Abstract: To implement a high-gain amplifier in a microwave frequency band, it is proposed to interconnect amplification circuits and to cover the housing that contains them with a lid. In the space between the lid and the amplification circuits, inside the housing, waveguides are provided whose cutoff frequency is such that it allows none of the modes that can be present at the frequencies of the working band to propagate. It is shown that, by forming such waveguides in said space, instead of filling it with absorbents, much better radio isolation is obtained between the output and the input to avoid interfering reinjections. As a result, in the same housing, it is possible to achieve amplification of up to 90 dB, whereas, hitherto, the limit of 45 dB per housing could not be exceeded.

Abstract: The invention relates to a transition between a ridge waveguide and a planar circuit on which a conductor is provided. The transition includes at least one conductive link connecting the end of said ridge to said conductor between two contact points. According to the invention, the contact points face a common access provided for putting the conductive link in place. It is thus possible to implement the contact points industrially, e.g. by means of a thermocompression machine.