Design of miniaturised balun filter with tunable power division ratio and centre frequency. Issue 12 (1st June 2017)

• Record Type: Journal Article
• Authors: Zhu, Chuanming; Xu, Jin; Kang, Wei; Hu, Zhenxin; Wu, Wen
• Is Part Of: Electronics letters. Volume 53:Issue 12(2017)
• Page Start: 787
• Page End: 789
• Publication Date: 2017-06-01
• Subjects: baluns -- transmission lines -- varactors -- filters; miniaturised balun filter design -- tunable power division ratio -- centre frequency -- PDR -- varactor diode -- slide rheostat -- transmission line -- electrical length -- passband frequency -- dual‐mode resonators; Electronics -- Periodicals; 621.381
• DOI: 10.1049/el.2017.0866
• Languages: English
• ISSNs: 0013-5194

Abstract

Abstract : A miniaturised balun filter with tunable power division ratio (PDR) and centre frequency is presented. Compared with the conventional balun filter, the proposed one with a varactor diode and a slide rheostat loaded onto transmission line (TL) reduces the electrical length of TL from 180° to 108°. Meanwhile, the varactor diode and slide rheostat are also utilised to control the PDR at two output ports. Moreover, passband frequency can be tuned by controlling the varactor diodes loaded onto the dual‐mode resonators. The proposed balun filter achieves a tunable power division from 1:1 to 3:1 and 28.6% wide frequency turning with better than 12 dB return loss. The total electrical size of fabricated circuit is 0.23 × 0.12 λg .