Non-linear transmission line device

A microwave frequency oscillator for producing an RF signal, said microwave frequency oscillator comprising:

• a non-linear transmission line containing at least one element of magnetic material having in use a magnetic bias field along a given axis;
• an input for applying an input signal to the transmission line for being modulated thereby;
• and
• an output for the modulated signal;
• wherein said magnetic element has opposed end regions spaced along said axis, and at least one of said end regions is profiled to at least reduce demagnetisation of said material in said end region;
• wherein said magnetic material exhibits gyromagnetic properties, such that the input signal is modulated as a result of gyromagnetic precession effect, and wherein said magnetic material contains one or more of the following:
• garnet-structured ferrite and spinel type ferrite;
• wherein said magnetic element is of elongate generally rectilinear solid form and having first and second opposed end regions transverse to the longitudinal axis, said magnetic bias arrangement being configured to apply a bias field extending generally longitudinally, and wherein the magnetic element tapers in thickness towards at least one of said end regions, thereby to provide a tapered longitudinal cross section;
• and
• wherein said magnetic element has a height, width, and length, and the height and width are each less than 10% of the length.

A microwave frequency oscillator for producing an RF signal, said microwave frequency oscillator comprising:

• a non-linear transmission line containing at least one element of magnetic material having in use a magnetic bias field along a given axis, wherein:
• said magnetic element has opposed end regions spaced along said axis, and at least one of said end regions is profiled to at least reduce demagnetisation of said material in said end region;
• said magnetic element is of hollow cylindrical form, and at least one end region thereof is externally tapered, with a wall thickness of the magnetic element decreasing towards a free end thereof;
• and
• said magnetic element has a height, a width, and a length, and the height and the width are each less than 10% of the length;
• an input for applying an input signal to the transmission line for being modulated thereby;
• an output for the modulated signal;
• and
• a coaxial electrical conductor arrangement, with a first electrically conducting element passing through the hollow part of the magnetic element, and a concentric conductor element surrounding and spaced from said magnetic element, the coaxial conductor arrangement being adapted in use to receive an input pulse at one end and to deliver an output signal at another end, wherein the end of the magnetic element proximate said output end is externally tapered.