Compact four bands hybrid filtering antenna using step impedance resonators and tuning stub transition structures

Abstract

A novel compact four bands hybrid filtering antenna composed of a hybrid radiator and a four bands bandpass filter is presented. The hybrid radiator is constructed using the micro-strip line fed, the square-ring and the T-stub near the ground plane. The proposed four bands bandpass filter is composed of two parts, one is two-step impedance resonators (SIRs) and the other is the tuning stub transition structure. With tuning stub transition structure, two SIRs effectively match to 50 hybrid radiator. Furthermore, the geometry of the proposed filter is U-shaped with the micro-strip fed around the hybrid radiator. The evolution of the hybrid radiator and the construction of the four bands bandpass filter using the two SIRs and the transitions are discussed in detail. The proposed filtering antenna not only possesses numerous operation bands with good band edge gain selectivity but also reduces the occupied size in the modern communication device. The overall size of the proposed filtering antenna is 33mmx36.4mmx0.508mm, and the operation frequencies are 1.8/2.45/3.5/5.2GHz bands for GSM1800/WLAN/WiMAX applications. The measured results agree with simulated outcomes.