摘要:

AbstractThis paper discusses the design and characteristics of power combining and power dividing‐combining by means of traveling‐wave power divider/combiners using waveguides. First, the perfect power combining condition is given when the divider/combiner is used as a single power combiner. From the numerical analysis based on the equivalent circuit, it is shown that a highly efficient power combining is possible over a very broad frequency range. It is shown also that the degradation of the combining efficiency with respect to the deviation of the input amplitudes and phases from the designed values is small.For a power dividing‐combining system using two identical power divider/combiners, it is shown that a broadband characteristic can be obtained, the bandwidth increases with a number of branches, and the performance degradation by failure of one of the devices in the unit amplifiers can be kept minimum by appropriate choices of the device location. Further, the four‐ and six‐way power dividing‐combining experiment has been carried out at X‐band. The validity of the theory was confirmed. In the six‐way power dividing‐combining, a broadband characteristic was realized as evidenced by the bandwidth of 2.87 GHz with a combining efficiency of more than −0.5 dB and of 3.90 GHz with a return loss

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790501

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

年代:1996

数据来源: WILEY

摘要:

AbstractThe optical absorption mechanism of a semiconductor optical modulator with electron‐depletion absorption control was theoretically and experimentally investigated. In the doped direct transition semiconductor material, optical absorption increased when electrons were depleted. In the region where electrons are depleted, the number of electrons in the conduction band and holes in the valence band decrease, the impurity energy level shifts due to the decrease of the screening effect and the internal electric field strength increases. Because of these phenomena, the band‐to‐band electron transition probability increases. As a result, the optical absorption increases in the modu

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790502

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

年代:1996

数据来源: WILEY

摘要:

AbstractThis paper describes the design, fabrication, and performance of wideband monolithic lossy match power amplifiers employing prematching circuits, which make the frequency‐dependence of input and output impedance of FETs small. First, it is shown theoretically that a wide bandwidth can be achieved by using prematching circuits in the design of lossy match power amplifiers. Second, a novel constant‐resistance network and a parallel resonant circuit are proposed as prematching circuits. Impedance matching methods using prematching circuits are also described. Finally, by employing these prematching circuits in the design and fabrication of a C∼K band‐power amplifier, it is experimentally shown that the impedance matching methods using prematching circuits are useful in the design of wideband lossy match power amplifiers. The amplifier exhibits a linear gain of 10 ± 2.3 dB, a saturated power of 28.3 ± 1 dBm, and a drain efficiency of 12.6 ± 2.2 percent over 5∼21 GHz. These measured performances are in good agreement with the calculated results. The prematching circuits, which make the frequency‐dependence of input and output impedance of FETs small, are useful for achieving a wide bandwidth of lossy match power amplifiers. In addition, the parallel resonant circuit, which comprises only reactive elements, is also useful in the design of output matching circuits for achieving high gain

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790503

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

年代:1996

数据来源: WILEY

摘要:

AbstractIn this paper, voltage controlled self‐temperature compensated oscillators made with NS‐GT cut quartz resonators (VC‐S‐TCXOs in what follows) are introduced and their frequency stability (obtained by controlling input voltage to VC‐S‐TCXO) is discussed. An oscillator circuit consists of a CMOS inverter, a variable capacitor diode, resistors, and capacitors. The primary oscillator frequency of the coupled quartz resonator is first derived from the electric equivalent circuit of the oscillator. The oscillator frequency is given by a function of the coupling coefficient, which in turn is given as a function of the load capacitanceCL. Since frequency stability by controlling the input voltage to VC‐S‐TCXO is dictated by the VC circuit, the VC circuit was investigated in detail in order for the circuit independent of temperature to be obtained. Using the VC circuit, the oscillator frequency was controlled by the input voltage and the temperature stability of the oscillator frequency was less than 4 × 10−9at a temperature range of ‐30 to 85 °C. Furthermore, it has been demonstrated experimentally that the frequency stability of the VC‐S‐TCXO directly after voltage control does not depend on the frequency temperature characteristics of the quartz resonator, time interval between the voltage control, or r

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790504

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

年代:1996

数据来源: WILEY

摘要:

AbstractIn the analysis of a general linear system including the electromagnetic wave transmission systems, it is often necessary to derive system functions such as the immittance function and the transfer function from the frequency characteristics. In solving these problems, it is possible to use the Herglotz‐Cauer theorem for the immittance function and Hosono's theorem for the transfer function. In these theorems, it is necessary to calculate integrals on the frequency when the system function is derived. There are a limited number of cases that can be solved analytically. However, when Hosono's theorem is combined with the fast inversion of Laplace transform (FILT), it is predicted that such a combination is a powerful tool for analyzing the transient phenomena of the electromagnetic wave propagating in plasma, waveguides, and optical fibers. To confirm such a prediction, the transient phenomena of the electromagnetic wave propagating in a plasma were analyzed as an example so that the effectiveness was supporte

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790505

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

年代:1996

数据来源: WILEY

摘要:

AbstractThe authors have been studying the double‐tubed coaxial line‐type microwave plasma chemical vapor deposition (MPCVD). The discharge tube of the present MPCVD is a dual‐tube structure made of a fused quartz outer discharge tube and stainless steel inner tube. The authors have discovered that the ion bombardment energy can be controlled without varying the electron densities and temperature by changing the potential of the substrate placed in a spatial after‐glow plasma. In the present research, it is found that the ion bombardment energy can also be controlled by changing the potential of the inner tube placed in the discharge plasma. However, the electron densities and temperature have exhibited a tendency different from the one when the substrate potential is varied. Hence, a theoretical calculation has been carried out on the electron densities and temperature based on Maxwell‐Boltzmann distribution. It is found that a different tendency can be explained from the fact that the electrons successively vanish on the deposition chamber wall from the higher‐energy side as the plasma spatial potential is reduced from about 13 V to 4 V so that the electron velocity distribution

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790506

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

年代:1996

数据来源: WILEY

摘要:

AbstractTo analyze the light scattered from a magneto‐optical disk, a method is proposed for calculating the light scattered from a magnetic material with grooves. The model used is divided by an infinite boundary between the free space or an isotropic dielectric and an isotropic magnetic material. By using the relative permittivity of the isotropic magnetic materiel, the governing equation for the magnetic material is derived from Maxwell's equations. The three‐dimensional boundary element method is applied to this equation. The boundary element equation for free space or an isotropic dielectric material is the one in which the boundary element method is applied to a general Helmholtz equation. The one in the magnetic material is obtained by adding the volume integral in the magnetic material to the general equation. If boundary elements are large, the integral in the magnetic material near the boundary is evaluated at too small a value. The numerical results oscillate with only the foregoing method. To resolve this problem with taking practical memory size and computation time into consideration, an attenuating term is added to Green's function used in the integration in the magnetic material. With the method proposed, the optical scattering from a magnetic material can now be analy

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790507

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

年代:1996

数据来源: WILEY

摘要:

AbstractSRAMs and ROMs are installed on high‐performance ASICs as the memory macrocells. This paper discusses the design of mask ROMs as the macrocells from the viewpoint of the high‐speed and low‐power dissipation. NOR‐type memory cell array configuration is adopted, and the memory content is set using the LSI mask for contact process. A memory cell programming method is proposed where the source of the MOS transistor and the GND line are connected or disconnected according to the memory content. In this method, the adjacent colls can share the contact area to a bit‐line. This helps to reduce the p‐n junction capacitance, which dominates the parasitic capacitance of the bit‐line, to be halved. Using a reference voltage generator, the bit‐line is controlled close to GND level, which improves the detection sensitivity of the current‐mirror sense amplifiers. The small‐amplitude operation of the bit‐lines is realized and the access time is reduced. As a technique to reduce the power dissipation, the virtual GND lines are introduced, which are controlled by the column address signals. The lines are controlled to the floating state in the stand‐by mode so that the dynamic power dissipation is reduced. A test chip was designed and fabricated by a 0.5‐μm CMOS process, and the address access time of 7.2 ns was obtained for the 4

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790508

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

年代:1996

数据来源: WILEY

摘要:

AbstractBarrier layerless submicron damascene interconnection has been realized by using a combination of novel aluminum chemical vapor deposition (AI‐CVD) and chemical mechanical polishing (CMP) techniques. A new nucleation method with tetrakis‐dimethyl‐amino titanium (TDMAT) gas pretreatment has enabled AI‐CVD to fill trenches without using a barrier layer which causes high resistivity. As a result, this technology achieved Al damascene interconnections with resistance as low as 600 ω/cm with half‐micron wide line and an aspect ratio of 3. This line resistance is one‐third of that for a conventional reactive ion‐etched Al line with an asp

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790509

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

年代:1996

数据来源: WILEY

摘要:

AbstractA new method is proposed to compensate for chromatic dispersion and self‐phase modulation in a transmission fiber with a loss using optical phase conjugate (OPC). The ratio of the optical Kerr effect and the dispersion was designed to be equal at each position before and after the OPC. The pulse shape is precompensated before OPC by transmission through a fiber with large dispersion whereas the transmission line consists of an optical amplifier repeated fiber link with a small dispersion. A computer simulation demonstrates effective compensation for waveform distortion in a 40‐Gb/s no‐return‐to‐zero (NRZ) intensity‐modulated light transmission. The method will be effectively applied to both wavelength demultiplexing method (WDM) systems and long‐haul transmi

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790510

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

年代:1996

数据来源: WILEY