Printed Phased Array Antennas With Trenches for Wider Scan Range
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Solution Overview
Problem
Phased array antennas are limited by grating lobes and surface waves, which restrict their scan range and performance, especially in wide frequency bands and wide scan ranges, due to radiation pattern deformation and high return loss.
Innovation Solution
The implementation of phased array antennas with extended scan range is achieved by altering surface waves and coupling through the use of trenches or grooves in the substrate and the use of Surface Mount Technology (SMT) components with reduced size and gaps between antenna elements, reducing the dielectric constant and minimizing the need for exotic materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If phased array antennas use conventional printed circuit board substrates, then manufacturing is simple and cost-effective, but surface waves cause radiation pattern deformation and limit scan range
Solution Approach 1:
The patent applies this principle by incorporating air vents (through-holes) in the ground plane of the PCB substrate. These vents create a porous structure that disrupts surface wave propagation paths, reducing their harmful effects on radiation patterns while maintaining the overall simplicity of PCB manufacturing. The air-filled vents act as barriers to surface waves without requiring complex material substitutions.
Solution Approach 2:
The patent modifies the substrate parameters by creating localized variations in the ground plane structure through air vents. This changes the effective dielectric constant and surface wave propagation characteristics in specific regions, allowing suppression of surface waves in scan directions without affecting other performance parameters. The parameter change is achieved through structural modification rather than material substitution.
2Power
If antenna elements are placed closer together to increase array density, then gain increases, but coupling to surface waves increases and scan range is limited
Solution Approach 1:
The patent introduces air vents in the ground plane as intermediary structures between antenna elements. These vents act as mediators that disrupt the coupling path between antenna elements and surface waves, allowing dense element placement for high gain while preventing surface wave interference. The ground plane with vents serves as an intermediary layer that manages the interaction between elements and substrate modes.
3Adaptability or versatility
If the scan range is extended beyond the visible range, then coverage is improved, but grating lobes appear causing radiation pattern aliases
Solution Approach 1:
The patent extracts or removes the problematic surface wave modes from the system by introducing air vents that disrupt their propagation. By taking out these harmful surface wave components through strategic vent placement in the ground plane, the antenna can achieve extended scan range without the harmful effects of grating lobes and radiation pattern aliases that would otherwise occur.
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 approach effectively moves the blind-scan angle towards the edge of the visible range, enhancing the scan range without compromising other performance parameters, making it suitable for applications like 5G communications and millimeter-wave technologies.
Implementation Method 1
altering surface waves and coupling through the use of trenches or grooves in the substrate
Data Source
AI summary
Different approaches that aim to extend scan range of phased array antennas by means of altering surface waves and/or altering the coupling are disclosed. One approach includes providing a phased array antenna where a surface of a substrate that houses antenna elements of the array includes openings such as trenches or grooves. Such openings in the surface effectively reduce the dielectric constant of the substrate, are easy to manufacture, and may reduce or eliminate the need to use exotic and expensive low-k dielectric materials. Another approach includes providing a phased array antenna where antenna elements are disposed over a substrate in the form of surface mount (SMT) components that are reduced in size/footprint. Using SMT antenna elements with a reduced size allows achieving the same gain while spacing antenna elements farther apart with gaps in between the antenna elements, thus also reducing the overall dielectric constant of the substrate.