Recent microwave IC's reach to the extent of high operating frequencies at which bonding wires limit their performance as dominant parasitic components. Double bonding wires separated by an internal angle have been firstly characterized using the Method of Moments with the incorporation of the ohmic resistance calculated by the phenomenological loss equivalence method. For a 30$^{\circ}$ internal angle, the calculated total reactance is 45% less than that of a single bonding wire due to the negative mutual coupling effect. The radiation effect has been observed decreasing the mutual inductance, whereas for parallel bonding wires it greatly increases the mutual inductance. This calculation results can be widely used for designing and packaging of high frequency and high density MMIC's and OEIC's.

The radiation characteristics of the subreflector of a shaped dual offset reflector antenna are analyzed by the uniform theory of diffraction(UTD). The discrete shaped subreflector profile is transformed into an analytic function by the global interpolation. To obtain the first and the second derivative terms on the surface, the local interpolation method is used. The reflection point needed for the geometrical optics(GO) is found by using the multi-dimensional function minimizing algorithm. The radiation pattern of a Gregorian type shaped subreflector is presented. The characteristics of the radiation patterns for various feed edge taperings and frequencies are examined.

It is important to test the various kinds of interconnect faults between chips on a card/module. When boundary scan design techniques are adopted, the chip to chip interconnection test generation and application of test patterns is greatly simplified. Various test generation algorithms have been developed for interconnect faults. A new interconnect test generation algorithm is introduced. It reduces the number of test patterns by half over present techniques. It also guarantees the complete diagnosis of mutiple interconnect faults.

We have analyzed the double insulating layer consisting of anodic oxide and ZnS through TEM experiments. The use of double insulating layer for HgCdTe surface passivation is one of the promising passivation method which has been recently studied deeply and the double insulating layer is formed by the evaporation of ZnS on the top of anodic oxide layer grown in H$_{2}$O$_{2}$ electrolyte. The structure of anodic oxide layer on HgCdTe is amorphous but the structure of oxide layer after the evaporation of ZnS has been changed to micro-crystalline. The interface layer of 150.angs. thickness has been found between ZnS and anodic oxide layer and is estimated to be ZnO layer. The results of analysis on the chemical components of ZnS, the interface layer and anodic oxide layer have showed that Zn has diffused into the anodic oxide layer deeply while Hg has been significantly decreased from HgCdTe bulk to the top of oxide layer. The formation of ZnO interface layer and the change of structure of anodic oxide layer after the evaporation of ZnS are estimated to be defects or to induce the defects which might possibly affect the increase of the positive fixed charges shown in C-V measurements of HgCdTe MIS.

A fiber-optic temperature sensor utilizing an optical absorption device (InP) was fabricated. The spectrum of transmitted light through an InP device was obtained at the three temperatures(249 K, 369 K). A stabilized LED(light emmiting diode) driver, photoreceiver, and signal proocessing electronics were designed. An intensity referencing technique was adopted in order to minimize the fluctuation of output signal due to external pertubation of the transmitting optical fiber. The optical absorption edge of the InP device moves to longer wavelength at a rate of 0.42 nm / K, and energy gap of InP is 1.35 eV at room temperature. From these results, it is concluded that the InP device has temperature dynamic range of 300 K with LED of center wavelength of 940nm and spectral width of 50nm. The designed fiber-optic temperature sensor system showed good linearity within the temperature range from -30$^{\circ}C$ to + 150$^{\circ}C$.

An optical digital parallel processor using Self-Pumped Phase Conjugate Mirror and liquid crystal spatial light modulator is presented and experimentally implemented. To use self-pumped PCM as memory, the mechanism for phase conjugation in two coupled interaction regions with the photorefractive crystal BaTiO$_{3}$ is investigated, especially the temporal behavior and effects of incident beam position. The optical design and implementation of matrix-vector multiplication using LCSLM and PCM memory is presented.

The trend of compact size, light weight, low power consumption in the portable telecommunication equipments demands large scale integration and low voltage operation of chips and the minimization of the number of the components in the telecommunication terminal. According to the trend, existing chip components are modulized and are integrated as a part into a bigger chip. This paper is about the development of the peripheral units of micro-controller for mobile telecommunication terminal. Peripherals consist of DMA controller, Interrupt controller, timer, watchdog timer, clock generator, and power management unit. They are designed to be integrated with EU(Execution Unit) and BIU(Bus Interface Unit) into a 16 bit micro-controller which will be used as a core of an ASIC for next generation digital mobile telecommunication terminal. At first, whole block of the micro-controller was described by VHDL behavioral model and simulated to verify its overall operation. Then, watchdog timer, clock generator and power management unit were directly synthesized by using VHDL synthesis tool. Rest of the pheriperal units were designed and simulated by using Compass Design Tool.

This paper suggests a method for optimal power assignment of the satellite transponder input carriers in the Multi-level & Multi-bandwidth system. The interference and the noise effects analyzed for the optimal power assignment are intermodulation product caused by the nonlinear transponder characteristics, adjacent channel interference, co-channel interference, and thermal noise in the satellite link. The Fletcher- Powell algorithm is used to determine the optimal input carrier power. The performance criteria for optimal power assignment is classified into 4 categories according to the CNR of destination receiver earth station to meet the requirement for various satellite link environment. We have performed mathematical analysis of objective functions and their derivatives for use in the Fletcher-Powell algorithm, and presented various simulation results based on mathematical analysis. Since the satellite link, it is meaningful to model and analyze these effects in a unified manner and present the method for optimal power assignment of transponder input carriers.

This paper proposes a new modulation scheme of $\pi$/4-DQPSK with stepped phase for a frequency selective fading channel. In the proposed modulation scheme, the phase of transmitted signal is shifted in the mid of a symbol duration in order to reduce the effect of multipath delay spread. It reduces the irreducible error of $\pi$/4-DQPSK over a frequency selective fading channel. It is shown that $\pi$/4-DQPSK with stepped phase achieves smaller average bit error probability than regular $\pi$/4- DQPSK by simulation. The former achieves much smaller average bit error probability than the latter for small TEX>${\tau}/T_{s}$.

Two multiple access protocols are proposed for a multichannel WDM optical fibre local area network or metropolitan area network in which users are interconnected using a passive star topology. Each user has a single tunable transmitter and a single tunable receiver. A transmitter sends a control packet before its data packet transmission so that its intended receivers can tune to the proper data channel wavelength. The maximum throughput of the proposed protocols are independent of the effective normalized propagation delay which may include the transmitter and receiver tuning times and the processing delays. The maximum throughputs of the protocols are analyzed and compared with those of the existing ones by numerical examples. The message delay of the R- Aloha/synchronous N-server switch protocol which is suitable for the queued users is also analyzed.

Inter-processor communication is required to manage resources in ATM switching system where processors are distributed. ATM switching system, which was developed in our institute, does't have dedicated communication path for inter-processor communication, but use the ordinary switching network same as user data. Therefore, we should test communication paths and equipments before running various application software programs. In this paper, we propose a method to test communication paths between processors in ATM switching system and describe an implemented program using this method.

In this paper, we develope an ATM switch simulator in order to evaluate the HAN/B-ISDN ATM switch currently being developed by ETRI. It models the basic cell switching functions of the target ATM switch with priority control and multicasting features and it also supports such various traffic models as random or bursty traffic, balanced or unbalanced traffic, multicast traffic models. Using this simulator, we can evaluate the performances of the ATM switch in terms of various performance indices, i.e. cell delay, cell loss probability, etc., and this simulator can be utilized in the system parameter tunings such as the common buffer size and address buffer size.

In this paper, we propose a dynamic bandwidth allocation scheme for the transmission of VBR video source through ATM based BISDN. In order to efficiently evaluate the required bandwidth, the characteristics of the VBR video sources generated by the MPEG coder are analyzed with variations in the number of GOP and quantizer scale. The required bandwidth for VBR video source is estimated by a prediction algorithm using scene and frame correlations as well as the statistical properties of the VBR video source. Scene correlation represents a strong correlation among the adjacent slices in a frame, and frame correlation represents a strong correlation among the frames. The statistical properties based on the traffic parameters of video sources such as peak rate, average rate, and standard deviation of source are determined through simulation. The performance of the proposed bandwidth allocation scheme is evaluated in terms of the over-allocated bandwidth, bandwidth utilization, and cell loss rate with variations in the quantizer scale and the number of GOP. It is shown that the results of simulation based on the proposed scheme are superior to those of the conventional methods.

In this paper an elliptic response dual-mode 4-pole bandpass filter was designed, manu-factured, and tested. A dual-mode filter having two stages cascaded double-tuned cavities which are resonant in two independent orthogonal TE113 circular-cavity modes and provide a bandpass response. A 4-pole dual-mode elliptic function bandpass filter has a center frequency of 14.022 GHz with a bandwidth of 36 MHz which is the first channel of the KOREASAT up-link frequency. The measured experimental results of a dual-mode filter are 1 dB insertion loss in the passband and 20 dB out-of-rejection.

The propagation characteristics of the symmetric and the asymmetric shielded coplanar waveguide with finite metallization thickness is analyzed by boundary integral method employing the equivalence principle. Since the Green's function and the basis functions are composed of sinusoidal functions, the integration in Galerkin's method is solved analytically. The propagation constants of the fundamental and the first higher order mode are obtained and the effects of strip thickness, substrate permittivity, and the asymmetry of the structure are calculated.

Wavelet transform technique is applied to two important electromagnetic problems:1) to analyze the frequency-domain radar echo from finite-size targets and 2) to the integral solution of two- dimensional electromagnetic scattering problems. Since the frequency- domain radar echo consists of both small-scale natural resonances and large-scale scattering center information, the multiresolution property of the wavelet transform is well suited for analyzing such ulti-scale signals. Wavelet analysis examples of backscattered data from an open- ended waveguide cavity are presented. The different scattering mechanisms are clearly resolved in the wavelet-domain representation. In the wavelet transform domain, the moment method impedance matrix becomes sparse and sparse matrix algorithms can be utilized to solve the resulting matrix equationl. Using the fast wavelet transform in conjunction with the conjugate gradient method, we present the time performance for the solution of a dihedral corner reflector. The total computational time is found to be reduced.

In this paper, shielded suspended coplanar waveguide with multiple anisotropic substrates is analyzed by the point matching method in the quasi-TEM mode appoximation. The characteristic impedance and the effective dielectric constant are calculated by varying the width of center strip and gap between the center strip and the ground strip. And also the characteristic parameters are calculated as a function of ${\varepsilon}_{x}/{\varepsilon}_{y}$) and a permitivity of the support substrate. Approaching the ground strip to infinity, the values of the characteristic parameters are found to be in good agreement with the other results by variational method.

This paper presents a method not only to detect moving targets from ISAR data corrupted by heavy clutter but to effectively extract the moving targets' signitures that are necessary for acquiring the velocities and images of the targets. In this method, input ISAR data are coherently processed such that echoes due to the moving targets are transformed to be in-phase and then integrated. It is shown that targets' signitures are localized in the transformed two-dimensional domain, leading to dramatic improvement of signal-to-noise (SNR) ration. The extent of the improved signal-to-noise ratio is analyzed and results implemented with simulated ISAR data are presented.