An improved analytical model for static pull-in voltage of a flexured MEMS switch

Microsystem Technologies - This paper presents the design of low-k meander based MEMS shunt capacitive switch with beam perforations. A closed form model to accurately calculate the pull-in voltage...     

Highly efficient uneven multi-level linc transmitter

To improve power efficiency in a transmitter, a novel method is proposed, this being an uneven multi-level linear amplifier with a nonlinear component (UMLINC). Compared to a normal multi-level LINC (MLINC), the UMLINC employs a new uneven multi-level signal component separator (UMSCS) that significantly improves transmitter efficiency.     

A 1.9-GHz DECT CMOS power amplifier with fully integratedmultilayer LTCC passives

We present the first demonstration of a CMOS power amplifier (PA) utilizing fully integrated multilayer low-temperature co-fired ceramic (LTCC) high-Q passives for 1.9-GHz digital European cordless telecommunications (DECT) applications. The inductor and capacitor library were built in a multilayer LTCC board using a compact topology. An inductor Q-factor as high as 100 with a self-resonant frequency (SRF) as high as 8 GHz was demonstrated. Measured results of the CMOS-LTCC PA show good agreement with the simulated results exhibiting 48% power added efficiency, 26-dBm output power and 17-dB gain at 1.9 GHz with a 3.3-V drain supply voltage. This result is the first significant step toward a compact DECT transceiver module development utilizing fully integrated multilayer LTCC passives and a standard CMOS technology     

Enhanced input range dynamic comparator for pipeline analogue-to-digital converter

A new dynamic comparator with enhanced input range is reported. Input trip point deviations from ideal values are shown to be less than a conventional comparator over a wide input range. This new dynamic comparator can be beneficial to low supply voltage analogue- to-digital converters (ADCs), especially to pipeline ADCs.     

Compact planar and vialess composite low-pass filters using folded stepped-impedance resonator on liquid-Crystal-polymer substrate

A compact composite low-pass filter, designed by the image parameter method and semilumped component approach, will be described and results for cutoff frequency ranging from C- to V-band will be presented. This composite design combines four filter sections and the presence of a strong attenuation pole near the cutoff frequency provides an extremely sharp attenuation response, while ensuring good matching properties in the passband, making this filter design very attractive for harmonic spurious response suppression or diplexing. The lumped-element schematic of the filter has been implemented using a combination of a stepped-impedance filter and folded stepped-impedance resonators. The overall folded layout has been optimized using full-wave simulation and occupies an ultra-compact area of only 5/spl times/5 mm/sup 2/ for a C-band filter. Measured results exhibit rejection of the attenuated pole greater than 40 dB. Similar filter designs have been realized for C- and V-bands. These filters have been fabricated on a liquid-crystal-polymer substrate demonstrating a high performance, ultra-compact, and very low-cost solution for RF and millimeter-wave applications.     

Cryogenic operation of third-generation, 200-GHz peak-f/sub T/, silicon-germanium heterojunction bipolar transistors

We present a comprehensive investigation of the cryogenic performance of third-generation silicon-germanium (SiGe) heterojunction bipolar transistor (HBT) technology. Measurements of the current-voltage (dc), small-signal ac, and broad-band noise characteristics of a 200-GHz SiGe HBT were made at 85 K, 120 K, 150 K, 200 K, and 300 K. These devices show excellent behavior down to 85 K, maintaining reasonable dc ideality, with a peak current gain of 3800, a peak cut-off frequency (f/sub T/) of 260 GHz, a peak f/sub max/ of 310 GHz, and a minimum noise figure (NF/sub min/) of approximately 0.30 dB at a frequency of 14 GHz, in all cases representing significant improvements over their corresponding values at 300 K. These results demonstrate that aggressively scaled SiGe HBTs are inherently well suited for cryogenic electronics applications requiring extreme levels of transistor performance.     

Chemical investigation of Erythrina variegata Linn. seed proteins

Proteins were extracted from deoiled seeds of Erythrina variegata Linn., a potential source of non-conventional seed, in aqueous solutions of various pHs or by different concentrations of NaCl, KCl, CaCl₂ and MgSO₄ at pH 7.0. Nitrogen contents of the seeds and deoiled seeds showed good protein content. Fractionation of protein was done to separate albumin, globulin, prolamine and glutelin. Amino acid analysis of the total protein isolates (TPI) and the fractions isolated (except prolamine) identified 17 amino acids, most of which were essential. The molecular weights of TPI and the fractions were determined by SDS–PAGE electrophoresis. The results showed that TPI was composed of twelve bands, eight for globulin, nine for prolamine and six for glutelin. Studies on surface structure of the proteins and seed flour by scanning electron microscopy (SEM) are also included.     

Two-dimensional 8×8 photoreceiver array and VCSEL drivers forhigh-throughput optical data links

Two custom GaAs integrated circuits (ICs) have been developed for enabling vertical cavity surface emitting laser (VCSEL) arrays to be used for high throughput spatial division multiplexed (SDM) optical data links. A 16-channel driver IC was developed to drive the VCSEL array and an 8×8 monolithic photoreceiver, which spatially matches the VCSEL array, was developed for receive. Both of these circuits were fabricated in a standard commercial GaAs MESFET process with parasitic photodetectors used for the photoreceivers. Power dissipation and circuit size were primary design challenges for both circuits. The present 8×8 array size along with an estimated usable channel speed of 1 Gb/s allows for an aggregate throughput of 64 Gb/s     

Super-low-noise performance of direct-ion-implanted 0.25-μm-gateGaAs MESFET's

The authors report on advanced ion implantation GaAs MESFET technology using a 0.25-μm `T' gate for super-low-noise microwave and millimeter-wave IC applications. The 0.25×200-μm-gate GaAs MESFETs achieved 0.56-dB noise figure with 13.1-dB associated gain at 50% I_DSS and 0.6 dB noise figure with 16.5-dB associated gain at 100% I_DSS at a measured frequency of 10 GHz. The measured noise figure is comparable to the best noise performance of AlGaAs/GaAs HEMTs and AlGaAs/InGaAs/GaAs pseudomorphic HEMTs