An efficient reconfigurable multiplier architecture for Galois field GF(2)

This paper describes an efficient architecture of a reconfigurable bit-serial polynomial basis multiplier for Galois field GF(2^m), where 1<m≤M. The value m, of the irreducible polynomial degree, can be changed and so, can be configured and programmed. The value of M determines the maximum size that the multiplier can support. The advantages of the proposed architecture are (i) the high order of flexibility, which allows an easy configuration for different field sizes, and (ii) the low hardware complexity, which results in small area. By using the gated clock technique, significant reduction of the total multiplier power consumption is achieved.     

Response of Granular La1− xCaxMnO3 Film to 10 GHz and 35 GHz Frequency Electromagnetic Radiation

The nonbolometric response of La_1???xCa_xMnO₃ film to 10 GHz and 35 GHz frequency electromagnetic radiation is investigated in the case when, in addition to the strong electric field of the wave, the film is subjected to a stationary electric bias field. Dependences of responses on the radiation power P at temperature T = 80 K are presented. In the low power region, a linear dependence of the response on P is observed at both frequencies whereas for high powers the dependence behaves as ~P ^1/2. The obtained results are explained taking into account that the nonbolometric response originates from the intergranular junctions that operate in the reverse current regime. There two effects take place: (i) at low powers the detection resistance decreases with increasing power P, and (ii) at higher powers in addition to that the film resistance decreases as P ^1/2 due to the avalanche of charge carriers in the electric field of the electromagnetic wave.     

An analytic model to estimate the avalanche breakdown voltage improvement for LDD devices

An analytic model is presented to estimate the avalanche breakdown voltage improvement for various lightly doped source-drain (LDD) structures. In this model, the voltage drop across the lightly doped drain region is assumed to be responsible for breakdown voltage improvement. The voltage drop is calculated by assuming a two-dimensional potential distribution in the rectangular section of the n^? region. This section is treated as a volume obeying Gauss' law, thereby enabling the mobile and immobile charges contained in it to be related to the electric fields normal to its surface without considering the detailed distribution of the charges inside. The calculated results agree well with experimental and two-dimensional simulation data for a wide range of processing parameters.     

任意信源数和认证符数的Cartesian认证码的构造(Ⅱ)

对于任意两个相互无关的参数k,n,该文提出了一种基于正交排列的迭代方法,并以该方法为主构造了一类信源数目为k,认证符数目为n的Cartesian认证码。在信源和编码规则分布等概的条件下,敌方模仿攻击和替换攻击成功的概率均为1/n。在相同的k,n条件下,与已知的笛卡儿积构造法相比,迭代法所构造的Cartesian认证码的编码规则数目更少。     

Size dependence saturation and absorption of PbS quantum dots

The saturation intensity for lead sulfide quantum dots in a titanium dioxide-glycerol matrix (PbS/TiO₂-glycerol) on a glass substrate has been studied as a function of quantum cluster concentration and cluster size. The saturation intensity in these materials is strongly dependent on the size of the semiconductor nanocrystals, their concentration, or the sample thickness. The samples are reflective at a certain range of the incoming intensity of the optical field and become transparent over a threshold intensity beyond which the output and input intensities are linearly related. The system studied involves very dilute distribution of PbS QD of dimension∼10 nm embedded in a matrix of TiO₂-glycerol. Since the distribution is relatively constant in each deposited layer, the total number of QDs in a given area is proportional to the thickness. We found that the threshold of power separating absorption-bleaching, Pth is linearly related to the thickness, with values of Pth ∼few mW/cm², more than 2-3 orders of magnitude below that of QDs with dimension∼1 μm, representing a typical solid.     

The distribution functions for the linear complexity of periodic sequences

Linear complexity is an important standard to scale the randomicity of stream ciphers. The distribution function of a sequence complexity measure gives the function expression for the number of sequences with a given complexity measure value. In this paper, we mainly determine the distribution function of sequences with period N =2n ^l = over F _q using Discrete Fourier Transform (DFT), where n and the characteristics of F _q are odd primes, gcd (n, q) = 1 and q is a primitive root modulo 2n ^l . The results presented can be used to study the randomness of periodic sequences and the analysis and design of stream cipher.     

InGaAsSb(Gd)/InAsSbP double heterostructure lasers (λ=3.0–3.3 µm) for diode laser spectroscopy

Data on threshold currents, the differential quantum efficiency, the emission spectrum, current tuning, and radiation power of mesastripe InGaAsSb(Gd)/InAsSbP double heterostructure lasers with λ=3.0–3.3 µm and a cavity length of 70–150 µm in a temperature range of 50–107 K are reported. In the experiments, the threshold currents I _th<10 mA, a total output power of 0.5 mW/facet, and a single-mode power of 0.43 mW at 77 K in the cw regime were obtained. Lasers operated in the single-mode regime at currents I≤6I _th, the spectral purity was as high as 650: 1, the tuning rate was 210 cm^?1/A, and the tuning range was 10 cm^?1 wide. An example of methane detection at 3028.75 cm^?1 is presented.     

A silicon-on-insulator metal–semiconductor field-effect transistor with an L-shaped buried oxide for high output-power density

We describe a novel silicon-on-insulator metal–semiconductor field-effect transistor with an L-shaped buried oxide (LB-SOI MESFET) and its maximum output power density (P_max). To optimize the surface electric field and improve the breakdown voltage, we eliminated part of the oxide and replaced it with n-type silicon. By creating an n⁺–n region on the source side and modifying the electric field distribution, the breakdown voltage improved by 42% compared to a conventional device. Channel control is realized by varying the depletion layer width underneath the metal gate contact. This modulates the thickness of the conducting channel and thus controls the current between the source and the drain. Continuation of the n-type silicon on top of the buried oxide after the gate metal changes the depletion layer and increases the total channel charge for conduction, so the drain current increases by a factor of five compared to a conventional SOI MESFET. In addition, P_max is increased by a factor of 17.7 with respect to a conventional structure, which is important for large-signal analog applications. Consequently, our novel LB-SOI MESFET has superior electrical characteristics.     

Large-signal analysis of the silicon pnp-BARITT diode

A numerical large-signal analysis of the silicon pnp BARITT diode is presented. This extends previous works to practical device structures. The diode admittance, power generation density, efficiency and quality factor are studied as functions of oscillation amplitude, frequency and bias current density. The results are found to be in substantial agreement with large-signal experimental measurements. A typical pnp structure optimised for operation at 10 GHz has an active region doping density of 2 × 10¹⁵/cm³, a width of 5.5 μm and a punch-through voltage of 40 V. Negative resistance occurs over the frequency range from about 8 GHz to about 14 GHz. The device Q at 10 GHz varies from a small-signal value of about ?10 to a large-signal value of about ?100. The conversion efficiency at 10 GHz is about 5% at a bias current density of 25 A/cm² and falls to about 2% at 200 A/cm². Maximum r.f. power output occurs at an r.f. amplitude of about 15 V and rises with bias current density to a maximum value of about 170 W/cm² at 200 A/cm².     

Two-electron tin centers formed in lead chalcogenides as a result of nuclear transmutations

It is shown that the emission [^119mmSn(^119mSn)] and absorption (¹¹⁹Sn) Mössbauer spectra of impurity tin atoms in lead chalcogenides are identical. It is assumed that the mechanism of emergence of multi-charged tin ions as a result of conversion isomeric transition in the parent ^119mmSn atom is valid only for free atoms, whereas the final charge state of a stabilized daughter atom in condensed media with a high concentration of charge carriers is the charge state of the parent atom. The large value of recoil energy for ¹¹⁹Sb atoms after radioactive decay of parent ^119mTe atoms gives rise to a significant number of displaced ^119mSn atoms; however, a greater fraction of ^119mSn atoms after the ^119mTe → ¹¹⁹Sb → ^119mSn decay remains in the anionic sublattice and are antisite defects. In contrast to tin atoms in the cationic sublattice, the ^119mSn antisite defects are found to be electrically inactive centers.     

Power losses and optimum operation conditions of silicon quasi-Read diodes

Efficiency of x-band SD and DD silicon quasi-Read diodes as a function of modulation level are calculated taking into account the power losses in the unswept layer. It is found that the diode conductivity is the dominating factor in determining the power losses when operated in the small- to intermediate-modulation level, although the power losses increase with increasing r.f. voltage swing due to modulation ascending as well as mobility diminishing in this range of modulation. At large modulation condition, when the diode residual field is raised to such an extent that carrier drift velocity reaches its scattering limited value, the rapidly growing residual field results in serious losses independent of the material mobility. As a result, the optimum-modulation level falls in the intermediate-modulation region for each case. The optimum-modulation level almost remains unchanged when the bias is tripled from J_dc = 500 to 1500 A/cm² in most cases, while there are trade-offs in output power and efficiency when the bias current of the diode is increased. The best x-band DDSI quasi-Read diode we explored shows that the device is capable of an optimum efficiency η_m = 20.9% and output power P_m = 3.2 W at bias density J_dc = 500 A/cm² and an optimum modulation index m = 0.47.     

The nonlinear self-defocusing electromagnetic surface waves in a metalised ferrite film

The dispersion relations for TE s-polarized nonlinear electromagnetic surface waves guided by a metallised ferrite film, surrounded by a nonlinear self-defocusing dielectric cover with intensity dependent refractive indices have been computed. Numerical results are also illustrated to show the propagation characteristics for different values of the film thickness, and at a fixed value of the dielectric-ferrite interface nonlinearity. It has been found that the surface waves exist in both directions of propagation, where the external field is applied. The propagation of these waves is non-reciprocal, and has a resonant interaction in the reverse direction. The power flow carried by the structure has also been calculated for different values of the slab thickness. The non-reciprocity has also been obsorved, and the power flow level can been controlled by the film thickness. of semi-infinite gyromagnetic and nonlinear media². If we increase the operating frequency, the power flow level changes at a fixed film thickness, forβ ≥ 0 and forβ ≤0 as in Figs.4. There exist a limited eigenvalues (solutions) with f=17.8GHz forβ ≥ 0, and for different values of the operating frequency forβ ≤ 0. So the eigenvalues and the power flow level can be varied as the operating frequency is tunned. At f=17.8GHz forβ ≥ 0, as in fig.4b, to some value of the power flow there correspond two propagation wave index, which are being related to bistable states of nonlinear surface. All the above mentioned behaviours exhibit the characteristics of microwave switches, isolators, and limiters and could be used in some experimental applications in Microwave Engineering Technology. The other parameters effects as the magnetic field, magnetization, types of ferrite etc. on the dispersion characteristics and the power flow are now under consideration.     

Performance of 12-μm- to 15-μm-Pitch MWIR and LWIR HgCdTe FPAs at Elevated Temperatures

Infrared (IR) focal-plane arrays (FPAs) with higher operating temperatures and smaller pitches enable reduced size, weight, and power in infrared systems. We have characterized a large number of medium- and long-wavelength IR (MWIR and LWIR) FPAs as a function of temperature and cutoff wavelength to determine the impact of these parameters on their performance. The 77-K cutoff wavelength range for the MWIR arrays was 5.0 μm to 5.6 μm, and 8.6 μm to 11.3 μm for the LWIR. The dark currents in DRS’s high-density vertically integrated photodiode (HDVIP)^® FPAs (based on a front-side- illuminated, via-interconnected, cylindrical-geometry N+/N/P architecture) are dominated by Auger-7 recombination from 120 K to 200 K for the MWIR and 70 K to 100 K for the LWIR. In these temperature ranges the FPA operability is generally limited not by dark current defects but by noise defects. Pixels with high 1/f noise should produce a tail in the root-mean-square (rms) noise distribution. We have found that the skewness of the rms noise distribution is the simplest measure of an array’s 1/f noise, and that the rms noise skewness typically shows little variation over these temperature ranges. The temperature dependence of the defect counts in normal arrays (wet etched prior to CdTe interdiffusion) increases as n _i, while nonstandard arrays (ion milled or plasma etched prior to CdTe interdiffusion) can have high 1/f noise and defect counts that vary as n _i ² . Our models indicate that, if the dominant dark current is due to diffusion, then the 1/f noise varies as n _i ² , whereas if depletion current dominates, then the 1/f noise varies as n _i. Systemic 1/f noise is not an issue for DRS’s standard MWIR FPAs at 110 K to 160 K, or for standard LWIR FPAs at 77 K to 100 K.     

Temperature and Voltage Offsets in High-<Emphasis Type="Italic">ZT</Emphasis> Thermoelectrics

Thermodynamic temperature can take on different meanings. Kinetic temperature is an expectation value and a function of the kinetic energy distribution. Statistical temperature is a parameter of the distribution. Kinetic temperature and statistical temperature, identical in Maxwell–Boltzmann statistics, can differ in other statistics such as those of Fermi–Dirac or Bose–Einstein when a field is present. Thermal equilibrium corresponds to zero statistical temperature gradient, not zero kinetic temperature gradient. Since heat carriers in thermoelectrics are fermions, the difference between these two temperatures may explain voltage and temperature offsets observed during meticulous Seebeck measurements in which the temperature–voltage curve does not go through the origin. In conventional semiconductors, temperature offsets produced by fermionic electrical carriers are not observable because they are shorted by heat phonons in the lattice. In high-ZT materials, however, these offsets have been detected but attributed to faulty laboratory procedures. Additional supporting evidence for spontaneous voltages and temperature gradients includes data collected in epistatic experiments and in the plasma Q-machine. Device fabrication guidelines for testing the hypothesis are suggested including using unipolar junctions stacked in a superlattice, alternating n/n ⁺ and p/p ⁺ junctions, selecting appropriate dimensions, doping, and loading.     

Dynamic characteristics of double-barrier nanostructures with asymmetric barriers of finite height and widths in a strong ac electric field

The theory of the interaction of a monoenergetic flow of injected electrons with a strong high-frequency ac electric field in resonant-tunneling diode (RTD) structures with asymmetric barriers of finite height and width is generalized. In the quasi-classical approximation, electron wavefunctions and tunneling functions in the quantum well and barriers are found. Analytical expressions for polarization currents in RTDs are derived in both the general case and in a number of limiting cases. It is shown that the polarization currents and radiation power in RTDs with asymmetric barriers strongly depend on the ratio of the probabilities of electron tunneling through the emitter and collector barriers. In the quantum mode, when δ = ? ? ? _r = ?ω ? Γ (? is the energy of electrons injected in the RTD, ? is Planck’s constant, ω is the ac field frequency, ? _r and Γ are the energy and width of the resonance level, respectively), the active polarization current in a field of E ≈ 2.8?ω/ea (e is the electron charge and a is the quantum-well width) reaches a maximum equal in magnitude to 84% of the direct resonant current, if the probability of electron tunneling through the emitter barrier is much higher than that through the collector barrier. The radiation-generation power at frequencies of ω = 10¹²–10¹³ s^?1 can reach 10⁵–10⁶ W/cm² in this case.     

Battery level A/D conversion with fuel gauge sense voltage cancellation in 40 nm CMOS technology

A new integrated approach for battery voltage conversion inside portable devices is presented. It is specifically suited for latest Fuel Gauge techniques and exploits an A/D converter that operates as a General Purpose ADC inside the system. A peculiar solution for an analog cancellation of the Coulomb counter sense resistor voltage drop on the battery level measurement is disclosed. A prototype made by this battery voltage buffer and a 10-bit A/D converter has been integrated in a 40 nm CMOS process with double oxide option, resulting to a total power consumption of about 950 μW, and an active area of 0.174 mm².     

An Analytical Approach to Outage Analysis and Critical Cooperation Ratio in Coded Cooperation

In this paper, we analyze the performance of a coded cooperation based communication system using independent flat Nakagami-m fading channels. We examine the outage behavior of the cooperative system constrained on instantaneous received power which follows the Gamma distribution. The expression for outage probability of the coded cooperative communication system is derived which is applicable for arbitrary value of parameter m and contains single integral terms only. Finally, we present an analytical approach to evaluate the critical cooperation ratio that minimizes the total outage probability of the cooperative system.     

Modified drift field model for high-low transition in solar cells

A theoretical discussion is presented for the understanding of the back surface pp⁺ transition used in solar cells. It is shown that quasi-neutrality of space charge is a good approximation if the back surface diffusion is fairly deep. The error involved in the drift field model developed by assuming a quasi-neutrality of the space charge is compared with that inherent in the abrupt high-low junction model. The analysis shows that the back surface boundary, when measured from the heavily doped p⁺ side, effectively exists at a distance much larger than the impurity diffusion depth and the recombination current in the base is always less than its value estimated from the abrupt junction model. The voltage in the pp⁺ transition is due to the change in electric field by the excess carriers injected by light and drops across those regions of the cell where the injected carrier density is appreciable.     

A new kind of compound solid-state quasi-optical power combiner

In this paper, a new kind of solid-state quasi-optical power combiner is presented. It consists of two or more singlecavity multiple-device power combiners and a Fabry-Perot cavity. The experimenal results using six Gunn diodes at X-band show that the total output power is higher than 400 mW, the total combining efficiency is as high as 83%, and the frequency stability is better than 10^?5.