A novel fiber-optic twist sensor based on a dual-polarization distributed Bragg reflector (DBR) fiber grating laser is proposed and experimentally demonstrated. By beating the signal between the two polarizations of the laser which operates at 1543.154 nm, a signal of 30.78 MHz in frequency domain is observed. The twist will change the fiber birefringence, and resulting in the beat frequency va...

In this paper we present a high gain dual-polarized planar etched slot array for use in wireless local area networks (WLAN). Two sets of four collinear slots are used as radiators for each polarization. Each set of four collinear slots is constructed as a centre-fed long slotline, with etched crossovers to split the slotline in four resonant and in-phase half-wavelength slots. A reflector etche...

For elastic reverse-time migration, one constructs elastic source and receiver wavefields using a source function and multi-component data, and then applies an imaging condition to the reconstructed wavefields. A widely used imaging condition is crosscorrelation of individual wave modes separated in both wavefields, e.g., compressional (P) waves and shear (S) waves. One difficulty in elastic mi...

The "extinction theorem" is used to prove that the fields of reflector antennas determined by integration of the current on the illuminated surface of the reflector are identical to the fields determined by aperture field integration with the Kottler-Franz formulas over any surface Sa that caps the reflector. As a corollary to this equivalence theorem, the fields predicted by integration of the...

We study comprehensively using numerical simulations a new class of resonators, based on a circular photonic crystal reflector. The dependence of the resonator characteristics on the reflector design and parameters is studied in detail. The numerical results are compared to analytic results based on coupled mode theory. High quality factors and small modal volumes are found for a wide variety o...

We present a novel air-bridge subwavelength grating reflector with very high reflectivity to be used as a top mirror in a VCSEL structure. We explain the design method, model the structure using both RCWA and FDTD, and predict the characteristics of a Fabry-Perot structure built with this reflector. We describe the fabrication of the suspended grating.

This paper presents the shaped reflector antenna by using backscattering technique to achieve the completely broad-beam radiation pattern. The radiation synthesis method for shaped reflector that has to illuminate a predefined circular area are presented by using a variety of discretization of elementary geometrical functions such as, triangular, quadratic, circular, guassian, cosine, squared c...

Evacuated tube solar water heater systems are widely used in China due to their high thermal efficiency, simple construction requirements, and low manufacturing costs. CPC evacuated tube solar water heaters with a geometrical concentration ratio C of less than one are rare. A comparison of the experimental rig of evacuated tube solar water heater systems with and without a mini-CPC reflector wa...