2. Tunable Wideband Microwave Filter Modules Using Ferromagnetic Resonance (FMR) Tuning in Planar Layer- and Magnonic-Structures
"New integrated microwave band-stop and band-pass filter modules have been realized and magnonic bandgaps tuning demonstrated for potential applications in wideband communications and signals processing."

Wideband tunable band-stop and band-pass filters (BSF and BPF) that possess frequency selectivity with high absorption level and large absorption bandwidth are essential in many communication and radar systems for suppression of frequency parasitics, spurious bands or harmonics. The objective of this research is to devise and realize such tunable BSF and BPF modules operating at carrier frequencies up to Ku-band. Three BPF modules of distinct architectures have been realized. The modules utilize a pair of FMR-tuned YIG/GGG thin-film band-stop filter (BSF) in cascade. Each BSF is capable of high peak-absorption level and large absorption bandwidth by using a meander line with multiple segments of step-impedance low-pass filter (SILPF) together with non-uniform bias magnetic fields. Additional broadening and tuning of passband has also been accomplished usin variable capacitance diodes (varactors). Figs.1(a) and (b) show the latter module and tuning of its passband, respectively.

In contrast to the optical bandgaps in conventional photonic crystals, the microwave bandgaps in magnonic crystal are tunable by a bias magnetic field. An excellent agreement between the calculated bandgaps and field-tuning for the magnetostatic volume waves in a 1-D YIG/GGG magnonic structure with periodic variation in YIG layer thickness and the experimental results has been achieved.



Fig.1(a)



Fig.1(b)



  • Selected Recent Publications

    1. "An Approach for Analysis of Magnetostatic Volume Waves in Magnonic Crystals" K.H. Chi, Y. Zhu, R.W. Mao, J.P. Dolas, and C.S. Tsai (J. of Applied Physics, 109, 07D320 (2011)2011).
    2. "A Varactor- and FMR-Tuned Wideband Band-Pass Filter Module with Superior Frequency Selectivity" Y. Zhu, R.W. Mao, and C.S. Tsai, ( IEEE Trans. Magn., 47,284-288, Feb. 2011).
    3. "A Compact X-Band Tunable Band-Pass Filter Module Using A Pair of Microstrip Composite Band-Pass Filters in Cascade" Y. Zhu, G. Qiu, K.H. Chi, B.T. Wang, and C.S. Tsai, IEEE Trans. Magn., 46 (6), 1424-1427, Jun 2010.
    4. "A Tunable X-band Band-Pass Filter Module Using YIG/GIG Layer on RT/Duroid Substrate" Y. Zhu, G. Qiu, K.H. Chi, B.T. Wang, and C.S. Tsai, IEEE Trans. Magn., 45 (10), 4195-4199, Oct. 2009.
    5. "Wideband Microwave Filters Using Ferromagnetic Resonance Tuning in Flip-Chip YIG-GaAs Layer Structures" C.S. Tsai and G. Qiu, IEEE Trans. Magn.,Vol. 45, pp.656-660, 2009.
    6. "Enhanced Microwave Ferromagnetic Resonance Absorption and Bandwidth Using A Microstrip Meander-Line Step-Impedance Low Pass Filter in A YIG-GaAs Layer Structure" G. Qiu, C.S. Tsai, M.M. Kobayashi, and S.T. Wang, Special Issue of Journal of Applied Physics, 103, 07E915, April 15, 2008.
    7. "A YIG/GGG/GaAs-Based Magnetically Tunable Wideband Microwave Band-pass Filter Using Cascaded Band-stop Filter." G. Qiu, C. S. Tsai, B. S. T. Wang, Y. Zhu, IEEE Trans. Magn.,Vol. 44, 3123-3126, 2008.
    8. "Ferromagnetic Films with Magnon Bandgap Periodic Structures: Magnon Crystals." Y.V. Gulyaev, S.A. Nikitov, C.S. Tsai, et al., JETP Letters,77, 567-570, 2003.(selected for inclusion in Virt. J. of Nanoscale Sci. and Tech.)

     

    Last revision: 12/2010. Site designed by James Dolas and Yun Zhu.