Folded Rotman Beamformer Layout for Wideband mmWave Phase Shift
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Solution Overview
Problem
Achieving a constant progressive phase shift between adjacent antennas over a wide bandwidth is a significant challenge for beamformers in millimeter-wave (mmW) radar systems, particularly in phased array systems operating in the high-frequency microwave spectrum, which affects the resolution and range of radar systems.
Innovation Solution
The use of compact beamformers incorporating a Rotman lens and folded waveguides, which facilitate phase-shifting electromagnetic waves and support high-density waveguiding components, enabling efficient coupling with amplifiers and delay lines without increasing the system size, thus enhancing angular resolution and signal-to-noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional beamformers are used in mmW phased array systems, then the system can operate at high frequencies, but achieving constant progressive phase shift over wide bandwidth becomes difficult
Solution Approach 1:
The patent transitions from planar waveguide layouts to three-dimensional folded waveguide structures. By folding the waveguides in multiple dimensions and using vertical stacking withvia connections, the system achieves compact phase shifting paths that maintain constant progressive phase shift across wide bandwidths at mmW frequencies
Solution Approach 2:
The patent implements nested waveguide structures where waveguides are folded back on themselves and stacked vertically. The folded waveguides are nested within a compact housing with multiple layers connected via via holes, creating a space-efficient configuration that maintains electromagnetic performance
2Measurement precision
If high-density waveguiding components are used to improve angular resolution, then the scanning resolution improves, but the system size increases
Solution Approach 1:
The patent uses vertical stacking of waveguide layers connected by via holes to achieve high component density without increasing the horizontal footprint. Multiple waveguides are arranged in vertical columns, allowing high angular resolution scanning while maintaining a compact overall system volume
Solution Approach 2:
The patent combines multiple functional components into integrated assemblies. The folded waveguides are merged with the housing structure, and multiple waveguide functions (phase shifting, signal routing) are combined within the same three-dimensional space, reducing overall system size
3Ease of operation
If folded waveguide geometry is used to access electromagnetic signals, then coupling with amplifiers and control modules is facilitated, but the waveguide routing complexity increases
Solution Approach 1:
The patent divides the waveguide system into discrete modular sections with standardized folding patterns. Each folded waveguide segment can be independently routed and connected via via holes, making the complex routing manageable through systematic segmentation rather than monolithic design
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
The folded beamformers provide reliable, efficient true-time-delay devices that support frequency-independent beamforming, improving angular resolution and reducing costs compared to traditional active electronically scanned arrays (AESAs).
Implementation Method 1
a Rotman lens including a dielectric insert bounded by a set of array ports and a set of beam ports opposite one another along a first direction, the dielectric insert configured to guide microwave signals between the set of array ports and the set of beam ports
Implementation Method 2
Waveguides transport electromagnetic waves along a fixed path by confining the electromagnetic field within an extended structure
Implementation Method 3
Each plane of the beamformer includes one or more sets of miter bends, each set of miter bends configured to redirect waveguides of the first or second set, each miter bend of each set redirecting a corresponding one of the waveguides to or from a second direction orthogonal to the principal plane
Data Source
AI summary
Microwave radar systems using compact form factor devices are described. Examples of such devices include a “folded” beamformer. The beamformer includes: a linear array of microwave antennas; a principal plane including: a Rotman lens; a first set of coplanar microwave waveguides; and a second set of coplanar microwave waveguides; and a series of one or more first planes parallel to the principal, each first plane including the first set of waveguides. Each plane of the beamformer includes one or more sets of miter bends, each set of miter bends configured to redirect waveguides of the first or second set. The beamformer can be configured for use in a radar system, either as a receiver (RX) beamformer, a transmitter (TX) beamformer, or as a combined transceiver (TRX) beamformer. The radar system can also include a second beamformer for receiving and transmitting using two separate beamformers.