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EP-4128433-B1 - MICROWAVE OR MILLIMETER WAVE PASSIVE COMPONENTS OR DEVICES

EP4128433B1EP 4128433 B1EP4128433 B1EP 4128433B1EP-4128433-B1

Inventors

  • FLEURY, Romain
  • KHATIBI MOGHADDAM, Maliheh

Dates

Publication Date
20260506
Application Date
20210323

Claims (15)

  1. Microwave or millimeter wave passive device (1) comprising: - a hollow waveguide (5) including a first wall structure (11) and a second wall structure (15) extending in a guiding direction (GD), an interconnecting base (17) extending between the first and second wall structures (11, 15), and an enclosure (EWS) extending between the first and second wall structures (11, 15), the enclosure (EWS) being located opposite the interconnecting base (17); and - at least one array (7) of radiatively coupled resonant structures (9) enclosed inside the hollow waveguide (5), the at least one array (7) of radiatively coupled resonant structures (9) being configured to provide radiatively coupled local resonators (LR) and at least one microwave or millimeter wave frequency passband (FPB) for providing at least one selected microwave or millimeter wave signal, the array (7) extending along the guiding direction (GD) and being located between the first and second wall structures (11, 15), wherein each resonant structure (9) extends from the interconnecting base (17) into the hollow waveguide (5) to define a microwave or millimeter wave subwavelength resonant structure, and wherein successive resonant structures (9) are separated by a microwave or millimeter wave subwavelength distance, wherein a resonance frequency (f r ) of the resonant structures (9) or of each of the resonant structures (9) is below or less than a cut-off frequency (f c ) of the hollow waveguide (5) , wherein each coupled resonant structure (9) is configured to provide or generate a local resonator (LR) local to the resonant structure (9), and the resonant structures (9) are directly electrically and magnetically coupled to one other to permit energy to be directly coupled from one resonant structure (9) to another and guide the at least one selected microwave or millimeter wave signal along the guiding direction (GD) for output from the microwave or millimeter wave passive device (1), and wherein the at least one array (7) of radiatively coupled resonant structures (9) is configured to generate at least one hybridization bandgap (HBG) in a frequency characteristic or dispersion curve characterizing microwave or millimeter wave propagation in the microwave or millimeter wave passive device (1), the at least one hybridization bandgap being located in a frequency range higher than the at least one microwave or millimeter wave frequency passband (FPB).
  2. Microwave or millimeter wave passive device (1) according to the previous claim, characterized in that the at least one hybridization bandgap (HBG) is a stopband of the microwave or millimeter wave passive device (1).
  3. Microwave or millimeter wave passive device (1) according to the previous claim 1 or 2, characterized in that the resonance frequency (f r ) of each of the resonant structures (9) is above or greater than the at least one microwave or millimeter wave frequency passband (FPB) generated by the at least one array (7) of radiatively coupled resonant structures (9).
  4. Microwave or millimeter wave passive device (1) according to anyone of the previous claims, wherein the resonance frequency (f r ) of each of the resonant structures (9) is located in the at least one hybridization bandgap (HBG).
  5. Microwave or millimeter wave passive device (1) according to anyone of the previous claims, further including a first metamaterial port or connector (19A) including a plurality of radiatively coupled resonant structures (9B) configured to couple or transfer an electromagnetic wave into the microwave or millimeter wave passive device (1), and/or a second metamaterial port or connector (19B) including a plurality of radiatively coupled resonant structures (9B) configured to transfer an electromagnetic wave out of the microwave or millimeter wave passive device (1), the at least one array (7) being located between the first and second metamaterial ports, wherein the resonance frequency (f r ) of the resonant structures (9) of the at least one array (7) is lower than a resonance frequency of the resonant structures (9B) of the plurality of radiatively coupled resonant structures (9B) of the first and/or second metamaterial port.
  6. Microwave or millimeter wave passive device (1) according to any one of the previous claims, wherein the hollow waveguide (5) is configured to support at least one or a plurality of evanescent modes or waves of microwave or millimeter electromagnetic radiation that couple or interact with the local resonators (LR) of the resonant structures (9) to provide a subwavelength guided mode in the microwave or millimeter wave passive device (1) defining the at least one microwave or millimeter wave frequency passband (FPB) of the microwave or millimeter wave passive device (1); wherein the subwavelength guided mode and the at least one microwave or millimeter wave frequency passband (FPB) are entirely below or entirely less than the resonance frequency (f r ) of each of the resonant structures (9).
  7. Microwave or millimeter wave passive device (1) according to anyone of the previous claims, wherein a width (W) of the hollow waveguide (5) is less than two-times a height (h r ) of one or each resonant structure (9); or wherein a width (W) of the hollow waveguide (5) is tapered or gradually changes along the guiding direction (GD), and a height (h) of the hollow waveguide (5) is tapered or gradually changes along the guiding direction (GD); or wherein a periodicity, radius, or height (h r ) of the resonant structures (9) is tapered or gradually changes along the guiding direction (GD).
  8. Microwave or millimeter wave passive device (1) according to anyone of the previous claims, wherein the hollow waveguide (5) extends along the guiding direction (GD) in a twisted manner or in a curved manner to define at least one bend; wherein resonant structures (9) of the at least one array (7) are relatively inclined with respect to each other along the guiding direction (GD) of the twisted hollow waveguide (5).
  9. Microwave or millimeter wave passive device (1) according to claim 1, wherein a distance between the array (7) and the first wall structure (11) and/or the second wall structure (15) defines a bandwidth of the microwave or millimeter wave frequency passband (FPB).
  10. Microwave or millimeter wave passive device (1) according to anyone of the previous claims, wherein the microwave or millimeter wave passive component is configured to define a bandwidth of the microwave or millimeter wave frequency passband (FPB) by changing a cut-off frequency (f c ) of the hollow waveguide (5).
  11. Microwave or millimeter wave passive device (1) according to anyone of the previous claims, wherein the resonant structures (9) are configured to generate the hybridization bandgap; or wherein each resonant structure (9) comprises or consists of an elongated conductive element of subwavelength extension or length; or wherein a resonance frequency (f r ) of the resonant structure (9) is defined by a length or elongated extension of the resonant structure (9).
  12. Microwave or millimeter wave passive device (1) according to anyone of the previous claims, further including a resonant metamaterial located between the at least one array (7) of radiatively coupled resonant structures (9) and the first wall structure (11), and a resonant metamaterial located between the at least one array (7) of radiatively coupled resonant structures (9) and the second wall structure (15); wherein the resonant metamaterial is configured to induce a forbidden frequency band and comprises or consists of a plurality or bed of elongated conductive bodies (25).
  13. Microwave or millimeter wave passive device (1) according to anyone of the previous claims 1 to 11, wherein the hollow waveguide (5) is resonant metamaterial-free or artificial wall-free between the at least one array (7) of radiatively coupled resonant structures (9) and the first wall structure (11), and is resonant metamaterial-free or artificial wall-free between the at least one array (7) of radiatively coupled resonant structures (9) and the second wall structure (15).
  14. Microwave or millimeter wave passive device (1) according to anyone of the previous claims 1 to 4 and 6 to 13 further including a first terminal or probe (19A) and a second terminal or probe (19B), the array (7) being located between the first and second terminals (19A, 19B), wherein the first terminal or probe (19A) and/or the second terminal or probe (19B) comprise or consist of a strip terminal or probe.
  15. Microwave or millimeter wave passive device (1) according to claim 5, wherein the first metamaterial port and/or the second metamaterial port includes a hollow waveguide configured to support a transverse electric, TE, mode of microwave or millimeter electromagnetic radiation, and the plurality of radiatively coupled resonant structures of the first and/or second metamaterial port are enclosed inside the hollow waveguide, wherein the resonance frequency of the resonant structures of the plurality of radiatively coupled resonant structures of the first metamaterial port is higher than a cut-off frequency of the hollow waveguide of the first metamaterial port, and/or the resonance frequency of the resonant structures of the plurality of radiatively coupled resonant structures of the second metamaterial port is higher than a cut-off frequency of the hollow waveguide of the second metamaterial port; or a width (W) of the hollow waveguide of the first metamaterial port is greater than two-times a height (h r ) of the resonant structures or of each resonant structure of the first metamaterial port, and/or a width (W) of the hollow waveguide of the second metamaterial port is greater than two-times a height (h r ) of the resonant structures or of each resonant structure of the second metamaterial port; or wherein the radiatively coupled resonant structures of the first metamaterial port are arranged in a periodic or aperiodic pattern, or arranged randomly inside the hollow waveguide of the of the first metamaterial port, and/or the radiatively coupled resonant structures of the second metamaterial port are arranged in a periodic or aperiodic pattern, or arranged randomly inside the hollow waveguide of the of the second metamaterial port; or wherein a height (h r ) of the resonant structures of the first metamaterial port and a distance between resonant structures of the first metamaterial port define a frequency or frequency range at or in which at least one selected microwave or millimeter wave signal is admitted into the microwave or millimeter wave passive device (1).

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application claims priority to international patent application PCT/IB2020/052819 filed on March 25, 2020. FIELD OF THE INVENTION The present invention relates to microwave or millimeter-wave passive components or devices and in particular to microwave or millimeter-wave waveguide components or devices such as microwave or millimeter wave filters, diplexers, and multiplexers. More particularly, the present invention concerns subwavelength or deep subwavelength microwave or millimeter-wave waveguide components or devices such as microwave or millimeter wave filters, diplexers, and multiplexers based on locally resonant materials or metamaterials. BACKGROUND Waveguide technology is widely used for construction of microwave passive devices such as filters, allowing for low loss and high-power handling capability. They are regularly used in satellite communications and radar systems, however, they are typically larger than the wavelength, leading to somehow bulky and heavy metallic components, which can be a problem in some applications, including embedded technologies. The next decade is likely to see a considerable rise in demand for small satellite communications, such as Cube/nano/micro/mini satellites, due to their low mass and small size that enables several satellites to be launched simultaneously from a single-vehicle launcher. Finding solutions for compact and lightweight microwave waveguide components is, therefore, a much-sought need in the development of these future technologies. Conventional transmission media, regularly used for the implementation of Microwave/Millimeter-wave components, include rectangular waveguides, microstrip lines, coplanar waveguides, and substrate integrated waveguides. Researchers have been nonetheless looking for a solution to improve plenty of technological factors in the design of microwave components, such as lower cost, smaller size, less weight, increased system density, cross-talk suppression, and protected packaging [1]. However, while the microstrip and coplanar lines are known as robust and low-cost transmission lines, they suffer from potentially higher insertion loss due to the presence of lossy dielectric materials and low power-handling capabilities. Thus, in high-power applications, such as radars and space communication systems, microwave components are traditionally implemented based on waveguide technology [2]. Hollow rectangular waveguides, which are commonly used to realize low-loss antenna system components, are typically massive and bulky, due to the geometrical scaling governed by operating frequency [3][4] (at GPS frequency the typical waveguide width is 10 cm). Moreover, for realizing a filter or other microwave passive components, which operate based on wave interferences, the necessity of cascading several bulky waveguide cavities drastically increases the size of the components (a GPS frequency filter can be half a meter long). Therefore, compactions and low weight of microwave components have become critical issues, especially for small satellite systems. The demand for miniaturizing microwave passive components is evident when we consider cube/ nano/ micro satellites [5], with a remarkable growing demand, which is typically several kilograms and composed of cubic units with sizes around 10 cm × 10 cm × 11.35 cm. Therefore, the size of the connected microwave components, attached to the antenna feed, has to be less than the size of one unit [6]. For the design of waveguide passive devices, different topologies and techniques have been already proposed and implemented, mainly based on E-plane or H-plane irises, stubs, posts, and corrugation [2], [7], [8]. All the dimensions of these filters directly scale with the operating wavelength. The traditional strategies mostly use the direct coupled-cavity configuration, as a cascade connection of waveguide cavities with different cross-sections. For more complex filtering functions, canonical waveguide filters, involving couplings between nonadjacent cavities have also been studied, in which the multiport rectangular waveguide junctions need to be considered as additional basic blocks. Another method for the design of the filters is based on employing the evanescent modes [9]. In this technique, the filter is essentially composed of a hollow waveguide housing, which transmits the energy between standard waveguide access ports through shunt capacitive elements. Despite the width of these filters is slightly smaller than the conventional ones, and the operating frequency is below the cut off frequency of the dominant mode, there is no impressive length reduction that can be observed in this type of microwave filters[10]-[13]. Among all microwave passive components, diplexers and multiplexers have more complexity and are used to connect two or more channels to a common port. They are playing a vital role in the satellite systems. Diplexers enable two si