Basically, there are two modes in which reactance (parametric) amplifiers can be operated. In one mode, there is no negative conductance associated with the terminal impedances of the amplifier, and consequently absolute stability results. However, the maximum available power gain for this mode of operation is limited to the ratio of the output signal frequency (the sum of the input signal frequency and the pump frequency) to the input signal frequency. In the second basic mode of operation, the terminal impedances of the amplifier contain negative conductance components. Consequently, the amplifier is potentially unstable but can give large gain at the expense of reduced bandwidth. In designing low-noise receiving systems for microwave frequencies, one is led to consider the use of the negative conductance type of reactance amplifier in order to obtain sufficient gain so that the overall system noise factor is determined by the low-noise reactance amplifier stage. Until recently, however, the values of gain-bandwidth products achieved in practice with this type of amplifier have been disappointingly low. A theory is presented in which voltage gain-fractional bandwidth products for two negative conductance types of reactance amplifiers are analyzed in terms of pertinent nonlinear-capacitance diode and circuit parameters. Low-frequency prototype models of these types of reactance amplifiers were designed in accordance with the theory, and the measured operating characteristics were found to be in excellent agreement with the large values predicted by theory. At microwave frequencies, gain-bandwidth products substantially lower than those obtained at low frequencies may result because of the effects of diode lead inductance and the selectivity of the associated microwave circuits. Designs for minimizing these effects are discussed, and experimental results obtained at microwave frequencies are presented. Designing amplifiers in accordance with the theory also provides a nearly optimum noise figure.

Low-noise microwave reactance amplifiers with large gain-bandwidth products

This bibliography is restricted to books and periodical articles published prior to October, 1959. No attempt has been made to include the voluminous material to be found in technical reports, patents or similar sources.

Parametric Devices and Masers: An Annotated Bibliography

It is shown that the parametric amplifier and frequency converter can be described by four equations whose coefficients form a matrix that is symmetrical. Because of this symmetry, the calculations for gain, bandwidth, and noise figure yield simple and manageable results. By regarding the matrix as a nodal admittance array, an equivalent conductance circuit is constructed. The derived expressions show that, for low noise figure, the idlefrequency should be much higher than the signal-frequency. This is also the requirement for wide bandwidth. Numerical examples of amplifier and converter design are given.

Symmetrical Matrix Analysis of Parametric Amplifiers and Converters

This paper summarizes briefly the chronology of the development of parametric transducers. The early works of Michael Faraday (1831), F. Melde (1859), and Lord Rayleigh (1883) are cited as mechanical examples and the pioneering work of L. Kuhn, J. Zenneck, E. F. W. Alexanderson and R. V. L. Hartley are cited as electrical examples. A very brief resume of selected contributions follows, dating from the work on H. Q. North's diodes in 1945 to the present flurry of excitement beginning in 1954, created by the development of the Signal Corps-Bell Laboratories Task 8 varactor diodes. A list of 200 selected references is included.

Some Notes on the History of Parametric Transducers

A low-noise, microwave amplifier has been constructed using two non-linear capacitor microwave p-n junction diodes in a balanced hybrid system Power gains in excess of 30 db with effective input noise temperatures less than 290°K have been observed at a frequency of 2900 mc

The Reactatron-A Low-Noise, Semiconductor Diode, Microwave Amplifier

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The Reactatron-A Low-Noise, Semiconductor Diode, Microwave Amplifier