Showing papers on "Negative resistance published in 1978"

p-n-p-n optical detectors and light-emitting diodes

Abstract: Light-emitting diodes with the high-radiance Burrus configuration have been made with an internal p-n-p-n structure which causes an S -type negative resistance. The devices were double heterostructures using InGaAsP material. By using the proper external load impedance and bias voltage, the negative resistance can be used to obtain bistable operation with switching from low current to high current triggered by a small current (e.g., 1 μA). Light coupled into the center junction can be used as the source of signal current. Since light output is proportional to the total current, this type of device can be used as a light-signal repeater.

Negative resistance oscillator working in ghz range - has dielectric resonator connected to negative resistance element and mounted on dielectric substrate

Abstract: The negative resistance oscillator works in the GHz region. The oscillator is based on a dielectric resonator associated with a negative resistance element. The resonator, normally cylindrical, has one metallised end face mounted on an isolating substrate (2) such as alumina or silica. The substrate is laid on one inside surface of an 'L' cross section base (40) which carries on its remaining face a variable capacity diode (50) or varactor, e.g. a Schottky diode, a decoupling capacitance (7) to earth and a second decoupling capacitor (9). Both capacitors are in parallel and spaced by about a quarter wavelength of the oscillator frequency forming a low - pass filters. The positive supply is taken to earth and the negative to one side of the diode.

New ideal active inductance and frequency-dependant negative resistance using d.v.c.c.s./d.v.c.v.s.: applications in sinusoidal-oscillator realisation

Abstract: A new grounded-capacitor simulation of driving-point impedances of the form as and bs2, corresponding to ideal inductance and frequency-dependent negative resistance (f.d.n.r.) elements, respectively, is presented. The configurations use the minimum of passive components with the d.v.c.c.s./d.v.c.v.s. as the active element. Applications of the active inductance and f.d.n.r. are then proposed in the realisation of some single-resistor-controlled RC oscillators.

Impedance-matching circuit using negative low-noise resistance

Abstract: A circuit is disclosed for impedance matching an electrical signal-generating transducer to an electrical signal-processing amplifier while substantially retaining both the original signal-to-noise power ratio and the original signal amplitude at the input to the amplifier. A load resistance of a value substantially equal to twice the characteristic resistance of the transducer is coupled across the amplifier input, while a negative low-noise resistance approximately equal in magnitude to the source resistance is coupled in series with the load resistance. A transmission line having a characteristic impedance approximately equal to the transducer resistance is coupled between the transducer output and the series-coupled load resistance and negative resistance.

Characteristics of negative-resistance nonsinusoidal oscillators

Abstract: This paper discusses the general characteristics of negative-resistance oscillators for which the voltage waveform across the active device consists not only of the fundamental voltage component but also of substantial harmonic voltage components. It is shown that a stability criterion, equivalent to that described by Kurokawa for sinusoidal voltage oscillators, must be satisfied at each frequency. The waveform components are derived from the fact that, when oscillating, the diode dynamic admittance at each frequency must always be equal to the negative of the load admittance at that frequency. The analysis is applied to two different practical circuits which give rise to LSA relaxation oscillations and good agreement is obtained between theory and experiment.

Pulsed power supply

Abstract: An improved pulsed power supply for a solid state diode oscillator is shown. In the preferred embodiment a voltage equal to the threshold voltage of a negative resistance diode oscillator is applied continuously through an appropriately sized resistor and at least one normally nonconducting transistor is connected in parallel with such resistor, the transistor being arranged to be turned to its conducting state when a driver produces a control pulse, thereby to cause the negative resistance diode oscillator to oscillate.

Stabilisation circuit for microwave oscillator - has high Q resonant circuit coupled to waveguide via slot at one sixth wavelength from active device

Abstract: The stabilisation circuit is used with a microwave oscillator whose active device, e.g. a negative resistance device is located between the broad faces of a section of rectangular waveguide operated below its cutoff frequency. The distance between the active device and a coupling slit in the narrow face of the waveguide is roughly 6. The coupling slit between oscillator and resonator is chosen so that the latter determines the former's frequency.

An improved GAMBIT device structure

Abstract: An improved device structure is presented for the gate modulated bipolar transistor (GAMBIT). By forming vertical walled collector regions, the GAMBIT voltage-controlled negative-resistance characteristic has been made to occur at low collector voltages without the presence of the threshold voltage observed for the planar diffused devices. The negative resistance of these devices varies exponentially with the reciprocal of the gate bias and increases with collector depth as expected from analysis.

Microwave oscillator circuit with Gunn or IMPATT diode - has diode in cavity resonator to produce continuous or pulsed millimetre waves

Abstract: The microwave oscillator has a negative impedance device, e.g. a Gunn or IMPATT diode. The diode is located in a cavity resonator and produces continuous or pulsed millimeter waves of e.g. 35 GHz. The diode (4) is located in the centre of a normal section of waveguide acting as a cavity resonator. There is a filter resonator (2) which prevents power passing out via the DC supply line of the diode. An impedance transformer (3) is located on the opposite side to the diode earth connection to match the diode to the cavity resonator.

A thermal relaxation oscillator for temperature measurements

Abstract: A relaxation oscillator, using a temperature dependent resistance associated with a negative resistance dipole, is described. It is shown that the frequency of oscillation is a linearly increasing function of the ambient temperature. Experimental results to confirm the theory are included.

Negative resistance amplifier

Abstract: PURPOSE:To enable high output and high gain while controlling the amplifier so that it is not oscillated, by effectively utilizing solidstate amplifying element.

The avalanche diode high-level microwave noise source

Abstract: Extends an earlier analytic theory of the microwave avalanche diode (IMPATT) and describes the way in which RF induced, low-frequency negative resistance arises in such devices. With certain microwave circuit constraints, this negative resistance gives rise to a controlled instability which results in a microwave noise spectrum of bandwidth similar in magnitude to the avalanche diode oscillator tuned circuit bandwidth. The noise spectrum is centred on the normal microwave operating frequency of the avalanche diode oscillator and is typically of mW output power level.

Microwave magnetron system with negative resistance diode enhancement - has capacitive coupling to inhibit parasitic operation

Abstract: A microwave cavity gp. or magnetron is used which has enhanced power output. The high output is obtained by inclusion, within the central volume, of semiconductor diodes which have negative resistance characteristics at U.H.F. The diode circuit operates the minimal parasitic effects and losses and consists of an array of such diodes and passive components arranged symmetrically about the magnetron axis. The diodes (4) working at around 10GHz functioning in pairs in phase opposition are connected to the inward edges of the cavity walls (3) and to a central conductor (5) which provides bias. The walls are interconnected by straps to ensure the correct operating mode. Parasitic operation is inhibited by resistive and capacitive (7) coupling symmetrically arranged about the axis.

6-12GHz Transmission Type Dielectric Resonator Transistor Oscillators

Abstract: This paper discusses the design of 6-12GHz dielectric resonator transistor oscillators using the concept of transistor negative resistance and their frequency tuning range which satisfy the required frequency stability. The various types of dielectric resonator oscillators are briefly described.

Substrate-fed CMOS memory device

Abstract: A novel structure of a negative resistance diode for high density static RAM cell is described. The diode, called Substrate-Fed CMOS (SF-CMOS) diode, consists of weak depletion type p- and n-MOSTs, whose drains are formed in the p-well and n-substrate, respectively. The structure enables supplying a diode current via substrate. Drain currents for the FETs, which operate in the subthreshold region, are controlled by back-gate bias, resulting in a sharp negative resistance with an "OFF" current below 1pA. The SF-CMOS diode plus a transfer-gate transistor and a load element make up a memory cell. The feasibility of using a polysilicon resistor, a leaky diode and a MOSFET for the load element is discussed. An eight-by-eight cell array of SF-CMOS cells with MOSFET loads is fabricated and examined. Using a 5µm line width and 3µm spacing design rule, the obtained cell size is 1440µm2, compared with 3000µm2required for a six-transistor cell. A 4096-word by 1-bit static RAM has been designed using SF-CMOS cells. The obtained chip size is as small as 14.9mm2. READ and WRITE operations of the RAM are similar to those of single transistor cells, except that SF-CMOS cells need no refresh operation. A 45 ns access time has been obtained with 5-volt V DD , using computer simulation.

Zeroocross swtching circuit

Abstract: PURPOSE:To provide an operation of on-off control made near around a zero-cross of the power supply voltage, by such means that with a combination made between a voltage divider resistance and a pair of negative resistance elements, their connection be directly made to AC terminal and a firing signal obtained for switching circuit of the power supply.

Microwave oscillator temp. compensator - has second resonating line section with variable temp. compensating short circuit

Abstract: The temperature compensator, for a microwave oscillator, consists of a negative resistance device, a section of line, a resonator of high Q and low temp. dependence, and a load. The section of line (1) is constructed as a second resonator (R1) with a variable short circuit (K1) to compensate for temperature changes. This short circuit slider has a temp.-compensating dielectric and/or temp. compensating tuning post. The variable short circuit acts as a movable piston which changes the length (1) between itself and the dielectric (E).

Switching conduction in ion-irradiated layers in GaAs

Abstract: Experiments have been performed to investigate whether switching phenomena are observable in ion-irradiated GaAs It is found that the V/I characteristics of H2+-and N+-irradiated layers show both negative resistance and switching from a high resistance to a low resistance state Ion irradiation may thus be a useful method of fabricating switching devices

86 GHz High Power IMPATT Negative Resistance Amplifier

Abstract: Describes the development of a millimeter-wave two-stage IMPATT negative resistance amplifier, using a Si DDR IMPATT diode sealed in a ceramic package to obtain a gain of 10 dB and an output power of 18 dBm in the 86 GHz frequency range.

A New Configuration Providing Negative Resistance at a Higher Frequency than that of the Negative Resistance Device by Itself

Abstract: It is shown that the combination of a negative resistance at frequency w and a varactor frequency multiplier/divider can produce a negative resistance at frequency 2w. Experimental results are presented on an injection locked oscillator at 2W using this combination.

Interface circuit between HV and LV networks - has optical coupling employing LED and phototransistor

Abstract: The interface circuit is used to transfer signals from a HT network to a LT network, respectively coupled to a HT or LT source. The circuit comprises an input stage supplied from the HT source and employing a transistor (T1) in the DC supply circuit for a light-emitting diode, forming part of an optical coupling. The output stage of the interface circuit includes a phototransistor (PT) forming the other part of the optical coupling and associated with a second transistor (T2) so as to form a current amplifier. The transistor (T1) in the input stage has its base coupled to the circuit input via two resistors (R1, R2) and coupled to the HT source via a negative resistance (R3).

Resonant circuits using Gunn diodes

Abstract: The paper deals with some special features of Gunn diode operation in a resonant circuit, which arise from the non-linear characteristics of the diode's complex impedance. Autonomous and non-autonomous modes of operation for Gunn diode oscillators are discussed. The considerable influence that the non-linearity of the Gunn diode's domain capacitanee has on the operation of such systems is shown. Parametric phenomena caused by this non-linearity are examined. The method used allows a complete study of such systems by comparatively simple but correct treatment of the problems. The results obtained can be successfully used in the study of resonant circuits with microwave transistors, IMPATT diodes and Josephson junctions. All the results are experimentally proved.