Theory Of Cavity Resonators Research Articles

Broadband complementary ring-resonator based terahertz antenna.

A broadband terahertz antenna based on complementary ring-resonator is designed. The complementary ring-resonator is etched in the ground plane to stimulate the generation of a new resonant frequency. After loading the resonator, the bandwidth of the antenna can increase by 111% compared with the one without complementary ring. The cavity resonance theory is used to explain the performance and mechanism of the complementary ring resonator. The radius of the complementary ring is the major impact parameter that can significantly determine the new resonant frequency. This work provides a way to design the broadband terahertz antenna.

Broadband absorption enhancement in a-Si:H thin-film solar cells sandwiched by pyramidal nanostructured arrays

A new thin-film solar cell structure with a broadband absorption enhancement is proposed. The active a-Si:H film is sandwiched by two periodic pyramidal structured layers. The upper dielectric pyramidal layer acts as matching impedance by gradual change of the effective refractive index to enhance the absorption of the active layer in the short wavelength range. The lower metallic pyramidal layer traps light by the excitation of Fabry-Perot (FP) resonance, waveguide (WG) resonance and surface plasmon (SP) mode to enhance the absorption in the long wavelength range. With the cooperation of the two functional layers, a broadband absorption enhancement is realized. The structure parameters are designed by the cavity resonance theory, which shows that the results are accordant with the finite-difference time-domain (FDTD) simulation. By optimizing, the absorption of the sandwich structure is enhanced up to 48% under AM1.5G illumination in the 350-900 nm wavelength range compared to that of bare thin-film solar cells.

Normal spectral emittance of a nickel metal surface with rectangular microcavities

AbstractSpectral control of thermal radiation emitted from rectangular microcavities (0.5×0.5×0.5µm3) was investigated through emission experiments at high temperatures. The microcavities were fabricated on a mirror‐finished Ni metal surface. Through measurement of the normal spectral emittance, the maximum emittance was obtained around a wavelength of 0.87µm, which was very close to that (0.894µm) estimated from the cavity resonance theory. The emittance reached a maximum value of 0.95, and then decreased drastically with increasing wavelength, from the cut‐off wavelength. For a longer wavelength range from 1.7µm, it was equal to the emittance of the mirror‐finished surface. © 2009 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20248

Broadband Acoustic Liner Based on the Mechanism of Multiple Cavity Resonance

In this paper the mechanism of multiple cavity resonance is proposed to broaden the absorption bandwidth of an acoustic liner. The basic idea is that, when the backcavity of the liner is divided into subcavities of different size, many resonances relating to different lengths are produced so that the peaks of sound absorption become more closely distributed and take effect jointly to afford high attenuation over a large bandwidth. To study this mechanism, a cavity-resonance theory is first established to describe the coupling effect of the acoustic modes inside the subcavities and arrives at a general formula for the multiple resonance frequencies. Furthermore, a more rigorous propagation model is developed that is capable of predicting the effect of a multiresonance acoustic liner on the sound attenuation in a duct. A verification experiment is also carried out in the situation of a rectangular duct without mean flow. When compared with the experiment, the theory well predicts the resonance frequencies, while the propagation model also gives reasonably good prediction for the magnitude of the transmission loss. Both the theoretical and experimental results demonstrate the potential of the present method in improving the broadband performance of an acoustic liner.

The muong-factor by cavity resonance theory

It is shown that a cavity-resonance model by which the muon/electron mass ratio was recently determined as 206.7683078 yields also a muong-factor of 2(1.001 165 918), both of these quantities being in accord with their measured values.

Theory of cavity resonators having a nonreciprocal filler

Theory of cavity resonators having a nonreciprocal filler