Yasuaki Kinoshita

Planar resonator and integrated oscillator using magnetostatic waves

A simple planar resonator using a magnetostatic wave (MSW) excited by aluminum finger electrodes with two bonding pads was realized on YIG/GGG (yttrium-iron-garnet film on a gadolinium-gallium-garnet crystal) substrate with two reflection edges. The tunable MSW resonator chip (2 mm*5 mm) exhibited a sharp notch filter response, as deep as 20-35 dB, and a high loaded Q up to 2000, which was tunable over the microwave frequency range from 2 to 4 GHz. A small tunable oscillator (8 cm/sup 3/) was experimentally demonstrated using the MSW planar resonator and a silicon bipolar transistor integrated on a ceramic microwave circuit substrate. Microwave oscillation with spectral purity, at the same level as that of YIG sphere technology, was observed at 3 GHz. The experimental results indicate the technical areas where improvement must be made to realize a practical oscillator configuration.<<ETX>>

Voltage controlled oscillators with planar MSW resonators

A 5-GHz-band voltage-controlled oscillator has been developed using a planar MSW (magnetostatic wave) resonator. The magnetic circuit has been designed using a finite element method and an NdFeB magnet, which well compensates the temperature dependence of the MS forward volume wave. The impedance matching of planar MSW resonators to a negative-resistance circuit is discussed. The developed MSW-voltage-controlled oscillators satisfy the requirements of a portable TV link. The output frequency can be linearly tuned over a 1-GHz span and the phase noise is better than -115 dBc/Hz at 100 kHz off-carrier through the tunable range. some practical points such as size, power consumption, and stability under temperature variation and mechanical vibration are also considered.<<ETX>>

Low loss and high performance SAW filters for 800 MHz mobile telephone transceiver

Low loss surface acoustic wave (SAW) filters have been developed for use in the radio frequency circuits of the mobile telephone transceiver. Both the UHF (800 MHz) and VHF (90 MHz) band-pass filters have exhibited high performance, and the employment of the SAW filters has shown advantages in UHF/VHF circuit integration for mass production.

Fluctuation Distribution of Collimated and Focused Gaussian Beams Propagated through a Random Medium

Three-dimensional distributions of the log-amplitude and phase fluctuations of a gaussian beam propagating through a randomly inhomogeneous medium are studied by evaluating their mean-square values. Diagrams are given of the lines of equal fluctuations of normalized log amplitude and phase for a collimated beam and a focused beam. The dependence of the three-dimensional fluctuation distribution upon the beam shape as functions of the beam radius and the focal length is discussed.

Further Correlation Studies of Gaussian-Beam Fluctuations Caused by a Random Medium

Study of autocorrelations of the fluctuations in a gaussian beam propagating through a random medium of gaussian inhomogeneity is extended in this paper to considerations of the spatially transverse autocorrelations of the log-amplitude or phase fluctuations at two off-axis positions over the cross section of the collimated and focused beams. Two-dimensional autocorrelation distributions with respect to one fixed off-axis point are obtained over the beam cross section at and near the focal position of a focused beam. The cross correlations of log-amplitude and phase fluctuations for the collimated and focused gaussian beams propagating through a random medium have also been evaluated as functions of the wave parameter, the normalized focal length, and the source-aperture size. A comparison is made among the cross-correlation coefficients for plane, spherical, and gaussian beams.