Patent ID: 7446629

Claim:
An antenna duplexer comprising: an antenna terminal; a transmission terminal; a receiving terminal; a transmission filter connected between the antenna terminal and the transmission terminal; and a receiving filter connected between the antenna terminal and the receiving terminal, wherein: one of the transmission terminal and the receiving terminal is a balanced type terminal, and another of the transmission terminal and the receiving terminal is an unbalanced type terminal; at least one of the transmission filter and the receiving filter includes a surface acoustic wave resonator; the balanced type terminal is connected to a longitudinal mode coupled surface acoustic wave filter, both the transmission filter and the receiving filter include a film bulk acoustic resonator serially connected to the antenna terminal and at least one of the transmission filter and the receiving filter includes a film bulk acoustic resonator connected in parallel between the antenna terminal and ground; and a number of film bulk acoustic resonators connected in parallel between the antenna terminal and ground is less than a number of film bulk acoustic resonators serially connected to the antenna terminal.