Abstract: A tunable, microwave filtering device comprises a microstrip line, a dielectric resonator capable of being coupled to the microstrip line, a coplanar line capable of being coupled to the resonator, an active element, such as a varactor for example, mounted on the coplanar line, the variable impedance of which enables the frequency tuning of the device. The invention can be applied to the making of a tunable microwave frequency discriminator, the making of a microwave oscillator and the frequency stabilization of a tunable oscillator.

Abstract: Particle detector comprising a vacuum envelope in which there are provided a thin planar target made from a material which can emit secondary electrons when a given particle of sufficient energy strikes the target and an electron multiplier comprising a plurality of thin planar amplifying plates made from a material able to emit secondary electrons when struck by electrons with a sufficient energy, said plates being parallel to the target and spaced from one another, the secondary electrons emitted by the target and by each of the plates being accelerated by an appropriate potential difference established between the target and the closest plate and between the various plates, wherein the materials forming the target and the amplifying plates are porous.