Mobile radio terminal and surface acoustic wave antenna duplexer

摘要

An antenna duplexer is reduced in size, so that a dual-band/triple-band mobile radio terminal small in size and light in weight is realized. An off-set PLL modulation system is adopted, and a transmitting system of the antenna duplexer is constituted by switches. Further, in mounting an SAW filter, a multi-layer substrate is adopted, matching circuits and so on are formed by lumped-constant circuit elements, and the SAW filter is received in a space provided on the multi-layer substrate.