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The low-complexity RF MEMS switch at EADS: an overview
This paper gives an overview of the low-complexity radio frequency microelectromechanical systems (RF MEMS) switch concept and technology of EADS Innovation Works in Germany. Starting in 2003, a capacitive switch concept, which is unique in several aspects, was developed to address specific needs in the aeronautic and space. Thermally grown silicon oxide as dielectric layer, the silicon substrate
Error-rate analysis of the OFDM for correlated Nakagami- fading channel by using maximal-ratio combining diversity
In this paper, we have analyzed the performance of correlated Nakagami-m fading channel by using the maximal-ratio-combing diversity at the receiver. A closed-form mathematical expression is derived for the average bit error rate (BER) for binary phase-shift keying (BPSK) and average symbol-error-rate (SER) for M-Quardrature amplitude modulation (M-QAM) scheme in terms of the higher transcendental
Fixed ground stations for multi-satellite geostationary missions
Multi-satellite missions, such as the next generation of geostationary satellites, require a ground station able to support an arbitrary number of satellites that can fly wherever within a pre-determined sky region, called control box. The use of high frequencies, around 26 GHz, imposes on the ground station high antenna gains to compensate for the noise temperature collected at those frequencies
W-band beam-steerable MEMS-based reflectarray
This paper presents recent advances on reconfigurable reflectarrays at the University of Perugia. In particular, the activities carried out in the framework of the FP7 project ARASCOM (?MEMS and Liquid Crystal based? Agile Reflectarray Antennas for Security and COMmunication). As for ARASCOM outcomes, the purpose of the project is the design of a very large reconfigurable reflectarray controlled w
New insights into reliability of electrostatic capacitive RF MEMS switches
Among other reliability concerns, the dielectric charging is considered the major failure mechanism which hinders the commercialization of electrostatic capacitive radio frequency micro-electro-mechanical systems (RF MEMS) switches. In this study, Kelvin probe force microscopy (KPFM) surface potential measurements have been employed to study this phenomenon. Several novel KPFM-based characterizati
Wide band via-less transition from FG-CBCPW to microstrip
A novel wideband transition from finite ground-conductor backed-CPW (FG-CB-CPW) to microstrip has been demonstrated in 8?23 GHz band. Proposed transition provides a very low-loss alterative to microstrip/coplanar lines at higher frequencies. Simulated results are detailed for both alumina and silicon substrates. Simulated results are validated on alumina substrate providing more than 100% bandwidt
Evaluating and predicting lifetime in capacitive MEMS switches
An empirical model has been proposed which provides an excellent fit to the drift of pull-in and release voltages of a MEMS capacitive switch due to bulk dielectric charging. This model correctly fits the linear time dependence over short time spans and transitions to a logarithmic dependence over longer time spans. Using this model to fit measured data enables a quick and efficient determination
Synthesis of randomness in the radiated fields of antenna array
An alternative approach is based on statistically computed signal analysis technique for the design of antenna array exhibiting lower side lobes in their radiation pattern. New and generalized expressions for the array factor of all physically realizable linear antenna arrays are introduced. An algorithm based on the statistically computed signal analysis is designed. By considering the random ele
Mode matching technique-based modeling of coaxial and circular waveguide discontinuities for material characterization purposes
In this paper, it is proposed to use a cylindrical cell for the characterization of dielectric material. The extraction of complex permittivity is based on inverse gradient approach where the full-wave simulation results are mapped to experimental data to extract the complex permittivity. As the operational frequency of radio frequency (RF)/microwave devices is increased, it becomes difficult to a
An accurate modeling technique for antennas and nonlinear RF power amplifier mixed simulation
The design of agile active antennas requires an efficient modeling methodology in order to quantify the impact of other components on the array radiation pattern, and especially the influence of power amplifiers (PA). Therefore, the performance prediction of PA on TX chains is of prime importance. This article describes two different approaches for active antenna applications. The first one concen