Abstract: Apparatus for determining the electrical characteristics of a superconductive material in a range of microwave frequencies and in a range of cryogenic temperatures has the material incorporated within a resonant cavity mounted on a cold finger for maintaining the material at a predetermined temperature. A pair of test waveguides extend oppositely of the cavity and terminate in separable waveguide junctions for passage of microwave energy to measure the microwave characteristics of the cavity as affected by the superconductive material. The cavity and test waveguides are enclosed in a vacuum chamber from which the cold finger extends for connection to controlled temperature cryogenic cooling equipment. The chamber also contains a plurality of calibration waveguides which extend parallel to the test waveguides, each calibration waveguide terminating oppositely in separable junctions.

Abstract: A microwave power combiner having a spherical region from which six rectangular waveguides extend oppositely along mutually orthogonal diameters. The long dimension of each waveguide cross section extends along a diagonal of a cube circumscribing the region and extends orthognally to this long dimension of the opposite waveguide. One waveguide is an input for an injection locking signal, and four waveguides are inputs for power to be combined in the region from oscillators controlled by the signal. No circulator is required, and the combined power may be output through the remaining waveguide or through the injection locking input waveguide. A number of the combiners may be connected with the output of one combiner serving as an injection locking input or as one power input to another of the combiners.

Abstract: An antenna array for combining in space microwave energy from a number of cillators, such as IMPATT diodes, which are controllable by injection locking. The array has elements individually driven by the oscillators, but an injection locking signal is provided in the usual manner only to the oscillator of a central element. The other oscillator are injection locked through mutual coupling between the central element and the other elements so that coherent radiation is output by the array. The radiation may be steered by phase shifters between the elements and their oscillators.

Abstract: An inside collet assembly for positioning an IMPATT diode precisely axially long and coaxially of a cylindrical cavity. The assembly serves for convenient removal and repositioning of the diode within the cavity and provides effective electrical and thermal connection to the diode. The assembly is not significantly larger in diameter than the cavity and does not require surfaces producing undesired reflections of microwaves within the cavity.

Abstract: A system for quasi real-time computer aided characterization of symmetrical -way microwave power combining structures which utilizes a network analyzer to measure scattering parameters of said combining structure at various RF frequencies and at desired transmission routes through said combining structure. The routes are selected by a coaxial switching network which is controlled by said network analyzer which also computes and outputs the maximum combining efficiency, .eta., and the input impedance of the ith port under conditions of maximum combining efficiency, Zic.

Abstract: A tuned cavity with a number of coaxial circuit microwave sources spaced about the cavity and disposed oppositely of the cavity from flat loads which suppress oscillations of the sources at undesired frequencies, the loads being adjacent to the cavity to provide wide bandwidth and a compact structure and yet spaced from the cavity a distance substantially less than the wavelengths of the operating frequencies so as to not interfere significantly with the electromagnetic fields in the cavity.