A novel and compact microstrip ultra-wideband (UWB) bandpass filter (BPF) based on a triple-mode resonator is designed, fabricated and measured. The proposed resonator is composed of a coupled line ...with a half-pass characteristic, which is connected directly with each other at one end and is short-circuited to the grounding plane at the other end. A simple structure and design approach to the proposed filter is provided and demonstrated. To implement the design on a microstrip, the directly tapped-transition input/output ports are used to excite the coupled-line multi-mode resonator. The measured results are in good agreement with the electromagnetic simulated results. The proposed filter shows a 3 dB fractional bandwidth of 117.3% at the central frequency (/)) with a return loss of better than 12 dB and an insertion loss of < 0.5 dB within the passband response. PUBLICATION ABSTRACT
Radial line slot array (RLSA) antennas have attractive features, such as high gain, high efficiency, and planar low profile, but their gain-bandwidths have been limited to less than 10%. This article ...presents a method to significantly increase the gain-bandwidth of RLSAs to over 30%. The key to the method is the application of a nonuniform radial TEM waveguide as opposed to the radially uniform TEM waveguide used in conventional RLSAs. Hence, the condition for maximum radiation is satisfied at a wide range of frequencies by different sections of the RLSA. To demonstrate the concept, several circularly polarized RLSA designs and one prototype are presented. The measured results of the prototype demonstrate an unprecedented 3 dB gain-bandwidth of 27.6%, a peak gain of 27.3 dBic, 3 dB axial ratio bandwidth greater than 31.1%, and a 10 dB return loss bandwidth greater than 34.8%. The overall measured bandwidth of the RLSA in which gain variation and axial ratio are within 3 dB and return loss is greater than 10 dB is from 9.7 to 12.8 GHz or 27.6%. Its extremely high measured gain-bandwidth product per unit area (GBP/A) of 88 indicates excellent overall performance in terms of bandwidth, gain, and area.
A broadband hybrid power amplifier using a gallium nitride (GaN) high electron mobility transistor (HEMT) is presented. A discrete GaN HEMT bare die with 1.25 mm of gate width is used, and a compact ...size of 8.3 × 12.7 mm is achieved by using a feedback technique based on lumped elements. The power amplifier operates from 100 to 1000 MHz, and shows more than 12.8 dB gain and higher than 30.7 dBm output power in the overall bandwidth. Power added efficiency of 61.3% was acquired at the mid-band frequency and more than 54.5% throughout the bandwidth. PUBLICATION ABSTRACT
We investigated molecular mobility and oxygen diffusion in amorphous solid films of I--lactalbumin (I--La) using phosphorescence from the xanthene probe erythrosin B in order to elucidate the ...molecular mechanism(s) that control oxygen permeability in amorphous solid proteins. Emission peak energy and bandwidth were determined by fitting spectra to a lognormal bandwidth function; intensity decays were fit to a stretched exponential function to determine the lifetime and the stretching exponent. Peak emission energy decreased gradually over the range from a20 to over 120 degree C, indicating a gradual increase in the matrix dipolar relaxation rate. Bandwidths were constant at low temperature but increased dramatically above a1450 degree C, indicating that the dynamic heterogeneity of the protein matrix increased at high temperature. Emission lifetimes decrease gradually at low and more steeply at high temperature, indicating that the rate of matrix collisional quenching increased with temperature. Arrhenius analysis of the rate constant for non-radiative decay showed a gradual increase in quenching indicative of matrix softening. Comparison of lifetimes in air and N2 (A-oxygen) monitored oxygen permeability. Oxygen permeability became detectable at about 0 degree C and appeared to correlate with matrix mobility. The emission spectrum shifted to higher energy as a function of time following excitation, whereas the phosphorescence lifetime decreased with increasing emission wavelength; both behaviors provided strong evidence for distinct sites within the protein matrix varying in molecular mobility. Phosphorescence spectroscopy thus provides a simple tractable tool for monitoring conditions that activate oxygen diffusion in amorphous solid foods.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
This paper presents an ultra-low-power second-order Chebyshev active-RC complex filter for a low-IF ultra-low-power receiver. By utilising a pole-cancellation push-pull buffer with feedforward phase ...compensation technology, the operational amplifier (opamp) realises superior stability while maintaining high gain bandwidth and ultra-low power consumption. A second-order complex filter with four proposed opamps and an adaptive bias fabricated in standard 180 nm CMOS process consumes only 460 mu W at 1.8 V power supply. The measured centre frequency is 3 MHz and bandwidth is 2 MHz, while it achieves 32 dB image rejection ratio at the centre frequency.
We demonstrate a solution-processed colloidal quantum dot (CQDs) photodetector with the configuration of a field-effect transistor (FET), in which the drain and source electrodes are fabricated by a ...shadow mask. By blending PbS CQDs into the hybrid blend, poly(3-hexylthiophene) (P3HT) and 6,6-phenyl-C sub(61)-butyric acid methylester(PCBM), the photosensitive spectrum of the nanocomposite blend is extended into the near-infrared region. A FET-based photodetector ITO/PMMA (180 nm)/P3HT:PCBM:PbS (110 nm)/Al, in which PMMA (polymethylmethacrylate) acts as the dielectric layer and P3HT:PCBM:PbS (in weight ratio of 1:1:1) as the active layer, shows a broad spectral bandwidth, a responsivity of 0.391 mA W super(-1) and a specific detectivity of 1.31 x 10 super(11) Jones are obtained at V sub(GS) = 1 V under 600 nm illumination with an intensity of 30 mu W cm super(-2). Therefore, it provides an easy way to fabricate such a FET-based photodetector with a channel length of some hundreds of micrometers by a shadow mask.
The bandwidth of tapered slot antennas (TSAs) is usually limited by the bandwidth of the feed used and typically does not exceed a few octaves, even though the TSA itself possibly can operate at a ...wider frequency range. Presented, and discussed, is a planar TSA feeding scheme that makes use of an external 1808 hybrid. Design guidelines and analytical formulas are presented for this hybrid connection scheme.
A multiservice radio-frequency identification (RFID) antenna with wideband axial ratio (AR) response around 2.4 GHz is presented in this study. This antenna offers dual band operation. The prototype ...follows a configuration constituting a driven element (radiator) and a parasitic element. The first band offers a voltage standing wave ratio (VSWR) bandwidth (3:1) of 183 MHz (0.85–1.04 GHz). The VSWR bandwidth (3:1) for the second band is 2.77 GHz (2–4.77 GHz). It also offers a 3 dB AR bandwidth of 1.1 GHz (2.1–3.2 GHz). The 2:1 VSWR bandwidth of 0.9 GHz (2.1–3 GHz) and cross-polarisation in the second band makes this antenna suitable for 2.4 GHz RFID reader applications. The other services supported by the proposed antenna include global system for mobile communication (0.88–0.96 GHz), long-term evolution (2.3–2.4 GHz), wireless fidelity (2.4–2.5 GHz), bluetooth low energy (2.4 GHz) and worldwide interoperability for microwave access (3.5 GHz). To extract the multiservice characteristics, it is necessary to integrate this antenna to a handheld computing platform. For assessing the performance in such a platform, the prototype is optimised and merged with a larger ground plane of size 170 mm × 130 mm and studied in the course of this study.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
In this investigation, we propose and investigate a wavelength converter by using a cost-effective and uncooled TO-can package reflective semiconductor optical amplifier with $\sim $ similar to 1.2 ...GHz bandwidth. In this measurement, the converted data rate can support 1.25a10 Gbit/s on-off keying modulation rates by using the cross gain modulation technique.
In this paper, a new multi loop sigma-delta ( capital sigma Delta ) modulator is proposed which employs one order redundant noise shaping in the first stage so the effect of the quantization noise ...leakage is minimized. Thus, analog circuit requirements are considerably relaxed compared to the conventional Multi-stAge-noise-SHaping (MASH) structures. This enhancement makes the structure appropriate for low voltage and broadband applications. The proposed architecture is compared with traditional high-order structures, and the advantages are demonstrated by both the analysis and behavioral system level simulations. As a prototype, the proposed MASH 3-2 sigma-delta modulator is designed, and the detailed design procedure is presented from the system level to the circuit level in a 90nm CMOS technology. Circuit level simulation results show that the modulator achieves a peak signal-to-noise and distortion ratio of 79.4dB and 79dB dynamic range over a 10MHz bandwidth with a sampling frequency of 160MHz. It consumes 35.4mW power from a single 1V supply. Copyright copy 2012 John Wiley & Sons, Ltd. A new Multi-stAge-noise-Shaping sigma delta modulator is proposed which employs one order redundant noise shaping in the first stage so the effect of the quantization noise leakage is reduced. As a prototype, A MASH 3-2 sigma-delta modulator is designed in a 90nm CMOS technology. The modulator achieves a peak SNDR of 79.4dB over a 10MHz bandwidth with a sampling frequency of 160MHz and consumes 35.4mW power from a single 1V supply.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
