Antenna Module With Shifted Patch Groups for Millimeter Wave Isolation
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Solution Overview
Problem
In antenna modules with multiple patch antennas, poor isolation between adjacent antennas in frequency bands with short wavelengths, such as the millimeter wave band, leads to degradation of communication quality due to wrapping-around of unnecessary signals.
Innovation Solution
The antennas are arranged in a configuration where each set of antenna groups is periodically shifted in both the polarization direction and the direction perpendicular to it, increasing the interval between adjacent antennas and improving isolation, while the feeder lines are kept approximately equal in length to minimize loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple patch antennas are arranged in an orthogonal configuration with small pitch to free space wavelength ratio, then beam pattern performance is improved, but isolation between adjacent antennas deteriorates
Solution Approach 1:
The patent transitions from a two-dimensional orthogonal arrangement to a three-dimensional arrangement by stacking antenna groups at different heights (different z-coordinates) above the dielectric substrate. This vertical dimension provides additional spatial separation between adjacent antennas while maintaining the required pitch-to-wavelength ratio for optimal beam pattern performance.
Solution Approach 2:
Multiple antenna groups are nested at different vertical levels above the dielectric substrate, with each antenna group positioned at a different height. This nesting approach allows compact arrangement while achieving improved isolation through vertical separation, effectively solving the contradiction between maintaining small pitch ratios and achieving adequate isolation.
2Quantity of substance
If pitch between adjacent patch antennas is decreased for millimeter wave band operation, then antenna density is improved, but signal wrapping around radio-frequency circuit component increases
Solution Approach 1:
By introducing vertical separation through different z-coordinates for antenna groups, the patent achieves compact horizontal pitch suitable for high antenna density while using the vertical dimension to prevent signal wrapping around the radio-frequency circuit component mounted on the substrate.
Solution Approach 2:
The dielectric substrate acts as an intermediary layer between the antenna groups and the radio-frequency circuit component. By positioning antenna groups at different heights above the substrate, the substrate provides isolation and prevents direct coupling that would cause signal wrapping, while still allowing compact pitch arrangement.
Data Source
AI summary
An antenna module includes a dielectric substrate, multiple patch antennas provided at a first main surface side of the dielectric substrate, and an RFIC mounted at a second main surface side of the dielectric substrate. The multiple patch antennas include multiple sets of antenna groups each composed of the multiple patch antennas periodically arranged at a pitch Px in the X-axis direction, which is one of a polarization direction and a direction perpendicular to the polarization direction. The multiple sets of antenna groups are periodically arranged at a pitch Py in the Y-axis direction, which is the other of the polarization direction and the direction perpendicular to the polarization direction, and each of the multiple sets of antenna groups is arranged so as to be shifted from another antenna group adjacent in the second direction by an offset distance Dx in the first direction.