Plasmonic metamaterial is an artificially designed material that consists of nano meter scale metal resonator array. By engineering such materials, we can create unprecedented optical materials such that they can interact directly with the magnetic component of the light. In this paper, theoretical background, fabrication techniques, and applications of plasmonic metamaterials are reviewed.
In this review, we describe recent developments in functional metamaterials based on coupled resonators. We first consider coupled resonator metamaterials that mimic electromagnetically induced transparency (EIT). We present a circuit model for EIT-like metamaterials and introduce a new coupled resonator in which the coupling is provided by a field gradient so that the group velocity can be varied by varying the incident angle. We then describe the principles for enhancing second harmonic generation (SHG) in nonlinear resonant metamaterials. Optical and microwave experiments of SHG in singly resonant metamaterials are presented. A method for further enhancing SHG using a doubly resonant metamaterial is also described.
In this paper, dielectric-resonator-based metamaterials are reviewed. They are classified mainly into several schemes with explanations of their propagation mechanisms. In addition, recent progress on 1-D, 2-D, and 3-D composite right/left handed metamaterial structures based on one-dielectric-resonator scheme with magnetic dipoles embedded in ε-negative host medium are shown along with their applications.
A superior-order curvature corrected bandgap reference (BGR) is proposed. The BGR features itself by adding only an extra NMOS transistor to a first-order BGR. The extra transistor generates a piecewise nonlinear corrected current to reduce its temperature coefficient (TC) and forms a negative feedback to decrease the variation of offset and TC caused by mismatch. Measurement result shows the proposed BGR achieves most optimal TC of 2.8ppm/°C in the temperature range of -40∼125°C. The variation of offset and TC among different samples are reduced by the negative feedback effectively.
This paper proposes an architecture-level solution to suppress the phase noise of local oscillators in wireless-transceiver LSIs. Because a phase-looked loop (PLL) supplies only one local oscillator (LO) frequency for multiple channels, large loop bandwidth of the PLL can be used for suppressing the phase noise. Simulation results show that a sixteen-channel grouping can suppress the phase noise more than 24dB in narrow-band wireless systems. Channel selection in receive mode can be ensured by a variable intermediate frequency (IF) complex band-pass filter. Local-leak and image signals in transmit mode can be suppressed by a quadrature up-conversion mixer and radio frequency (RF) band-pass filter with high-IF configuration. A digital-analog converter, analog-digital converter, and digital LSI are in charge of modulation and demodulation of the variable-IF signals.
In this letter, a minimum jitter probability (MJP) route selection algorithm for wireless mesh networks (WMNs) is proposed. To create the MJP algorithm, the inter-arrival packet jitter probability mass function (PMF) for differentiated service (DiffServ) priority classes is derived, which considers the effect of retransmissions due to packet errors in WMNs. Simulation results show the effectiveness of the proposed MJP algorithm compared to the popular minimum hop (MH) and expected transmission count (ETX) WMN routing schemes.
This paper describes a single-ended CMOS chopper amplifier for 1/f noise reduction of n-channel MOS transistors and its application to a low-noise high-gain switched-capacitor (SC) amplifier for sensor interface circuits. Since the chopping is used inside of the operational transconductance amplifier (OTA), this amplifier can be used for high output impedance sensors. To investigate the effect of the proposed chopping technique, a test chip was fabricated using 0.25µm mixed-signal CMOS process. The total input-referred noise is greatly reduced by using a high chopping frequency of 256kHz to 20µVrms from 295µVrms without chopping.
In this paper, a novel active block for analog signal processing is presented, namely the current controlled current differential current conveyor (CCCDCC). This multi terminal block has most features of the well-known CCII (Second Generation Current Conveyor) and CCCDTA (Current Controlled Current Differencing Tranconductance Amplifier) to simplify the realization of current-mode analog filters suitable for signal processing. The proposed block and its applications were simulated in 0.18µm CMOS process at ±0.9V supply voltages. All of results were obtained by Hspice and with a high detailed transistor library.
This paper proposes a novel scan disabling-based BIST-Aided Scan Test (BAST) scheme to reduce test data volume and test power. In this scheme, a linear feedback shift register (LFSR) with an extra input generates test vector for each slice in multiple scan chains according to a deterministic test set with don't-care bits. A hold logic, which is inserted between the LFSR and the scan chains, holds the outputs of the LFSR when the held vector is compatible with next slices. With the hold operation, the hold logic also can be used to select the best vector by the hold logic among the generated vectors. Using the scan disabling technique, the generated or held vector will not be shifted into the scan chains unless it is compatible with its corresponding slice. An automatic test equipment (ATE) only needs to store the control signals, not test vectors. The proposed scheme, based on the standard scan and using any test set with don't-care bits, is widely applicable and easy to deploy. Experimental results show the proposed scheme achieves a higher compression gain and lower test power than previous low-cost schemes for cases where the number of specified bits in the test set is relatively few.
This paper presents the application of chiral metamaterial covers for improving the circularly polarized microstrip antenna performance. Semi-planar chiral metamaterial structures with a near zero refractive index are designed and utilized for enhancing the directivity of circularly polarized single and array patch antennas. Numerical results show that the directivity of the antennas is significantly improved.