Mushroom structure exhibits unique electromagnetic properties that have led to a wide range of application in microwave and antenna community. This paper focuses on the electromagnetic band-gap (EBG) characteristic of the mushroom structure with the suspending microstrip line, and a new concept of the mushroom interlaced periodic arrayal has proposed. By the simulated and measured results, it is verified that the mushroom structure with the suspending microstrip line can generate multi-band EBG characteristic. Moreover, we use the new concept to design a new triplexer circuit. The triplexer can integrate three kinds of communication systems with each other, which operate at frequencies including GSM 1800MHz, WiFi 2.45GHz, and WiMAX 3.5GHz, respectively.