Cavity Active Array Antenna Module for Lower RF Feed Loss
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Solution Overview
Problem
Current multi-layer printed circuit board-based integration of millimeter-wave phased array antennas faces challenges such as increased signal loss due to longer and more complex RF feed lines, difficulty in dual-polarization wiring, and inefficient stack-up design, leading to high costs and complexity.
Innovation Solution
The active array antenna module employs a dielectric substrate cover plate with metal patterns, a metal frame defining openings, and a multi-layer antenna main board with RF feed lines, integrated circuits, and a metal back frame, forming cavity antenna units with a simpler structure that reduces the number of layers and improves efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multi-layer printed circuit board integration is used to increase the number of array elements, then the gain and bandwidth are improved, but the RF feed lines become longer and more complex, causing greater signal loss
Solution Approach 1:
The patent transitions from planar feed line routing on PCB layers to three-dimensional cavity structures. The feed lines are routed through vertical vias and cavity walls rather than along horizontal PCB traces, effectively moving the signal path into the third dimension. This reduces the total feed line length and eliminates the need for complex multi-layer routing while maintaining connection to all array elements.
Solution Approach 2:
The antenna array is divided into multiple independent cavity units, each containing subset of antenna elements. This segmentation allows each cavity to have its own localized feed network, eliminating the need for long feed lines that would otherwise connect all elements across multiple PCB layers. Each cavity operates as an independent module with optimized local routing.
2Adaptability or versatility
If dual-polarization specification is implemented, then the versatility and bandwidth are improved, but the wiring complexity and number of PCB layers increase significantly
Solution Approach 1:
The patent combines both polarization feeds and multiple element connections within a single integrated cavity structure. Each cavity contains multiple antenna elements with dual polarization capabilities, and the feed network is merged into the cavity walls and floor, eliminating the need for separate wiring layers for each polarization and element connection.
Solution Approach 2:
The cavity structure itself acts as an intermediary that provides both mechanical support and electrical feeding. The cavity walls and floor serve as both structural boundaries and RF feed paths, mediating between the signal source and multiple antenna elements while providing dual-polarization support without requiring additional wiring complexity.
3Adaptability or versatility
If sufficient bandwidth is achieved by increasing antenna-ground plane spacing, then the frequency range is improved, but the PCB thickness and stack-up design complexity increase
Solution Approach 1:
The patent utilizes the vertical dimension within the cavity structure to achieve the required antenna-ground plane spacing. Instead of increasing PCB thickness horizontally, the design creates vertical air gaps and cavity spaces that provide the necessary spacing for bandwidth while maintaining a compact overall form factor. The cavity depth provides the electrical length without requiring thick PCB substrates.
4Quantity of substance
If a 12-layer high-density interconnected stack structure is used, then the integration density is improved, but the actual utilization efficiency decreases and calibration difficulty increases
Solution Approach 1:
The patent extracts the feed network and grounding structures from the conventional PCB layer stack and relocates them to the three-dimensional cavity structure. This removes unnecessary PCB layers that do not contribute to functional performance, reducing the effective layer count from 12 to a much smaller number while maintaining all necessary electrical connections and improving utilization efficiency.
Data Source
AI summary
An active array antenna module includes a cover plate, a metal frame, an antenna main board, a back frame, and a plurality of first fixing structures. The first fixing structures fix the back frame, the metal frame, and the cover plate, so that the antenna main board is fixed between the metal frame and the back frame, so that each of a plurality of antenna units of the antenna main board corresponds to each of a plurality of openings defined by the metal frame and each of a plurality of metal patterns of the cover plate to form a cavity antenna unit, and the active array antenna module includes a plurality of the cavity antenna units.