A new type of mode converter that converts TE30 to TE10 mode is proposed. As an example of the ease of fabrication, holes can be drilled at the top of a metallic waveguide and dielectric rods inserted. This converter is useful for application as a power divider or power combiner.

In this paper, we extend the conventional error-trellis construction for convolutional codes to the case where a given check matrix H(D) has a factor Dl in some column (row). In the first case, there is a possibility that the size of the state space can be reduced using shifted error-subsequences, whereas in the second case, the size of the state space can be reduced using shifted syndrome-subsequences. The construction presented in this paper is based on the adjoint-obvious realization of the corresponding syndrome former HT(D). In the case where all the columns and rows of H(D) are delay free, the proposed construction is reduced to the conventional one of Schalkwijk et al. We also show that the proposed construction can equally realize the state-space reduction shown by Ariel et al. Moreover, we clarify the difference between their construction and that of ours using examples.

The ITU-T J.83 Annex B is a widely adopted standard in North America for digital video and audio transmission over coaxial cable. This paper proposes a new parallel processing architecture of the parity checksum generator and syndrome generator specified in the standard for packet synchronization and error detection. The proposed parallel processing architecture removes the performance bottleneck occurring in the conventional serial processing architecture, leading to significant decrease in processing time for generating a parity checksum in transmitter and a syndrome in receiver. Implementation results show that the proposed parallel processing architecture reduces the processing time by 92% for parity checksum generation and by 81% for syndrome generation over the conventional serial processing architecture.

An integral equation approach with a new solution procedure using moment method (MoM) is applied for the computation of coupled currents on the surface of a printed dipole antenna and inside its high-permittivity three-dimensional dielectric substrate. The main purpose of this study is to validate the accuracy and reliability of the previously proposed MoM procedure by authors for the solution of a coupled volume-surface integral equations system. In continuation of the recent works of authors, a mixed-domain MoM expansion using Legendre polynomial basis function and cubic geometric modeling are adopted to solve the tensor-volume integral equation. In mixed-domain MoM, a combination of entire-domain and sub-domain basis functions, including three-dimensional Legnedre polynomial basis functions with different degrees is utilized for field expansion inside dielectric substrate. In addition, the conventional Rao-Wilton-Glisson (RWG) basis function is employed for electric current expansion over the printed structure. The accuracy of the proposed approach is verified through a comparison with the MoM solutions based on the spectral domain Green's function for infinitely large substrate and the results of FDTD method.

The paper demonstrates a novel two-peak negative differential resistance (NDR) circuit combining Si-based metal-oxide-semiconductor field-effect-transistor (MOS) and SiGe-based heterojunction bipolar transistor (HBT). Compared to the resonant-tunneling diode, MOS-HBT-NDR has two major advantages in our circuit design. One is that the fabrication of this MOS-HBT-NDR-based application can be fully implemented by the standard BiCMOS process. Another is that the peak current can be effectively adjusted by the controlled voltage. The peak-to-valley current ratio is about 4136 and 9.4 at the first and second peak respectively. It is very useful for circuit designers to consider the NDR-based applications.

Radiation of a Hertzian dipole placed within a cylindrical cavity with narrow slots is investigated. Narrow axial and transverse slots are considered. Scattered fields are expanded in terms of eigenfunctions and boundary conditions are enforced to obtain a set of simultaneous equations. Computations are performed to check the validity of the formulation.

We study the high-frequency asymptotic analysis methods for the scattered fields by a cylindrically curved conducting surface excited by the incident wave on the curved surface from the convex side. We first derive the novel hybrid ray-mode solution for the scattered fields near the concave surface by solving a canonical problem formulated under the assumption that the cylindrically curved conducting surface possesses only one edge. Then by applying the ray tracing technique and the idea of Keller's GTD (Geometrical Theory of Diffraction), the solutions derived for the canonical problem are extended to account for the problem of the radiation from and the scattering by the other edge of the cylindrically curved surface. We confirm the validity of the novel asymptotic representations proposed in the present study by comparing both with the numerical results obtained from the method of moment and the experimental results performed in the anechoic chamber.

A system that has an array of dielectric rods at the center of a waveguide was previously suggested for single mode propagation with a wide frequency range. However, it is difficult to introduce the wave source from a coaxial cable, due to use of the TE10-like and TE20-like modes. In this investigation, an asymmetric setup of the dielectric rods is proposed for better coupling efficiency of the TE10 mode.

An alternative polynomial expansion for electromagnetic field estimation inside three-dimensional dielectric scatterers is presented in this article. In a continuation with the previous work of authors, the Tensor-Volume Integral Equation (TVIE) is solved by using the Galerkin-based moment method (MoM) consisting of a combination of entire-domain and sub-domain basis functions including three-dimensional polynomials. Instead of using trivial power polynomials, Legendre polynomials are adopted for electromagnetic fields expansion in this study. They have the advantage of being a set of orthogonal functions, which allows the use of high-order basis functions without introducing an ill-condition MoM matrix. The accuracy of such approach in MoM is verified by comparing its numerical results with that of exact analytical method such as Mie theory and conventional procedures in MoM. Besides, it is also confirmed that the condition number of the MoM matrix obtained with the proposed approach is lower than that of the previous approaches.

A uniform circular array (UCA) is a well-known array configuration which can accomplish estimation of 360 field of view with identical accuracy. However, a UCA cannot estimate coherent signals because we cannot apply the SSP owing to the structure of UCA. Although a variety of studies on UCA in coherent multipath environments have been done, it is impossible to estimate the DOA of coherent signals with different incident polar angles. Then, we have proposed Root-MUSIC algorithm with a cylindrical array. However, the estimation performance is degraded when incident signals arrive with close polar angles. To solve this problem, in the letter, we propose to use SAGE algorithm with a cylindrical array. Here, we adopt a CLA Root-MUSIC for the initial estimation and decompose two-dimensional search to double one-dimensional search to reduce the calculation load. The results show that the proposal achieves high resolution with low complexity.

In this paper, we propose a simple peak power reduction (PPR) method based on adaptive inversion of parity-check block of codeword in BCH-coded OFDM system. In the proposed method, the entire parity-check block of the codeword is adaptively inversed by multiplying weighting factors (WFs) so as to minimize PAPR of the OFDM signal, symbol-by-symbol. At the receiver, these WFs are estimated based on the property of BCH decoding. When the primitive BCH code with single error correction such as (31,26) code is used, to estimate the WFs, the proposed method employs a significant bit protection method which assigns a significant bit to the best subcarrier selected among all possible subcarriers. With computer simulation, when (31,26), (31,21) and (32,21) BCH codes are employed, PAPR of the OFDM signal at the CCDF (Complementary Cumulative Distribution Function) of 10-4 is reduced by about 1.9, 2.5 and 2.5 dB by applying the PPR method, while achieving the BER performance comparable to the case with the perfect WF estimation in exponentially decaying 12-path Rayleigh fading condition.

The wave absorber composed of cylindrical bars arranged periodically and metallic mesh for improving visibility is proposed for ETC, and characteristics of reflectivity and shielding effect are evaluated analytically and experimentally. As a result, reflectivity of -10 dB and shielding effect of -25 dB are obtained for circularly polarized wave when the gap between cylindrical bars is 30 mm. Therefore, realization of proposed wave absorber for installing between ETC lanes can be clarified.

A metallic waveguide with dual in-line dielectric rods can propagate electromagnetic waves more than two times higher than the cutoff frequency region and without higher modes [1]. If the straight portion in the waveguide has even symmetry, then dielectric rods are only required in the bent portion. Connection losses between the portions are improved by adding other dielectric rods.

Yamada, Harashima, and Miyakawa proposed to use a trellis constructed based on a syndrome former for the purpose of Viterbi decoding of rate-(n-1)/n convolutional codes. In this paper, we extend their code-trellis construction to general rate-k/n convolutional codes. We show that the extended construction is equivalent to the one proposed by Sidorenko and Zyablov. Moreover, we show that the proposed method can also be applied to an error-trellis construction with minor modification.

We have fabricated a polymer solid-state microstructure for optical application by two-photon-induced polymerization technique. The photopolymerization resin contains conventional laser-dye and dendrimer. A dendrimer can encapsulate the laser-dyes, limiting cluster formation and intermolecular energy transfer, and promising a high level of optical gain. The effect can be extended to prepare an optically active microstructure using the two-photon-induced polymerization technique. We fabricated a polymeric microcavity, which consisted of < 400 nm-linewidth strips arranged in layer-by-layer structure. The periodic variation in the refractive index gave rise to Bragg reflection. A laser emission was measured in the microcavity under optical excitation. The spectral linewidth was about 0.1 nm above the lasing threshold. We investigate both the material functions in the molecular scale and controlling the device structure for desired applications such as a polymer distributed feedback structure.

The wave absorber which is formed by arranging cylindrical bars periodically composed of magnetic loss material and metallic bars is proposed for improving ETC environment, and characteristics of reflection loss and shielding effect are analyzed and measured. As a result, the change of various characteristics can be confirmed quantitatively by changing the thickness of magnetic loss material covering around a metallic bar and the pitch interval between bars. Furthermore, it is clarified that reflection loss of -9 dB and shielding effect of -25 dB are obtained at 5.8 GHz when the covering thickness of material is 1.5 mm and the pitch interval is 16.0 mm. Therefore, the wave absorber formed by arranging cylindrical bars that satisfies various characteristics required for the improvement of ETC environment can be realized.

Binary sequences with two-level periodic autocorrelation correspond directly to cyclic (v, k, λ)-designs. When v = 4t-1, k = 2t -1 and λ = t-1, for some positive integer t, the sequence (or design) is called a cyclic Hadamard sequence (or design). For all known examples, v is either a prime number, a product of twin primes, or one less than a power of 2. Except when v = 2k-1, all known examples are based on quadratic residues (using the Legendre symbol when v is prime, and the Jacobi symbol when v = p(p+2) where both p and p+2 are prime); or sextic residues (when v is a prime of the form 4a2 + 27). However, when v = 2k-1, many constructions are now known, including m-sequences (corresponding to Singer difference sets), quadratic and sextic residue sequences (when 2k-1 is prime), GMW sequences and their generalizations (when k is composite), certain term-by-term sums of three and of five m-sequences and more general sums of trace terms, several constructions based on hyper-ovals in finite geometries (found by Segre, by Glynn, and by Maschietti), and the result of performing the Welch-Gong transformation on some of the foregoing.

In this paper, dosimetry of an in vitro exposure apparatus based on a cylindrical waveguide is performed. The SAR distributions are first obtained numerically by using FDTD method. The thermal fields in the medium are then estimated by numerical calculations of the equation of heat conduction. The maximum temperature rise for 17.9 W/kg average SAR during 3000 s exposure is about 2 on the bottom of the medium where cells are located. The thermal distribution is relatively uniform near the center of the dish and the temperature in this region is around 38.7. The results of the numerical calculation are experimentally supported. The results provide the electromagnetic and thermal characteristics of the exposure apparatus, which will define the exposure conditions of the planned experiments using this apparatus.

Mainly, a uniform linear array (ULA) has been used for DOA estimation of coherent signals because we can apply the spatial smoothing preprocessing (SSP) technique. However, estimation by a ULA has ambiguity due to the symmetry, and the estimation accuracy depends on the DOA. Although these problems can be solved by using a uniform circular array (UCA), we cannot estimate the DOA of coherent signals because the SSP technique cannot be applied directly to the UCA. In this paper, we propose to estimate 2-dimensional DOA (polar angles and azimuth angles) estimation of coherent signals using a cylindrical array which is composed of stacked UCAs.

Dynamic non-linearities are of more importance in highly-linear high-speed applications such as software radios. In this paper, a fully-analytical approach to estimate the statistics of dynamic non-linearity parameters of pipeline analog-to-digital converters (ADCs) in the presence of circuit non-idealities is presented. These imperfections include the capacitor mismatches and the non-idealities in the operational amplifiers (op-amps). The most two important ADC dynamic non-linearity parameters, the spurious-free dynamic range (SFDR) and the signal-to-noise-and-distortion ratio (SNDR) are quantified here and closed-form formulas are presented. These formulas are useful for design automation as well as hand calculations of highly-linear pipeline ADCs. Behavioral simulations are presented to show the accuracy of the proposed equations.