Launch structures for a hermetically sealed cavity
An apparatus includes a substrate containing a cavity and a dielectric structure covering at least a portion of the cavity. The cavity is hermetically sealed. The apparatus also may include a launch structure formed on the dielectric structure and outside the hermetically sealed cavity. The launch structure is configured to cause radio frequency (RF) energy flowing in a first direction to enter the hermetically sealed cavity through the dielectric structure in a direction orthogonal to the first direction. Various types of launch structures are disclosed herein.
1. An apparatus, comprising:
a substrate having a cavity;
a dielectric structure covering at least a portion of the cavity, the cavity being hermetically sealed; and
a launch structure formed on the dielectric structure and outside the hermetically sealed cavity, the launch structure configured to cause radio frequency (RF) energy flowing in a first direction to flow through the dielectric structure to the hermetically sealed cavity in a direction orthogonal to the first direction.
2. The apparatus of claim 1 , wherein the dielectric structure includes a first portion and a second portion, the second portion is thinner than the first portion, and the launch structure resides on the second portion.
3. The apparatus of claim 1 , wherein the launch structure includes a radio frequency (RF) feed, a dielectric layer over the RF feed, and a ground reflector on a side of the dielectric layer opposite the RF feed.
4. The apparatus of claim 1 , wherein the dielectric structure has opposite first and second surfaces, the first surface faces toward the cavity, the second surface faces away from the cavity, the launch structure includes a coplanar waveguide on the second surface, and the apparatus further comprises a metal layer between the dielectric structure and the substrate, the metal layer including an iris through which the RF energy enters the cavity from the coplanar waveguide, the iris underlying a portion of the coplanar waveguide and overlying the cavity.
5. The apparatus of claim 4 , wherein the iris includes a bowtie-shaped iris.
6. The apparatus of claim 4 , wherein the iris includes a chevron-shaped iris.
7. The apparatus of claim 1 , wherein the launch structure includes:
a coplanar waveguide including a signal transmission element between two ground elements; and
a metal ground ring to which each of the two ground elements electrically connects;
the signal transmission element terminating at the center of the metal ground ring.
8. An apparatus, comprising:
a substrate having a cavity;
a dielectric structure covering at least a portion of the cavity, the cavity being hermetically sealed;
a launch structure formed on the dielectric structure and outside the hermetically sealed cavity, the launch structure configured to cause radio frequency (RF) energy flowing in a first direction to flow through the dielectric structure to the hermetically sealed cavity in a direction orthogonal to the first direction; and
a transceiver electrically coupled to the launch structure, the transceiver configured to inject a transmit signal into the cavity through the launch structure, to receive a receive signal from the cavity through the launch structure, and to generate an error signal based on the transmit signal and the receive signal, and to dynamically adjust a frequency of the transmit signal based on the error signal.
9. The apparatus of claim 8 , wherein the dielectric structure includes a first portion and a second portion, the second portion is thinner than the first portion, and the launch structure resides on the second portion.
10. The apparatus of claim 8 , wherein the launch structure includes a radio frequency (RF) feed, a dielectric layer over the RF feed, and a ground reflector on a side of the dielectric layer opposite the RF feed.
11. The apparatus of claim 8 , wherein the launch structure includes:
a coplanar waveguide including a signal transmission element between two ground elements; and
a metal ground ring to which each of the two ground elements electrically connects;
the signal transmission element terminating at the center of the metal ground ring.
12. The apparatus of claim 8 , wherein the dielectric structure has opposite first and second surfaces, the first surface faces toward the cavity, the second surface faces away from the cavity, the launch structure includes a coplanar waveguide on the second surface, and the apparatus further comprises a metal layer between the dielectric structure and the substrate, the metal layer including an iris through which the RF energy enters the cavity from the coplanar waveguide, the iris underlying a portion of the coplanar waveguide and overlying the cavity.
13. The apparatus of claim 12 , wherein the iris includes a bowtie-shaped iris.
14. The apparatus of claim 12 , wherein the iris includes a chevron-shaped iris.