The authors propose a multiple shaped beam antenna which uses a single shaped reflector and simple feeds. This new type of multibeam antenna is very attractive for satellite communications and broadcasting because its beam-forming network is much simpler than conventional multibeam reflector antennas which uses cluster feeds. The design method for shaping the reflector surface is described, which is based on the concept of an equivalent array. By using this method, a design example is shown, in which the Japanese main islands are covered with four beams and twofold frequency reuse is operated. Also, the basic performance of this new antenna is clarified numerically.

Conical beam pattern is well suited for low mobile or maritime mobile antennas used in cheap and low G/T satellite communication system. Various solutions have been already proposed to generate circular polarized conical patterns; some authors use single microstrip patch working on higher order modes [1], [2], while others have built arrays of patches [3]-[5]. The present letter describes the design of an array of slot fed patches with its feed network and the experimental results which have been obtained in S-band.

The beam propagation method (BPM) is a powerful and manageable method for the analysis of wave propagation along weakly guiding optical waveguides. However, the effects of reflected waves are not considered in the original BPM. In this paper, we propose two simple modifications of the BPM to make it relevant in characterizing abrupt discontinuities in weakly guiding waveguides at which a significant amount of reflection is expected to be observed. Validity of the present modifications is confirmed by the numerical results for abrupt discontinuities in step-index slab waveguides and butt-joints between different slab waveguides.

The finite-difference beam-propagation method is applied to the analysis of hollow slab waveguides (HSWs). The attenuation constants for the TE0 and TE1 modes are evaluated and compared with those obtained by the perturbation theory. The propagating field and differential power loss in the transition from a straight HSW to a bent HSW are revealed and discussed.

The characteristics of an open-boundary Cherenkov laser for an electromagnetic wave with a continuous frequency spectrum are numerically analyzed. A given power spectral density for the input wave is found to get concentrated around the frequency where the spatial growth rate is maximum, as it grows along the electron beam. In addition, the frequency for the maximum growth rate is found to shift gradually to higher values. Furthermore, by gradually increasing the permittivity of the dielectric waveguide along it, we can always get the maximum power spectral density at the frequency where the spatial growth rate initially becomes maximum at the input.

A multi-beam airborne pulsed-Doppler radar (MBR) system is presented and its clutter rejection performance compared with conventional phased array radar (PAR)'s by PRF tuning is discussed. The pulsed-Doppler radar equations taking account of the multi-beam operation are introduced and some kinds of computer simulations for seeking the conditions to get maximum signal to clutter ratio are carried out. As a results of this, it is cleared that same order of signal to clutter ratio improvement gotten in high PRF operation by conventional PAR can be realized at lower PRF operation by MBR on clutter free area, and higher clutter rejection effect, which is proportional to beam numbers, is obtained under affection of both of mainlobe and sidelobe clutters with order of beam numbers. This also means observable numbers of range bin are increased in MBR operation.

This paper describes IC-oriented high-performance AlGaAs/GaAs heterojunction bipolar transistors that were fabricated to demonstrate their great potential in applications to high-speed integrated circuits. A collector structure of ballistic collection transistors with a launcher (LBCTs) shortens the intrinsic delay time of the transistors. A novel and simple self-aligned fabrication process, which features an base-metal-overlaid structure (BMO), reduces emitter- and base-resistances and collector capacitance. The combination of the thin-collector LBCT layer structure and the BMO self-alignment technology raises the average value of cutoff frequency, fT, to 160 GHz with a standard deviation as small as 4.3 GHz. By modifying collector thickness and using Pt/Ti/Pt/Au as the base ohmic contact metal in BMO-LBCTs, the maximum oscillation frequency, fmax, reaches 148 GHz with a 114 GHz fT. A 2:1 multiplexer with retiming D-type flip-flops (DFFs) at input/output stages fabricated on a wafer with the thin-collector LBCT structure operates at 19 Gbit/s. A monolithic preamplifier fabricated on the same wafer has a transimpedance of 52 dBΩ with a 3-dB-down bandwidth of 18.5 GHz and a gain S21 OF 21 dB with a 3-dB-down bandwidth of 19 GHz. Finally, a 40 Gbit/s selector IC and a 50 GHz dynamic frequency divider that were successfully fabricated using the 148-GHz fmax technologies are described.

Bi2Sr2CuOx (Bi(2201)) thin films have been fabricated by atomic layer-by-layer deposition using ion beam sputtering (IBS) method. During the deposition, 14 wt%-ozone/oxygen mixture gas of typical pressure of 5.010-5 Torr is supplied with ultraviolet light irradiation for oxidation. XRD and RHEED investigations reveal that a buffer layer with compositions different from Bi(2201) is formed at the early deposition stage of less than 10 units cell and then Bi(2201) oriented along the c-axis is grown.

The beam propagation method (BPM) is a powerful and manageable method for the analysis of wave propagation along weakly guiding optical waveguides. However, the effects of reflected waves are not considered in the original BPM. In this paper, we propose two simple modifications of the BPM to make it relevant in characterizing waveguide discontinuities at which a significant amount of reflection is expected to be observed. Validity of the present modifications is confirmed by the numerical results for the slab waveguide discontinuities and the butt-joints between different slab waveguides which either support the dominant mode or higher order modes.

Power transmission properties are investigated for a butt-joint which contains an air gap between an isotropic planar waveguide and an anisotropic one whose optical axis is lying in the plane defined by the propagation axis and the normal of the waveguide surface. New transmission coefficients are introduced for estimating the optical-power which is launched out into the gap from the incoming waveguide. Wave propagation through the gap is analyzed on the basis of the BPM concept. And the power transmitted across the interface between the gap and the outgoing waveguide is evaluated by means of the overlap integral of the field profiles. The effects of the air gap and the refractive index of filling liquid as well as axial displacement and angular misalignment are discussed on the basis of numerical results.

Digital neural networks are suitable for WSI implementation because their noise immunity is high, they have a fault tolerant structure, and the use of bus architecture can reduce the number of interconnections between neurons. To investigate the feasibility of WSIs, we integrated either 576 conventional neurons or 288 self-learning neurons on a 5-inch wafer, by using 0.8-µm CMOS technology and three metal layers. We also developed a new electron-beam direct-writing technology which enables easier fabrication of VLSI chips and wafer-level interconnections. We fabricated 288 self-learning neuron WSIs having as many as 230 good neurons.

To speed up a guided-probe diagnosis process, the number of probed lines needs to be reduced. This paper presents two efficient probing line determination methods by which the number of probed lines is either small or minimum. The concept of fault probability is introduced to reflect the fact that not all gates have the same probability to be faulty. Experimental results show the effectiveness of the proposed methods.

Focused Ion Beam (FIB) trimming techniques for circuit optimization for GaAs MMICs by adjusting the parameters of IC components such as resistors, capacitors, microstrip lines, and FETs have been developed. The adjustment is performed by etching of the components and depositing of metal films for micro-strip lines. This technology turned out to be in need of only half a day to optimize the circuit pattern without any further wafer processes, while a conventional method that is comprised of revising mask pattern and following several cycles of wafer process has needed 0.5-1.0 year requiring huge amount of development cost. This technology has been successfully applied to optimization of an X-band low dissipation current single stage MMIC amplifier, and has shown its great feasibility for shortening the turn around time.

A new redundancy technique especially suitable for ultra-high-speed static RAMs (SRAMs) has been developed. This technique is based on a decoding-method that uses two kinds of fuses without introducing any additional delay time. One fuse is initially ON and can be turned OFF afterwards, if necessary, by a cutting process using a focused ion beam (FIB). The other is initially OFF and can be turned ON afterwards by a connecting process using laser chemical vapor deposition (L-CVD). This technique is applied to a 64 kbit SRAM having a 1.5-ns access time. The experimental results obtained through an SRAM chip repaired using this redundancy technique show that this technique does not introduce any increase in the access time and does not reduce the operational margin of the SRAM.

A glass precursor resist (GPR) is designed on the basis of an idea of conversion of organosilicon polymer to an inorganic substance by lithographic procedure. Developed chemical amplification resist system is composed of poly (di-t-butoxysiloxane) and a photoacid generator. It has a high sensitivity of 1.6 µC/cm2, a resolution of 0.2 µm and an extremely high O2-RIE durability compared with bottom resist. Exposed film changed into silicate glass, and it was confirmed by IR spectra.

This paper reviews the application of optical technologies to phased array antennas. The performance of the fibre transmission medium and of sources and detectors is reviewed, leading to simple expressions for transmission loss and noise performance. Both coherent and non-coherent beam forming techniques are considered. Future trends, including the use of optical amplifiers and coherent signal generation, will also be discussed.

Theoretical and experimental evaluations of the horizontal rotating and tilting of the base station antenna beam show that these techniques are effective in reducing delay spread. Result show good agreement between predicted and measured values.

Three custom LSIs for EB60, a direct wafer exposure electron beam system, have been developed using 0.8 µm BiCMOS and SST bipolar technologies. The three LSIs are i) a shot cycle control LSI for controlling each exposure cycle time, ii) a linear matrix computation LSI for coordinate modification of the exposure pattern data, and iii) a position calculation LSI for determining the precise position of the wafer. These LSIs allow the deflection corrector block of the revised EB60 to be realized on a single board. A new adaptive pipeline control technique which optimizes each shot period according to the exposure data is implemented in the shot-cycle control LSI. The position calculation LSI implements a new, highly effective 2-level pipeline exposure technique, the levels refer to major-field-deflection and minor-field-deflection. The linear-matrix computation LSI is designed not only for the EB60 but also for a wide variety of parallel digital processing applications.

Charges in buried oxide layers formed by wafer bonding were evaluated by capacitance-voltage (C-V) measurements. In this study, silicon-insulator-silicon (SIS) and metal-oxide-silicon (MOS) capacitors were fabricated on bonded wafers. For analyzing C-V curves of SIS structures, C-V simulation programs were developed. From the analysis, we conclude that approximately 2 1011/cm2 negative charges were distributed uniformly in the oxide. The effect of the experimental conditions during wafer bonding on generated charges in buried oxides is also discussed.

This is a partly expository paper discussing how point processes with certain "bursty" features can be qualitatively modelled by the Markovian arrival process, a generalization of the Poisson or Bernoulli processes which can be used to obtain algorithmically tractable matrix solutions to a variety of problems in probability models.