Negative Resistance Amplifier Research Articles

DESIGNING A REFLECTION-TYPE NGD NETWORK USING OPEN AND SHORT SHUNT STUBS FOR WIDEBAND ELECTRICALLY SMALL ANTENNAS

Wireless communication devices such as mobile phones play a vital role in our daily life. They need to cover an increasingly wide frequency band with low profile antennas. Electrically small antennas (ESAs) comply with these requirements. However, they are subject to gain-bandwidth limits when matched with passive matching networks. Non-Foster reactive elements have been proposed to bypass those restrictions. This paper addresses designing negative group delay NGD-based non-Foster networks to overcome stability problems when using Negative Impedance Converters (NICs) in order to realise on-Foster reactive circuits. The NGD network model was designed using open short stubs to achieve a non-Foster behaviour, and to act as a negative capacitor in the frequency range of interest. This technique of compensating the inherent loss of the proposed NGD network in the reflection mode was to realise a new structure of reactive non-Foster elements. It involves a negative resistance amplifier and a Lange coupler. The proposed technique is applicable to antenna matching where both transmit and received capabilities are required. It was simulated and the experimental results of the new NGD network circuit were introduced.

Negative resistance amplifier circuit using GaAsFET modelled single MESFET

Negative resistance devices have attracted much attention in the wireless communication industry because of their low cost, better performance, high speed, and reduced power requirements. Although negative resistance circuits are non-linear circuits, they are associated with distortion, which may either be amplitude-to-amplitude distortion or amplitude-to-phase distortion. In this paper, a unique way of realizing a negative resistance amplifier is proposed using a single metal-semiconductor field-effect transistor (MESFET). Intermodulation distortion test (IMD) is performed to evaluate the characteristic response of the negative resistance circuit amplifier to different bias voltages using the harmonic balance (HB) of the advanced designed software (ADS 2016). The results obtained are compared to those of a conventional distributed amplifier. The findings of this study showed that the negative resistance amplifier spreads over a wider frequency output with reduced power requirements while the conventional distributed amplifier has a direct current (DC) offset with output voltage of 32.34 dBm.

A novel EER structure for reducing complexity using negative resistance amplifier

This letter presents a novel envelope elimination and restoration (EER) structure using the negative resistance class F power amplifier. Due to the extremely high gain characteristic of the negative resistance amplifier in very narrow bandwidth, it operates in saturation mode. This characteristic is applied to the proposed EER. Using this technique, a limiter, a drive amplifier, and a class F power amplifier in conventional EER can be substituted with the negative resistance class F power amplifier. This technique greatly reduces the complexity of conventional EER without degradation of efficiency and linearity. The measured results show efficiency of 60% and less than-26 dBc IMD levels for two-tone test in PCS band at 27-dBm output power.

Optimum noise measure configurations for transistor negative resistance amplifiers

A new method, using the noise matrix approach, has been developed for determining the optimum reactive terminations for a transistor employed as a low-noise negative-resistance element in a reflection-mode amplifier. This new method corroborates the less efficient graphical method the authors reported earlier. It is established theoretically and demonstrated numerically that the optimum noise measure of a transistor used in a reflection-mode amplifier is independent of the choice of active terminal and is identical to the optimum noise measure of the same transistor when used in a conventional transmission-mode amplifier.

High gain millimetric negative resistance low noise amplifiers

The limited gain available from GaAs FETs and HEMTs at millimetric frequencies can be overcome by using the devices in a negative resistance amplifier configuration. The advantage of the solid-state negative resistance amplifier over the transmission amplifier is that the gain available is not limited by the active device used. It has been shown that, over a narrow bandwidth, significantly higher gain can be obtained from a negative resistance amplifier, when compared to a transmission amplifier using the same device, while maintaining the same overall noise performance. This has been demonstrated experimentally using a 0.25 μm HEMT device.

A unipolar transistor with negative output resistance

In this work a three-terminal active solid state device, that operates well into submillimeter-wave frequencies is proposed. The activity of this device is due to negative output resistance. The origin of the negative output resistance is shown to be injection and transit-time delays that any finite sized device possesses. Generating proper injection delays utilizing specially designed tunneling junctions and combining these injection delays with transit-time delays a novel hot electron transit time transistor (HETT) is introduced and its small signal analysis is carried out. Having three terminals in an active device provides isolation between input and output and completely integrated monolithic negative resistance amplifiers can be fabricated, without the need for non-reciprocal circuit components, like circulators. It is shown that negative output resistance should also be observed in transistors due to inherent intrinsic delays.

Frequency limitations in circuits composed of linear devices

The author investigates limitations on the frequency response of networks constructed out of components specified by their small signal models. Tellegen's theorem is used to find tight bounds on the maximum frequency of oscillation. The problem is reduced to deciding whether zero is in the numerical range of a complex non-Hermitian matrix. A decision method is presented, and transistor and negative resistance amplifier examples are developed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

On Lossless Reciprocal and Nonreciprocal Matching Networks of an Active Load

A general matching theory between an arbitrary passive impedance and an active load impedance is presented. It extends the broadband matching theory to include both lossless reciprocal and nonreciprocal networks. Application of the result to the design of nonreciprocal negative-resistance amplifier is given. The significance of the present approach is that the realization of the equalizer is accomplished by means of the driving-point synthesis based on the Darlington theory. The result enlarges the domain of realizable broadband matching networks. An illustrative example is presented to show the design procedure and the conditions under which a lossless nonreciprocal network is realized for an active load.

Resonant tunneling transistors with controllable negative differential resistances

Three-terminal devices based on resonant tunneling through two quantum barriers separated by a quantum well are presented and analyzed theoretically. Each proposed device consists of a resonant tunneling double barrier heterostructure integrated with a Schottky barrier field-effect transistor configuration. The essential feature of these devices is the presence, in their output current-voltage ( <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">I_{D} - V_{D}</tex> ) curves, of negative differential resistances controlled by a gate voltage. Because of the high-speed characteristics associated with tunnel structures, these devices could find applications in tunable millimeter-wave oscillators, negative resistance amplifiers, and high-speed digital circuits.

Multistage negative-resistance amplifier circuit design using nonideal circulators

Using a broadband equivalent circuit of a lossy, nonideal circulator, single-stage and multistage negative-resistance amplifier circuits are studied to determine the effect of circulators and isolators on performance. It is found that feedback phenomena controlled by circuit phase shifts play an important part in determining the amplifier response.

An equivalent circuit for narrow-band nonideal circulators

The scattering parameters of a simple equivalent circuit based upon modification of an earlier circuit of Bosma [1] are derived and compared with previously published experimental results to demonstrate the suitability of the equivalent circuit for use in the analysis of microwave circuits such as circulator-coupled single-stage and multi-stage negative-resistance amplifiers. The approach followed here can be generalized to obtain circuit models for broad-band circulators.

Stability measure for negative-resistance amplifiers

A measure of the stability of reflection-type negative-resistance amplifiers is defined as the distance between the actual driving-point immittance of the active one-port and its value that would cause instability. The measure has a simple physical interpretation and demonstrates the gain-stability trade-off.

Theory of Noise and Transfer Properties of IMPATT Diode Amplifiers

A theory is formulated which describes quantitatively the noise and transfer properties of IMPATT diode reflection-type negative resistance amplifiers. This theory is based on the method used in the large-signal theory of noise in IMPATT diode oscillators by the present authors. The theory takes into account the signal dependence of the noise generation in the diode, the noise and/or modulation present in the input signal, and also the intermodulation effects occurring between the various frequency bands. The equations are conveniently arranged in matrix form; such a formulation makes it easier to obtain quantitative results in terms of measurable noise and modulation parameters. Agreement between measured and theoretically predicted AM and FM noise of injection-locked oscillators is good. The usefulness of the theory is illustrated by results of calculations on minimum attainable noise of a given amplifier, maximum noise allowable on the input signal, AM-FM conversion, phase distortion, bias modulation, and the correlation between various types of noise.

Theory and explicit formulas for the design of optimum non-reciprocal negative-resistance amplifiers

General relations for the design of negative–resistance amplifiers using tunnel diodes are derived. Using these relations, explicit formulas for the element values of an optimum non-reciprocal negative–resistance amplifier having Butterworth or Chebyshev transducer power-gain characteristics of arbitrary order are presented. In developing the theory and formulas, we allow the frequency-dependent load impedance, and also include the series parasitic inductance used in the equivalent circuit representation of a tunnel diode. Thus, the design of such amplifiers is reduced to simple arithmetic.

Negative temperatures and negative dissipation

Negative absolute temperature, defined in terms of the Boltzmann factor, corresponds to an upside-down energy pyramid. The example of the laser shows population inversion to be accompanied by the switch from absorption to emission, that is, from positive to negative dissipation, from increasing disorder throughout a system to increasing order in a subsystem. Early treatments of the negative-temperature concept are by Onsager and by Ramsey. Ramsey’s ’’essential requirements’’ are shown to be too strong. A TS diagram for a Carnot cycle operating between two negative temperatures clarifies the origin of amplification. Some biological negative-resistance amplifiers (nerve, muscle), in particular those involving ordered arrays of water molecules, are conjectured to have negative-temperature subsystems.

Computer-oriented synthesis of wide-band non-uniform negative resistance amplifiers†

This paper presents a synthesis procedure which provides design values for broad-band amplifiers using non-uniform negative resistance devices. Employing a weighted least squares optimization scheme, the technique, based on an extension of procedures for uniform negative resistance devices, is capable of providing designs for a variety of matching network topologies. It also provides, for the first time, quantitative results for predicting the effects of parameter element variations on overall amplifier performance. The technique is also unique in that it employs exact partial derivatives for optimization and sensitivity computation. In comparison with conventional procedures, significantly improved broad-band designs are shown to result.

On linear and non-linear negative-resistance and negative-conductance parametric amplifiers and oscillators

The negative resistance and the negative conductance (which is not the reverse of the negative resistance) caused by a time-varying capacitance are calculated for the degenerate and the non-degenerate parametric amplifier. In the latter part these values are calculated for circuits with a semi-conductor diode as a voltage-variable capacitor, which gives rise to a non-linear differential equation. In this case the amplitude of the parametric oscillator could he calculated.

Gain expansion in negative-resistance amplifiers

It is shown that the gain expansion in negative- resistance amplifiers does not necessarily imply that the magnitude of device negative conductance increases with signal level.

The Effects of Package Parasitics on the Stability of Microwave Negative Resistance Devices

The results of investigations of the effect of parasitic package elements on the behavior of negative resistance amplifiers are presented. Three different package styles were considered. Also two different lead configurations were used. The packages were all mounted in 7-mm coaxial transmission line. The impedance of packages with and without leads was measured from 4 to 18 GHz using a manual network analyzer. These data were used as the basis for calculations to determine the values of elements in a simple three-element equivalent circuit model of the package. Using the equivalent circuit model experimentally derived for each package style, the impedance seen by the chip through the package to a 50-/spl Omega/ load was calculated. Broad-band curves of the impedance seen by the chip are presented. The experimentally derived model of the package permits matching of chip and package for stability.

Large-Signal Equivalent Circuit for IMPATT-Diode Characterization and Its Application to Amplifiers

A frequency-independent lumped equivalent circuit is proposed for characterizing the large-signal behavior of IMPATT diodes. It has five elements including a negative resistance, two of which are quadratic functions of the single-frequency RF voltage across the device. It is used for computer-aided analysis and the design of reflection-type negative-resistance amplifiers employing IMPATT diodes. The frequency response of the amplifier is calculated for different input power levels and the nature of the results is found to be in agreement with published experimental results.