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In terms of scattering parameters, the equation transducer power gain is shown to be capable of representation as a family of circles of constant gain from which the design of load and source terminations to achieve a restricted bandwidth can be obtained. This is an extension of an earlier approach which only allowed either load reflection coefficient or source reflection coefficient to be considered in a given design. Through the use of a specification statement of VSWR, it is shown how a marginal stability factor can be derived. From the study of the interaction between the input and output reflection coefficients, a detuning factor is analytically derived to correlate the interaction between the input and output reflection coefficients. Either of these factors can be chosen and used to select optimum input and output reflection coefficients which provide stable operation for an amplifying stage that is to employ a conditionally stable active element. An example using these factors is given.

An exact method, involving the line vector z, is developed for calculating the characteristic impedances of stepped impedance transformers having maximally-flat and Chebyshev characteristics. It is also shown that this leads to considerable economy of effort compared with earlier methods.

Because of the relative simplicity of measurement of scattering parameters of active two-ports at frequencies up to the lower microwave region, investigations have been made into the application of these parameters to the design of UHF amplifiers. The theory of generalized scattering parameters has been developed by Kurokawa, applied to two-port power-flow analysis by Bodway, and used in the design of a single-stage UHF amplifier by Froehner. In this last paper, the bandwidth limitations imposed by the matching networks were not considered, nor was the capacitive matching arrangement to a purely resistive load fully developed. Both of these topics are the subject of this short paper, in which the relevant design expressions are also given.

It was recently suggested that a class of functions, termed unit-real functions, were more directly applicable to resistor transmission-line circuits than the positive-real functions of lumped-parameter network theory. In the paper, the definition of unit-real functions is extended, and a test procedure is given for them. The conditions applying to the use of two types of lossless cascade lines and of lossless stubs of arbitrary characteristic impedance are developed in terms of unit-real functions. A synthesis procedure is described, and a typical practical example is given.

A form of the microwave reflectometer which yields a reflection-coefficient angle as well as modulus is discussed and its analysis presented.A simple compensation method is described whereby the measurement errors due to imperfect performance of the directional couplers can partially be eliminated and partially be allowed for.Finally, the measurement accuracy obtainable from this reflectometer system is shown to be approximately that obtainable from the conventional slotted waveguide section, and hence the system provides an alternative to the slotted section at the millimetre wavelengths.

The design of an active filter, suitable for use as the stabilizing element in an a.c. control system, is discussed, The modulating frequency characteristics presented show the relative insensitivity of the filter to tolerance, temperature and carrier drift effects.