Radio frequency device with non-uniform width cavities
A microwave or radio frequency (RF) device includes a substrate and a cover. The substrate has a first surface and an opposing second surface, the first surface including a first RF component and a second RF component electrically coupled to the first RF component in series. The cover is disposed over the first surface of the substrate, where the cover includes a first portion with a first width covering the first RF component, where the first portion and the first surface define a first waveguide cavity having the first width, and a second portion with a second width, less than the first width, covering the second RF component, where the second portion and the first surface define a second waveguide cavity having the second width.
1. A radio frequency (RF) device, comprising
a substrate having a first surface and an opposing second surface;
a first RF component supported by the first surface of the substrate, the first RF component comprising a band-pass filter exhibiting one or more harmonics in a first frequency range;
a second RF component supported by the first surface of the substrate and electrically coupled to the first RF component in series, the second RF component comprising a low-pass filter having a cut-off frequency below the first frequency range; and
a cover disposed over the first surface of the substrate, the cover including:
a first portion having a first width and covering the first RF component, the first portion and the first surface define a first waveguide cavity having the first width, and
a second portion having a second width, less than the first width, and covering the second RF component, the second portion and the first surface define a second waveguide cavity having the second width.
2. The RF device of claim 1 , wherein the first portion of the cover and the second portion of the cover have a first height and a second height, respectively, in relation to the first surface of the substrate, and wherein the first height is equal to the second height.
3. The RF device of claim 1 , wherein the first width has a value between 0.2 inches and 0.4 inches, and the second width has a value between 0.1 inches and 0.4 inches.
4. The RF device of claim 1 , wherein the first portion of the cover includes a first sidewall and a second sidewall, and wherein the second portion includes a third sidewall and a fourth sidewall.
5. The RF device of claim 4 , wherein the first sidewall is separated from the third sidewall by a first gap.
6. The RF device of claim 5 , wherein the second sidewall is separated from the fourth sidewall by a second gap.
7. The RF device of claim 6 , wherein the first gap is equal to the second gap.
8. The RF device of claim 4 , wherein the first sidewall is continuous with the third sidewall.
9. The RF device of claim 8 , wherein the second sidewall is separated from the fourth sidewall by a gap.
10. The RF device of claim 4 , wherein the first surface of the substrate defines a first slot and a second slot, and wherein at least a portion of the third sidewall is disposed in the first slot and at least a portion of the fourth sidewall is disposed in the second slot.
11. The RF device of claim 10 , wherein the first sidewall and the second sidewall are separated from a perimeter of the first RF component by at least a first distance.
12. The RF device of claim 11 , wherein the first distance is at least 0.008 inches.
13. The RF device of claim 4 , wherein the substrate includes a ground plane disposed on the second surface.
14. The RF device of claim 13 , wherein the substrate includes:
a plurality of side surfaces that extend between the first surface and the opposing second surface; and
conductive material disposed on at least a portion of the plurality of side surfaces, the conductive material electrically connected to the ground plane.
15. The RF device of claim 14 , wherein at least a portion of the first sidewall and at least a portion of the second sidewall are in contact with the conductive material.
16. The RF device of claim 4 , wherein the first portion includes a first top plate that extends between the first sidewall and the second sidewall, the first top plate covering the first RF component.
17. The RF device of claim 16 , wherein the second portion includes a second top plate that extends between the third sidewall and the fourth sidewall, the second top plate covering the second RF component.
18. The RF device of claim 17 , wherein the first top plate is continuous with the second top plate.