Radar Sensor Package Cavity for End-Fire mmWave Radiation
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Solution Overview
Problem
Radar sensor chip packages in electronic devices typically exhibit a broad-side transmission pattern due to the presence of a ground plane, which can lead to reduced efficiency in the end-fire direction, making it challenging to achieve efficient end-fire radiation without modifying the ground plane or PCB layout.
Innovation Solution
The integration of a radar sensor chip package with a cavity on a printed circuit board (PCB) allows for end-fire radiation patterns despite the presence of a ground plane. The cavity is defined by conductive surfaces and has dimensions that excite resonant modes of the mmWave signal, enabling transmission through the open side of the cavity in an end-fire direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a planar antenna structure is used with a ground plane, then the antenna structure is simple and compact, but the transmission pattern becomes predominantly broad-side with reduced end-fire efficiency
Solution Approach 1:
The patent introduces a cavity dimension (depth) below the planar antenna structure to transform the radiation pattern from broad-side to end-fire. The cavity creates a resonant structure that redirects the electromagnetic energy transmission direction, achieving end-fire radiation while maintaining the simplicity of the planar antenna geometry.
Solution Approach 2:
The cavity acts as an intermediary structure between the planar antenna and the ground plane. It mediates the interaction between these two elements, allowing the antenna to achieve end-fire radiation pattern without direct contact or complex modification of the ground plane, thus maintaining manufacturing simplicity while improving radiation efficiency.
2Ease of manufacture
If the ground plane is modified to achieve end-fire radiation, then end-fire efficiency improves, but the PCB layout and device functionality are affected
Solution Approach 1:
The patent segments the antenna system into three independent parts: the planar antenna structure, the cavity structure, and the ground plane. This segmentation allows each component to be designed and optimized independently, enabling end-fire radiation through cavity design without requiring modifications to the ground plane or PCB layout, thus preserving device adaptability.
Solution Approach 2:
The cavity serves as an intermediary that achieves end-fire radiation without requiring direct modification of the ground plane. It provides a solution that improves radiation efficiency while leaving the PCB layout and ground plane intact, maintaining full adaptability for device integration.
3Ease of manufacture
If the planar antenna structure is disposed outside the ground plane periphery, then end-fire radiation is achieved, but the device design becomes less compact
Solution Approach 1:
Instead of moving the antenna horizontally outside the ground plane periphery, the patent utilizes the vertical dimension by introducing a cavity below the antenna. This dimensional change achieves end-fire radiation while keeping the antenna structure compact and integrated within the device footprint, maintaining device compactness.
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 achieves efficient end-fire radiation without modifying the ground plane or PCB layout, providing a compact and reliable solution for electronic devices, particularly in portable devices where space is limited.
Implementation Method 1
the width dimension and a height dimension of the cavity are such that a mmWave signal output by the mmWave RF integrated circuit and transmitted by the planar antenna structure excites at least one resonant mode of the cavity
Data Source
AI summary
A radar device comprising: a printed circuit board (120), PCB, comprising a ground plane (1202), a radar sensor chip package (130) mounted on the PCB (120) and comprising a mm Wave radio frequency, RF, integrated circuit (1302) and a planar antenna structure (1304) configured as an antenna-in-package and oriented in a plane parallel to the ground plane (1202), wherein the mmWave RF integrated circuit (1302) is configured to output a mmWave signal (1360) to be transmitted by the planar antenna structure (1304), and a cavity (140), wherein the radar sensor chip package (130) is arranged in the cavity (140), the cavity (140) having an open side (1402), and the cavity (140) being defined by a conductive rear wall surface (1404) opposite the open side (1402), a pair of mutually opposite and conductive sidewall surfaces (1406), a conductive top surface (1408), and a conductive bottom surface (1410), wherein at least a portion of the conductive bottom surface (1410) is formed by at least a portion of the ground plane (1202) of the PCB (120), and wherein the sidewall surfaces, the top surface, and the bottom surfaces (1406, 1408, 1410) each extends from the rear wall surface (1404) towards the open side (1402) of the cavity (140).