Dielectric resonator antenna

About: Dielectric resonator antenna is a research topic. Over the lifetime, 8199 publications have been published within this topic receiving 111090 citations. The topic is also known as: DRA.

Stacked Conical Ring Dielectric Resonator Antenna Excited by a Monopole for Improved Ultrawide Bandwidth

Abstract: Stacked conical ring dielectric resonator antennas (DRA) excited by an axi-symmetric coaxial monopole are investigated numerically and experimentally for improved bandwidth. The bandwidth improvement is due to an extra resonance which occurs near the frequency where the monopole height is about a full wavelength. We consider two cases of the hybrid antenna: one case in which the tips of both cones face up and a second case in which the top cone is inverted to form a “sand-glass” shaped DRA. Measured data were obtained to validate the results of simulations. The proposed hybrid antennas can easily offer a fractional impedance bandwidth up to 138% along with monopole type radiation pattern. The antennas have a relatively low peak gain around the extra resonance.

The Radiation of Electromagnetic Power by Microstrip Configurations

Abstract: A new technique for calculating the radiation losses of microstrip configurations is presented. The method applies if the wavelength is large compared to the width of the conducting strip and the thickness of the dielectric wafer. It is shown that the radiated power, which is partly carried by "space waves" and partly by "surface waves," can be computed in terms of the specific inductance and the specific capacitance of the transmission line, without making any assumptions regarding the current distribution in the microstrip. It appears that the fraction of the radiated power carried by surface waves contains the frequency to a higher power than does the fraction carried by space waves and is therefore relatively small. The investigated configurations are the infinitely long transmission line excited by a voltage-slit, the half-wavelength straight resonator, the full-wavelength circular resonator, and the quarter-wavelength hair-pin resonator. It follows that the quality factor of the straight resonator and the circular resonator are inversely proportional to the square of the frequency, whereas the quality factor of the hairpin resonator is inversely proportional to the fourth power of the frequency.

Semiconductor laser devices

Abstract: It is possible to narrow the emission spectrum linewidth of a semiconductor laser device by coupling optically an external resonator with one end surface of the semiconductor laser. However, the structure of the external resonator should match the phase of the light emitted by the laser. Heretofore, this matching has been effected by adjusting the length of the external resonator, and hence productivity and reproducibility have not been good. According to this invention, characteristics of the external resonator can be adjusted electrically to be matched with the phase of the emitted light owing to the fact that the external resonator is made of a material, whose refractive index can be varied electrically. Therefore the semiconductor laser device according to this invention is very practical.

Circularly Polarized Semi-Eccentric Annular Dielectric Resonator Antenna for X-Band Applications

Abstract: In this letter, a compact single-feed circularly polarized dielectric resonator antenna is proposed for X-band applications. The radiator comprises a semi-eccentric annular dielectric resonator (DR), which is a semi-elliptical DR with a hollow elliptical cylinder. A vertical coaxial probe is located adjacent to a cutting surface of the DR to excite the proposed antenna. The two main design parameters, the aspect ratio of the elliptical DR and the feeding position, were optimized, and a prototype of the antenna was fabricated and tested. The experimental results exhibit a $-$ 10-dB reflection bandwidth of 29.14% (9.41–12.62 GHz) and a 3-dB axial-ratio bandwidth of 5.71% (10.37–10.98 GHz). The measured peak gain varies from 4.17 to 4.78 dBic.

Hybrid photonic surface-plasmon-polariton ring resonators for sensing applications

Abstract: We introduce a hybrid photonic surface plasmon ring resonator which consists of a silicon nitride (Si3N4) dielectric traveling-wave ring resonator vertically coupled to a thin layer of metallic strip ring resonator made of Silver (Ag) on top The cladding is assumed to be porous alumina on top of the metal layer, which provides more surface area for the adsorption of target molecules and their efficient interaction with the surface plasmon wave excited at the metal-cladding interface Simulations show that this hybrid structure has a large refractive index sensitivity due to the excitation of surface plasmon waves and also a relatively narrow resonance linewidth due to the large quality factor of the photonic ring resonator The Finite Element method is used to systematically design the hybrid structure and to investigate the performance of the hybrid resonator as a refractive index sensor The proposed structure is very compact and can be implemented on a chip in an integrated platform Thus, it can be used for lab-on-a-chip sensing applications and is capable of being spectrally and spatially multiplexed for muti-analyte sensing