Electromagnetic dielectric structure adhered to a substrate and methods of making the same

1. An electromagnetic, EM, device, comprising:

a substrate comprising a dielectric layer and a first conductive layer;

at least one dielectric structure comprising at least one non-gaseous dielectric material that forms a first dielectric portion that extends outward from a first side of the substrate, the first dielectric portion having a first average dielectric constant;

wherein the at least one dielectric structure and the substrate comprise a bonded interface therebetween, the bonded interface comprising at least one of:

an intermediate layer located in between the dielectric structure and the substrate, the intermediate layer having a roughened surface; or

an adhesive material located in between the dielectric structure and the substrate, the adhesive material having a second dielectric constant.

2. The device of claim 1 , further comprising at least one via that extends at least partially through the substrate from a first side toward an opposing second side of the substrate.

3. The device of claim 2 , wherein

the at least one dielectric structure comprises a second dielectric portion that is contiguous and seamless with the first dielectric portion;

the second dielectric portion extends into the via of the substrate, the via comprising a retrograde surface; and

the at least one dielectric structure comprises a mechanical interlock between the second dielectric portion and the retrograde surface of the via of the substrate.

4. The device of claim 1 , wherein the intermediate layer is present and wherein the intermediate layer has a surface roughness defined by an average peak to valley distance of 0.5 to 5 micrometers.

5. The device of claim 4 , wherein the intermediate layer is the same material as the first conductive layer.

6. The device of claim 1 , comprising the adhesive material.

7. The device of claim 1 , wherein the EM device comprises a dielectric resonator antenna, DRA, and the at least one dielectric structure is at least part of the DRA.

8. The device of claim 6 , wherein the adhesive material comprises a dielectric filler comprising ceramic particles.

9. The device of claim 8 , wherein the dielectric filler comprises titanium dioxide.

10. The device of claim 1 , wherein the second dielectric constant is matched to the first dielectric constant.

11. A method of making an electromagnetic, EM, device, comprising: a substrate comprising a dielectric layer and a first conductive layer;

at least one dielectric structure comprising at least one non-gaseous dielectric material that forms a first dielectric portion that extends outward from a first side of the substrate, the first dielectric portion having a first average dielectric constant wherein the at least one dielectric structure and the substrate comprise a bonded interface therebetween, the bonded interface comprising at least one of: an intermediate layer located in between the dielectric structure and the substrate, the intermediate layer having a roughened surface; or an adhesive material located in between the dielectric structure and the substrate, the adhesive material having a second dielectric constant, the method comprising:

injection molding a dielectric composition onto the substrate to form the device, the dielectric composition forming at least part of the at least one dielectric structure.

12. The method of claim 11 , wherein a mold temperature after the injection molding is 0 to 250° C., or 23 to 200° C. and is optionally maintained for 0.5 to 10 min.

13. The method of claim 11 , wherein the injection molding comprises filling the mold with the dielectric composition in 0.1 to 10 seconds, or 0.5 to 5 seconds, or 0.2 to 1 second.

14. The method of claim 11 , wherein no visible delaminations are present between the dielectric structure and the substrate.

15. The method of claim 11 , further comprising forming a mechanical interlock between the dielectric composition and the substrate by etching the substrate prior to injection molding the dielectric composition onto the substrate.

16. The method of claim 11 , further comprising forming the intermediate layer on a conductive layer of the substrate; wherein forming the intermediate layer optionally comprises exposing the conductive layer to an oxidizing agent, wherein the oxidizing agent preferably comprises at least one of HNO 3 , H 2 SO 4 , AgNO 3 , H 2 O 2 , HOCl, KOCl, KMnO 4 , or CH 3 COOH.

17. The method of claim 11 , further comprising depositing an adhesive material onto the substrate prior to the injection molding.

18. The method of claim 11 , wherein the dielectric composition comprises a dielectric filler; wherein the dielectric filler has a multimodal particle size.

19. The method of claim 18 , wherein the dielectric filler comprises a first plurality of particles having a first average particle size and a second plurality of particles having a second average particle size; wherein the first average particle size is greater than or equal to 7 times, or greater than or equal to 10 times, or 7 to 20 times the second average particle size.

20. The method of claim 11 , wherein the dielectric composition comprises at least one of a flow modifier, a silane, or a flame retardant.

21. The method of claim 11 , further comprising transmitting an ultrasonic wave onto at least one of the dielectric composition or the substrate during or after the injection molding.

22. The method of claim 11 , wherein the dielectric composition comprises a thermoplastic polymer.

23. The method of claim 22 , wherein an injection temperature of the dielectric composition during the molding is greater than a melt temperature of the thermoplastic polymer; preferably the injection temperature is 40° C. to 220° C., or 40° C. to 160° C., or 100° C. to 220° C.

24. The method of claim 11 , wherein an injection pressure during the injection molding is 65 to 350 kPa.