| 摘要 |
<p>A transmission band filter (110) having a series of elements (111, 113, 115) each composed of a film bulk acoustic resonator and grounded shunt elements (112, 114) is connected between a transmission port (102) and an antenna port (106). A reception band filter (130) having a series of elements (131, 133, 135) each composed of a film bulk acoustic resonator and grounded shunt elements (132, 134, 136) is connected between a reception port (104) and the antenna port (106). A film bulk acoustic resonator (150) for adjustment is connected between the antenna port (106) and the ground. The resonance frequency of the adjusting film bulk acoustic resonator (150) lies between the upper limit frequency of the transmission frequency pass band of the transmission band filter (110) and the lower limit frequency of the reception frequency pass band of the reception band filter (130). Therefore a transmission/reception switch such that the switch can be a monolithic element, the breakdown power is good, the size is small, and the cost is low is provided.</p> |
