Tunable microminiaturized microwave filters

Claim 2

A tunable microwave filter comprising in combination: a. a composite substrate including a first rectangular dielectric ferromagnetic part and at least one second rectangular dielectric non-ferromagnetic part, said first and second parts being arranged side by side in contact with each other; b. a conductive pattern formed of at least three thick film conductors located side by side on one face of said substrate, capacitively coupled to each other, the central one of said conductors extending at least partially over both parts of said substrate; c. a continuous conductive sheet on the face of said substrate opposite said one face; d. connecting plugs connected to the other two of said film conductors; e. external means for establishing an adjustable D.C. magnetic field within said ferromagnetic substrate part; and f. magnetic shielding means for concentrating said magnetic field within said substrate.

Claim 3

A tunable microwave filter according to claim 1 in which said means for establishing an adjustable D.C. magnetic field consists in two permanent magnets located on both sides of said substrate and two electromagnets located on both sides of said substrate serially connected To an adjustable current feed.

Claim 4

A tunable microwave filter comprising in combination: a. a composite substrate including a first part of insulating dielectric non-magnetic material and a second part of ferromagnetic material, said parts being arranged in side by side contiguous relation; b. a continuous conductive plate on a first face of said substrate; c. a conductive thick film pattern on a face of said substrate opposite said first face, said pattern having at least three capacitively coupled strips, the first and third of which serve as matching sections and the second as a resonator, said second strip being disposed over both substrate parts, the relationship being such that where: lambda o is the wavelength in air of the energy propagating in the filter, epsilon 1 is the permittivity of the dielectric of said substrate first part, epsilon 2 and Mu are respectively the permittivity and the permeability of said substrate second part, L1 and L2 are respectively the length of said second strip extending on said substrate first and second parts; d. external means for establishing an adjustable D.C. magnetic field within said substrate second part; e. shielding means for concentrating said magnetic field within said substrate; and f. two connecting plugs respectively connected to said first and third thick film strips.

Claim 5

A tunable microwave filter comprising in combination: a. a composite substrate including a first part of insulating dielectric non-magnetic material and a second part of ferromagnetic material, said parts being arranged in side by side contiguous relation; b. a continuous conductive plate on a first face of said substrate; c. a conductive thick film pattern on a face of said substrate opposite said first face, said pattern having at least three capacitively coupled strips, the first and third of which serve as matching sections and the second as a resonator, said second strip being disposed over both substrate parts, the relationship being such that where: lambda o is the wavelength in air of the energy propagating in the filter, epsilon 1 is the permittivity of the dielectric of said substrate first part, epsilon 2 and Mu are respectively the permittivity and the permeability of said substrate second part, L1 and L2 are respectively the length of said second strip extending on said substrate first and second parts; d. external means for establishing an adjustable D.C. magnetic field within said substrate second part; e. shielding means for concentrating said magnetic field within said substrate; and f. two connecting plugs respectively connected to said first and third thick film strips.