FIELD

Embodiments of the present disclosure are directed to an antenna system with a combined pocketed electromagnetic interference shielding cover and heat sink containing a dielectric and cooling fluid.

BACKGROUND

Phased array antenna systems have a variety of applications in present day communications and surveillance systems. For example, phased array antenna systems can be used in high performance wireless communications networks, such as Multi Input Multi Output (MIMO) antenna arrays associated with fifth generation 5G cellular communications systems. As another example, phased array antenna systems can be used in RADAR surveillance and tracking systems. In such applications, the beam pattern produced by the antenna is often dynamically steered. It is desirable to locate the electronic componentry required for steering the antenna beam and for amplifying transmitted or received signals in close proximity to the elements of the antenna. However, high power levels and increases in the density of the electrical circuit designs due to the close packaging of circuit elements and the inclusion of steering or other circuitry increase the potential for interference between different circuit elements due to coupling, and increase the amount of heat generated per unit area. Accordingly, contemporary antenna systems operating in association with high frequency, high power systems, need a way to remove heat from the systems in order to ensure reliable operation. In addition, there is a need to control electromagnetic interference (EMI) from external high frequency electrical signal interference and from neighboring elements and associated electronics of the antenna itself.

A common way of shielding circuits operating at radio frequencies for EMI mitigation purposes is with a metallic hat or cover. For a large array of components, such as a phased array or an active electronically scanned array (AESA) application, the EMI cover can be provided as a plate with a number of individual pockets, one for the electrical components associated with each antenna element, for isolation. However, such arrangements can result in inadequate cooling for the circuit elements contained within the pockets. In order to provide cooling for heat generating electronic components, various cooling systems have been devised. For instance, thermosiphon or heat pipe arrangements in which a cooling fluid is circulated through cooling channels routed across or near the electronic components have been developed. However, these cooling systems have been provided separately from the EMI elements. Accordingly, providing both EMI shielding and cooling in various electronic systems, including radio frequency systems, has been complicated and relatively expensive. In addition, the ability of such systems to provide effective EMI shielding and thermal management has been less than desired.

SUMMARY

Embodiments of the present disclosure are directed to methods and systems for providing electronic systems, such as but not limited to multiple element antenna systems, with integrated EMI shielding and thermal management components. More particularly, embodiments of the present disclosure provide an electromagnetic interference shielded heat sink with a cooling fluid contained within shielded pockets or volumes to provide for adequate cooling of shielded electrical components. The cooling fluid can be contained entirely within individual EMI shield pockets or volumes, where one EMI shield pocket is provided for electronic components or circuit elements associated with each antenna element. In accordance with further embodiments, fluid flow paths can be established between pockets of adjacent antenna elements. In accordance with still other embodiments of the present disclosure, the fluid can be circulated to a radiator or other cooling component, in addition to being circulated through one or more pocket volumes.

Systems in accordance with embodiments of the present disclosure include an antenna system having a plurality of antenna or radiating elements formed on a common plane comprising a first surface of an antenna circuit board. Circuit elements (e.g., for beam shaping, power, or signal processing) are placed on a second surface of the antenna circuit board. In general, one circuit element or set of circuit elements is provided for each antenna element. The circuit elements can include integrated circuits, discrete circuit elements, or the like. In addition, the second surface of the antenna circuit board is connected to a pocketed EMI shielded heat sink. The EMI shielded heat sink includes a cover surface and shield walls that define EMI shield pockets, with one EMI shield pocket formed for the circuit elements of each antenna element. Ends of the shield walls opposite the cover surface are joined to the second surface of the antenna circuit board, forming shielded volumes containing the circuit elements. A cooling fluid is placed in the shielded volume, promoting the removal of heat from the circuit elements. In accordance with at least some embodiments of the present disclosure, adjacent shielded volumes are connected to one another by channels or passages formed in the shield walls, thereby allowing the cooling fluid to flow between different shielded volumes. In accordance with still other embodiments of the present disclosure, the cooling fluid can be circulated through a radiator or other cooling apparatus, in addition to through one or more shielded volumes.

Methods in accordance with embodiments of the present disclosure include providing an array antenna having antenna elements on one side of a substrate, and circuit elements on an opposite side of the substrate. More particularly, the antenna can be configured as a planar array, with antenna elements arranged in one or more rows and columns. In addition, the circuit elements can generally be provided in sets, with one set of circuit elements for each of the antenna elements. The method further includes providing a pocketed EMI shielded heat sink, with a planar shield surface, and walls sized to define pockets capable of containing the circuit element sets for each of the antenna elements formed on an interior side of the planar shield surface. According to the method, the pockets are filled with a cooling fluid. The ends of the walls of the pocketed EMI shielded heat sink are then joined to the second side of the circuit board, sealing the fluid in the volumes defined by the pockets. The cooling fluid can entirely fill the pockets. Alternatively, the cooling fluid can partially fill the pockets, leaving a head space in which vapor can collect after the EMI shielded heat sink is joined to the circuit board. In accordance with at least some embodiments of the present disclosure, flow channels or paths are formed between adjacent pockets, allowing cooling fluid to flow between the different pockets. The flow can be induced by an external system, such as a pump, or can be induced by convection currents. Where channels are formed, such channels can interconnect all of the volumes defined by the pockets, or subsets of the volumes.

Additional features and advantages of embodiments of the present disclosure will become more readily apparent from the following description, particularly when taken together with the accompanying drawings.

