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

• Published in: IET microwaves, antennas & propagation antennas & propagation, 2018-06, Vol.12 (7), p.1126-1131
• Main Authors: Chen, Keng-Hsien, Lo, Yu-Chen, Lee, Yi-Shi, Wu, Sung-Jung, Tarng, Jenn-Hwan
• Format: Article
• Language: English
• Subjects: antenna feeds; antenna radiation patterns; band edge gain selectivity; band‐pass filters; compact four‐band hybrid filtering antenna; filter geometry; filtering antenna; four‐band bandpass filter; frequency 1.8 GHz; frequency 2.45 GHz; frequency 3.5 GHz; frequency 5.2 GHz; GSM1800‐WLAN‐WiMAX applications; hybrid radiator; microstrip antennas; microstrip line feed; microstrip lines; Research Article; SIR; square‐ring; step impedance resonators; tuning; tuning stub transition structure; tuning stub transition structures; two‐step impedance resonators; T‐stub; UHF antennas
• ISSN: 1751-8725; 1751-8733; 1751-8733
• DOI: 10.1049/iet-map.2017.0830

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 Ω 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 33 mm × 36.4 mm × 0.508 mm, and the operation frequencies are 1.8/2.45/3.5/5.2 GHz bands for GSM1800/WLAN/WiMAX applications. The measured results agree with simulated outcomes.