Showing papers on "Negative resistance published in 1997"

Bipolar junction transistor (BJT)--resonant tunneling diode (RTD) oscillator circuit and method

Abstract: A BJT, an inductor, and an RTD are configured to define a negative resistance oscillator circuit that is suitable for monolithic integration. The BJT is forward biased so that the RTD operates at a DC operating point (I Q ,V Q ) on its characteristic I-V curve in its negative differential resistance region. The thermal noise inherent in the circuit causes it to start oscillating about the DC operating point (I Q ,V Q ) where the RTD's negative resistance R n provides positive feedback that amplifies the oscillations until equilibrium is established thereby producing a sinusoidal waveform. The low power BJT/RTD oscillator operates at power levels approximately one-tenth those of known integrated feedback oscillators and oscillates at frequencies in the hundreds of Ghz range that are currently only achievable using waveguide oscillators.

Resonant-tunneling transmission-line relaxation oscillator

Abstract: Experimental and numerical results are presented for a high-frequency oscillator consisting of a resonant-tunneling diode (RTD) series-embedded in a transmission line, one end of which is short circuited and the other end terminated with a load resistor. Like relaxation oscillators, the ac voltage across the RTD is a square wave. However, the current wave form (and hence the load wave forms) consists of a sequence of sharp pulses that are essentially locked to the fundamental mode of the transmission line.

Millimeter wave oscillator based on a quasiplanar superlattice electronic device

Abstract: We report on a millimeter wave oscillator based on a quasiplanar superlattice electronic device (SLED). The SLED, a lateral structured GaAs/AlAs superlattice, showing, at room temperature, a negative differential conductance, was provided with two terminals lying in one plane and mounted in a waveguide structure. The oscillator delivered radiation, in a relative bandwidth of 10−5, that was tunable by about 10% around 70 GHz and had a power of 100 μW; depending on the voltage across the superlattice, additional oscillation lines (up to 180 GHz) appeared. We associate the generation of radiation with a current oscillation caused by traveling dipole domains in the superlattice.

Nonlinear Physics with Maple for Scientists and Engineers

Abstract: Part 1 Theory: introduction non-linear systems - part I non-linear systems - part II topological analysis analytic methods the numerical approach limit cycles forced oscillators non-linear maps non-linear PDE phenomena numerical simulation inverse scattering method. Part 2 Experimental activities: introduction to non-linear experiments - spin toy pendulum driven eardrum non-linear damping enharmonic potential iron core inductor non-linear LRC circuit tunnel diode negative resistance curve tunnel diode self-excited oscillator forced Duffing equation focal point instability compound pendulum stable limit cycle Van der Pol limit cycle relaxation oscillations - neon bulb relaxation oscillations - drinking bird relaxation oscillations - tunnel diode hard spring non-linear resonance curve - mechanical non-linear resonance curve - electrical non-linear resonance curve - magnetic sub-harmonic response - period doubling diode - period doubling five-well magnetic potential power spectrum entrainment and quasiperiodicity quasiperiodicity Chua's butterfly route to chaos driven spin toy mapping.

Active inductor oscillator with wide frequency range

Abstract: An active inductor oscillator includes a tank circuit for generating a first differential signal, a common-mode inverting differential buffer for generating a second differential signal in response to the first differential signal, and an integrating circuit for generating a third differential signal in response to the second differential signal. The third differential signal is applied to the tank circuit, and lags the first differential signal. A differential transistor pair in the tank circuit provides active inductance in response to the third differential signal, and a cross-coupled transistor pair in the tank circuit provides negative resistance that amplifies the first differential signal in response to the first differential signal. Currents through the tank circuit, buffer, and integrating circuit are essentially identical to one another and move in unison with an externally applied reference current that controls the oscillation frequency. As a result, the oscillator can achieve a wide range of oscillation frequencies. The buffer adds 180 degrees of phase shift to the common-mode loop, thereby providing negative common-mode feedback that prevents lock-up. The tank circuit, buffer and integrating circuit use differential transistor pairs that reduce phase jitter due to external common-mode noise sources.

Shift register using negative resistance devices

Abstract: A high speed digital static shift register includes a series-connected pair of resonant tunneling diodes (RTDs) 22, 24 to achieve a bistable operating state. A clocked switch 20 provides the means of setting the binary state of this bistable pair. In order for one bistable pair to drive a following pair, a method of providing isolation and gain using a buffer amplifier 26 between the two pairs of RTDs is also provided. In one embodiment, the buffer amplifier comprises enhancement FET 30 and depletion load FET 28.

Temperature stabilized oscillator and proximity switch containing the oscillator

Abstract: In an oscillator comprising a resonant circuit (L, C, R CU ) and an amplifier circuit (V, R 1 , R 2 , R 3 ) connected as a negative resistance (R n ), a direct current source (I 1 ) is connected in series with the resonant circuit (L, C, R CU ). In this way, a signal (U CU ) is provided being a measure for the resistance of the oscillator circuit coil (L). By using this signal (U CU ), a control circuit (V 1 , M; V 2 , V 3 , M) controls the negative resistance (R n ) inversely proportional to the resistance (R CU ) of the oscillator circuit coil (L). This affords a simple stabilization of the temperature behavior of the oscillator circuit (L, C, R CU ) and allows the low price manufacture of inductive proximity switches having a great switching distance which function safely in a broad temperature range.

An analytic method of microwave transistor oscillator design

Abstract: An analytic method of microwave transistor oscillator design is developed, allowing one to define explicit expressions for optimum values of feedback elements and load through immitance parameters of the active two-port network. A negative resistance concept is used to design a series feedback microwave GaAs FET oscillator with optimized feedback elements and maximum output power in terms of the transistor impedance parameters. A large-signal model for GaAs FET is derived, based on its small-signal Z parameters and DC characteristics. Numerical results verify the validity of the design method.

Integrated semiconductor device having negative resistance formed of MIS switching diode

Abstract: A memory cell of an SRAM includes an access transistor, and an MIS switching diode. The access transistor has a drain electrode connected to a bit line of a corresponding column, a source electrode connected to a storage node, and a gate electrode connected to a word line of a corresponding row. The threshold voltage of the access transistor is small than the threshold voltage of a bit line load transistor. The MIS switching diode is connected between the storage node and a second power supply potential node. The switching initiate voltage of the MIS switching diode is greater than the difference between the first potential and the threshold voltage of the bit line load transistor, and smaller than the difference between the first potential and the threshold voltage of the access transistor. Thus, data can be read/written and held accurately.

Tunnel transistor and storage circuit

Abstract: PROBLEM TO BE SOLVED: To provide a tunnel transistor which has a plurality of negative resistance characteristics by providing a source electrode, a drain electrode and a gate electrode to be formed on a source, a drain and an insulation layer. SOLUTION: When a positive voltage is applied to a drain electrode 8, three n -p tunnel junctions in all between each left edge of P -GaAs connecting areas 9 and the left edge of a P -GaAs drain 3 and channel layers 4 are permitted to be the forward-direction bias wherein negative resistance appears. Two n -p tunnel junctions between the right edge of the p -GaAs connecting areas 9 and the channel layers 4 are permitted to be reverse-direction bias which has low resistance characteristics. Thus, among the n -P tunnel junctions, three tunnel junctions are forward-direction bias, and the two tunnel junctions are reverse-direction bias. Since reverse-direction bias tunnel junction has extremely low resistance compared with forward-direction bias tunnel junction, current between the source 2 and the drain 3 is decided by the tunnel junction characteristics of the high resistance forward-direction bias, and three negative resistance characteristics are permitted to continuously appear.

Voltage controlled oscillator

Abstract: A voltage controlled oscillator comprises: a negative resistance circuit (112) made up of a transistor (114) and a feedback circuit (115) for applying positive feedback to said transistor (114) and a resonating circuit (113) for selecting an oscillation frequency when a signal is passed back and forth between said negative resistance circuit (112) and said resonating circuit (113). Control for varying said oscillation frequency is carried out by varying a D.C. bias voltage applied to said oscillator. The linearity between the D.C. bias voltage and the oscillation frequency is improved by redimensionning the feedback circuit to reduce the feedback strength. This is achieved by setting the length of a transmission line in the feedback circuit.

Electronic circuit, filter device using it and radio equipment

Abstract: PROBLEM TO BE SOLVED: To perform an operation without distortion even if the signal of a high peak level is inputted at the time of the low power source voltage by the adjustment of the distribution of the capacity values in an FDNR(frequency- dependent negative resistance), to make the high resistance generated by the input of a signal into a small value by an equivalent conversion and to reduce parasitic capacity accompanying the resistance. SOLUTION: In the FDNR type active filter composed on an integrated circuit, an FDNR circuit 10 is realized by connecting the inversion input 16 of an operational amplifier 14 with each one end of first capacity 11 and an impedance element 6, connecting the output terminal 17 of the operational amplifier 14 with each one end of the impedance element 6 and the second capacity 12 and connecting the other ends with each other of the first capacity 11 and the second capacity 12. In the impedance element 6, a resistance 7 and a resistance 8 are serially connected, the connection terminals of the resistances 7 and 8 are connected with the one end of a resistance 9 and the other end of the resitance 9 is alternatingly grounded. The size of the value of the second capacity 12 is larger than that of the first capacity 11.

Active load characterization of a microwave transistor for oscillator design

Abstract: This paper describes the use of a six-port active load measurement system to determine the optimal large-signal loading of transistors for the design of microwave oscillators providing maximum output power. Our system has been used to measure the optimal large-signal terminating impedance for a potentially unstable microwave transistor and to apply the device line characterization technique. This technique, which is used to characterize a negative resistance monoport and predict the level of oscillator output power, is implemented for the first time using active loading. An oscillator designed using our measurements generated an output power of 11.3 dBm at a frequency of 3.5 GHz. This result is in good agreement with the value predicted from the device line technique and our measurement system.

Device using piezoelectric element

Abstract: PROBLEM TO BE SOLVED: To provide a device using a piezoelectric element capable of reducing or cancelling the equivalent resistance component or damping capacity component of the piezoelectric element on a circuit SOLUTION: A negative circuit 2 is provided parallelly to the piezoelectric element 1 A negative resistance value is equivalently set in the negative circuit 2 and the equivalent resistance component Rm is reduced or cancelled by the negative resistance value A current Is1 going in and out of the piezoelectric element 1 from the negative circuit 2 and the current Is2 going in and out of the negative circuit 2 from the piezoelectric element 1 become equal, the current is not supplied from the negative circuit 2 to the circuit or element Z2 of a poststage and the other circuit is not affected

An investigation of the I-V relationship of double barrier resonant tunneling diodes in oscillating conditions

Abstract: The measured I-V characteristics of the double barrier resonant tunneling (DBRT) diode is distorted in the negative differential conductance region if the device is unstable. This paper presents a study of the I-V curve of the DBRT diode in oscillating conditions. This task is fulfilled using an accurate large signal model and PSPICE simulations. First, the PSPICE DBRT diode model is presented. Then the circuit model used for nonlinear simulations is described. Based on the simulation results, concluding remarks with regards to DBRT diode behavior are derived.

Super-lattice semiconductor device of negative resistance, method for varying it in negative resistance, and microwave oscillation circuit

Abstract: PROBLEM TO BE SOLVED: To provide a supper-lattice semiconductor device which can be more enhanced both in negative resistance and in current density than a tunnel diode. SOLUTION: Barrier layers 21-0 to 21-N and quantum well layers 22-0 to 22-N are alternately laminated into an intrinsic semiconductor layer 15 of super-lattice structure, and this super-lattice semiconductor device 10 is equipped with a pin diode element composed of the intrinsic semiconductor layer 15 and two electrodes 11 and 12 which sandwich in the semiconductor layer 15 between them. When a reverse bias voltage intermediate between a first voltage Vb1 and a second voltage Vb2 higher than the first voltage Vb1 is applied between the electrodes 11 and 12, the Γ point level of the quantum well layers 22-0 to 22-N and the point X level of a barrier layer separated from the quantum well layer by an adjacent barrier layer and a quantum well layer, are made to resonate with each other. The barrier layers 21-0 to 21-N and the quantum well layers 22-0 to 22-N are so set in thickness, as to enable the X point level of the barrier layers 21-0 to 21-N and the Γ point level of an adjacent quantum well layer to resonate with each other when a reverse bias voltage higher than the second voltage Vb2 is applied.

Controlling chaos in a chaotic circuit controlled by voltage pulse

Abstract: In this paper, we discuss controlling chaos in a chaotic circuit. Our circuit is a negative resistance LC oscillator whose amplitude is controlled by DC voltage pulses. First, we show that the Poincare map of this oscillator is derived rigorously as a one-dimensional mapping. This mapping satisfies Li-Yorke's extended period three condition. Hence, the mapping has a n-periodic point for any natural number n, and the appearance of chaos in Li-Yorke's sense is explained. Furthermore, an occasional proportional feedback method (OPF method) for piecewise-linear systems is applied to this oscillator. Each unstable orbit can be stabilized, and periodic orbits with one to ten period are successfully stabilized in circuit experiments.

GaAs MMIC large tuning-range active bandpass filter using negative resistance circuit

Abstract: A second order large tuning-range bandpass active filter has been developed with GaAs MMIC technique using negative resistance circuits and integrated planar Schottky diodes designed and optimized in theory developed by the authors. The filter has a 200 MHz 3 db-bandwidth and a 600 MHz tuning-range of centre frequency, from 1.6 GHz to 1 GHz, and occupies an area of 1.6/spl times/1.8 mm/sup 2/ on the wafer including all biasing elements.

Room temperature differential negative resistance in an Al/Zn0.61Cd0.39Se/n+-InP device

Abstract: Experimental data are presented on the current–voltage characteristics of an Al/ZnCdSe/n+-InP device from 77 to 300 K. A strong negative differential resistance under forward bias was observed for temperature higher than 145 K. The peak-to-valley current ratio was measured to be 30 at room temperature. In the reverse bias region the device behaves as a leaky Schottky diode.

The observation of subharmonic peculiarities of I-V characteristic of edge-type Josephson junction chains placed in microwave resonator

Abstract: The spectrums of own Josephson radiation and I-V characteristics of one-dimensional chains of edge-type Nb Josephson junction placed into microwave resonator have been studied. The interaction with the external resonator caused synchronization of junctions forming the chain. This effect was detected experimentally. In the hysteresis region of I-V characteristic we have found the presence of own radiation area. Its bounds are determined by the value of junction characteristic voltage and are practically independent from the value of chain bias voltage. The studies of negative differential resistance region of I-V characteristic shows the presence of thin structure which may be interpreted as a set of subharmonic steps caused by the coupling of Josephson junction own radiation with external microwave resonator.