In general, a known dielectric resonance apparatus includes a resonator having a circular electrode on a surface of a dielectric substrate and power-supply lines which are arranged on the dielectric substrate and which are arranged in the vicinity of ends of the resonator (see, for example, Patent Document 1).
Furthermore, a known oscillation apparatus using a dielectric resonance apparatus includes an oscillator block which oscillates signals having predetermined oscillation frequencies and a dielectric resonator block constituted by a TM010-mode resonator used for setting the oscillation frequencies (see, for example, Patent Document 2). In such an oscillation apparatus, the oscillator block and the dielectric resonator block are separately configured using dielectric substrates. In addition, the dielectric constants and the thicknesses of the dielectric substrates are suitably set for the oscillator block and the dielectric resonator block. Accordingly, a substrate having a low dielectric constant is used for the oscillator block, for example, whereby the accuracy of dimension is relatively enhanced. On the other hand, a substrate having a high dielectric constant and a large thickness is used for the dielectric resonator block, whereby the Q factor is enhanced. Furthermore, mass production of the oscillator apparatus is facilitated by using of the oscillator block and the resonator block in combination.
A known waveguide dielectric resonator includes a substantially cuboid dielectric block (see, for example, Patent Document 3). Such a dielectric resonator includes an input/output electrode having a short-circuit point connected to a ground electrode so as to face a surface on which the dielectric block is implemented. Furthermore, the dielectric resonator is excited using the input/output electrode.
Patent Document 1: Japanese Unexamined Patent Application Publication No. 7-336106
Patent Document 2: Japanese Unexamined Patent Application Publication No. 11-234009
Patent Document 3: International Publication No. WO 2002/078119 pamphlet
In Patent Document 1, the distance between each of the power-supply lines and the ground is set to be larger than the distance between the resonator and the ground so that the power-supply lines and the resonator are strongly coupled with each other. In this case, the thickness of the dielectric resonance apparatus tends to be large since a large space is necessary in the thickness direction of the dielectric substrate, for example, so that a large distance between each of the power-supply lines and the ground surrounding the power-supply lines is ensured. Furthermore, since the power-supply lines are arranged outside of the resonator, the area of the dielectric resonance apparatus also tends to be large. Accordingly, the size of the dielectric resonance apparatus is increased.
In Patent Document 2, a frequency control circuit for controlling the oscillation frequency and a terminating resistor are arranged on the dielectric substrate of the dielectric resonator block. Since the dielectric substrate used for the dielectric resonator block has a high dielectric constant, the cost tends to be increased, and furthermore, the area of the dielectric substrate tends to be increased. This leads to the problem that the production cost of the oscillation apparatus is increased.
Moreover, in Patent Document 3, since a waveguide dielectric resonator is used, the electric characteristics of the resonator is determined in accordance with the length and width of the dielectric block. As processing methods of the dielectric block, a method for processing the dielectric block by baking after injection molding and a method for processing the dielectric block by cutting (dicing) after baking of a dielectric body have been proposed. However, such processing methods lead to large manufacturing error, and therefore, the desired accuracy of dimension is not obtained. Accordingly, it is necessary to enhance accuracies of the length and the width of the dielectric block by performing polishing after formation of the dielectric block, resulting in increased production cost. Furthermore, since an input/output electrode is arranged on the dielectric block which should be subjected to high-accuracy outer-shape processing, the amount of coupling between the dielectric resonator and the input/output electrode is changed if the dielectric block and the input/output electrode are slightly displaced with respect to each other. Consequently, variation of amounts of coupling between individual dielectric resonators and corresponding input/output electrodes is likely to be generated, and variation of the electric characteristics of the resonators becomes large.