| 摘要 |
The invention is a dielectric resonator in the shape of a truncated cone and variations with a longitudinal through hole. The truncated cone shape physically displaces the H11 mode from the TE mode in the longitudinal direction of the cone. Particularly, the TE mode tends to concentrate in the base of the cone while the H11 mode tends to concentrate at the top of the cone. By truncating the cone so as to eliminate the portion of the cone where the H11 mode field exists, yet keep the portion of the cone where the TE mode exists, the H11 mode can be virtually eliminated while having no effect on the magnitude of the TE mode. Resonators in accordance with the invention may be used to build low-loss compact and/or variable bandwidth filters, oscillators, and other circuits, particularly microwave circuits. The conical resonators are arranged relatively to each other within an enclosure in a very efficient and compact design that enhances coupling and the adjustability between adjacent resonators. A plurality of conical dielectric resonators may be arranged in the enclosure such that the longitudinal orientation of each resonator is inverted relative to its adjacent resonator(s). Alternately, the conical resonators may be arranged in a radial pattern relative to each other. The invention also comprises a spiral coupling loop that provides greater magnetic flux in the same physical volume. Further, conical resonators can be positioned relative to microstrips on printed circuit boards and other substrates so as to provide enhanced electromagnetic coupling between the resonator and the microstrip. Particularly, because the TE mode tends to be concentrated in the base portion of the resonator, the resonator can be mounted upside down to the substrate in the vicinity of the microstrip. In this manner, the TE mode field concentration is positioned above and more closely to the microstrip than with cylindrical resonators. Accordingly, the TE mode field can be positioned much closer to the microstrip than previously possible. |
