Bistable switching in a planar Gunn diode

This paper presents experimental and theoretical results showing that bistable switching, due to an anode-triggered trapped domain (TD), can be realized in a Gunn diode with an anode notch. The characteristics of the anode-triggered TD have been made clear by computer simulations. Bistable switching has been confirmed experimentally by using a planar Gunn diode with a groove, which was intentionally dug close to the anode.     

A periodic planar Gunn diode power combining oscillator

Several planar periodic power combining oscillators containing two to six Gunn diodes operating in the X-band region are discussed. The maximum power combining efficiency, 126.7% was obtained from the three-diode oscillator. The frequency dependence of all the power combiners on the bias voltage variation seemed to be independent of the number of diodes. Injection locking was maintained over a large variation of the bias voltage     

Pulse generation in planar Gunn devices with varying nL product

Measurements of the current reduction in planar Gunn devices by domain nucleation are reported. The devices were made of epitaxially grown GaAs layers. The measurements showed a decrease of the current reduction, relative to the threshold current Ith, with decreasing nL product, beginning at about nL = 1013 cm?2, where n is the electron concentration and L is the length of active channel.     

Dynamic elastance of a Gunn diode

The time-varying elastance of a Gunn diode is deduced by the application of a simple domain-growth and decay model. The time variation of the elastance is seen to be significantly different from the previously assumed ideal pulsed nature.     

Rectangular-pulse generator and memory element with a Gunn diode

A circuit which utilises a Gunn diode with a coaxial line to generate rectangular waves is described. This circuit operating in the frequency range up to 200MHz can also behave as a memory element.     

Delay structures with planar Gunn devices

A pulse delay obtained with the aid of the domain travelling effect in Gunn devices is described. For this purpose, the planar Gunn devices contain, in addition to a trigger electrode, a capacitive electrode for coupling out the signal. Experimental results are given for the single component and a monolithic integrated cascade circuit. The devices are appropriate for constructing dynamic shift registers in the sub-nanosecond range.     

Domain width in a dielectrically loaded Gunn diode

The width of the travelling high-field domain in a Gunn diode has been determined for a device with one surface loaded by a dielectric material (LiNbO3). The domain width inferred from the shape of the acoustic pulse that is generated in the adjacent piezoelectric dielectric material.     

Theoretical study of a Gunn diode in a resonant circuit

A computer simulation of a GaAs Gunn diode in a parallel resonant circuit has been made to determine the optimum device and circuit parameters. The maximum dc to RF efficiency, 5 to 8 percent, is obtained when the product of doping and length is between 10¹²and 2 × 10¹²cm^-2, the product of frequency and length is 10⁷cm/s, and the bias voltage divided by length is 8000 V/cm for a load resistance of30 R_{0}where R0is the low-voltage resistance of the diode. The product of output power and load resistance varies with frequencyfasC f^{2}whereCis 12,000 watt-ohm-GHz²for a load resistance of50 R_{0}. The frequency can be varied over an octave tuning range by the resonant circuit.     

GaAs planar Gunn digital devices with subsidiary anode

GaAs planar Gunn digital devices with a subsidiary anode are proposed. The subsidiary anode is effective in suppressing the pathological growth of the high-field layer near the anode. Gate triggering by small input pulses below 100 mV is possible     

Small-signal 2-terminal impedance of a thin Gunn diode

An approximate expression for the 2-terminal r.f. impedance of a thin Gunn diode is derived. From this, one can deduce a parallel equivalent circuit for the diode. The results are compared with the 1-dimensional model of Engelmann and Quate, and it is shown that the finite transverse dimensions of the diode can considerably affect its shunt capacitance. This result is applied to rederive a known stability criterion for thin Gunn diodes, and to correct the l.s.a. conditions of Copeland if thin diodes are being used.     

Gunn diode oscillator constructed in nonradiative dielectric waveguide

The physical construction of a Gunn diode oscillator in non-radiative dielectric waveguide is described. A stripline construction is used for biasing, and the diode is mounted so as to feed a slot which in turn launches the wave into the wave-guide.     

Spice-aided modelling of the UC3842 current mode PWM controller with selfheating taken into account

This paper deals with the problem of modelling current mode PWM controllers with the use of SPICE. The monolithic integrated circuit UC3842 is considered in the paper. Two isothermal models of UC3842 known in the literature are compared, tested and discussed. A new electrothermal model (ETM), including selfheating, of the considered controller is proposed and described in detail. The experimental verification of the ETM showed its much greater accuracy compared to the isothermal models of the investigated device.     

A planar bipolar diode with relativistic electrons

The paper presents a detailed study of the characteristics of a bipolar diode with relativistic electrons and of the influence of the intrinsic azimuthal and external longitudinal magnetic fields on the adequacy of the theory of bipolar and unipolar electron flows. Questions on the urgency of the use of bipolar beams in modern devices, including plasma microwave electronic ones, are considered.     

3G畅想:国内客户将如何选择移动运营商?

随着3G新业务即将到来，国内固网运营商逐步涉足移动通信服务领域，并显示出一定的竞争实力，同时．更换运营商的成本正在降低．客户更换移动运营商的现象也在增多。研究客户在选择移动运营商时的考虑因素，对于运营商把握未来的客户市场非常重要。     

High-bit-rate pulse regeneration and modulation of injection lasers with a planar Gunn device

A simple circuit with a Schottky-barrier-gate Gunn device is presented, which works as a pulse regenerator and modulator for laser diodes. Modulation depth and bias voltages of both Gunn device and laser are separately adjustable, allowing quick adaption for different laser diodes. The circuit was tested with a p.c.m. word at 1.5 Gbit/s.     

CW operation of GaAs planar Gunn diodes with evaporated contacts

The modification of an evaporated contact GaAs Gunn diode is reported in which geometry control is used to achieve improved terminal characteristics. The devices operate in a CW mode at a reduced terminal voltage and have excellent trigger response.     

Doping of IV-VI semiconductors and the energy spectrum of holes with resonance states taken into account

Kinetic phenomena in the Pb_0.5Sn_0.5Te solid solution have been studied in wide ranges of concentrations and temperatures in the case of two types of acceptor doping: with overstoichiometric tellurium and with a combination of equal amounts of Na and Te atoms; in the latter case, two additives amounting to 1.0 and 1.5 at % of each element have been used. Hole densities attained in this case significantly exceeded the largest values corresponding to the Pb_0.5Sn_0.5 Te:Te samples. For both types of acceptors, the hole concentration in the solid solution is found to be a factor of 2 higher than in PbTe with the same level of doping. The specific features of behavior of the Hall coefficient, thermopower, and electrical conductivity are interpreted in the context of a model of a single-valence-band spe ctrum with a wide band of resonant levels. The mechanism of formation of resonant levels in PbTe and Pb_0.5Sn_0.5 Te solid solutions is discussed.     

Design fabrication of low noise Gunn diode with consideration of a thermocompression bonding effect

In order to reduce 1/f noise generated by Gunn diodes, an experimental study was made on the effects of thermocompression bonding on Gunn oscillator noise. It is found that carrier traps at dislocations introduced into the Gunn diode by the thermocompression process increase the Gunn oscillator noise significantly. An optimum thermocompression bonding condition for minimizing Gunn diode 1/f noise is described, taking into account such parameters as doping density and device area.     

Difference-frequency generation in a butt-join diode laser

The intracavity difference-frequency generation in the middle-infrared region in the GaAs/InGaAs/InGaP butt-join diode lasers with quantum wells is experimentally studied.     

Noise in Gunn-oscillators depending on surface of Gunn diode

By chemical treatment of the surface of the Gunn element, the f.m. and a.m. noise can be improved. A possible explanation is given. For this case, traps on the surface exist and McWhorter's model is applied.