Abstract: A broad-band microwave amplifier including a semiconductor TRAPATT diode generating a microwave signal at its fundamental, second and third harmonic frequencies. Energy is extracted at the second harmonic frequency and a certain impedance loading is provided at the fundamental and third harmonic frequencies by an open-ended tapered microstrip idler circuit connected in parallel with the diode. The tapered idler circuit also provides a predetermined relatively small rate of change of impedance with respect to frequency changes to obtain a wide instantaneous bandwidth of the amplifier.

Abstract: A frequency tunable microwave apparatus including a semiconductor TRAPATT diode generating a microwave signal at its fundamental, second and third harmonic frequencies. Energy is extracted at the second harmonic frequency and a certain impedance loading is provided at the fundamental frequency and third harmonic by a variable impedance hybrid idler circuit. The hybrid idler circuit comprises a distributed transmission line serially connected to a lumped variable capacitor. Variations in the capacitance of the variable capacitor tune the fundamental frequency without substantially varying the impedance loading conditions of the diode allowing energy to be extracted at the second harmonic frequency throughout the tunable frequency range.

Abstract: An improved method of electrically interconnecting a plurality of spaced semiconductor elements adjacent to a substrate, each element having a mesa shape with a top surface spaced apart from the substrate and a side surface, includes coating the side surfaces of the elements with a protective material, filling in the space above the substrate and in between the elements with a temporary support material, depositing a continuous electrically-conductive layer on the support material and in electrical contact with the top surfaces of a plurality of the elements, and then removing the temporary support material to form an electrically-conductive homogeneous air-bridge. The protective material protects the elements from being exposed to the temporary support material. By this method, a plurality of metallized air-bridges can be formed simultaneously.