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.

Wideband measurement of the dielectric constant of an FR4 substrate using a parallel-coupled microstrip resonator

Abstract: We have made a wideband measurement of the real part of the dielectric constant of flame retardant #4 epoxy (FR4), a common high-frequency printed-circuit-board insulator. We designed a novel test circuit, an electrically long parallel-coupled microstrip resonator, which was etched on a 0.014-in FR4 substrate, manufactured by NELCO, Melville, NY. We used a computer model of the resonator to extract the dielectric constant at the frequencies of zeroes in its measured transmission response. By adjusting the model's dielectric constant, we tuned the frequency of each zero to match the measured frequency, yielding the dielectric constant at that frequency. To validate our method and results, we present a simple, but original proof that the frequencies of zeroes in the resonator's transmission response are insensitive to input and output mismatches. Additionally, we compare the measured and predicted response of a two-stub filter designed with our measured data. The fabricated filter's measured return loss and insertion loss from 3 to 12 GHz are within 1% of the predictions of Agilent Technology's Momentum.

Ultra-compact microdisk resonator filters on SOI substrate.

Abstract: The evanescent coupling of a 1.5 µm radius silicon microdisk with one or two Silicon-On-Insulator waveguides is studied. Thanks to the high refractive index contrast between Silica and Silicon materials, this very-small-diameter microdisk exhibits the highest quality factor measured in wavelength range from 1500 nm to 1600 nm. Coupled to a single monomode waveguide, the optical resonator behaves as a stop-band filter. Even if the microdisk is a largely multimode resonator, only its fundamental modes are efficiently excited. The filter’s transmission is measured for different gap between the waveguide and the resonator. The critical coupling is clearly observed and gives access to 1.63 nm linewidth. A 20 dB decrease of the transmission signal is also observed. Coupled to two waveguides, the resonator becomes a compact symmetric wavelength-demultiplexer. In this case, the optimal response comes from a compromise between the gap and the desired linewidth dropped in the second waveguide. Finally, our measurements are also compared to analytic models showing a good agreement especially for the critical gap prediction.

Optical routing/switching based on control of waveguide-ring resonator coupling

Abstract: An optical wave power control device and method enables signal control, such as modulation and switching, to be effected with the application of very low power to a controller which is in optical communication with a recirculating mode resonator (200) and an optical propagation element. The propagation element is in power communication with a high-Q volumetric resonator. Power of a chosen resonant wavelength is coupled into the resonator, where it circulates with very low loss and returns to the propagation element. By applying a control signal into the controller, the propagated power can be varied between substantially full and substantially zero amplitudes. Loss factors can be maintained such that the resonator is overcoupled (i.e. parasitic losses are less than coupling losses). A critical coupling condition can be induced by a small swing in the controller, causing a disproportionate change in the output optical signal. The controller is preferably embodied in an interferometer (116) in the optical path of the resonator, and the control signal can be an applied voltage, current, or optical signal.

Frequency-Tunable Differentially Fed Rectangular Dielectric Resonator Antennas

Abstract: The frequency-tunable differentially fed rectangular dielectric resonator antenna (DRA) loaded by chip capacitors or chip varactors is investigated. Two conducting strips are attached on two opposite DRA side walls for soldering the loading elements. In each loading case, a frequency-tunable DRA with good match and stable radiation patterns can be obtained. Also, the cross-polarized field level is relatively low. Reasonable agreement between the measured and simulated results is obtained. It is found that the frequency tuning ratio can be controlled by the loading elements and the sizes of the DRA and conducting strips. In particular, for the varactor-loaded case, a frequency-reconfigurable DRA can be obtained by varying the biasing voltage of the varactors.

Piezoelectric transducer and method for mounting same

Abstract: Piezoelectric transducer apparatus which includes a resonator section peripherally supported by a hollow cylindrical housing section formed as an integral part of the resonator section. Electrodes are disposed about the resonator section to produce a vibration-exciting electric field in response to a signal appearing on the electrodes.