The high-speed and low-power system LSIs in recent years have crucial need for managing power supply noise so that it might not substantially affect the circuit functionality and performance. The decoupling capacitance is known as an effective measure for suppressing the power supply noise. In this paper, we propose a design methodology for decoupling capacitance budgeting, in which the decoupling capacitance is distributed appropriately over the LSI chip area in order to suppress the power supply noise of each local region. For efficient budgeting, we introduced a new concept of power-capacitance ratio, which is the ratio of power dissipation to capacitance. The proposed method first performs a simplified power supply noise analysis by using a lumped circuit model to determine the total required on-chip capacitance, and calculate the power-capacitance ratio. Then, in the layout design phase, the decoupling capacitance budgeting is performed by using the above power-capacitance ratio as a guideline. The effectiveness of the proposed method was verified by using SPICE simulations on example chip models of 90 nm technology node. The verification results show that, even for a chip with very wide on-chip variation in power density, the proposed method can suppress the power supply noise of each local region effectively.

This paper presents the formulation for the evaluation of external coupling in the alternating-phase feed single-layer slotted waveguide array antenna with baffles by using the Spectrum of Two-Dimensional Solutions (S2DS) method. A one-dimensional slot array is extracted from the array by assuming the periodicity in transversal direction and introducing the perfect electric conductors in the external region. The uniform excitation over the finite array is synthesized iteratively to demonstrate the fast and accurate results by S2DS. A unit design model with the baffles is introduced to determine the initial parameters of the slot pair which accelerate the iteration. Experiment at 25.3 GHz demonstrates good uniformity of the aperture field distribution as well as the effects of the baffles. The directivity is 32.7 dB which corresponds to the aperture efficiency 90.5% and the reflection is below -15.0 dB over 1.3 GHz.

A new elliptic-function bandpass filter (BPF) is proposed, which utilizes an inter-digital coupled line (IDCPL) as a left-handed transmission line. The IDCPL is employed in order to realize a negative coupling between non-adjacent resonators in a wideband BPF. As the authors' knowledge, the left-handed operations of the IDCPL has rarely utilized before, although the IDCPL itself has been widely used in many microwave circuits without being paid attention to the left-handed operations. Measured characteristics of two BPFs are presented in this paper, one is targeted for 3-4 GHz WiMAX systems, and the other is for 3-5 GHz ultra wideband communication systems (UWB).

A transceiver macro for high-speed data transmission via cable in vehicles is proposed. The transceiver uses ac coupling and bi-directional interface topology for protecting LSIs against unexpected short of cable and harness/chassis and has a spread-spectrum-clocking (SSC) generator that reduces noise due to electromagnetic interference. A driver current control has been used for fast switching of data direction on ac-coupled interfaces. An adaptive bandwidth control has been used in a Δ ∑ PLL to improve SCC significantly. A test chip has been fabricated and shows stable and bi-directional data communication with data rate of 162 to 972 Mbps through 20-m cable. Thanks to an optimum calibration of the SSC-PLL bandwidth, it reduces peak power at 33 kHz by -23 dB and provides 2% modulation at a data rate of 810 Mbps.

A simple model of inductor-coupled bistable oscillators is shown to exhibit pulse wave propagation. We demonstrate numerically that there exists a pulse wave which propagates with a constant speed in comparatively wide parameter region. In particular, the propagating pulse wave can be observed in non-uniform lattice with noise. The propagating pulse wave can be observed for comparatively strong coupling case, and for weak coupling case no propagating pulse wave can be observed (propagation failure). We also demonstrate various interaction phenomena between two pulses.

This paper investigates the performance of multiple monopole antennas mounted on a card-type terminal, which is expected to be used in the systems beyond 3 G, based on the calculated and measured radiation patterns for the 2.0 GHz. We characterize the feasible performance of quarter-wavelength monopole antennas mounted on a card-type terminal in a multiple antenna configuration with narrow element spacing of less than a half-wavelength assuming that the antennas used must satisfy the space restrictions of the mobile terminal. Performance figures of merit for the multiple antenna performance include the beamforming gain, correlation coefficient, and MIMO channel capacity. Furthermore, we investigate the influence of a finite ground plane on the characteristics of multiple monopole antennas using a typical antenna configuration comprising a simple finite ground plane and multiple monopole antennas to discuss the fundamental characteristics.

Two dual-band bandpass filters (BPFs) based on the doubly parallel-coupled stepped impedance resonators (SIRs) structures have been proposed in this paper. The coupled-SIRs with/without open-stub-loads are introduced in the filter design. The dual-band filters exhibiting multiple zeros design operate at 2.45/5.2-GHz for the WLAN applications. Two three-staged filters composed of four SIRs have been proposed with the tapped-line adapted in the I/O sections. A five-staged filter is constructed based on the same design principle to achieve a better band-rejection. The proposed filters have the advantages of a much wider bandwidth in both the passbands without sacrificing the passband's insertion loss and passband flatness. The design procedure for a conventional parallel-coupled microstrip lines model is still suitable to design the proposed filters. The proposed filters have achieved almost twice the bandwidth of a conventional parallel-coupled lines configuration under the same design parameters. The experiments have been conducted to verify filter performance. Measured results are in good agreement with the full-wave simulation results.

MUSIC-based estimation of direction of arrival (DOA) using universal steering vector (USV) is experimentally studied. A four-element array antenna and a four-channel receiver are employed for the experiment. In order to improve the accuracy of DOA estimation, USV which has already included the effect of mutual coupling between array elements and effect of array elements themselves is compensated to further include the electric delay and loss of four channels in the receiver. The compensated USV (C-USV) approach proposed in this paper does not need the time-consuming measurement of array element pattern because the compensating matrix for USV is obtained by measuring the S parameters between RF input ports of the feeding cables and IF output ports of the receiver. The experimental results of MUSIC-based DOA estimation show that C-USV approach is an accurate, effective and practical method for the MUSIC-based DOA estimation.

Developing LSIs with EMI suppression, particularly for use in automobiles, is important for improving warranties and customer acquisition. First, we describe that the measures against EMI noise caused by a X'tal oscillator are important. Next, we present a practical method for analyzing the noise with models of the inside and outside of a chip. In addition, we propose a within-chip measure against EMI noise that takes chip cost into account. The noise is suppressed by using an appropriate resistance and capacitance on the power line. Simulation results demonstrated the method's effectiveness in suppressing noise.

We propose and demonstrate a simple one-bus two-ring configuration where the two rings are mutually coupled that has advantages over the one-ring structure. Unlike a one cavity system, it can exhibit near critically-coupled transmission with a broader range of loss. It can also significantly enhance the cavity finesse by simply making the second ring twice the size of the bus-coupled one, with the enhancement proportional to the intensity buildup in the second ring.

A wireless transceiver utilizing inductive coupling has been proposed for communication between chips in system in a package. This transceiver can achieve high-speed communication by using two-dimensional channel arrays. To increase the total bandwidth in the channel arrays, the density of the transceiver should be improved, which means that the inductor size should be scaled down. This paper discusses the scaling theory based on a constant magnetic field rule. By decreasing the chip thickness with the process scaling of 1/α, the inductor size can be scaled to 1/α and the data rate can be increased by α. As a result, the number of aggregated channels can be increased by α2 and the aggregated data bandwidth can be increased by α3. The scaling theory is verified by simulations and experiments in 350, 250, 180, and 90 nm CMOS.

Chip-level substrate coupling analysis uses F-matrix computation with slice-and-stack execution to include highly concentrated substrate resistivity gradient. The technique that has been applied to evaluation of device-level isolation structures against substrate coupling is now developed into chip-level substrate noise analysis. A time-series divided parasitic capacitance (TSDPC) model is equivalent to a transition controllable noise source (TCNS) circuit that captures noise generation in a CMOS digital circuit. A reference structure incorporating TCNS circuits and an array of on-chip high precision substrate noise monitors provides a basis for the verification of chip-level analysis of substrate coupling in a given technology. Test chips fabricated in two different wafer processings of 0.30-µm and 0.18-µm CMOS technologies demonstrate the universal availability of the proposed analysis techniques. Substrate noise simulation achieves no more than 3 dB discrepancy in peak amplitude compared to measurements with 100-ps/100-µV resolution, enabling precise evaluation of the impacts of the distant placements of sensitive devices from sources of noise as well as application of guard ring/band structures.

This paper presents a free access mat consisting of tightly coupled double layered microstrip resonator array to provide an easy access for devices in short range wireless communications. While in a conventional wireless access system the electromagnetic wave is radiated from a device to another through the free space using built-in antennas, the proposed wireless access system uses the free access mat to propagate the wave and the proximate coupling between the waveguide and the devices. The propagation loss in the mat is small, which is demonstrated by numerical simulation for basic elements of the free access mat. We also demonstrate small transmission loss including the coupling loss between dipole antennas and the free access mat. Finally experimental confirmation for all demonstrated characteristics is provided so that the free access mat is effective as a novel waveguide for a short range wireless access systems.

A new unified method is proposed to calculate the basic resonator parameters, i.e., the resonant frequency, external Q, unloaded Q and coupling coefficient in the time domain. By exciting the resonator from a weakly coupled external circuit, one can inject only a narrow resonant spectrum from the broad spectrum of the excitation pulse. The resonant frequency is easily counted by the number of zero crossings of the internal field intensity, whereas the Q's are calculated by the decay rate of the field amplitude. The coupling coefficient computed by the energy exchange rate between two resonators completes the new time domain algorithm.

This paper presents an efficient diagnosis scheme for RAMs. Three March-based algorithms are proposed to diagnose simple functional faults of RAMs. A March-15N algorithm is used for locating and partially diagnosing faults of bit-oriented or word-oriented memories, where N represents the address number. Then a 3N March-like algorithm is used for locating the aggressor words (bits) of coupling faults (CFs) in word-oriented (bit-oriented) memories. It also can distinguish the faults which cannot be identified by the March-15N algorithm. Thus, the proposed diagnosis scheme can achieve full diagnosis and locate aggressors with (15N + 3mN) Read/Write operations for a bit-oriented RAM with m CFs. For word-oriented RAMs, a March-like algorithm is also proposed to locate the aggressor bit in the aggressor word with 4 log2B Read/Write operations, where B is the word width. Analysis results show that the proposed diagnosis scheme has higher diagnostic resolution and lower time complexity than the previous fault location and fault diagnosis approaches. A programmable built-in self-diagnosis (BISD) design is also implemented to perform the proposed diagnosis algorithms. Experimental results show that the area overhead of the BISD is small--only about 2.17% and 0.42% for 16 K8-bit and 16 K128-bit SRAMs, respectively.

The averaged equation for an arbitrary number of oscillators coupled by nonlinear coupling scheme invented by S. Nagano, is derived. This system is invented as a model of uni-cellular slime amoeba. By using the averaged equation, we investigate the synchronization characteristics of five coupled oscillators and a large number of coupled oscillators. In particular, we present the statistical property of coupled oscillators in terms of coupling factor γ. We also investigate the effect of linear and nonlinear coupling terms for achieving synchronization, and confirm that the nonlinear coupling term plays an important role for strong synchronization than linear coupling term does.

Electromagnetic scattering properties of metamaterial cylinders due to a line source are studied by a multilayer algorithm based on eigenfunctional expansion. Closed forms of electric and magnetic fields are formulated. Both the fields inside the cylinder and field in outer space are plotted for different sizes of the cylinder. The focusing phenomena and the wave propagation in the presence of metamaterial cylinders are investigated and shown. Electromagnetic field distributions are presented for subwavelength metamaterial cylinders and cylinders fabricated by magnetoelectric materials, and resonant scattering and focusing properties are reported. Special designs of scatterer cloaking are proposed and calculated by multilayer algorithm which can reduce scattering cross sections.

High-resolution Direction-of-Arrival (DOA) estimation techniques for antenna arrays have been widely desired in many applications such as smart antennas, RF position location, and RFID system. To realize high-resolution capability of the techniques, precise array calibration is necessary. For an array of single-mode elements, a calibration matrix derived by the open-circuit method is the simplest one. Unfortunately, calibration performance of the method is not enough for the high-reslution DOA estimation techniques. In this paper, we consider problems of the calibration matrix derived by the method, and show that errors in the matrix can be effectively removed by an optimal diagonal weight coefficient. In the proposed compensation technique, the number of newly introduced parameters, or unknowns, is only one for an array of the identical elements. Performance of the simple compensation technique is verified numerically and experimentally.

This paper describes a capacitive voltage probe (CVP) that can measure a common-mode voltage on a cable without touching its conductor. This CVP has two coaxial electrodes: the inner electrode works as a voltage pickup and the outer one shields the inner electrode. These electrodes separate into two parts for clamping to the cable. Using a high input impedance circuit, this probe measures the common-mode voltage by detecting the voltage difference between the two electrodes. The probe characteristics are evaluated by measuring its linearity and frequency response. The results show that this probe has a dynamic range of 100 dB and flat frequency response from 10 kHz to 30 MHz. Deviations in sensitivity due to the position of the clamped cable in the inner electrode and to differences in the cable radius are evaluated theoretically and experimentally. The results indicate that the influence of the cable position can be calibrated. Finally, measured data obtained using both an impedance stabilizing network (ISN) and a CVP are compared to confirm the validity of the CVP. The results show that data measured by the CVP closely agreed with that obtained by the ISN. Therefore, the CVP is useful for EMC measurements to evaluate common-mode disturbances.

Antenna array is essential factor for multiple- input multiple-output (MIMO) wireless systems. Since the antenna array is composed of closely spaced elements, the mutual coupling among the elements cannot be ignored for the best performance of the array. Mutual coupling affects the MIMO channel, so the performance of a MIMO system, including channel capacity and diversity, varies with the degree of mutual coupling. The effect of mutual coupling is a function of the antenna load impedance. Therefore, designing an optimal element-matched array for a MIMO system requires consideration of the optimal matching condition for the array elements, the one that maximizes the channel capacity. We evaluated the effects of mutual coupling with various matching conditions in dipole arrays, and investigated their effects on the path correlation and channel capacity of MIMO systems. Simulation showed that the conventional conjugate matching of each element is still suitable for closely spaced elements except when the separation is about less than 0.1λ. Theoretical consideration of the received power of a closely-spaced-element array is also provided to show the effects of mutual coupling.