1-6hit |
Ikuo SUEMUNE Makoto FUKUSHIMA Tai-Ho CHIANG Tadasu KAWANO
Large-signal analysis of an IMPATT diode is presented, where the effect of harmonic-frequency circuits is included. The particle current and the AC voltage in a diode are expanded into Fourier series, and their harmonic components are related with each other by the corresponding impedances of the harmonic-frequency circuits. The numerical results show that the oscillation power of the IMPATT diode is considerably increased by the appropriate choice of the harmonic-frequency circuits. The theoretical model is also applied to an actual IMPATT oscillator. The oscillation characteristics of the circuit is clarified by the numerical calculations, and the results are almost in good agreement with the experiment.
Ikuo SUEMUNE Toyosaka MORIZUMI Syoko SHIOKAWA Tsutomu YASUDA
Surface acoustic wave (SAW) propagations along
Ikuo SUEMUNE Toyosaka MORIIZUMI Atsuhiro MATSUDA Tsutomu YASUDA
A simple theoretical model for surface acoustic wave (SAW) ΔV/V waveguides on anisotropic crystals is presented. Applying the theory to the waveguides on Y-cut LiNbO3, the dispersion relations are calculated. Experimental results of the velocity dispersion were shown to be in a reasonable agreement with the theory. Although the observation of the SAW field revealed a small discrepancy from the theoretically predicted profile outside the waveguide, it can be concluded that the present model gives a very good approximate method to the study of ΔV/V waveguides on anisotropic substrates.
The equivalent circuit constants of a packaged IMPATT diode were precisely determined from measured impedance data employing numerical calculations. The errors included in the element values are estimated to be small from the comparison of the measured and the calculated input impedances of the circuits.
Atsuhiro MATSUDA Toyosaka MORIIZUMI Ikuo SUEMUNE Tsutomu YASUDA
Ikuo SUEMUNE Masamichi YAMANISHI Nobuo MIKOSHIBA Tadasu KAWANO
Acoustic distributed feedback (ADFB) lasers with stripe active regions for current injections have been theoretically analysed. The theory is based on a coupled-mode analysis employing Bragg guided modes. The characteristic equation of oscillation for the two-dimensional DFB laser is derived in an explicit form. The mode spectra and the threshold gains for the onset of the oscillation of the ADFB laser are obtained, and the characteristics of the two-dimensional mode structure is discussed. Also discussed is the effect of complex photoelastic constants.