the National Priorities Research Program of the Qatar National Research Fund (a member of the Qatar Foundation) under the award no. NPRP 7-410-2-169 and the United States National Science Foundation under the award no. 1642488 . The authors thank Professor Melot, Professor Marinescu, their students: Nicholas H. Bashian and Eric Johnson, and Mohit Dave at the University of Southern California for providing access to their laboratory facilities to perform some of the experiments described in this paper. Authors are also grateful to Lafarge, U.S. for donating the cement used in the experimental work.Scopu

Migration of contaminants by gas phase transfer from carton board and corrugated board box secondary packaging into foods

The gas phase transfer of substances from carton board (CB) and corrugated box board (CBB) through intervening layers to foods was studied. Substances covering a boiling point range of 252-425°C and a range of polarities were incorporated into CB and CBB secondary packaging. Benzophenone was present in some CB materials. Where it was not already present in CB or CBB secondary packaging, it was deliberately incorporated for transfer studies. Transfer of substances was measured in nine foodstuff types stored in the secondary packaging at ambient and sub-ambient temperature. The foods were packaged in primary packaging materials that would be used in retail. Two food types were packed and stored in both single- and multipack formats. Foods were sampled at 0, 10, 30, 90 and 200 days and analysed by gas chromatography-mass spectrometry after high-performance size exclusion chromatography clean-up. Percentage transfer was between 0 and 100%. The overall trends were increased transfer of substances with increased storage time; a more rapid transfer of the more volatile substances compared with the less volatile ones and higher levels of transfer of the more volatile substances. No transfer of diheptyl phthalate (DHP) (bp 425°C) as an incorporated substance was detected to any foods over the test period. The presence of an additional layer of packaging (multipack versus single pack) was shown to reduce transfer up to fourfold over 200 days and to increase the lag period for transfer. In terms of slowing transfer, metallized PP/PP laminate proved a more effective barrier than PP which was more effective than paper. It is postulated that there is a cut-off threshold for transfer at ambient and sub-ambient temperatures. Substances that are less volatile than the cut-off are anticipated not to transfer from secondary packaging to foods stored for up to 200 days, where the substances are present in the packaging at or below the levels tested in this study (up to 1 mg dm-2). In this study the volatility cut-off threshold lay between that of 2,2-dimethoxyphenylacetophenone (2,2-DMPAP) (an incorporated substance with bp 352°C) and DHP. Ideally, the cut-off threshold should be expressed in terms of vapour pressure in the packaging material. In practical terms, it may be more appropriate to express as partition coefficient as this is simpler to determine experimentally