Waveguide filters

Patent metadata

Field	Value
Publication number	US-12166257-B2
Application number	US-202017625848-A
Country	US
Kind code	B2
Filing date	Jun 9, 2020
Priority date	Jul 12, 2019
Publication date	Dec 10, 2024
Grant date	Dec 10, 2024

Abstract

A filter for filtering an electromagnetic wave and a filter design method are provided. The filter comprises a cavity with a first plate and a second plate, the first and second plates are opposite to each other. The first plate comprises a number of elements distributed on the side of the first plate facing the cavity, wherein a location of each element on the first plate is defined in a coordinate system. The second plate comprises a number of elements distributed on the side of the second plate facing the cavity according to the locations of the elements on the first plate, wherein each element is distributed on the second plate with an offset with respect to a corresponding element on the first plate.

First claim

The invention claimed is:

1. A filter designed to filter an electromagnetic wave comprising:
a cavity with a first plate and a second plate, the first and second plates are opposite to each other, wherein
the first plate comprises a number of elements distributed on the side of the first plate facing the cavity, wherein a location of each element on the first plate is defined in a coordinate system; and
the second plate comprises a number of elements distributed on the side of the second plate facing the cavity according to the locations of the elements on the first plate, wherein each element is distributed on the second plate with an offset with respect to a corresponding element on the first plate,
wherein the elements are any of holes or recesses, and wherein the filter comprises electromagnetic band gap, EBG, surfaces on sides of the first and second plates to constrain the electromagnetic wave to propagate along a direction of the cavity from one end to the other, and as the electromagnetic wave is traversing about the elements in the cavity, specific wavelengths are filtered.

2. The filter according to claim 1 is a waveguide filter, wherein the cavity is a rectangular parallelepiped.

3. The filter according to claim 1 further comprising two side plates to prevent leakage of wave energy at the sides of the filter and constrain the electromagnetic wave to propagate along a direction of the cavity from one end to the other, and as the electromagnetic wave is traversing about the elements in the cavity, specific wavelengths are filtered.

4. The filter according to claim 1 , wherein the filter is made by any one of metal material, dielectric filled printed circuit board material.

5. The filter according to claim 1 , wherein the coordinate system is a three-dimensional orthonormal coordinate system defined by x-y-z-axes with an origin and a center plane between and in parallel with the first and second plates, wherein the x-axis corresponds to a distance from the origin along a transversal direction of the first and second plates, the z-axis corresponds to a distance from the origin along a longitudinal direction of the first and second plates and the y-axis corresponds to a distance from an element to the center plane perpendicular to the first and second plates.

6. The filter according to claim 5 , wherein the number of the elements on the first plate are distributed according to a rectangular lattice in x and z directions, and wherein the location of each element on the second plate is defined according to a combination of coordinate transformations in the x and z directions and a mirroring transformation in y direction such that each element is distributed on the second plate with an offset with respect to a corresponding element on the first plate in two directions.

7. The filter according to claim 6 , wherein the location of each element on the second plate is defined according to coordinate transformations defined by

G
1

≡

{

x
→

x
+

α
x

⁢

d
x

/
2

y
→

-

β
x

⁢
y

z
→
z

⁢

G
2

≡

{

x
→
x

y
→

-

β
z

⁢
y

z
→

z
+

α
z

⁢

d
z

/
2

where parameters α x , α z , are within interval [0; 1] and corresponding to the offsets in x and z directions respectively, parameters d x , d z , are periodicities of each element in x and z directions respectively, parameters β x , β z are positive real numbers and corresponding to scaling factors in the mirroring transformation.

8. The filter according to claim 6 wherein the location of each element on the second plate is defined according to a coordinate transformation defined by

G
≡

{

x
→

Assignees

• Ericsson Telefon Ab L M

Inventors

• Pucci Elena
• Quevedo-Teruel Oscar
• Monje Real Alberto
• Fonseca Nelson

Classifications

• H01P11/007

  Manufacturing frequency-selective devices (resonators H01P11/008) · CPC title

• H01P11/002

  Manufacturing hollow waveguides · CPC title

• H01P3/12

  Hollow waveguides (H01P3/20 takes precedence) · CPC title

• H01P1/2005

  Electromagnetic photonic bandgaps [EPB], or photonic bandgaps [PBG] · CPC title

• H01P1/207 Primary

  Hollow waveguide filters (H01P1/212, H01P1/213, H01P1/215, H01P1/219 take precedence) · CPC title