Microwave or millimeter wave passive components or devices

Microwave or millimeter wave passive device comprising:

• a hollow waveguide including a first wall structure and a second wall structure extending in a guiding direction, and an interconnecting base extending between at least the first and second wall structures,
• at least one array of radiatively coupled first resonant structures enclosed inside the hollow waveguide, the at least one array of radiatively coupled first resonant structures configured to provide radiatively coupled local resonators and at least one microwave or millimeter wave frequency passband for providing at least one selected microwave or millimeter wave signal, the array extending along the guiding direction and being located between at least the first and second wall structures, wherein each first resonant structure extends from the interconnecting base into the hollow waveguide to define a microwave or millimeter wave subwavelength resonant structure, and wherein successive resonant structures are separated by a microwave or millimeter wave subwavelength distance, and
• wherein an operating frequency fo of the microwave or millimeter wave passive device is located in the at least one microwave or millimeter wave frequency passband, and
• the at least one array of radiatively coupled first resonant structures is configured to generate at least one hybridization bandgap in a frequency characteristic characterizing microwave or millimeter wave propagation in the microwave or millimeter wave passive device, wherein the at least one hybridization bandgap is a stopband frequency range in which the microwave or millimeter wave propagation is prohibited by fano-interference between a propagating electromagnetic wave and localized resonance modes of the first resonant structures;
• and wherein the at least one hybridization bandgap is located in a frequency range higher than the at least one microwave or millimeter wave frequency passband;
• and
• a resonance frequency fr of the each of the first resonant structures is located in the at least one hybridization bandgap, the resonance frequency fr being the frequency of the local resonator generated by the first resonant structure;
• and
• a subwavelength guided mode, that is a propagating mode of the waveguide of the microwave or millimeter wave passive device, having the operating frequency fo that is (i) below or less than a resonance frequency fr of the first resonant structures, and (ii) located in the at least one microwave or millimeter wave frequency passband.