A filter comprising: N dielectric layers, N being an integer greater than or equal to 4, a plurality of stripline resonators (14, 15), each stripline resonator (14, 15) lying in a plane in parallel with a first plane of a three-dimensional rectangular coordinate system, and inductively coupled to another stripline resonator (14, 15) of the plurality of stripline resonators (14, 15); a first plurality of ground planes (20, 21, 29) oriented in parallel to the first plane, at least a first ground plane of the first plurality of ground planes (20, 21, 29) being a first outermost ground plane and having a first window therein; a first outermost layer of the N dielectric layers has adjacent thereto the first outermost ground plane of the first plurality of ground planes (20, 21, 29); N-2 intermediate dielectric layers of the N dielectric layers are configured such that each intermediate dielectric layer separates an intermediate ground plane of the first plurality of ground planes (20, 21, 29) from at least one stripline resonator (14, 15); the Nth dielectric layer is a second outermost layer of the N dielectric layers having an adjacent second outermost ground plane of the first plurality of ground planes (20, 21, 29), the first and second outermost ground planes of the first plurality of ground planes encompassing the first outermost dielectric layer, the Nth dielectric layer, the N-2 intermediate dielectric layers and the intermediate ground planes of the first plurality of ground planes, and a first input/output port (31, 32) having a conductor electrically connected to a first stripline resonator (14, 15) of the plurality of stripline resonators (14, 15), the conductor extending perpendicularly away from the first stripline resonator (14, 15) of the plurality of resonators (14, 15) toward the first window in the first outermost ground plane, wherein two intermediate dielectric layers of the N-2 intermediate dielectric layers each encompass a first pair of the plurality of stripline resonators (14, 15), the first pair lying in a same plane, separated from each other by a first distance and inductively coupled by a coupling stripline. N dielectric layers, N being an integer greater than or equal to 4, a plurality of stripline resonators (14, 15), each stripline resonator (14, 15) lying in a plane in parallel with a first plane of a three-dimensional rectangular coordinate system, and inductively coupled to another stripline resonator (14, 15) of the plurality of stripline resonators (14, 15); a first plurality of ground planes (20, 21, 29) oriented in parallel to the first plane, at least a first ground plane of the first plurality of ground planes (20, 21, 29) being a first outermost ground plane and having a first window therein; a first outermost layer of the N dielectric layers has adjacent thereto the first outermost ground plane of the first plurality of ground planes (20, 21, 29); N-2 intermediate dielectric layers of the N dielectric layers are configured such that each intermediate dielectric layer separates an intermediate ground plane of the first plurality of ground planes (20, 21, 29) from at least one stripline resonator (14, 15); the Nth dielectric layer is a second outermost layer of the N dielectric layers having an adjacent second outermost ground plane of the first plurality of ground planes (20, 21, 29), the first and second outermost ground planes of the first plurality of ground planes encompassing the first outermost dielectric layer, the Nth dielectric layer, the N-2 intermediate dielectric layers and the intermediate ground planes of the first plurality of ground planes, and a first input/output port (31, 32) having a conductor electrically connected to a first stripline resonator (14, 15) of the plurality of stripline resonators (14, 15), the conductor extending perpendicularly away from the first stripline resonator (14, 15) of the plurality of resonators (14, 15) toward the first window in the first outermost ground plane, wherein two intermediate dielectric layers of the N-2 intermediate dielectric layers each encompass a first pair of the plurality of stripline resonators (14, 15), the first pair lying in a same plane, separated from each other by a first distance and inductively coupled by a coupling stripline.