Abstract: A high performance, low cost variable attenuator is disclosed with minimal size and weight requirements. The variable microwave attenuator of the present invention includes a microwave stripline transmission line connecting the input and the output thereof; first and second ground planes are disposed on opposite sides of the transmission line; and a dielectric card having a metallization pattern is disposed on at least a portion thereof. The card is adapted for variable interposition between the transmission line and the first ground plane to provide variable attenuation of microwave energy. A specific teaching of the invention relates to the design of the metallization pattern to provide vernier attenuation.

Abstract: Thermal compensation for frequency control of microwave resonators through utilization of bimetallic boundary motion type phenomena is described, the resonator being rectangular and preferably having composite broad walls of integral layers, one of which having a relatively lower thermal expansion coefficient than another of the layers and each having an initial deformation in a stabilized curvature condition to render these walls frequency sensitive.

Abstract: A microwave resonator operating in the TE.sub.11 circular mode with a pair of iris plates defining the resonator, each iris including an elliptical aperture centrally disposed therein, the resonator having a rotary joint midway between the irises at the location of a current null so that the two half portions of the resonator may be rotated with respect to each other in order to provide a desired relative iris axis alignment for an infinitely variable coupling value between a minimum value determined by the minor axis dimension of the elliptical apertures and a maximum value determined by the major axis dimension thereof.