- Date:
- 2006-2009
- Theme:
- System design and RF
- Funding:
- Department
In this project, the spectrum monitor for cognitive radio is explored. The main challenge of the cognitive radio application is to draw a spectrum map covering a wide range of frequency fast and accurate enough while consuming lower power and keeping lower cost compared with main transceiver circuits, hence a unique receiver (spectrum monitor) must be designed. In this project, the target frequency range covers from 2GHz to 5GHz, which is a potential band for the cognitive radio, and the sensitivity/frequency resolution is to set to -80dBm/200kHz for strong signal detection of most communication systems.
To design such a RF system from system level, a novel method involving the concept of figure of merit is adopted to find a proper solution to balance different aspects of the receiver, including the performance, the power and the cost. By analysing the theory and the statistics collection for key blocks in RF system through years, this method can provide a general guide of trade-off between the power consumption and performance of receiver for the following several years and the trade-off among the performance.
Because of its unique application, some of the key blocks of the spectrum monitor are different from those in popular receivers. the low cost and high integration requirement prompt the design of a lumped element on chip passive band pass filter for IF selection. And a ring oscillator based digital tuning integer frequency synthesizer is designed to fulfill the wide tunig range and the low cost specifications. These components are designed on the 130nm standard digital CMOS technology to keep the lowest cost for portable devices.
The entire spectrum monitor system design involves the specially designed blocks(PLL, BPF) in circuit level simulations, fabrication and measurements as well as the collected existing blocks(such as wideband LNA, high linearity mixer, the base band low pass filter and ADC) since these components are more conventional. The trade-off and evaluation of the receiver solutions will be provided and analyzed.
Primary investigator
Associated research group
- Nano Research Group
- Theme:
- MEMs and NEMs
- Funding:
- EPSRC
The aim of this project is to levitate and manipulate micromachined objects of various sizes and shapes using electrostatic fields. The project is part of a multidisciplinary EPSRC project that aims to develop new laser ion sources. Recent experiments have demonstrated that high-power laser irradiation of micro-targets generates intense, high-energy beams of protons, ions, neutrons, electrons, gamma, and x-rays. This process requires micro-targets to be suspended without physical means of attachment, because such supports are known to perturb the ion-beam production mechanism and generate unnecessary debris. To achieve the vision of a target delivery system using micromachining technology, micromachined objects (material silicon) are levitated by electrodes against the force of gravity. This is achieved by rapidly applying pulses of voltages of constant amplitude to the levitation electrodes, depending on whether the disk has been displaced in positive or negative z-direction. A voltage of 10V is sufficient for a disk with diameter between 30-100 um. The same electrodes can capacitively measure in which direction the disk has been displaced, and then energise electrode so that a counterbalancing force is actuated on the disk. Other application areas of such a system are micromachined gyroscopes and accelerometers with levitated proof mass, RF systems, and electrostatic switches and actuators.
Primary investigators
- mk1
- is2
- clc06r
Associated research groups
- Nano Research Group
- Southampton Nanofabrication Centre
- Date:
- 2007-
- Themes:
- Nanophotonics and Biomimetics, Nanoelectronics
Inspired by nature's highly - evolved technique of producing antireflection in the eyes and wings of some species of moth, densely-packed pillars with heights and spacings of approximately 200 nm are created for use in solar cells. The effective refractive index gratings that are produced allow for broad range of wavelengths and angles of incidence to be antireflected efficiently. We are investigating ways to produce high quality antireflection layers on silicon using nanosphere lithography, a cheap, large-area and massively parallel self-assembly method.
Primary investigators
- pjs05r
- Darren Bagnall
Associated research groups
- Nano Research Group
- Southampton Nanofabrication Centre
- Date:
- 2006-2009
- Theme:
- Nanophotonics and Biomimetics
- Funding:
- Department
Planar waveguides are different from photonic crystal fibres (PCFs) in that planar waveguides require high nonlinear coefficient core material for achieving the desired nonlinear effects within a short distance of propagation. The most significant advantage of planar waveguides is their capability of integration with other components to constitute a building block in integrated optical circuits. The goal of this project is to design the planar waveguides with different geometries, including rib, ridge, taper, and photonic crystals, to achieve low cost on chip nonlinear devices that are capable to perform high efficiency nonlinear processes such as optical parametric amplification, supercontinuum generation (SCG), and etc.
Primary investigators
- Martin Charlton
- Pavlos Lagoudakis
- rc05r
Associated research groups
- Nano Research Group
- Southampton Nanofabrication Centre
- Date:
- 2006-2010
- Theme:
- Nanophotonics and Biomimetics
- Funding:
- Department
Planar waveguides are different from photonic crystal fibres (PCFs) in that planar waveguides require high nonlinear coefficient core material for achieving the desired nonlinear effects within a short distance of propagation. The most significant advantage of planar waveguides is their capability of integration with other components to constitute a building block in integrated optical circuits. The goal of this project is to design the planar waveguides with different geometries, including rib, ridge, taper, and photonic crystals, to achieve low cost on chip nonlinear devices that are capable to perform high efficiency nonlinear processes such as optical parametric amplification, supercontinuum generation (SCG), and etc.
Primary investigators
- Martin Charlton
- Pavlos Lagoudakis
- rc05r
Associated research groups
- Nano Research Group
- Southampton Nanofabrication Centre
Particles can show a wide range of movement patterns according to the characteristic of the AC electric field applied: because of their induced dipole they can shift to high (or low) field regions, rotate or align to the field. Particle behaviour has a strong dependence on how freely ions can move along the surface. Functionalising the surface of the particle with biological molecules changes the current flow around the particle, modifying the direction and the speed of its motion. Using 4 electrodes, it is possible to induce a controlled movement of the particles, in our case we are working with orientation and rotation. The motion of the particle at different frequencies can be recorded with a computer and then analyzed to estimate surface electrical properties. Different chemical reactions on the surface will lead to different properties. The aim of the project is to detect binding events of antibodies and DNA to the particles, once they have been functionalised with the appropriate probe biomolecules.
Primary investigators
- dm06r
- Hywel Morgan
Associated research groups
- Nano Research Group
- Southampton Nanofabrication Centre
Impedance spectroscopy (IS) represents a powerful label-free method for cell analysis. The technique allows quantitative measurement of the inherent electrical and dielectric properties of cells; such as membrane capacitance, membrane resistance, cytoplasmic conductivity and permittivity. These properties directly reflect the cellââ¬â¢s biological structure and metabolic state. Widespread use of IS has been limited by the technical complexity and time consuming nature of the measurement process. Measurements are typically performed on suspensions of cells, giving a population averaged value for the properties of the cell. This represents a significant drawback making the identification of cell sub-populations and cell sorting impossible. AC electrokinetic techniques such as electrorotation have allowed researchers to measure cell dielectric properties, at the single cell level, however it takes many minutes to measure each cell.
Recently, we have developed a high throughput micro impedance cytometer technology, capable of rapidly measuring the dielectric properties of individual cells in a flow though format similar to that of a traditional flow cytometer (>1000 cells per second). The general principle of the single cell impedance cytometry system is shown in the figure. The impedance of single cells is measured using micro-electrodes fabricated within a micro-channel (typical dimensions are 20üm by 40üm). The system can also measure the optical properties of the cell simultaneously with impedance, allowing independent identification of cell phenotype or physiological state through the use of fluorescent probes (e.g. DNA intercalating dyes, other cell markers).
We have demonstrated that the micro impedance cytometer system can differentiate between the three major human leukocyte sub-populations (monocytes, neutropils, T-lymphocytes), without the need for labelling, based on known differences in their cell membrane dielectric properties.
Primary investigators
- dh2
- Hywel Morgan
Secondary investigator
- Donna E. Davies
Associated research groups
- Nano Research Group
- Southampton Nanofabrication Centre
- Theme:
- MEMs and NEMs
- Funding:
- Department
Ultimate goal of the project is to develop a low voltage RF MEMS switch that can be easily interface to existing IC technology.
Primary investigators
Associated research groups
- Nano Research Group
- Southampton Nanofabrication Centre
- Date:
- 2005-2009
- Theme:
- Microfluidics and Lab-on-a-chip
We have developed electrodes to immobilise single cells and particles within a microfluidic channel inside a dielectrophoretic trap. The design is highly scalable, and suitable for trapping cells from culture in physiological media. Arrays of these traps have been used to separate mixed populations of fluorescently labelled cells, and these have been recovered and cultured.
Primary investigators
Secondary investigator
- rst05r
Associated research group
- Nano Research Group
- Date:
- 2007-
- Theme:
- MEMs and NEMs
- Funding:
- Department
The ultimate goal of this research is to create an analytical framework for the application of mechanical amplification in inertial sensors and MEMS in general. Effectively, after the proof of concept this will be used to improve the sensitivity of other more complex sensors such as gyroscopes.
Primary investigators
- izk07r
- mk1
- Harold Chong
Associated research groups
- Nano Research Group
- Southampton Nanofabrication Centre