Parametric effects in a microwave Read avalanche diode

The parametric effects in the microwave Read avalanche diode are studied using a simplified one-dimensional model. The signals of frequencies ω1and ω2interact with each via the pumping wave of frequencyomega_{0} = omega_{1} + omega_{2}, through the nonlinearity in avalanche. This paper shows the range in which the microwave Read avalanche diode has the parametric negative resistance, some typical values of the impedance matrix elements of the microwave Read avalanche diode, and shows that the small-signal impedance locus of the microwave Read avalanche diode on Smith chart coincides approximately with Kita's experimental results.     

Small-signal analysis of the gate-controlled diode

This paper describes the small signal behavior of MOS gate-controlled diodes. An expression for the capacitance of this device is developed from basic device physics equations. Computer calculations are compared with measured data and the model is seen to predict both the frequency and voltage dependence of the capacitance. The development of this model was made possible through the careful decomposition of teh basic MOS equations into time dependent and static parts.     

Small-signal model with frequency-independent elements for the avalanche region of a microwave negative-resistance diode

An experimentally derived four-element incremental model for the avalanche region of a microwave negative-resistance diode and a simplified measuring procedure for determining the element values are presented. The element values depend on bias but not on frequency. The four-element model predicts the same frequency behavior as the theoretically derived Gilden-Hines model when one degree of freedom is eliminated. Comparison with theory predicts a simple low-frequency (1-MHz) indirect measurement of device drift region carrier transit time.     

Small-signal noise measure of avalanche diodes

A study of small-signal noise measure of avalanche diodes is useful for establishing a reference for large-signal noise theories as well as to determine conditions for low noise operation in low power applications. Such a study depending largely on numerical calculations was presented by Haus et al. Similar results are derived by analytic techniques through the use of a second-order approximation for the avalanche current accounting for transport delay of the carriers in the avalanche region.A uniformly avalanching PIN diode is studied to derive the properties of the avalanche region. In the lossless case the noise measure has a minimum for a carrier transit angle of approximately 2π, while it is inversely proportional to frequency squared for smaller transit angles. Operation close to the avalanche frequency is favorable in a practical case because of parasitic series resistance.The effects of a drift region is included to obtain reasonable modeling of practical avalanche diodes. In the lossless case the impedance transformation and space-charge smoothing in the drift region cause a strong modulation of the noise measure with minima for drift transit angles π < θ_d < 2π and 3π < θ_d < 4π. The noise measure decreases for increasing avalanche widths. Series resistance limits the practical upper drift angle to approximately 1.2π due to the decrease of the negative resistance with frequency.Similar calculations have been carried out for double-drift-region diodes, and show that these in general are noisier than the corresponding single-drift structures in the small-signal limit.     

Small-signal model of the parallel-plane vacuum diode

A small-signal model of the parallel-plane vacuum diode is determined by employing the Lindholm?Hamilton systematic modelling theory.     

Large-signal analysis of a silicon Read diode oscillator

This paper presents theoretical calculations of the large-signal admittance and efficiency achievable in a silicon p-n-v-ns Read IMPATT diode. A simplified theory is employed to obtain a starting design. This design is then modified to achieve higher efficiency operation as specific device limitations are reached in large-signal (computer) operation. Self-consistent numerical solutions are obtained for equations describing carrier transport, carrier generation, and space-charge balance. The solutions describe the evolution in time of the diode and its associated resonant circuit. Detailed solutions are presented of the hole and electron concentrations, electric field, and terminal current and voltage at various points in time during a cycle of oscillation. Large-signal values of the diode's negative conductance, susceptance, average voltage, and power-generating efficiency are presented as a function of oscillation amplitude for a fixed average current density. For the structure studied, the largest microwave power-generating efficiency (18 percent at 9.6 GHz) has been obtained at a current density of 200 A/cm², but efficiencies near 10 percent were obtained over a range of current density from 100 to 1000 A/cm².     

Small-signal wave effects in the double-base diode

Frequency and transient response equations for the current-transfer ratios of the double-base diode are calculated from theory and checked experimentally. To obtain these results, the device is operated as a small signal amplifier in the negative-resistance region and the frequency response characteristics thus obtained are used to predict the device behavior. The effects of carrier recombination and electric field upon the response characteristics are evaluated and experimental results are presented.     

Small-signal performance of a quantum well diode

We study a small-signal performance of a quantum well (QW) diode with triangular emitter and collector barriers providing thermionic electron transport. Analytical expression for the QW diode admittance is obtained from the rigorous self-consistent small-signal analysis. Frequency dependence of the admittance is determined by a characteristic time of recharging of the QW, which is a strong function of temperature and parameters of the QW diode. Conductance as a function of temperature shows a local maximum corresponding to a resonance between a probe signal and recharging processes. Capacitance of the QW diode depends critically on the efficiency of the electron transport through the QW, and can significantly exceed all geometric capacitances associated with the device structure. Experimental data on conductance and capacitance of the QW diode as functions of temperature and frequency can be used to extract the parameters of the QW, such as QW recombination velocity, ionization energy, etc. Analytical analysis of transient currents in the QW diode allows a transparent explanation why an incremental charge-partitioning technique fails to calculate the capacitance even in the low-frequency limit     

Very-high-rank avalanche diode frequency multiplier

Recent experimental observations on silicon avalanche diode multipliers operated at about 35-GHz output frequency are presented. High-rank (up to 35) frequency multiplication is achieved with output power over 250 mW and conversion loss of 13 dB. The possibility of frequency multiplication by any integer n ranging from 8 to 35 with the same diode and without any idler circuit is pointed out. It is concluded that any output frequency can be selected between 28 and 39 GHz by varying the input frequency and the circuit tuning.     

Analog avalanche diode frequency division

The potential interest of analog, avalanche diode frequency dividers is demonstrated. Their fundamental operating principle relies on the use of an idler signal. Experiments performed on avalanche diode frequency dividers with division ratios of 2, 3, and 4 in the centimeter-wave range have pointed out the possibility of wide instantaneous bandwidth and interesting RF conversion efficiencies     

Characterization of avalanche diode TRAPATT oscillators

The characteristics of a coaxial avalanche diode oscillator circuit are calculated and compared with experimental results. The circuit admittance, as seen at the diode terminals, is calculated in the frequency domain for "optimally tuned" experimental conditions. The impulse response function of the circuit, as obtained from the transformed admittance, is used to obtain time-evolution solutions of the avalanche diode circuit system. The impulse response is more general than the previously employed differential equation characterization of a lumped element equivalent circuit. The simulation presented of the high-efficiency mode of oscillation allowed no adjustable parameters and is in excellent agreement with experiment. The simulation verifies the original TRAPATT [1] explanation for the high-efficiency mode of oscillation.     

Noise in gallium arsenide avalanche Read diodes

The noise and signal properties of Read-type avalanche diodes under large-signal levels are examined. In contrast to most other previous theories, we include the saturation current in the equations rigorously from the beginning. We find that the noise performance is a strong function of the saturation current such that high saturation currents lead to lower noise performance. We compare the findings of our model with measurements on two very different Read-type avalanche diodes with a low-high-low profile. In agreement with theory, the lower noise diode has a higher saturation current. We also find experimentally that the noise measure of the diodes used as oscillators decreases with increasing power output. This feature is explained by the rising reverse saturation current with temperature which in some diodes more than compensates the normally increasing noise measure with power output.     

Power amplification using an avalanche diode

A silicon avalanche diode operating in the high-power highefficiency mode of oscillation has been used as a reflection amplifier at frequencies below the oscillation frequency. Saturated power-output levels in excess of 7 W peak have been obtained with 6dB gain at 767 MHz.     

Injection-locked avalanche diode oscillator FM receiver

An injection-locked-oscillator FM receiver has been built in X-band waveguide using an avalanche diode oscillator. Measurements of the output voltage as a function of peak frequency deviation of the input signal were made and compared with theoretical values. Good agreement between theoretical and measured performance indicates that the avalanche diode is adequately described by the van der Pol model and that linear broad-band performance can be expected of the receiver.     

Noise theory for the read type avalanche diode

An analysis is presented for the noise current spectrum of an avalanche diode under assumed conditions of ideal uniform avalanche behavior in a zone which is thin compared with the total high-field depletion zone. The result is applied to the Read diode amplifier. For a typical set of operating parameters, the theory predicts a noise figure on the order of 40 dB. Depending upon particular device parameters, lower noise figures may be 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.     

Oscillation mechanism of avalanche region of the IMPATT diode

The oscillation mechanism of the avalanching region of the IMPATT diode is clarified by referring to the cavity resonator and feedback theories. When the avalanche takes place, the microwave electric field and the particle currents grow spacially. But the spacial growth does not directly mean the self-oscillation, as there exists the reflection loss at the region edges. When the gain due to the avalanche exceeds the reflection loss, the self-oscillation can take place. The preceding phenomena are analyzed by the conception of the open-loop transfer gain in feedback theory.     

A potentially low-noise avalanche diode microwave amplifier

A sequence of AlGaAs, GaAs heterojunctions can be used to generate a series of potential steps that are just large enough to accelerate conduction-band electrons to energies above the impact-ionization threshold while valence-band holes do not obtain this much energy. The smaller difference in the valence-band heterojunction discontinuity and the higher scattering rate for holes than conduction-band electrons are shown to suppress the initiation of impact ionization by valence-band holes in this structure. The resulting transit-time device is predicted to be a relatively low-noise amplifier or oscillator that can be used in the microwave region and will be insensitive to small fluctuations in the power supply voltage.     

Microwave Si avalanche diode with nearly-abrupt-type junction

Microwave Si avalanche diodes with a nearly-abupt-type junction have been made. The maximum output power so far obtained in CW operation is 1.1 watts at 12 GHz with an efficiency of 7.7 percent. The maximum efficiency observed is 8.0 percent. The improved performance over the previously reportedp nu nstructure, for which the best result was 250 mW at 12 GHz with an efficiency of 2.8 percent results from a reduction in length of the avalanche region in the abrupt junction. In the previously reportedp nu ndiode the efficiency is still sharply increasing at the burnout point, while in the present diode the efficiency is nearly saturated at the burn-out point. The advantages and disadvantages of using different polarity of the diode (p on n or n on p) and different material (Ge) are given. Small-signal theory was used to analyze device operation.     

GaAs double-drift avalanche diode from vapour-phase epitaxy

p-type doping of GaAs grown by a vapour-epitaxy technique is accomplished in the range of 1015 cm?3 using a Zn source in a controlled-temperature zone, n-type doping is accomplished by admitting a controlled admixture of SnCl4 and AsCl3 into the system. Diodes were fabricated from a p?n?n+ substrate wafer and operated in an I?C TRAPATT mode in a compact circuit. TRAPATT action yields a spiky current waveform useful as a pulse generator.