Travelling wave applicator

The planar material to be processed 1s Inserted In a slot at the centre of the broad dimension along the waveguide length and absorbs an amount of energy from the travelling microwave field dependent upon the effective loss factor of the Insertion. Any remaining power Is absorbed by the matched water load, with very little energy reflected back towards the source. 

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In last years one observes a fast progress in synthesis and elaboration of non-centrosymmetric functionalized polymers for applications primarily in electrooptic modulation and frequency conversion. These materials possess large second order nonlinear optical susceptibility x and can be easily processed into good optical quality thin films for travelling wave applications. Essentially four types of polymeric structures have been developed, as shown in Fig. 1 ... 

Figure 23 A travelling wave applicator a) a source feeding a waveguide and a water load b) cross-section of the waveguide showing the position of the planar ceramic material. (After ref 14 by permission of Peter Peregrinus, Ltd).

Figure 24 A meander travelling wave applicator, permission of Peter Peregrinus, Ltd).

A family of vacuum-tube MMW sources is based on the propagation of an electron beam through a so-called slow-wave or periodic structure. Radiation propagates on the slow-wave structure at the speed of the electron beam, allowing the beam and radiation field to interact. Devices in this category are the traveling-wave tube (TWT), the backward-wave oscillator (BWO) and the extended interaction oscillator (EIO) klystron. TWTs are characterized by wide bandwidths and intermediate power output. These devices operate well at frequencies up to 100 GHz. BWOs, so called because the radiation within the vacuum tube travels in a direction opposite to that of the electron beam, have very wide bandwidths and low output powers. These sources operate at frequencies up to 1.3 THz and are extensively used in THZ spectroscopic applications [10] [11] [12]. The EIO is a high-power, narrow band tube that has an output power of 1 kW at 95 GHz and about 100 W at 230 GHz. It is available in both oscillator and amplifier, CW and pulsed versions. This source has been extensively used in MMW radar applications with some success [13]. 

G.H. Evans and R. Greif. A Study of Traveling Wave Instabilities in a Horizontal Channel Flow with Applications to Chemical Vapor Deposition. Int. J. Heat Mass Transf, 32(5) 895-911,1989. 

Uses. Hard ferrites are used widely in electromechanical devices, e.g., generators, relays, motors, and magnetos electronic applications, e.g., loudspeakers, traveling-wave lubes, and telephone ringers and receivers aniitheft tags, holding devices such as door closers, seals, and latches ... 

AC electric fields and includes dielectrophoresis (DEP), travelling wave dielectrophoresis (twDEP) and electrorotation (ROT). Generally, non-uniform electric fields are used in AC electrokinetics. The assumption that the uniform field solution for the dipole moment is valid, is referred to as the dipole moment approximation, and is sufficient if the size of the particle is small compared to the scale of the electric field non-uniformity, which is true for most cases. In this chapter, we describe the forces on particles due to the action of AC fields, and discuss applications for manipulation of particles. We finish with a discussion of scaling effects. 

Giles, K. Pringle, S.D. Worthington, K.R. Little, D. Wildgoose, J.L. Bateman, R.H., Applications of a travelling wave-based radio-frequency-only stacked ring ion guide. Rapid Commun. Mass Spectrom. 2004, 18, 2401-2414. 

Traveling waves are typical nonequilibrium phenomena encountered in numerous instances in physics, chemistry, biology, and other areas [129, 82, 309,310]. Reacting and diffusing systems described by the RD equation (2.3) represent a particular well-studied class of applications. Equation (2.3) is known as Fisher s equation, if the reaction term has the logistic form F p) = rp — p) ... 

Q Applications of Traveling Wave Ion Mobility-Mass Spectrometry... 

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