A rigorous analysis for a TM010 mode cylindrical cavity with insertion holes is presented on the basis of the Ritz-Galerkin method to realize accurate measurements of the complex permittivity of liquid. The effects of sample insertion holes, a dielectric tube, and air-gaps between a dielectric tube and sample insertion holes are taken into account in this analysis. The validity of this method is verified from measured results of some kinds of liquid.

A 2-dimensional cylindrical k-within-consecutive-(r, s)-out-of-(m, n):F system consists of m n components arranged on a cylindrical grid. Each of m circles has n components, and this system fails if and only if there exists a grid of size r s within which at least k components are failed. This system may be used into reliability models of "Feelers for measuring temperature on reaction chamber," "TFT Liquid Crystal Display system with 360 degree wide area" and others. In this paper, first, we propose an efficient algorithm for the reliability of a 2-dimensional cylindrical k-within-consecutive-(r, s)-out-of-(m, n):F system. The feature of this algorithm is calculating their system reliabilities with shorter computing time and smaller memory size than Akiba and Yamamoto. Next, we show some numerical examples so that our proposed algorithm is more effective than Akiba and Yamamoto for systems with large n.

In this paper, we proposed the doubly tapered electromagnetic periodic structure (DT-EPS) bandstop filters in coplanar waveguide (CPW) and cylindrical coplanar waveguide (CCPW). The DT-EPS bandstop filter not only can effectively improve the stopband rejection but also increase its bandwidth. In addition, this technique can significantly reduce the passband ripples compared with conventional case.

Brain subsystems have a high degree of information processing ability using nonlinear dynamics and although various neuron models and artificial neural networks have been investigated, the information processing functions of biological neural networks have not yet been clarified. Recently, various research efforts have confirmed that dendrites perform an important role in brain information processing. In this paper, we discuss the nonlinear characteristics of a hardware active dendrite model, in order to clarify information encoding and transmission via action potentials. That is to say, we show that our proposed model can reproduce the nonlinear characteristics of a biologically active dendrite. First, the hardware active dendrite model we propose is described. We next discuss the response characteristics for pulse stimuli using the model. As a result, when input pulses are applied to an active line, which is the basic structure of the dendrite model, it is shown clearly that backpropagation characteristics are acquired and that the characteristics are qualitatively in agreement with the characteristics of biological dendrites. Furthermore, we verify that the ratio of input to output frequency at the cell body is influenced by the backpropagation characteristics with two branches, which is the simplest structure in the active dendrite model. Thus, with backpropagation characteristics, the possibility that the model can carry out clearly the information processing of biological neural networks, is suggested.

It is known that Viterbi decoding based on the code trellis and syndrome decoding based on the syndrome trellis (i.e., error trellis) are equivalent. In this paper, we show that Scarce State Transition (SST) Viterbi decoding of convolutional codes is equivalent to syndrome decoding. First, we derive fundamental relations between the hard-decision input to the main decoder and the encoded data for the main decoder. Then using these relations, we show that the code trellis module for the main decoder in an SST Viterbi decoder can be reduced to a syndrome trellis module. This fact shows that SST Viterbi decoding based on the code trellis is equivalent to syndrome decoding based on the syndrome trellis. We also calculate the SST Viterbi decoding metrics for general convolutional codes assuming an AWGN channel model. It is shown that the derived metrics are equal to those of conventional Viterbi decoding. This fact shows that SST Viterbi decoding is equivalent to conventional Viterbi decoding, and consequently to syndrome decoding.

This paper presents the analysis of the impedance characteristics of a sectoral cylindrical cavity-backed axial slot antenna excited by a probe. The integral equations are derived based on boundary conditions of the proposed structure and they are expressed in terms of dyadic Green functions and unknown current densities. The dyadic Green functions are obtained by using the eigenfunction expansion method together with application of scattering superposition techniques. The unknown current densities are solved by the Method of Moments. The input impedance is subsequently determined from the unknown electric current density at the probe. Numerical results of input impedance and return loss are demonstrated as functions of frequency for various parameters such as cavity length, cavity radius ratio, slot location in φ direction, slot length and probe length. Calculated results are validated by the measurements. At the operating frequency, it is found that the result is sufficiently accurate. The results from this study are very useful for the design of a sectoral cylindrical cavity-backed axial slot array antenna excited by a probe with omnidirectional beam radiation.

In this paper, we propose a novel pulse-coupled neural network (PCNN) simulator using a programmable gate array (PGA) technique. The simulator is composed of modified phase-locked loops (PLLs) and a programmable gate array (PGA). The PLL, which is modified by the addition of multiple inputs and multiple feedbacks, works as a neuron. The PGA, which controls the network connection, works as nodes of dendritic trees. This simulator, which has 16 neurons and 32 32 network connections, is designed on a chip (4.73mm 4.73mm), and its basic operations such as synchronization, an oscillatory associative memory, and FM interactions are confirmed using circuit simulator SPICE.

The alternative c-means algorithm has recently been presented by Wu and Yang for robust clustering of data. In this letter, we analyze the convergence of this algorithm by transforming it into an equivalent form with the Legendre transform. It is shown that this algorithm converges to a local optimal solution from any starting point.

A large part of our daily lives is spent surrounded by buildings and other structures. In this paper, we used an infinitelength, multilayered cylindrical model to rigorously analyze the microwave specific absorption rate (SAR) of a human standing near a 90corner wall. At frequencies above 1 GHz, the interactions between the microwaves, the human body (including layer resonance), and the corner cause complex changes in the average SAR. We have shown numerically that the SAR with a corner present is up to four times larger than when there is no corner, and that the average SAR of TE waves at frequencies below 1 GHz is up to 10 times greater than when there is no corner.

The fields in the junctions between straight and curved rectangular waveguides are analyzed by using the method of separating variables. This method was succeeded because the authors developed the method of numerical calculation of the cylindrical functions of complex order. As a result, we numerically calculate the reflection and transmission coefficients in the junctions in various situations, and we compare these results with the results by the perturbation method and with the results by Jui-Pang et al.

This paper presents an iterative algorithm for decoding product codes based on syndrome decoding of component codes. This algorithm is devised to achieve an effective trade-off between error performance and decoding complexity. A simplified list decoding algorithm, which uses a modified syndrome decoding method, for linear block codes is devised to deliver soft outputs for iterative decoding of product codes. By adjusting the size of the list, the decoder can achieve a proper trade-off between decoding complexity and performance. Compared to the other iterative decoding algorithms for product codes, the proposed algorithm has lower complexity while offers at least the same performance, which is demonstrated by analyses and simulations. The proposed algorithm has been simulated for BPSK and 16-QAM modulations over both the additive white Gaussian noise (AWGN) and Raleigh fading channels. This paper also presents an efficient scheme for applying product codes and their punctured versions. This scheme can be implemented with variable packet size and channel data block.

An algorithm for augmenting a binary linear code is presented. The input to the code augmenting algorithm is (n,k,d) code C and the output is an (n,k*,d) augmented code C (k* k) satisfying C C and the Gilbert bound. The algorithm can be considered as an efficient implementation of the proof of Gilbert bound; for a given binary linear code C, the algorithm first finds a coset leader with the largest weight. If the weight of the coset leader is greater than or equal to the minimum distance of C, the coset leader is included to the basis of C.

In this paper, we show that a priori probabilities of information bits can be incorporated into metrics for syndrome decoding. Then it is confirmed that soft-in/soft-out decoding is also possible for syndrome decoding in the same way as for Viterbi decoding. The derived results again show that the two decoding algorithms are dual to each other.

A novel multiple-valued transfer gate (T-gate) consisting of multiple-junction surface tunnel transistors (MJSTTs) and hetero-junction FETs (HJFETs) was developed and its operation was confirmed by both simulation and experiment. The number of the devices required to form the T-gate can be drastically reduced because of the high functionality of the MJSTT; namely only three MJSTTs and three HJFETs are required to fabricate the three-valued T-gate. This number of transistors is less than half that of a conventional circuit. The fabricated circuit exhibited a basic T-gate operation with various logic functions. Furthermore, only one T-gate is needed to form a multiple-valued D-flip-flop (D-FF) circuit.

Theoretical and experimental aspects of GaN-based Gunn diodes are reviewed. Since the threshold field for Gunn effect in GaN (FTH>150 kV/cm) is reported to be much higher than in GaAs (FTH=3.5 kV/cm), the active layer of GaN-based devices can be made thinner (<3 µm) and doped higher (>1017 cm-3) than in conventional Gunn diodes. Consequently, GaN-based devices are expected to offer increased frequency and power capabilities. The advantages of GaN are demonstrated with the help of large-signal simulations of GaN and GaAs Gunn diodes. The simulations revealed that GaN diodes can be operated at a higher frequency (up to 760 GHz vs. 100 GHz) and with larger output power density (105 W/cm2 vs. 103 W/cm2) than GaAs diodes. Epitaxial layers of n+/n-/n+ GaN (1019 cm-3/1017 cm-3/1019 cm-3) designed for millimeter-wave operation were grown using MOCVD on SiC substrates. GaN Gunn diodes with 4 µm-thick active layers were fabricated using specially developed dry etching techniques. The RIE was optimized to allow deep low-damage etching and allowed reduction of contact resistivity of etched layers (RC10-6 Ωcm2). GaN diodes fabricated on SiC substrates with high thermal conductivity were tested on-wafer and demonstrated high voltage and current capability (60 V and 2.5 A). High frequency testing of these devices requires proper dicing, mounting on efficient heatsinks, and connection to appropriate oscillator cavities.

Sector antennas provide many advantages such as when combined with a narrow beam antenna, they become particularly effective in achieving high-speed wireless communication systems and they aid in simplifying the structure. These antennas have a drawback in that as the number of sectors increases, the antenna size rapidly increases. Therefore, downsizing the sector antenna has become a major research topic. A promising candidate is utilizing a phased-array type antenna; however, this antenna requires a phase-shifter circuit for beam scanning and generally the feeding circuit for this type of antenna is very complicated. To address these issues, we propose a self-selecting feeding circuit that is controlled by the same control circuit and is operated similarly to the conventional single port n-th throw (SPNT) switch. We fabricated a small cylindrical 12-sector antenna at 19 GHz employing the proposed feeding circuit for verification purposes. Furthermore, this paper clarifies the design method of this feeding circuit where the antenna diameter is 71 mm, and the results clearly show that the gain is more than 12 dBi.

There are so many methods of calculating the cylindrical function Zν(x), but it seems that there is no method of calculating Zν(x) in the region of νx and |ν|»1 with high accuracy. The asymptotic series presented by Watson, et al. are frequently used for the numerical calculation of cylindrical function Zν(x) where νx and |ν|»1. However, the function Bm(εx) included in the m'th term of the asymptotic series is known only for m5. Hence, the asymptotic series can not give sufficiently accurate values of the cylindrical functions. The authors attempt to develop programs for the numerical calculation of the cylindrical functions using this asymptotic series. For this purpose, we must know the function Bm(εx) of arbitrary m. We developed a method of calculating Bm(εx) for arbitrary m, and then succeeded in calculating the cylindrical functions in the region νx with high precision.

Debye's asymptotic series is frequently used for calculation of cylindrical functions. However, it seems that until now this series has not been used in all-purpose programs for numerical calculation of the cylindrical functions. The authors attempt to develop these all-purpose programs. We present some improvements for the numerical calculation. As the results, Debye's series can be used for the all-purpose programs, and it is found out that the series gives sufficient accuracy if some conditions are satisfied.

Hallen's integral equation for cylindrical antennas is modified to deal with finite gap excitation. Because it is based on more realistic modeling, the solution is more accurate, and the convergence is guaranteed. The new equation is written with a new excitation function dependent on the gap width. The moment method analysis is presented where the piecewise sinusoidal surface current functions are used in Galerkin's procedure. Total, external and internal current distributions can be determined. Numerical results for cylindrical antennas with wide variety of gap width and radius are shown, and are compared with the numerical results by the Pocklington type integral equation and those by measurement.

A combined mode-matching and moment method is proposed to calculate the capacitance matrix of wedge-supported cylindrical microstrip lines with an indented ground. Each indent is modeled as a multilayered medium in which the potential distribution is systematically derived by defining reflection matrices. An integral equation is derived in terms of the charge distribution on the strip surfaces. Galerkin's method is then applied to solve the integral equation for the charge distribution. The effects of strip width, strip separation, indent depth, and indent shape are analyzed.