Antenna, method for manufacturing the antenna, and communication apparatus including the antenna

摘要

The invention provides a small multimode antenna capable of commonly using a single feeding point at a plurality of frequencies. The antenna includes a radiating conductor 1 disposed above a ground conductor 6 and distributed-constant circuits 2 and 3 coupled to the radiating conductor. Each of the distributed-constant circuits is constructed by a transmission line and has a branch. One end of the radiating conductor and one end of the distributed-constant circuit 2 are connected to each other to be a connection point and, further, the other end of the radiating conductor and one end of the distributed-constant circuit 3 are connected to each other. The connection point is a single feeding point 9 using the ground conductor as an earth. The distributed-constant circuits 2 and 3 are designed as an equivalent circuit in which different stubs are connected in parallel with a transmission line, and impedance matching at a plurality of frequencies is realized at the feeding point.