Nonlinear operation of an analog frequency divider using a GaAs dual-gate FET has been studied theoretically and experimentally. It is shown that the log-log plot for basic input/output characteristics of the divider shows straight lines in the second, third, and fourth regions adjacent to the first narrow threshold region in the increasing order of input power magnitude. It is suggested from theoretical consideration that universality of the exponent K appearing in the P_outP_in^K relation holds at least approximately. The value of K in the second region is found to be about 3.0 theoretically and experimentally and is in agreement with the value reported in an earlier paper. The strict but obvious universality of K holds in the third and fourth region with K=1 and 0, respectively.

Electronic circuits operating from low-voltage power supplies are required in battery operated equipments and in monolithic ICs realized using high-frequency high-density integrated circuit technology. High-frequency active filters that are suited for monolithic implementation using integrators based on negative impedance converters (NICs) have been presented in the literature. In this paper a low-voltage NIC-integrator is presented along with some applications to high-order high-frequency active filters. Methods to compensate the losses of integrators suitable for high-frequency low-power applications are introduced. Realizations of high-order filters with transmission zeros without floating capacitors or additional summers are also presented. Experimental and simulation results are shown to confirm the validity of the proposed circuits.

A novel transistor, introducing metal and iusulator and using the quantum interference of hot electrons in the conduction band of an insulator as the operation principle, is proposed. The metal-insulator combination contributes to the reduction of the device size and obtaining high current density, low resistivity, and small capacitance, which result in the decrease of the response time of the device. Also, since this combination has the extremely high conduction band discontinuity, strong quantum interference can be obtained. The static I-V characteristics are analyzed and it is shown that there are multiple peaks useful for a variety of signal processing and logic applications. In addition, since the gradient between each peak and valley in the characteristics is steep, the device used as an amplifier has a high transconductance which contributes to the reduction of the response time. We show the possibility of subpicosecond response (0.2 ps) of this device theoretically.

The stability and output power of the fundamental transverse mode in a surface emitting laser has been studied by simulation. We have employed a 3-dimensional beam propagation method considering refractive index and gain changes due to carrier variations in an active medium by solving a diffusion equation. From this simulation, the higher order mode suppression ratio can be as large as 35 dB for injection levels higher than 1.5 times the threshold, and out of more than 10 mW can be expected when the diameter of one side mirror is about 5 µm and the active layer thickness d=0.5-1.0 µm.

This paper deals with electromagnetic wave scattering by an infinite plane metallic double grating with three dielectric layers in case of E- and H-waves excitations. The field expressions for this problem are obtained by making use of superposition of the results of the single grating case. The analytical method used here is based on the spectral domain method combined with the sampling theorem. Some numerical results are presented for the near fields such as the surface current distributions on the strips and for the far fields such as the frequency characteristics as well as the insertion loss from the viewpoint of a polarization discriminator.

An equilateral triangular reflector is inserted into an E-plane symmetrical T-junction in order to improve the wave transmission characteristics from the truncated-guide to the through-guide. The reflector is installed in contact with the wall of the through-guide facing the junction plane. In the case that the truncated-guide width b is equal to the through-guide width c, we find that the larger the top angle of the triangle is made, the better the wave transmission becomes. In particular, we can attain a remarkable improvement in obtuse triangles of the top angle θ100 and the height h0.6b. For instance, in the triangle of θ120 and h0.6b, at least 99.5 percent of the energy fed from the truncated-guide transmits evenly into the other two arms, and 0.5 percent at most reflects over the frequency range of 0.31b/λ_g0.37. The λ_g is the guided wavelength.

We have studied the oxidation state of Al/Hf and Ta/Hf bi-layered films by AES/XPS analysis. The anion transport process through the upper oxidized layer which is oxygen supply medium for Hf oxidation is examined. It is found that the oxidation reaction of Hf occurring with sufficient anion transport through the upper oxidized layer corresponds to the excellent properties as capacitors.