Electronically Tunable Resistorless Mixed Mode Biquad Filters

This paper presents a new realization of elec¬tronically tunable mixed mode (including transadmittance- and voltage-modes) biquad filter with single input, three outputs or three inputs, single output using voltage differ-encing transconductance amplifier (VDTA), a recently introduced active element. It can simultaneously realize standard filtering signals: low-pass, band-pass and high-pass or by selecting input terminals, it can realize all five different filtering signals: low-pass, band-pass, high-pass, band-stop and all-pass. The proposed filter circuit offers the following attractive feature: no requirement of invert-ing type input signal which is require no addition circuit, critical component matching conditions are not required in the design, the circuit parameters ω0 and Q can be set orthogonally or independently through adjusting the bias currents of the VDTAs, the proposed circuit employs two active and minimum numbers of passive components. Fur-thermore, this filter was investigated from the point of view of limited frequency range, stability conditions, effects of parasitic elements and effects of non-ideal and sensitivity. Thus, taking these effects and conditions into considera¬tion, working conditions and boundaries of this filter are determined. We also performed Monte Carlo, THD and noise analyses. Simulation results are given to confirm theoretical analyses

Filtering characteristics of hybrid integrated polymer and compound semiconductor waveguides

This paper reports a study on a compact filter fabricated using hybrid integration of compound semiconductors and polymers. A GaAs epilayer is glued onto a polymer channel waveguide forming a highly asymmetrical directional coupler. This approach results in a narrow band filter due to very different dispersion characteristics of the compound semiconductor and the polymer materials. Furthermore, fiber coupling loss has been significantly reduced, since the input and output coupling is done through the polymer waveguide. Filtering characteristics can be engineered by changing the thickness and the length of the semiconductor epilayer. This can be done precisely using etch stop layers and noncritical lithography. The spectral response of such a filter can also be tuned electronically either using the electro-optic properties of the compound semiconductor or the thermo-optic properties of the polymer

DV-EXCCCII Based Resistor-Less Current-Mode Universal Biquadratic Filter

This study aims to present a new resistor-less current-mode multi-input single-output universal filter. The current-mode’s design approach is used to obtain the proposed circuit. This circuit employs a single differential voltage extra-X current controlled current conveyor (DV-EXCCCII) and two grounded capacitors. This multifunction filter circuit offers low-pass, high-pass, all-pass, band-pass, and band-reject filters at a single output terminal without passive component matching constraints. The same circuit topology can obtain all second-order filter functions with different input conditions. The proposed circuit design is electronically adjustable with the bias current of DV-EXCCCII. Because of its high output impedance, this arrangement is suitable for cascading other current-mode circuits. The proposed circuit is simulated by Cadence Spectre with 0.18 µm UMC CMOS technology process parameters at ± 0.9 V supply voltages. The simulation results agree well with the theoretical concept of the proposed circuit

1.45GHz-1.55GHz Tunable RF Band-pass Filter

RF signals are used in the communication field in general. It has special band called microwave band which is the focus of this project. The idea of filtering comes from the need to transmit certain frequency of ranges of interest and block others. In this project the focus is on tunable filters using MEMS idea to solve the problem of complexity and price of the conventional tunable filters. The project focuses on L band to get the range from 1.45GHz to 1.55 GHz. The project starts by designing the low pass prototype and convert it to comb-line filter to find the capacitance range for the design of the tuneable capacitor using CMOS-MEMS technology. The tunable capacitor has to be modelled and designed. Theoretical modelling and ADS simulation determined the tuning range required for the capacitor is from 1.72pF to 1.84pF. A CMOS-MEMS fixed and tuneable capacitors were designed and simulated to achieve this range of capacitance and requires a voltage of 20V for tuning. Thus the objectives of the study have been achieved successfully and recommendations are made to achieve a wider frequency range for the filter and for integration of the filter with the tunable capacitor

Comprehensive optical and data management infrastructure for high-throughput light-sheet microscopy of whole mouse brains

Comprehensive mapping and quantification of neuronal projections in the central nervous system requires high-throughput imaging of large volumes with microscopic resolution. To this end, we have developed a confocal light-sheet microscope that has been optimized for three-dimensional (3-D) imaging of structurally intact clarified whole-mount mouse brains. We describe the optical and electromechanical arrangement of the microscope and give details on the organization of the microscope management software. The software orchestrates all components of the microscope, coordinates critical timing and synchronization, and has been written in a versatile and modular structure using the LabVIEW language. It can easily be adapted and integrated to other microscope systems and has been made freely available to the light-sheet community. The tremendous amount of data routinely generated by light-sheet microscopy further requires novel strategies for data handling and storage. To complete the full imaging pipeline of our high-throughput microscope, we further elaborate on big data management from streaming of raw images up to stitching of 3-D datasets. The mesoscale neuroanatomy imaged at micron-scale resolution in those datasets allows characterization and quantification of neuronal projections in unsectioned mouse brains

Devices based on surface plasmon interference filters

Devices based on surface plasmon filters having at least one metal-dielectric interface to support surface plasmon waves. A multi-layer-coupled surface plasmon notch filter is provided to have more than two symmetric metal-dielectric interfaces coupled with one another to produce a transmission spectral window with desired spectral profile and bandwidth. Such notch filters can form various color filtering devices for color flat panel displays

Miniaturized spectrometer radiometer based on MMIC technology for tropospheric water vapor profiling, A

Includes bibliographical references.The fabrication of a miniaturized ground-based water vapor profiling radiometer demonstrates the capability of monolithic microwave and millimeter-wave integrated circuit technology to reduce the mass and volume of microwave remote sensing instrumentation and to reduce substantially the necessary operational power consumption and size of the radiofrequency and intermediate-frequency sections. Since those sections comprise much of the mass and volume of current microwave receivers, the fabrication of this system represents an important contribution to the design of microwave radiometers. This miniaturized radiometer implementation is particularly well suited to benefit from the cost savings associated with mass production. The small size of the radiometer (24 × 18 × 16 cm) reduces the power required by the temperature control system and allows a rapid warm-up to the temperature set point as well as maintenance of a highly stable internal temperature. Exhibiting very similar statistical properties, the four channels of the radiometer have measured Allan times of greater than 40 s. Measurement results demonstrate that the instrument achieves a sensitivity of better than 0.2 K for 3 s of integration time. Preliminary comparisons of measured brightness temperatures with simulation results based on radiosonde data show good agreement, which are consistent with previously reported results.This work was supported by the National Science Foundation under Grant ATM-0456270 to Colorado State University and Grant ATM-0239722 to the University of Massachusetts Amherst