Multilayer PWB Phased Array Antenna with Integral RF Cage
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Solution Overview
Problem
Conventional phased array antennas are costly, large, and heavy, limiting their use due to high production costs and complex fabrication processes, which hinder their widespread adoption in both military and commercial applications, especially in applications requiring reduced size, weight, and cost while maintaining high performance.
Innovation Solution
A method for fabricating a panel array using a multilayer printed wiring board (PWB) with a single lamination step, incorporating flip-chip circuits and waveguide cages for improved RF performance, and utilizing a balanced feed slot coupling for dual linear polarization, which simplifies the fabrication process and reduces the number of fabrication steps, resulting in a low-cost, lightweight, and compact phased array antenna.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional phased array antennas are used, then high performance is achieved, but cost and size increase significantly
Solution Approach 1:
The patent combines multiple fabrication operations (imaging, etching, lamination, drilling, plating) into an integrated process flow where all layers are processed simultaneously rather than sequentially. The multilayer PWB is constructed by imaging all layers on individual boards, etching all layers including antenna elements and RF matching pads, laminating the boards together, then drilling and plating all holes through the laminated assembly in a single operation, eliminating the need for multiple separate fabrication cycles.
Solution Approach 2:
The patent divides the phased array antenna into modular components: a multilayer PWB substrate containing RF circuits and antenna elements, separate flip-chip circuits mounted on the PWB, and optional waveguide cages. This segmentation allows each component to be fabricated and tested independently before final assembly, simplifying the overall manufacturing process while maintaining high performance.
2Reliability
If multiple fabrication process steps are used for multilayer PWB, then RF performance is improved, but cost and manufacturing complexity increase
Solution Approach 1:
The patent performs preliminary actions by imaging and etching all circuit layers on individual boards before lamination. RF matching pads are etched in advance on specific layers. The boards are then laminated together and all holes are drilled and plated through the complete assembly in a single operation, rather than performing these operations separately on each layer. This preliminary preparation simplifies the final assembly process while ensuring high RF performance.
Solution Approach 2:
The multilayer PWB structure serves multiple functions simultaneously: it provides mechanical support, RF signal transmission, power distribution, and grounding. The same PWB layers that carry RF traces also provide ground planes and power planes. The drilled and plated holes serve both as mechanical interconnects between layers and as RF transmission paths, eliminating the need for separate structures for each function.
3Reliability
If back-drilling and back-filling operations are performed, then RF performance is improved, but cost increases and manufacturing time is extended
Solution Approach 1:
The patent performs the drilling and plating operation through the entire laminated PWB assembly in a single pass before any back-drilling or back-filling would be required. By drilling all holes through the complete multilayer structure in advance and plating them immediately, the need for subsequent back-drilling and back-filling operations is eliminated entirely. This preliminary drilling and plating approach reduces fabrication time and cost while maintaining RF performance.
4Weight of stationary object
If phased array antennas are made smaller and lighter, then portability and cost are improved, but fabrication complexity increases
Solution Approach 1:
The patent merges multiple fabrication operations into a single integrated process: all layers are imaged, etched, and laminated together in one sequence; all holes are drilled and plated through the complete assembly in a single operation. This consolidation reduces the number of separate fabrication steps required, making it feasible to produce compact, lightweight antennas without proportionally increasing fabrication complexity. The integrated process is particularly suited for high-volume production of smaller antennas.
Data Source
AI summary
A mixed-signal, multilayer printed wiring board fabricated in a single lamination step is described. The PWB includes one or more radio frequency (RF) interconnects between different circuit layers on different circuit boards which make up the PWB. The PWB includes a number of unit cells with radiating elements and an RF cage disposed around each unit cell to isolate the unit cell. A plurality of flip-chip circuits are disposed on an external surface of the PWB and a heat sink can be disposed over the flip chip components.