High dielectric substrate antenna for implantable miniaturized wireless communications and method for forming the same
An antenna structure for an implantable medical device (IMD) is provided including a lower dielectric biocompatible antenna portion positioned on a body side of the structure and a high dielectric portion including at least one dielectric substrate having a high dielectric constant positioned on a device side of the structure. The biocompatible antenna portion is derived from an antenna layer, a biocompatible surface layer, and at least one layer of biocompatible dielectric material (e.g., high temperature cofire ceramic (HTCC) material) that provides a matching gradient between the antenna and the surrounding environment. The high dielectric portion may include at least one layer of low temperature cofire ceramic (LTCC) material. The high dielectric portion may be bonded to the biocompatible antenna portion or cofired with the biocompatible antenna portion to form a single bilayer monolithic antenna structure having a lower dielectric HTCC biocompatible antenna portion and a high dielectric LTCC portion.
1. A multi-layer antenna for an implantable medical device (“IMD”), comprising:
a biocompatible antenna portion including:
an antenna formed from a biocompatible conductive material, and
at least one layer of biocompatible dielectric material; and
a high dielectric portion including:
a ground plane, and
at least one high dielectric substrate having a high dielectric constant positioned between the antenna and the ground plane,
wherein the at least one layer of biocompatible dielectric material in the biocompatable antenna portion includes a lower dielectric constant than the at least one high dielectric substrate in the high dielectric portion.
2. The multi-layer antenna of claim 1 , wherein the at least one high dielectric substrate is formed from a high dielectric ceramic material.
3. The multi-layer antenna of claim 2 , wherein the at least one high dielectric substrate comprises a low temperature co-fire ceramic (LTCC) material having a melting point between about 850 co and 1150 co and a cofireable paste having a high dielectric constant.
4. The multi-layer antenna of claim 1 , wherein the high dielectric portion is physically and electrically connected to the biocompatible antenna portion.
5. The multi-layer antenna of claim 4 , wherein the high dielectric portion is joined to the biocompatible portion through at least one bond that comprises one of a solder, a conductive epoxy and a metallurgical-based bond.
6. The multi-layer antenna of claim 1 , wherein the biocompatible portion and high dielectric portion are separately formed monolithic structures that are connected together.
7. The multi-layer antenna of claim 3 , wherein the at least one layer of biocompatible dielectric material in the biocompatible antenna portion comprises a high temperature co-fire ceramic (HTCC) material having a melting point between about 1100 co and 1700 co,
further wherein the biocompatible antenna portion and the high dielectric portion are joined together to form a single bilayer monolithic antenna structure having a lower dielectric HTCC biocompatible antenna portion and a LTCC high dielectric portion.
8. The multi-layer antenna of claim 7 , wherein the HTCC biocompatible antenna portion and the LTCC high dielectric portion are joined together by an adhering material.
9. The multi-layer antenna of claim 7 , wherein the HTCC biocompatible antenna portion and the LTCC high dielectric portion are cofired together.
10. The multi-layer antenna of claim 1 , wherein the ground plane in the high dielectric portion further provides a shielding layer for providing electromagnetic shielding between the antenna and the IMD to which the antenna is connected.
11. The multi-layer antenna of claim 1 , wherein the high dielectric portion further includes a layer of electromagnetic bandgap material.