Title :
A Novel Tunable Planar Isolator with Serrated Microstrip Structure
Author :
Wu, Jing ; Li, M. ; Yang, X. ; Beguhn, S. ; Sun, Nian X.
Author_Institution :
Dept. of Electr. & Comput. Eng., Northeastern Univ., Boston, MA, USA
Abstract :
A novel type of tunable isolator was presented, which was based on a polycrystalline yttrium iron garnet (YIG) slab loaded on a planar periodic serrated microstrip transmission line that generated circular rotating magnetic field. The direction of circular polarization inside the YIG slab with a DC magnetic bias perpendicular to the transmission line was proved to be opposite, RHCP for forward and LHCP for backward transmission. The non-reciprocal ferromagnetic resonance absorption leads to over 19 dB isolation and <; 3.5 dB insertion loss at 13.5 GHz with 4 kOe bias magnetic field applied perpendicular to the feed line. Furthermore, the tunable resonant frequency of 4 ~ 13.5 GHz was obtained for the isolator with the tuning magnetic bias field 0.8 kOe ~ 4 kOe. The proposed serrated microstrip isolator prototype should have many applications in RF front and other microwave circuits.
Keywords :
ferrite isolators; ferromagnetic resonance; garnets; microstrip lines; slabs; transmission lines; DC magnetic bias; LHCP; RHCP; YIG slab; backward transmission; bias magnetic field; circular polarization; circular rotating magnetic field; feed line; forward transmission; frequency 13.5 GHz; insertion loss; microwave circuits; nonreciprocal ferromagnetic resonance absorption; planar periodic serrated microstrip transmission line; polycrystalline yttrium iron garnet slab; serrated microstrip isolator prototype; serrated microstrip structure; tunable planar isolator; tunable resonant frequency; tuning magnetic bias field; Ferrites; Insertion loss; Isolators; Magnetic resonance; Microstrip; Saturation magnetization; Ferromagnetic resonance frequency; serrated microstrip isolator; tunable isolator; tunable reconfigurable RF systems; yttrium iron garnet;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2012.2195303