摘要:

AbstractVery high sensitivities can easily be achieved in optical fiber interference‐type sensors which are also sensitive to such external disturbances as low‐frequency phase changes of interference‐light, oscillations getting into the optical system in the form of frequency fluctuations, etc. To realize stable measurements, it is very important to suppress these effects.This paper investigates the second‐order optical phase‐locked loop (OPLL) developed to suppress such fluctuations due to external disturbances and treats an optical vibration sensor as an example. By introducing small‐amplitude phase variations into the interfering lights, a new detection method is adopted to investigate the effects of external disturbances. It can suitably be applied to fiber‐transmission type sensors to which it was difficult to apply the previous differential detection methods for the purpose of compensating external disturbances. The OPLL remains locked in at about 50‐Hz frequency pulling range and can suppress frequency and phase variations caused by external disturbances having frequency components o

ISSN:8756-663X    

DOI:10.1002/ecjb.4420741101

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractThe major angle corner reflector antenna is characterized by a large half‐power value width in the magnetic plane and a large front‐to‐back ratio. This antenna is considered a candidate for the fixed‐state antenna for radio communication within a limited space being studied by the authors. The analysis of radiation patterns of antennas of this type traditionally has been carried out by the induced electromotive force (EMF) method. In such calculations, the errors in the sidelobes have been substantial.In the analysis of the radiation pattern in this paper, the corner diffraction formula derived previously and the approximate corner diffraction formula for a hollow wedge corner which is newly derived by an asymptotic calculation from the equivalent edge electric and magnetic currents in the UTD are included in the application of the GTD (Geometric Theory of Diffraction). It is shown that by this approach an accurate analysis can be performed in both the E‐ and H‐planes. It is confirmed that the results by the GTD, by the MM (moment method), and by the experiments

ISSN:8756-663X    

DOI:10.1002/ecjb.4420741102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractRecently, malfunctions by crosstalk between signal lines have become a problem in an electronic circuit which has been more densely organized and handles signals at higher frequencies. To prevent malfunctions due to these noises, it is important to find the relationship of the crosstalk with the materials and structures of the circuit board. Especially, as the density is increased, the use of multilayered configuration is increased so that the understanding of the crosstalk between interconnects arranged in a three‐dimensional fashion is increasingly more important.Usually, the analysis of crosstalk has been carried out by means of the equivalent circuit analysis. It is not easy to adjust the number of discretizations and the analysis between the three‐dimensional (3‐D) interconnects.In reference to the foregoing, this paper describes a crosstalk analysis between parallel microstrips by means of the finite‐difference time‐domain (FD‐TD) method which, among the 3‐D electromagnetic field analysis methods, requires small memory and computational time. Good agreement is confirmed between the thoretical and experimental results on the crosstalk waveforms and the crosstalk coefficient. Hence, the effectiveness of the FD‐TD method for the crosstalk analysis has been confirmed. It is believed that the FD‐TD method is extremely effective for analysis in t

ISSN:8756-663X    

DOI:10.1002/ecjb.4420741103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractNew integral equations are introduced in which the transverse electromagnetic field components are unknown for the two‐dimensional (2‐D) electromagnetic scattering problems and electromagnetic waveguide problems. A numerical analysis by the boundary element method is proposed. The conventional integral equations in which the longitudinal electromagnetic field components are unknown are difficult to determine at certain angular frequencies and at certain longitudinal propagation constants for the electromagnetic scattering problem. In the waveguide problem, the spurious modes may enter as nonphysical solutions.The integral equations proposed in this paper do not have conventional difficulties. Here, the integral equations using the transverse electromagnetic fields are derived and the uniqueness of the solution is proven. Further, for practical examples, the integral equations are analyzed numerically by the boundary element methods so that the validity and effectiveness are investiga

ISSN:8756-663X    

DOI:10.1002/ecjb.4420741104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractThe beam propagation method proposed by Feit and Fleck is a powerful method for analyzing optical circuits. However, in this method, only the incident wave in the circuit is assumed and the Helmholtz equation is replaced with an approximate equation. Hence, it is not possible to compute the magnitude of the reflected wave. Even in the absence of the reflected wave, it is not possible to compute the incident wave accurately.To improve these deficiencies, this paper uses the Helmholtz equation directly instead of modifying it to an approximate form. The problem of instability is resolved by a certain restriction on the solution. Therefore, the reflected wave can also be analyzed with the incident wave.The method in this paper provides a solution more accurate than the conventional beam propagation method, even if there is no reflected wave present. The present method is applied to a tapered section of a dielectric slab waveguide and the radiation loss and the magnitude of the reflected wave are obtained numerically. It is shown that the magnitude of the reflected wave is negligibly small. The accuracy of the solution by the present method is discussed.

ISSN:8756-663X    

DOI:10.1002/ecjb.4420741105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractAC hot‐carrier degradation due to gate‐induced noise has been clarified, and a method to suppress noise and to predict ac lifetime is proposed. There have been many arguments on the ac degradation mechanism. This is because the degradation acceleration factor due to the measurement noise was not separated and caused confusion. In particular, the noise generated on the source‐drain electrodes during the gate pulse rise has been found to be an important factor in ac degradation acceleration.The noise is an inductive noise generated by the rapid change in channel current during gate on and off amplified by an inductance due to the source and drain interconnects. If the noise is suppressed, at least for the rise time of more than 10 ns, the carrier trapping and detrapping accompanied by the ac operation can be ignored, and the lifetime can be predicted by the dc hot‐carrier degradation lifetime and the duty cycle.In the future, attention must be given to the ac degradation acceleration due to the increase in the inductive noise by the interconnect scaling. Thus, an interconnect design rule based on the suppression of the source‐drain induced noise is

ISSN:8756-663X    

DOI:10.1002/ecjb.4420741106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractThe overwrite characteristic of an InPbTe phase‐change optical disk is investigated. It is found that the overwritable repetition number of the disk is dependent on the interface structure and adhesion strength between the reflective layer and dielectric layer. To realize optimum thermal conduction and optical characteristics for overwrite, an Mo/Au multilayer reflective structure was developed which has reflectivity and thermal conductivity comparable with those of an Au film. After improving the adhesion strength of the multilayer film to the ZnS‐SiO2dielectric film, the overwritable repetition number for 10−5BER increased from 105to 5

ISSN:8756-663X    

DOI:10.1002/ecjb.4420741107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractTo adequately demonstrate the parallel distributed processing and self‐learning capabilities of neural networks, a realization in hardware is the most appropriate approach. Therefore, a pulse‐density type neuron model was proposed in view of its ease of implementation in hardware. In this model, symbols are transmitted as streams of pulses, and symbol values are represented by the pulse densities. In addition, symbol calculations are all done digitally. An algorithm was developed which enables learning by backpropagation in layered networks, and the efficacy of the proposed neuron model was established through a software simulation. Next, a hardware neuron is constructed on a digital circuit board and its feedforward and learning processes as well as its error backpropagation capability are demonstrated. Using this board, a prototype hardware neural network was constructed which does not require any software and which performed handwritten digit recognition and learning. Finally, this neuron board capabilities were integrated in LSI using a gate array. The possibility of its use in implementing future large‐scale networks is disc

ISSN:8756-663X    

DOI:10.1002/ecjb.4420741108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractPhotofabrication developed for integrated circuits can be used to fabricate sensors with three‐dimensional structures and devices with many other types of structures. The micromachining technology is useful in forming a small‐sized, high‐performance sensor system. Using this technology, it is possible to form a system with a sensor, actuator, and electronic circuit on a silicon wafer.A thermo‐flow sensor was fabricated with two microheaters to detect small gas flow. It was found that this device was sensitive to detect an extremely low gas flow with high linearity. This flow sensor was used for an integrated mass‐flow controller and as an integrated magnetic oxygen sensor.An integrated capacitive pressure sensor also was developed with a capacitive detection circuit. The new feed‐through structure used for this sensor was used for other integrated sensors such as a tac

ISSN:8756-663X    

DOI:10.1002/ecjb.4420741109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractA surface plasmon is a charge density wave propagating along the interface between a metal on dielectric medium. Since the energy is concentrated at the interface, sensors that utilize the surface plasmon are extremely sensitive to both the charges in the dielectric properties and the geometry of the interface.A surface plasmon immunosensor to detect antibody and antigen immunoresponse has been developed. Here the sensitivity of the sensor is theoretically investigated and the experimental results of sensor sensitivity, the real‐time measurements and the problem of repeated utilization of the sensors are evaluated using α‐Feto‐protein (α‐FP) and goat IgG. In addition, the problem of deciding whether to use antibody or antigen as immobilized sensing medium is discussed based on the characteristics of surface plasmon and biomolecules. As a result, it is concluded that with an antigen immobilized sensor, the sensitivity is higher and the real‐time response can

ISSN:8756-663X    

DOI:10.1002/ecjb.4420741110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY