Low-Loss Waveguide Feed for Wafer-Scale ESA
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Solution Overview
Problem
Existing phased array antennas face challenges in providing cost-effective, low-loss phase shifting methods and dual-band operation, particularly with large losses in coplanar waveguide and microstrip feed implementations in wafer-scale integration for active electronically scanned arrays (ESAs).
Innovation Solution
A wafer-scale heterogeneous layered active ESA with a low-loss integrated waveguide feed structure, comprising multilayer subarray modules and waveguide subarray combiners using single or dual ridge waveguides, electric field probe coupling, and a second layer feed structure formed from high thermal conductivity materials for efficient energy distribution and beam steering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If coplanar waveguide or microstrip transmission lines are used for RF interconnection in wafer-scale integration, then device integration is achieved, but large losses occur
Solution Approach 1:
The patent introduces waveguide structures as an intermediary transmission medium between the coplanar waveguide/microstrip layers. The waveguide acts as a mediator that carries RF signals with significantly reduced loss compared to the planar transmission lines, while still maintaining integration within the wafer-scale architecture. The waveguide is formed by creating conductive walls within the substrate, providing a three-dimensional transmission path that reduces ohmic losses and radiation losses.
Solution Approach 2:
The patent transitions from two-dimensional planar transmission lines (coplanar waveguide and microstrip) to three-dimensional waveguide structures. By forming conductive walls that extend through the substrate thickness, the RF energy is confined in three dimensions, creating a waveguide mode that reduces losses. This dimensional transition allows the system to maintain integration while achieving the low-loss characteristics of waveguide transmission.
2Productivity
If wafer-scale integration is used to reduce costs and packaging requirements, then manufacturing efficiency improves, but RF interconnection losses increase
Solution Approach 1:
The waveguide structure serves as an intermediary that reconciles the conflict between wafer-scale integration and RF loss. It allows the benefits of wafer-scale manufacturing (integration, reduced packaging) to be maintained while introducing a transmission medium that minimizes RF losses. The waveguide is integrated into the wafer structure through conductive wall formation, maintaining the compact, integrated architecture.
Solution Approach 2:
The patent employs composite construction by forming waveguide walls within the substrate material. The waveguide structure combines the substrate material with conductive wall formations, creating a composite transmission structure that maintains the integrated wafer-scale architecture while providing the low-loss characteristics of waveguide transmission. This composite approach allows simultaneous achievement of integration and low loss.
3Speed
If phase shifters are added to all radiating elements for beam steering, then scan performance improves, but device complexity and cost increase
Solution Approach 1:
The waveguide structure serves multiple functions simultaneously: it acts as the RF transmission line, provides the phase shifting capability through its physical dimensions, and enables beam steering control. By making the waveguide properties (length, width, height, positioning) variable, a single structure achieves what would traditionally require separate phase shifter components, reducing overall system complexity.
Solution Approach 2:
The patent achieves phase shifting and beam steering by changing the physical parameters of the waveguide structure itself (dimensions, position, orientation) rather than adding separate phase shifter devices. The electrical phase is controlled by modifying the waveguide's physical characteristics, which simultaneously serves as the transmission medium and the phase control element, simplifying the overall system architecture.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution reduces losses and costs, enables efficient tiling of subarrays into arbitrarily sized apertures, and simplifies construction while maintaining high performance, effectively addressing the limitations of existing ESA designs.
Implementation Method 1
The waveguide subarray combiner feeds the T/R modules in the wafer stack subarray module using electric field probe coupling or aperture slot coupling
Implementation Method 2
The waveguide subarray combiner feeds the T/R modules in the wafer stack subarray module using electric field probe coupling or aperture slot coupling
Data Source
AI summary
A wafer-scale heterogeneous layered active electronically scanned array (ESA) utilizes a low-loss integrated waveguide feed. The ESA is formed from wafer-scale subarray modules each of which comprises a multilayer stack to form transmit/receive (T/R) modules. Waveguide subarray combiners feed the T/R modules. A subarray combiner is a waveguide assembly bonded to a bottom layer in the multilayer stack. The bottom layer is a ground plane forming a top waveguide broadwall of the combiner. The waveguide subarray combiner may be formed from a variety of waveguide types and feeds the T/R modules using electric field probe coupling or an aperture slot coupling. A second layer feed structure forms the subarray modules into the ESA and feeds the waveguide subarray combiners. The second layer feed structure uses waveguides to feed the waveguide subarray combiners using E-field probes or aperture slot coupling on the bottom waveguide broadwall.