PCB Slot Transition for Low-Loss MMIC-to-Air-Waveguide Radar
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Solution Overview
Problem
Automotive radar systems face challenges in achieving high gain with minimal aperture size and low cost, particularly due to significant dielectric loss in printed-circuit-board materials used in existing radar systems.
Innovation Solution
A radar assembly design that directly connects a monolithic-microwave-integrated-circuit (MMIC) to an air waveguide using a single FR4 circuit board with a transition-feature slot, minimizing dielectric loss and reducing manufacturing costs by eliminating the need for high-frequency substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If standard printed-circuit-board materials are used in existing radar systems, then manufacturing cost is reduced, but dielectric loss increases significantly
Solution Approach 1:
The patent extracts the problematic dielectric material from the signal path by introducing an air cavity that removes the standard PCB material between the MMIC and antenna elements, thereby eliminating the dielectric loss while maintaining compatibility with standard manufacturing processes
Solution Approach 2:
The patent creates a composite structure combining standard PCB material with an air cavity, where the air portion serves as the transmission medium for radar signals to minimize dielectric loss while the PCB provides structural support and electrical connections
2Loss of energy
If high-frequency substrates are used to reduce dielectric loss, then signal transmission efficiency is improved, but manufacturing cost increases
Solution Approach 1:
The patent uses inexpensive standard PCB materials for the board structure while replacing only the critical dielectric portion with an air cavity, achieving low loss performance without requiring expensive high-frequency substrates throughout the entire assembly
3Loss of energy
If a direct connection between MMIC and air waveguide is made, then dielectric loss is minimized, but manufacturing complexity increases
Solution Approach 1:
The patent merges the air cavity formation with the existing PCB manufacturing process by using the same lamination and drilling techniques, thereby achieving a direct MMIC-to-air-waveguide connection without adding significant manufacturing complexity
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 design enables efficient transmission and reception of radar signals with minimal loss while being economical to manufacture, maintaining compatibility with standard printed circuit board fabrication processes.
Implementation Method 1
a transition feature configured to couple radar signals between an arrangement of solder balls and a ridge air waveguide
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A radar assembly (10) includes a monolithic-microwave-integrated-circuit (12) (MMIC (12)), an antenna-element (20), and a single printed-circuit-board (18) (PCB (18)). The MMIC (12) includes an arrangement (14) of solder-balls (16) configured to couple radar-signals into or out of the MMIC (12). The antenna-element (20) includes a ridge-air-waveguide (24) configured to propagate radar-signals to or from one or more radiation-slots (22) of the antenna-element (20). The PCB (18) is directly attached to the MMIC (12). The PCB (18) includes a transition-feature (28) configured to couple radar-signals between the arrangement (14) of solder-balls (16) and the ridge-air-waveguide (24). The transition-feature (28) is characterized as a slot that extends between the arrangement (14) of solder-balls (16) and the ridge-air-waveguide (24). The transition-feature (28) may be an L-shaped-slot or a U-shaped-slot. The assembly (10) is designed/configured to be compatible with known printed circuit board fabrication processes.