We designed an ultra-high frequency (UHF: 300 MHz to 3 GHz) ferrite circulator to investigate magnetic parameters, which are suitable for a self-biased GHz circulator design. The size of the ferrite disk was 1.58 mm in thickness and 13.5 mm in diameter. The saturation magnetization (4πM s ) of 3900 Gauss, internal magnetic field (H in ) of 1 kOe, and ferromagnetic linewidth (ΔH) of 354 Oe were used in circulator performance simulation. The simulation results show the isolation of 36.4 dB and insertion loss of 2.76 dB at 2.6 GHz and were compared to measured results. A Ni-Zn ferrite circulator was fabricated based on the above design parameters. An out-of-plane DC magnetic field (H 0 ) of 4.8 kOe was applied to the fabricated circulator to measure isolation, insertion loss, and bandwidth. Experimental magnetic parameters for the ferrite were H in of about 1.33 kOe and 4πM s of 3935 Gauss. The isolation 43.9 dB and insertion loss of 5.6 dB measured at 2.5 GHz are in close agreement with the simulated results of the designed ferrite circulator. Based on the simulated and experimental results, we demonstrate that the following magnetic parameters are suitable for 2 GHz self-biased circulator design: 4πM r of 3900 Gauss, H a of 4.5 kOe, H c greater than 3.4 kOe, and ΔH of 50 Oe.

The result on magnetoluminescence study of the exciton in GaAs/AlosGao.sAs quantum wire (QWR) superlattice grown on vicinal GaAs substrate are reported. For 30 T, the diamagnetic shift is 7.8 meV for QWR of 4 nm wide, while it is 11 meV for QWR of 8 nm or wider. For 4 nm QWR, the diamagnetic shift remains the same up to 17 T for the magnetic field parallel and angled to the growth direction. But, it saturates in the angles geometry at 17 T where the cyclotron diameter becomes comparable to QWR width. If the lateral confinement model is introduced in the formation of exciton in QWR, the saturation can be interpreted as the breaking of inter-wire coupling.

Abstract-Planar gigahertz (GHz) inductors were fabricated based on high crystalline-anisotropy Zn 0.13 Co 0.04 Ni 0.63 Fe 2.2 O 4 (Zn-Co-Ni ferrite) and Ba 3 Co 2 Fe 24 O 41 (Co 2 Z hexaferrite) and characterized for inductance (L) and quality (Q) factor. The planar ferrite inductors show an L of 4.5 nH (Zn-Co-Ni), 5.6 nH (Zn-Co-Ni + low H k and f FMR Co 2 Z:), and 4.8 nH (Zn-Co-Ni + high H k and f FMR Co 2 Z:) at 2 GHz. The corresponding L-densities are 18.0, 22.4, and 19.2 nH/mm 2 , which are greater than 16.8 nH/mm 2 of the air-core inductor. With respect to the Q factor, the air-core and ferrite inductors exhibit Q factors of 6.7 (air-core), 4.8 (Zn-Co-Ni), 2.8 (Zn-Co-Ni + low H k Co 2 Z), and 4.0 (Zn-Co-Ni + high H k Co 2 Z) at 2 GHz. The tan δ µ of the ferrites caused a reduction in the Q factor. Nevertheless, the high H k and f FMR Co 2 Z ferrite inductor demonstrates a higher Q factor than that of the low H k and f FMR Co 2 Z inductor. It is, therefore, suggested that high resistivity, anisotropy, magnetization ferrite can produce large L density and Q factor GHz inductors.

The &man splitting and diamagnetic shift of heavy-hole exciton in GaAs/ ~0.2jGa0.75k multi-quantum wells (MQW) were investigated for various barrier widths by magnetoluminescence up to 30 T at 4.2 K. It is obtained that the diamagnetic shift is independent to the barrier width (LB), but the effective g-factor becomes smaller as LB decreases for a fixed QW width. Also repxted is the fine splitting due to the exchange interaction for LB I 50 A.