3,655 research outputs found
Integrated Aluminum Nitride Piezoelectric Microelectromechanical System for Radio Front Ends
This article summarizes the most recent technological developments in the realization of integrated aluminum nitride (AlN) piezoelectric microelectromechanical system (MEMS) for radio frequency (rf) front ends to be employed in next generation wireless communication devices. The AlN-based resonator and switch technologies are presented, their principle of operation explained, and some key experimental achievements showing device operations between 20 MHz and 10 GHz are introduced. Fundamental material, device, and fabrication aspects that needed to be taken into account for the demonstration of the first integrated rf MEMS solution based on the combination of AlN MEMS resonators and switches are highlighted. Given the ability to operate over a broad range of frequencies on a single silicon chip, the AlN MEMS technology is extremely attractive for the demonstration of reconfigurable and multiband rf transceivers. Next generation rf architectures that take advantage of large scale integration of AlN MEMS resonators and switches are briefly presented
MISAT: Designing a Series of Powerful Small Satellites Based upon Micro Systems Technology
MISAT is a research and development cluster which will create a small satellite platform based on Micro Systems Technology (MST) aiming at innovative space as well as terrestrial applications. MISAT is part of the Dutch MicroNed program which has established a microsystems infrastructure to fully exploit the MST knowledge chain involving public and industrial partners alike.
The cluster covers MST-related developments for the spacecraft bus and payload, as well as the satellite architecture. Particular emphasis is given to distributed systems in space to fully exploit the potential of miniaturization for future mission concepts. Examples of current developments are wireless sensor and actuator networks with plug and play characteristics, autonomous digital Sun sensors, re-configurable radio front ends with minimum power consumption, or micro-machined electrostatic accelerometer and gradiometer system for scientific research in fundamental physics as well as geophysics.
As a result of MISAT, a first nano-satellite will be launched in 2007 to demonstrate the next generation of Sun sensors, power subsystems and satellite architecture technology. Rapid access to in-orbit technology demonstration and verification will be provided by a series of small satellites. This will include a formation flying mission, which will increasingly rely on MISAT technology to improve functionality and reduce size, mass and power for advanced technology demonstration and novel scientific applications.
Reconfigurable Reflectarrays and Array Lenses for Dynamic Antenna Beam Control: A Review
Advances in reflectarrays and array lenses with electronic beam-forming
capabilities are enabling a host of new possibilities for these
high-performance, low-cost antenna architectures. This paper reviews enabling
technologies and topologies of reconfigurable reflectarray and array lens
designs, and surveys a range of experimental implementations and achievements
that have been made in this area in recent years. The paper describes the
fundamental design approaches employed in realizing reconfigurable designs, and
explores advanced capabilities of these nascent architectures, such as
multi-band operation, polarization manipulation, frequency agility, and
amplification. Finally, the paper concludes by discussing future challenges and
possibilities for these antennas.Comment: 16 pages, 12 figure
Reduced Switching Connectivity for Large Scale Antenna Selection
In this paper, we explore reduced-connectivity radio frequency (RF) switching
networks for reducing the analog hardware complexity and switching power losses
in antenna selection (AS) systems. In particular, we analyze different hardware
architectures for implementing the RF switching matrices required in AS designs
with a reduced number of RF chains. We explicitly show that fully-flexible
switching matrices, which facilitate the selection of any possible subset of
antennas and attain the maximum theoretical sum rates of AS, present numerous
drawbacks such as the introduction of significant insertion losses,
particularly pronounced in massive multiple-input multiple-output (MIMO)
systems. Since these disadvantages make fully-flexible switching suboptimal in
the energy efficiency sense, we further consider partially-connected switching
networks as an alternative switching architecture with reduced hardware
complexity, which we characterize in this work. In this context, we also
analyze the impact of reduced switching connectivity on the analog hardware and
digital signal processing of AS schemes that rely on channel power information.
Overall, the analytical and simulation results shown in this paper demonstrate
that partially-connected switching maximizes the energy efficiency of massive
MIMO systems for a reduced number of RF chains, while fully-flexible switching
offers sub-optimal energy efficiency benefits due to its significant switching
power losses.Comment: 14 pages, 11 figure
High Performance, Continuously Tunable Microwave Filters using MEMS Devices with Very Large, Controlled, Out-of-Plane Actuation
Software defined radios (SDR) in the microwave X and K bands offer the
promise of low cost, programmable operation with real-time frequency agility.
However, the real world in which such radios operate requires them to be able
to detect nanowatt signals in the vicinity of 100 kW transmitters. This imposes
the need for selective RF filters on the front end of the receiver to block the
large, out of band RF signals so that the finite dynamic range of the SDR is
not overwhelmed and the desired nanowatt signals can be detected and digitally
processed. This is currently typically done with a number of narrow band
filters that are switched in and out under program control. What is needed is a
small, fast, wide tuning range, high Q, low loss filter that can continuously
tune over large regions of the microwave spectrum. In this paper we show how
extreme throw MEMS actuators can be used to build such filters operating up to
15 GHz and beyond. The key enabling attribute of our MEMS actuators is that
they have large, controllable, out-of-plane actuation ranges of a millimeter or
more. In a capacitance-post loaded cavity filter geometry, this gives
sufficient precisely controllable motion to produce widely tunable devices in
the 4-15 GHz regime.Comment: 12 pages 14 figures 2 table
Programmable photonics : an opportunity for an accessible large-volume PIC ecosystem
We look at the opportunities presented by the new concepts of generic programmable photonic integrated circuits (PIC) to deploy photonics on a larger scale. Programmable PICs consist of waveguide meshes of tunable couplers and phase shifters that can be reconfigured in software to define diverse functions and arbitrary connectivity between the input and output ports. Off-the-shelf programmable PICs can dramatically shorten the development time and deployment costs of new photonic products, as they bypass the design-fabrication cycle of a custom PIC. These chips, which actually consist of an entire technology stack of photonics, electronics packaging and software, can potentially be manufactured cheaper and in larger volumes than application-specific PICs. We look into the technology requirements of these generic programmable PICs and discuss the economy of scale. Finally, we make a qualitative analysis of the possible application spaces where generic programmable PICs can play an enabling role, especially to companies who do not have an in-depth background in PIC technology
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