| 摘要 |
The present invention provides an unbalanced input and balanced output type SAW filter capable of obtaining stop-band attenuation approximately equivalent to that of an unbalanced input and unbalanced output type SAW filter. IDTs (12) (13) are respectively disposed on each side of a middle IDT (11). A comb electrode (11c) of the middle IDT (11) is connected with an input terminal (In) and other comb electrode (11b) is grounded. A comb electrode (12c) of the IDT (12) and a comb electrode (13b) of the IDT (13) are respectively connected with output terminals (Out 1) and (Out 2), and other comb electrode (12b) of the IDT (12) and other comb electrode (13c) of the IDT (13) are connected to each other and grounded. Electrode fingers (11a), (12a), (13a) of the middle IDT (11) and the side IDT (12), (13) are so arranged that adjacent electrode fingers of the middle IDT and the IDT on one side make a connection between terminals and the other adjacent electrode fingers of the middle IDT and the IDT on other side make a connection between a terminal and a ground.
|
