SiGe V Band Wide Tuning-Range VCO and Frequency Divider for Phase Locked Loop

A V-band wide tuning-range VCO and high frequency divide-by-8 frequency divider using Infineon 0.35 µm SiGe HBT process are presented in this paper. An LC impedance peaking technique is introduced in the Miller divider to increase the sensitivity and operation frequency range of the frequency divider. Two static frequency dividers implemented using current mode logic are used to realize dividing by 4 in the circuit. The wide tuning range VCO operates from 51.9 to 64.1 GHz i.e. 20.3% frequency tuning range. The measured phase noise at the frequency divider output stage is around -98.5 dBc at 1 MHz. The circuit consumes 200mW and operates from a 3.5Vdc supply, and occupies 0.6×0.8 mm2 die area.

A 60 GHz wide tuning range SiGe bipolar VCO for HDMI and wireless docking applications

A wide tuning range voltage controlled oscillator (VCO) with novel architecture is proposed in this work. The entire circuit consists of a VCO core, a summing circuit, a single-ended to differential (STD) converter and a buffer amplifier. The VCO core oscillates at half the desired frequency and the second harmonic of the VCO core is extracted by the summing circuit, which is then converted to a differential pair by the STD. The entire VCO circuit operates from 58.85 to 70.85 GHz with 20% frequency tuning range. The measured VCO gain is less than 1.6 GHz/V. The measured phase noise at 3 MHz offset is less than -78 dBc/Hz across the entire tuning range. The differential phase error of the output signals is measured by down converting the VCO output signals to low gigahertz frequency using an on-chip mixer. The measured differential phase error is less than 8°. The VCO circuit, which is constructed using 0.35 µm SiGe technology, occupies 770 × 550 µm2 die area and consumes 62 mA under 3.5 V supply.

Apparatus and method for adjusting filter frequency in relation to sampling frequency

A self-tuning filter is disclosed. The self-tuning filter includes a digital clocking signal and an input coupled to the digital clocking signal, whereby the input reads a value incident on the input when the digital clocking signal changes to a predetermined state. A clock-tunable filter is, furthermore, coupled to the digital clocking signal so that the frequency of the clock-tunable filter is adjusted in relation to a sampling frequency at which the digital clocking signal operates. The self-tuning filter may be applied to an input of a data acquisition unit and applied to an input having a variable sampling frequency. A method of controlling the frequency of a clock-tunable filter is also disclosed.

Tailoring Alphabetical Metamaterials in Optical Frequency: Plasmonic Coupling, Dispersion, and Sensing

Tailoring optical properties of artificial metamaterials, whose optical properties go beyond the limitations of conventional and naturally occurring materials, is of importance in fundamental research and has led to many important applications such as security imaging, invisible cloak, negative refraction, ultrasensitive sensing, transformable and switchable optics. Herein, by precisely controlling the size, symmetry and topology of alphabetical metamaterials with U, S, Y, H, U-bar and V shapes, we have obtained highly tunable optical response covering visible-to-infrared (Vis-NIR) optical frequency. In addition, we show a detailed study on the physical origin of resonance modes, plasmonic coupling, the dispersion of electronic and magnetic surface plasmon polaritons, and the possibility of negative refraction. We have found that all the electronic and magnetic modes follow the dispersion of surface plasmon polaritons thus essentially they are electronic- and magnetic-surface-plasmon-polaritons-like (ESPP-like and MSPP-like) modes resulted from diffraction coupling between localized surface plasmon and freely-propagating light. Based on the fill factor and formula of magnetism permeability, we predict that the alphabetical metamaterials should show the negative refraction capability in visible optical frequency. Furthermore, we have demonstrated the specific ultrasensitive surface enhanced Raman spectroscopy (SERS) sensing of monolayer molecules and femtomolar food contaminants by tuning their resonance to match the laser wavelength, or by tuning the laser wavelength to match the plasmon resonance of metamaterials. Our tunable alphabetical metamaterials provide a generic platform to study the electromagnetic properties of metamaterials and explore the novel applications in optical frequency.