PCB-to-Waveguide Iris Transition for 77 GHz Impedance Matching
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Solution Overview
Problem
Existing radar systems face challenges in efficiently radiating and coupling electromagnetic energy, particularly at high frequencies like 77 GHz, which affects their accuracy and efficiency in environmental mapping and obstacle avoidance.
Innovation Solution
The development of a dual open-ended waveguide (DOEWG) antenna system that includes multiple wave-dividing and wave-radiating channels, along with a printed circuit board (PCB) backplane for absorbing non-radiated energy, to optimize the coupling and radiation of electromagnetic waves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional waveguide structures are used at 77 GHz, then electromagnetic energy can be transmitted, but energy loss to heat and reflections increases
Solution Approach 1:
The waveguide structure is divided into multiple segments including a transition section with progressively changing dimensions. This segmentation allows gradual impedance transformation between the PCB transmission line and the radiating waveguide, reducing reflections and improving energy radiation efficiency at 77 GHz.
Solution Approach 2:
The waveguide transition structure employs continuous parameter changes in its geometric dimensions along the propagation path. The width and height of the waveguide vary progressively to match impedance between different sections, minimizing energy loss to heat and reflections while maintaining reliable signal transmission.
2Measurement precision
If tight beam focusing is implemented, then measurement accuracy improves, but antenna complexity and manufacturing difficulty increase
Solution Approach 1:
The antenna design uses a dual-open-ended waveguide structure that radiates in both directions along the waveguide axis. This dimensional approach creates two coherent radiation sources that can be phase-controlled to achieve tight beam focusing in the desired direction while simplifying the overall antenna structure compared to traditional single-direction phased arrays.
Solution Approach 2:
The waveguide structure serves multiple functions simultaneously: it acts as an impedance transformer, a phase controller, and a radiation element. The same structural features that enable impedance matching also provide the phase distribution needed for beam focusing, reducing overall antenna complexity while maintaining high measurement accuracy.
3Productivity
If PCB to waveguide coupling is implemented, then electromagnetic energy can be transmitted, but impedance mismatch causes reflections and energy loss
Solution Approach 1:
A transition section with progressively changing dimensions is introduced as an intermediary between the PCB transmission line and the radiating waveguide. This intermediate structure provides gradual impedance transformation, acting as a mediator that smoothly connects the two different transmission environments and minimizes reflections and energy loss.
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 enhances the efficiency of electromagnetic energy coupling and radiation, reducing unwanted reflections and improving the accuracy and reliability of radar systems, particularly in autonomous vehicle applications.
Implementation Method 1
the coupling component is configured to couple at least a portion of the reflected electromagnetic energy from the waveguide to the circuit board
Implementation Method 2
an attenuation component mounted on the circuit board and configured to absorb electromagnetic energy from the circuit board
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
The present application discloses embodiments that relate to an electromagnetic apparatus. In one aspect, the present apparatus includes a circuit board configured to propagate an electromagnetic signal. The apparatus also includes a waveguide configured to propagate an electromagnetic signal. The apparatus further includes a coupling port configured to couple a signal between the circuit board and the waveguide, where the coupling port has dimensions based on a desired impedance of the port.