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1.
A 0.18 μm CMOS low noise amplifier(LNA) by utilizing noise-canceling technique was designed and implemented in this paper. Current-reuse and self-bias techniques were used in the first stage to achieve input matching and reduce power consumption. The core size of the proposed CMOS LNA circuit without inductor was only 128 μm 9226 μm. The measured power gain and noise figure of the proposed LNA were 20.6 and 1.9 dB,respectively. The 3-dB bandwidth covers frequency from 0.1 to 1.2 GHz. When the chip was operated at a supply voltage of 1.8 V, it consumed 25.69 mW. The high performance of the proposed LNA makes it suitable for multistandard low-cost receiver front-ends within the above frequency range.  相似文献   

2.
A differential cross-coupled regulated cascode(RGC)transimpedance amplifier(TIA)is proposed. The theory of multi-stage common-source(CS) configuration as an auxiliary amplifier to enhance the bandwidth and output impedance of RGC topology is analyzed. Additionally, negative Miller capacitance and shunt active inductor compensation are exploited to further expand the bandwidth. The proposed RGC TIA is simulated based on UMC 0.18 μm standard CMOS process. The simulation results demonstrate that the proposed TIA has a high transimpedance of 60.5 d B?, and a-3 d B bandwidth of 5.4 GHz is achieved for 0.5 p F input capacitance. The average equivalent input noise current spectral density is about 20 p A/Hz~(1/2) in the interested frequency, and the TIA consumes 20 m W DC power under 1.8 V supply voltage. The voltage swing is 460 m V pp, and the saturation input current is 500 μA.  相似文献   

3.
This paper discusses fabrication and performance of novel circular spiral inductors on silicon. The substrate materials underneath the inductor coil are removed by wet etching process. In the fabrication process, fine polishing of the photoresist is used to simplify the processes and ensure perfect contact between the seed layer and the top of pillars. Dry etching technique is used to remove the seed layer. The results show that Q-factor of the inductor is greatly improved by removing silicon underneath the inductor coil. The spiral inductor with line width of 50 μm has a peak Q-factor of 10 for the inductance of 2.5 nH at frequency of 1 GHz, and the resonance frequency of the inductor is about 8.5 GHz. For the inductor of conductor width 80 μm, the peak Q-factor increases to about 17 for inductance of 1.5 nH in the frequency range of 0.05 -3.00 GHz.  相似文献   

4.
A fully integrated frequency synthesizer with low jitter and low power consumption in 0.18 μm CMOS (complementary metal-oxide semiconductor) technology is proposed in this paper.The frequency synthesizer uses a novel single-end gain-boosting charge pump, a differential coupled voltage controlled oscillator (VCO) and a dynamic logic phase/frequency detecor (PFD) to acquire low output jitter.The output frequency range of the frequency synthesizer is up to 1 200 MHz to 1 400 MHz for GPS (global position system) application.The post simulation results show that the phase noise of VCO is only 127.1 dBc/Hz at a 1 MHz offset and the Vp-p jitter of the frequency synthesizer output clock is 13.65 ps.The power consumption of the frequency synthesizer not including the divider is 4.8 mW for 1.8 V supply and it occupies a 0.8 mm×0.7 mm chip area.  相似文献   

5.
Using composite field arithmetic in Galois field can result in the compact Rijndael S-Box. However, the power con- sumption of this solution is too large to be used in resource-limited embedded systems. A full-custom hardware implementation of composite field S-Box is proposed for these targeted domains in this paper. The minimization of power consumption is implemented by optimizing the architecture of the composite field S-Box and using the pass transmission gate (PTG) to realize the logic functions of S-Box. Power simulations were performed using the netlist extracted from the layout. HSPICE simulation results indicated that the proposed S-Box achieves low power consumption of about 130 μW at 10 MHz using 0.25 μm/2.5 V technology, while the consumptions of the positive polarity reed-muller (PPRM) based S-Box and composite field S-Box based on the conventional CMOS logic style are about 240 μW and 420 μW, respectively. The simulations also showed that the presented S-Box obtains better low-voltage operating property, which is clearly relevant for applications like sensor nodes, smart cards and radio frequency identification (RFID) tags.  相似文献   

6.
A wideband dual-feedback low noise amplifier(LNA) was analyzed, designed and implemented using SiGe heterojunction bipolar transistor(HBT) technology. The design analysis in terms of gain, input and output matching, noise and poles for the amplifier was presented in detail. The area of the complete chip die, including bonding pads and seal ring, was 655 μm×495 μm. The on-wafer measurements on the fabricated wideband LNA sample demonstrated good performance: a small-signal power gain of 33 dB with 3-dB bandwidth at 3.3 GHz was achieved;the input and output return losses were better than-10 dB from 100 MHz to 4 GHz and to 6 GHz, respectively; the noise figure was lower than 4.25 dB from 100 MHz to 6 GHz; with a 5 V supply, the values of OP1 dB and OIP3 were1.7 dBm and 11 dBm at 3-dB bandwidth, respectively.  相似文献   

7.
Resonant frequencies of a piezoelectric drum transducer   总被引：1，自引：0，他引：1  
This paper presents a piezoelectric-metal structure called a drum transducer. An equation for calculating the resonance frequency of the drum transducer is obtained based on thin plate elastic theory of piezoelectric and metal material combined with the Rayleigh-Ritz method. The finite element method （FEM） was used to predict the excitation frequency of the drum transducer. To verify the theoretical analysis, the input impedance characteristic of the drum transducer was measured using an experimental method. The results obtained from theoretical analysis were in very good agreement with those from the FEM and experimental results. The effect of geometrical changes to the thick-walled steel ring of the drum transducer at the first resonance frequency is also described. The calculated results were found to be in good agreement with the FEM results. The results indicate that the first resonance frequency of the drum decreases with the increasing inner diameter of the thick-walled steel ring.  相似文献   

8.
The clock generator and OOK modulator for RFID (Radio Frequency Identification) presented in this paper consist of a current source and delay elements. The simple constant-gm structure is adopted in the current source design and the current consumption of the current source is only about 2 μA. The delay elements, the clock generator and OOK modulator are introduced in detail in the paper. The designed circuits are fabricated by 0.6 μm CMOS process. The area of the core circuit is only about 400 μmμ0 μm. The delay time of all three samples is in the range of 9 μs to 21 μs when the supply voltage varies from 2 V to 4 V. As the measured results satisfy the system requirements, these circuit structures are suitable for RFID application.  相似文献   

9.
A high speed column-parallel CDS/ADC circuit with nonlinearity compensation is proposed in this paper.The correlated double sampling (CDS) and analog-to-digital converter (ADC) functions are integrated in a threephase column-parallel circuit based on two floating gate inverters and switched-capacitor network.The conversion rate of traditional single-slope ADC is speeded up by dividing quantization to coarse step and fine step.A storage capacitor is used to store the result of coarse step and locate the section of ramp signal of fine step,which can reduce the clock step from 2 n to 2 (n/2+1).The floating gate inverters are implemented to reduce the power consumption.Its induced nonlinear offset is cancelled by introducing a compensation module to the input of inverter,which can equalize the coupling path in three phases of the proposed circuit.This circuit is designed and simulated for CMOS image sensor with 640×480 pixel array using Chartered 0.18μm process.Simulation results indicate that the resolution can reach 10-bit and the maximum frame rate can reach 200 frames/s with a main clock of 10MHz.The power consumption of this circuit is less than 36.5μW with a 3.3V power supply.The proposed CDS/ADC circuit is suitable for high resolution and high speed image sensors.  相似文献   

10.
Propagation characterization is one of the main building blocks for millimetre wave （MMW） communication. The Gaussian beam has attractive features to become a prospective wave form for millimetre radio communication, especially for the utility inside tunnels. A ray tracing method embedded with spectral features of Gaussian beam is employed to analyze mil- limetre wave propagation in a circle tunnel in this paper. In consideration of geometrical figure of the tunnel, the superposition behaviour of direct and reflective beams is analyzed via simplified approximation of Gaussian beam spectral feature. Then the propagation models are established to derive amplitude, phase, and delay spread of received wave. A typical straight tunnel model is used to simulate the propagation behaviour, where strong multi-path effect with deeply fading of signal intensity and dramatically enhancing of delay spread emerges. For investigation of the spectral feature of the multi-path effect, a reflection loss of 14 dB is taken into consideration at a designated point. To analyze the influences of frequency and transmission distance, the propagation characteristics at three different frequencies of 45 GHz, 65 GHz and 85 GHz are compared with the beam travelling down the tunnel. In addition, three different reflection losses of 14 dB, 20 dB, and 26 dB at the frequency of 65 GHz are also investigated to research the influence of the reflecting coefficient.  相似文献   

11.
The steady-state electrical conductivity,as well as the dielectric propertiesbetween 2×10~(-4)Hz and 100 kHz,and at 1 GHz,are reported for urease compressed powdersamples of low hydration.The results show that the large,low frequency dielectricdispersion,known as α-dispersion,is due to the build-up of a space charge of protons atthe sample-electrode interfaces.A smaller dispersion,appearing at higher frequencies,isconcluded to be associated with hindered motions of the peptide residues in the molecularstructure of urease.The extent of these polypeptide backbone motions is shown to bestrongly depended on the extent of enzyme hydration.This work is contributed to the de-velopment of conductimetric biosensors.  相似文献   

12.
This paper presents a multi-mode control scheme for a soft-switched flyback converter to achieve high efficiency and excellent load regulation over the entire load range. At heavy load, critical conduction mode with valley switching （CCMVS） is employed to realize soft switching so as to reduce turn-on loss of power switch as well as conducted electromagnetic interference （EMI）. At light load, the converter operates in discontinuous conduction mode （DCM） with valley switching and adaptive off-time control （AOT） to limit the switching frequency range and maintain load regulation. At extremely light load or in standby mode, burst mode operation is adopted to provide low power consumption through reducing both switching frequency and static power dissipation of the controller. The multi-mode control is implemented by an oscillator whose pulse duration is adjusted by output feedback. An accurate valley switching control circuit guarantees the minimum turn-on voltage drop of power switch. The prototype of the controller IC was fabricated in a 1.5-μm BiCMOS process and applied to a 310 V/20 V, 90 W flyback DC/DC converter circuitry. Experimental results showed that all expected functions were realized successfully. The flyback converter achieved a high efficiency of over 80% from full load down to 2.5 W, with the maximum reaching 88.8%, while the total power consumption in standby mode was about 300 mW.  相似文献   

13.
A 16×16 micro-strip antenna array with high gain characteristic was proposed for the 5.5 GHz WiMAX application. The T-junctions with a power ratio of 2∶1 were used to design the feed network. To correct the stepped discontinuity of impedance change in common multi-section impedance transformer, exponential line matching transformers were adopted in the WiMAX frequency band. The reflection coefficient was lower than-15 dB from 5.08 GHz to 5.87 GHz. The measured gain of the antenna array achieved 29.8 dBi on E-plane at 5.8 GHz.  相似文献   

14.
董宁 《海外英语》2012,(22):15-17,19
The target language input plays a significant role in the process of foreign language teaching and learning.One of the most influential studies about input is Krashen’s Input Hypothesis.It emphasized the importance of comprehensible input in foreign language learning.This thesis is mainly to study the significance of Input Hypothesis and its implication on reading teaching.The problems exited in reading teaching and some suggestions are given at last.  相似文献   

15.
Quasi-phase-matching(QPM) periodical poled LiNbO3 （PPLN） is designed and successfully fabricated to enable second harmonic generation (SHG),The samples were Z-cut 0.5 mm thick and grating period is A=6.8 μm for the first order QPM of contimual wave λ=1.064μm which is emitted by Nd:YAG laser at room temperature 27℃,The output single-pass SHG power was tested by an authorized optical system.The normalized max conversion efficiency is calculated to be 0.25% (W.cm)^-1,The fabrication and parameters calculated method are introduced,and testing scheme is described in this paper,Even some ideas to improve conversion efficiency are offered.  相似文献   

16.
We present a bulk micromachined in-plane capacitive accelerometer fabricated with an improved process flow, by etching only one-fifth of the wafer thickness at the back of the silicon while forming the bar-structure electrode for the sensing capacitor. The improved flow greatly lowers the footing effect during deep reactive ion etching （DRIE）, and increases the proof mass by 54% compared to the traditional way, resulting in both improved device quality and a higher yield rate. Acceleration in the X direction is sensed capacitively by varying the overlapped area of a differential capacitor pair, which eliminates the nonlinear behavior by fixing the parallel-plate gap. The damping coefficient of the sensing motion is low due to the slide-film damping. A large proof mass is made using DRIE, which also ensures that dimensions of the spring beams in the Y and Z directions can be made large to lower cross axis coupling and increase the pull-in voltage. The theoretical Brownian noise floor is 0.47 μg/Hz^1/2 at room temperature and atmospheric pressure. The tested frequency response of a prototype complies with the low damping design scheme. Output data for input acceleration from -1 g to 1 g are recorded by a digital multimeter and show very good linearity. The tested random bias of the prototype is 130 μg at an averaging time of around 6 s.  相似文献   

17.
We present a new sense amplifier circuit for EEPROM memory. The topology of the sense amplifier uses a voltage sensing method, having low cost and low power consumption as well as high reliability. The sense amplifier was implemented in an EEPROM realized with an SMIC 0.35-μm 2P3M CMOS embedded EEPROM process. Under the condition that the power supply is 3.3 V, simulation results showed that the charge time is 35 ns in the proposed sense amplifier, and that the maximum average current consumption during the read period is 40 μA. The novel topology allows the circuit to function with power supplies as low as 1.4 V. The sense amplifier has been implemented in 2-kb EEPROM memory for RFID tag IC applications, and has a silicon area of only 240 μm^2.  相似文献   

18.
Dynamic tests of three bonded and two unbonded full-prestressed concrete beams were carried out.The purpose was to seek the relation between prestressing force and natural frequency.Test results indicate that the frequency of prestressed concrete(PSC)beam increases with the increase in prestressing force approximately.The results are different from the dynamic characteristics of isotropic material beam subjected to compressive axial force which were put forward by Clough et al.The reason is that the beams were considered as isotropic,homogeneous,linear elastic material in the traditional analysis method.However,more accurate results are required in the analysis of frequency of PSC beam.The constitutive mode of PSC member is analyzed based on microstructure of concrete in this paper.The orthotropic linear elastic mode is used to analyze the relation between dynamic frequency and prestressing force of concrete beam,at the same time the equivalent stiffness of prestressed tendon relating to the prestressing force is added to the bending deformation stiffness of the beam.The analytical value agrees well with the test result,indicating that the current analysis method in this paper is feasible to full-prestressed concrete beam.  相似文献   

19.
Aiming at the surface integrity of titanium alloy Ti-6Al-4V in high speed side milling, a series of side mill- ing tests were carried out with uncoated carbide milling cutter at various milling speeds. Surface roughness, residual stress, subsurface microstructure and microhardness variations were investigated. The surface roughness measurement results present that the milling speed from 80 to 120 m/min fails to produce better and more stable roughness values compared with the result obtained from 320 to 380 m/min. The residual stresses in the feed direction and axial depth of cut direction are in similar trends for the two milling speed levels mentioned above. Moreover, the residual stress pro- duced at 320 to 380 m/min is lower and more stable than that at 80 to 120 m/min. The microstructure analysis shows that the volume of β phase in the near surface becomes smaller and the deformation of β phase in the near surface be- comes obvious with the increase of the milling speed. Subsurface microhardness variation was observed down to 200 μm below the machined surface at 80 to 120 m/min and down to 160 μm at 320 to 380 m/min. It is concluded that better surface integrity and higher material removal rate can be obtained at 320 to 380 m/min than at 80 to 120 m/min.  相似文献   

20.
The lattice Boltzmann method (LBM) is employed to simulate the uniform flow past a circular cylinder. The performance of the two-dimensional LBM model on the prediction of force coefficients and vortex shedding frequency is investigated. The local grid refinement technique and second-order boundary condition for curved walls are applied in the calculations. It is found that the calculated vortex shedding frequency, drag coefficient and lift coefficient are consistent with experimental results at Reynolds nu...  相似文献   

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