抄録
A cognitive radio system, which is researched to use a limited frequency resource effectively, requires a tunable filter with a wide variable frequency range. A resonator with wide band is required to realize the tunable filter. It was reported that a resonator composed of a Cu-electrode/15°YX-LiNbO3 had wide bandwidth of 12%. This time, authors attempted to fabricate an one-port resonator composed of a grooved Cu-electrode/4°YX-LiNbO3. As the result, it had a wider bandwidth of 17% of 1.3 times than that on Cu electrode/4°YX-LiNbO3. This resonator was applied to a tunable filter, and as the results, the tunable filter having tunable range of 6.8% in center frequency was experimentally realized using a band pass filter type circuit, and those having tunable range of 9 to 12% theoretically using a ladder type circuit.
