EBG Isolation for mmWave Radar Antenna Coupling
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Solution Overview
Problem
In packaged radio frequency devices, the proximity of transmit and receive antennas leads to strong coupling, which complicates the design of compact radar systems due to the large size contributed by antenna elements, necessitating a solution to minimize layout size while maintaining effective isolation.
Innovation Solution
The integration of an electromagnetic band gap (EBG) structure with artificial magnetic conductor cells between the transmit and receive antennas, which reduces coupling by acting as a high impedance boundary without affecting the electric field distribution, using a plurality of elementary cells forming adjacent columns coupled to a ground plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If transmit and receive antennas are placed close together in a compact package, then the device form factor is reduced, but mutual coupling between antennas increases
Solution Approach 1:
An electromagnetic band gap (EBG) structure is introduced as an intermediary element between the transmit and receive antennas. This EBG structure acts as a spatial separator that creates high impedance boundaries, effectively blocking electromagnetic coupling between the antennas while allowing the antennas to be positioned in close proximity within the compact package
2Area of moving object
If antenna elements are minimized in size, then the layout area is reduced, but isolation between transmit and receive antennas deteriorates
Solution Approach 1:
The EBG structure is strategically positioned at specific locations where electromagnetic field coupling is strongest between the transmit and receive antennas. By applying isolation measures locally at these critical coupling points rather than uniformly across the entire antenna structure, effective isolation is achieved while minimizing the additional layout area required
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 configuration effectively isolates the transmit and receive antennas, reducing mutual coupling and enabling a more compact radar system design without compromising performance, as demonstrated by improved isolation plots and reduced footprint.
Implementation Method 1
an electromagnetic band gap (EBG) structure with artificial magnetic conductor cells between the transmit and receive antennas, which reduces coupling by acting as a high impedance boundary
Data Source
Figure 1A~1B
Figure 1C
Figure 1D
AI summary
A packaged radar includes laminate layers, a ground plane associated with at least one of the laminate layers, a transmit antenna and a receive antenna associated with at least one of the laminate layers, and an electromagnetic band gap structure between the transmit antenna and the receive antenna for isolating the transmit antenna and the receive antenna, the electromagnetic band gap structure including elementary cells forming adjacent columns each coupled to the ground plane, and each elementary cell including a conductive planar element and a columnar element coupled to the conductive planar element.