Abstract: A filter device includes a transmission line formed by an electrically conducting strip printed on a surface of an electrically insulating substrate, the conducting strip having two ends respectively forming the two sole input and output connection ports of the filter device, and a plurality of resonators, each resonator including an electrically conducting strip printed on the surface of the substrate. The conducting strip of each resonator has a first end coupled to the transmission line and at least one second end that is free or connected to a ground so as to create an effective fundamental resonant wavelength specific to each resonator. For each pair of neighboring resonators of the plurality of resonators, the distance between the first ends of the two neighboring resonators is less than one tenth of the smallest effective fundamental resonant wavelength of the plurality of resonators.

Abstract: A filter device includes a transmission line formed by an electrically conducting strip printed on a surface of an electrically insulating substrate, the conducting strip having two ends respectively forming the two sole input and output connection ports of the filter device, and a plurality of resonators, each resonator including an electrically conducting strip printed on the surface of the substrate. The conducting strip of each resonator has a first end coupled to the transmission line and at least one second end that is free or connected to a ground so as to create an effective fundamental resonant wavelength specific to each resonator. For each pair of neighbouring resonators of the plurality of resonators, the distance between the first ends of the two neighbouring resonators is less than one tenth of the smallest effective fundamental resonant wavelength of the plurality of resonators.

Abstract: A device (10) for receiving and/or emitting an electromagnetic wave, comprising a medium (11) of dielectric material, a plurality of passive resonant elements (12) incorporated inside said medium, the plurality of passive resonant elements (12) comprising a frequency band-gap, two neighbor passive resonant elements belonging to the plurality being spaced apart from each other of a first distance lower than ?/4, and at least one active resonant element (13) incorporated inside said plurality, said active resonant element (13) having a second structure different from a first structure of the passive resonant elements (12), so that said active resonant element (13) has at least a second resonance frequency comprised inside the frequency band-gap of said plurality of passive elements (12).

Abstract: A device (10) for receiving and/or emitting an electromagnetic wave, comprising a medium (11) of dielectric material, a plurality of passive resonant elements (12) incorporated inside said medium, the plurality of passive resonant elements (12) comprising a frequency band-gap, two neighbour passive resonant elements belonging to the plurality being spaced apart from each other of a first distance lower than ?/4, and at least one active resonant element (13) incorporated inside said plurality, said active resonant element (13) having a second structure different from a first structure of the passive resonant elements (12), so that said active resonant element (13) has at least a second resonance frequency comprised inside the frequency band-gap of said plurality of passive elements (12).