Polarization-Independent Spatial Power Divider for Millimeter-Wave Antennas
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Solution Overview
Problem
Current millimeter-wave radar systems for automotive applications face challenges in achieving high cross-range resolution and polarimetric capabilities due to limitations in antenna size and coupling issues between transmitter and receiver antennas, leading to radar parallax and interference from leakage signals.
Innovation Solution
A polarization-independent spatial power divider using a composite dielectric plate with corrugated surfaces oriented at 45 degrees, designed to equally reflect and transmit signals for both transverse electric and transverse magnetic polarizations, minimizing signal difference and enabling good beam alignment while maintaining compatibility with fully polarimetric radar systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If two separate antennas are used for transmit and receive, then the antennas can be compact, but radar parallax occurs and beam alignment is only achieved over certain target distances
Solution Approach 1:
The patent combines transmit and receive antenna functions into a single integrated antenna structure with a shared aperture. The spatial power divider separates the transmit and receive signals within the same antenna system, eliminating the physical separation between transmit and receive antennas while maintaining distinct signal paths. This resolves the contradiction by achieving compact size through integration while maintaining precise beam alignment through shared aperture geometry.
2Measurement precision
If standard dual-polarized antenna configuration is used, then good beam alignment is achieved, but fully polarimetric radar system implementation is prevented
Solution Approach 1:
The patent segments the antenna aperture into four distinct sub-apertures (first, second, third, and fourth sub-apertures) that can independently control different polarizations. Each sub-aperture is fed by separate feed elements through the spatial power divider, allowing independent control of horizontal and vertical polarizations for both transmit and receive functions. This segmentation enables full polarimetric radar capability while maintaining good beam alignment through coordinated phasing of the segmented elements.
3Reliability
If transmit and receive antennas are separated, then coupling between them is reduced, but leakage signal interference with target detection persists
Solution Approach 1:
The patent introduces a spatial power divider as an intermediary component between the transmit and receive signal paths within the integrated antenna. This device uses spatial filtering and power division to separate transmit and receive signals while maintaining physical proximity of the antenna elements. The intermediary structure provides sufficient isolation to prevent leakage signal interference while allowing the compact integrated design to maintain reliable signal detection.
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 solution achieves high isolation and effective beam alignment between ports with minimal signal loss, enhancing cross-range resolution and polarimetric capabilities, suitable for higher millimeter-wave frequencies like 230 GHz, while maintaining compatibility with existing systems.
Implementation Method 1
The spatial power divider is comprised of a composite dielectric plate defining two opposing surfaces: a transmit surface and a receive surface. The transmit surface is orientated at forty-five degrees in relation to propagation direction of the transmit signal
Implementation Method 2
The spatial power divider is comprised of a composite dielectric plate defining two opposing surfaces: a transmit surface and a receive surface. The receive surface is orientated at forty-five degrees in relation to propagation direction of the receive signal
Implementation Method 3
The spatial power divider is comprised of a composite dielectric plate defining two opposing surfaces
Data Source
AI summary
A two-port antenna system is proposed that uses a polarization-independent spatial power divider to align the beams from two orthogonally oriented dual-polarized feeds. This antenna system is compatible with fully polarimetric radar and provides high port isolation. It simultaneously provides a common aperture for transmit and receive to minimize radar parallax. The spatial power divider is designed using a combination of all-dielectric metamaterial techniques and the concept of miniaturized-element frequency selective surfaces, and is fabricated on a silicon wafer using standard microfabrication technology.