Dynamics of Globally and Dissipatively Coupled Resonators

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Andrew B. Sabater ◽  
Jeffrey F. Rhoads

This work explores the dynamics of arrays of globally and dissipatively coupled resonators. These resonator arrays are shown to be capable of exhibiting seemingly new collective behaviors which are highly sensitive to the dispersion of the natural frequencies of the constituent resonators in the array, the intrinsic damping of the resonators in the array, and the magnitude of the global coupling coefficient that captures the strength of the dissipative coupling. These behaviors have been identified within the work as group attenuation, confined attenuation, and group resonance. Group and confined attenuation are associated with an absence of energy and are strongly dependent on the dispersion of the natural frequencies. In cases of moderate dissipative coupling, the effects of group and confined attenuation could be interpreted as frequency-dependent damping. In cases where the global coupling coefficient is large, group resonance is significant. This effect is synonymous with the resonances of the constituent resonators being shared and occurring at frequencies in between the isolated resonators' natural frequencies. Accordingly, one could view group resonance as the antithesis of localization, in that the localization of the modes of a conservatively coupled system with a finite dispersion of the constituent resonators' natural frequencies is most significant when the coupling is weak. The authors believe that collective behaviors, such as those described herein, have direct applicability in new single-input, single-output resonant mass sensors, and, with extension, a variety of other sensing and signal processing systems.

Author(s):  
Andrew B. Sabater ◽  
Jeffrey F. Rhoads

Examples of coupled resonator and oscillator arrays in engineering, scientific and mathematical contexts are diverse and abundant. However, when the technical scope is limited to mechanical systems, research typically focuses on arrays of resonators in which the coupling between the sub-units is conservative and nearest-neighbor in nature. In these arrays, if the sub-units are nominally identical, and the coupling is weak, collective behaviors such as localization, the spatial confinement of energy in distinct or limited regions, can be observed. In contrast, if the coupling is global and dissipative, very different collective dynamics are observed, namely, group resonance, confined attenuation, and group attenuation, the latter two of which are associated with the local absence of energy. This paper investigates these dynamic phenomena within the context of a generic, globally-, dissipatively-coupled system, which is motivated by recent work related to electromagnetically-coupled microresonator arrays. The results of this work have direct applicability in new single-input, single-output resonant mass sensors, and, with extension, a variety of other sensing and signal processing applications.


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Varun Srivastava ◽  
Abhilash Mandloi ◽  
Dhiraj Kumar Patel

AbstractFree space optical (FSO) communication refers to a line of sight technology, which comprises optical source and detector to create a link without the use of physical connections. Similar to other wireless communication links, these are severely affected by losses that emerged due to atmospheric turbulence and lead to deteriorated intensity of the optical signal at the receiver. This impairment can be compensated easily by enhancing the transmitter power. However, increasing the transmitter power has some limitations as per radiation regulations. The requirement of high transmit power can be reduced by employing diversity methods. This paper presents, a wavelength-based diversity method with equal gain combining receiver, an effective technique to provide matching performance to single input single output at a comparatively low transmit power.


2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Nabil Arsalane ◽  
Moctar Mouhamadou ◽  
Cyril Decroze ◽  
David Carsenat ◽  
Miguel Angel Garcia-Fernandez ◽  
...  

Emulation methodology of multiple clusters channels for evaluating wireless communication devices over-the-air (OTA) performance is investigated. This methodology has been used along with the implementation of the SIMO LTE standard. It consists of evaluating effective diversity gain (EDG) level of SIMO LTE-OFDM system for different channel models according to the received power by establishing an active link between the transmitter and the receiver. The measurement process is set up in a Reverberation Chamber (RC). The obtained results are compared to the reference case of single input-single output (SISO) in order to evaluate the real improvement attained by the implemented system.


Author(s):  
Tooran Emami ◽  
John M. Watkins

A graphical technique for finding all proportional integral derivative (PID) controllers that stabilize a given single-input-single-output (SISO) linear time-invariant (LTI) system of any order system with time delay has been solved. In this paper a method is introduced that finds all PID controllers that also satisfy an H∞ complementary sensitivity constraint. This problem can be solved by finding all PID controllers that simultaneously stabilize the closed-loop characteristic polynomial and satisfy constraints defined by a set of related complex polynomials. A key advantage of this procedure is the fact that it does not require the plant transfer function, only its frequency response.


1996 ◽  
Vol 118 (2) ◽  
pp. 350-353 ◽  
Author(s):  
M. A. Hopkins ◽  
H. F. VanLandingham

This paper extends to multi-input multi-output (MIMO) systems a nonlinear method of simultaneous parameter and state estimation that appeared in the ASME JDSM&C (September, 1994), for single-input single-output (SISO) systems. The method is called pseudo-linear identification (PLID), and applies to stochastic linear time-invariant discrete-time systems. No assumptions are required about pole or zero locations; nor about relative degree, except that the system transfer functions must be strictly proper. In the earlier paper, proofs of optimality and convergence were given. Extensions of those proofs to the MIMO case are also given here.


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