Base Station Antenna Feed Board Layout Using CPW and Microstrip Lines
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional base station antenna feed boards are crowded due to lengthy RF transmission lines, leading to high mutual coupling, as they are designed to maintain uniform phase delays across all radiating elements, which results in increased space requirements and insertion losses.
Innovation Solution
Incorporating coplanar waveguide (CPW) RF transmission lines that are longer than microstrip lines, allowing for reduced physical lengths of microstrip lines and increased spacing between transmission lines, thereby reducing mutual coupling and insertion losses, while maintaining desired phase relationships.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If RF transmission lines are made lengthy to ensure matching phase delays across all radiating elements, then phase uniformity is improved, but feed board area increases and mutual coupling increases
Solution Approach 1:
The patent applies different transmission line types (microstrip and CPW) to different radiating elements based on their specific requirements. Some elements use microstrip lines while others use CPW lines, allowing each element to have optimized transmission characteristics rather than forcing uniformity across all elements. This local differentiation enables phase matching without requiring all lines to be equally lengthy.
Solution Approach 2:
The patent changes the electrical parameters of transmission lines by using different types (microstrip vs. CPW) with different characteristic impedances and phase velocities. CPW lines have different electrical length characteristics compared to microstrip lines, allowing the patent to achieve phase matching by selecting appropriate line types and lengths rather than uniformly extending all lines.
2Stability of the object's composition
If RF transmission lines are made lengthy to ensure matching phase delays, then phase uniformity is improved, but insertion losses increase
Solution Approach 1:
Instead of using lengthy transmission lines for all elements, the patent applies different line types locally where needed. CPW lines are used for specific elements where they provide better electrical length characteristics, while microstrip lines are used elsewhere. This local optimization achieves phase uniformity without the penalty of uniformly lengthy lines and their associated losses.
Solution Approach 2:
The patent creates a composite transmission line system combining two different types (microstrip and CPW) on the same feed board. Each type has different loss characteristics and electrical properties, and their strategic combination allows the system to achieve phase matching with lower overall insertion losses than would be required using a single uniform line type.
3Ease of manufacture
If feed board is made compact to reduce cost, then manufacturing cost is reduced, but mutual coupling between transmission lines increases
Solution Approach 1:
The patent uses different transmission line types in different locations on the feed board. CPW lines are strategically placed where they provide better isolation characteristics, while microstrip lines are used in other areas. This local differentiation allows compact layout while managing mutual coupling through the inherent electromagnetic field distribution differences between line types.
4Stability of the object's composition
If all transmission lines are made equal length to ensure phase matching, then phase uniformity is improved, but feed board area increases due to meandering
Solution Approach 1:
The patent changes the electrical parameters by using different transmission line types with different phase velocities and electrical length characteristics. CPW lines naturally provide different electrical length for the same physical length compared to microstrip lines. This allows the patent to achieve phase matching by selecting appropriate line types and lengths without requiring all lines to be equally long and meandering.
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 reduces mutual coupling and insertion losses, improves power distribution, and enhances radiation pattern performance by allowing non-CPW transmission lines to match the phase shift of CPW lines while being significantly shorter, thus increasing isolation between ports.
Implementation Method 1
RF transmission lines that are coupled to the phase shifter. A first of the RF transmission lines may include a coplanar waveguide (CPW) that is coupled to a first of the radiating elements. A second of the radiating elements may be coupled to a second of the RF transmission lines that is shorter than the first of the RF transmission lines.
Data Source
AI summary
Base station antenna feed boards are provided. A base station antenna feed board includes a phase shifter and a hybrid radio frequency transmission line that is coupled to the phase shifter. The hybrid radio frequency transmission line includes a coplanar waveguide and a microstrip line. Related base station antennas are also provided.