Base Station RF Feed Network With Impedance-Matching Sector Paths
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Solution Overview
Problem
Conventional multi-sector antennas face significant power divider losses and complex feed network circuitry due to the use of multiple switching elements, making it difficult to efficiently direct RF energy to all or selected sectors.
Innovation Solution
The implementation of RF feed networks with impedance-matching paths of different impedances, each coupled to a quarter-wavelength RF transmission line stubs switchably connected to ground by switching elements, allows for simplified circuitry and reduced RF losses while providing high control over sector selection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple switching elements are used to direct RF energy to selected sectors, then sector selection control is improved, but power divider losses and feed network complexity increase
Solution Approach 1:
The patent changes the impedance parameter of transmission lines to achieve sector selection. By using transmission lines with specific impedance values (e.g., 50 ohms, 25 ohms, 17.7 ohms) and quarter-wavelength electrical lengths, the system can selectively connect different antenna sectors to the RF port through impedance transformation, eliminating the need for multiple switching elements and power dividers.
Solution Approach 2:
The invention extracts and removes the power divider network and multiple switching elements from the conventional feed system. By using a single switching element combined with impedance-matched transmission lines, the patent eliminates the complex power division circuitry that causes significant RF energy losses in traditional multi-sector antenna systems.
2Adaptability or versatility
If multiple switching elements are used in the feed network, then sector selection capability is improved, but device complexity increases
Solution Approach 1:
The patent uses impedance parameter changes in transmission lines to achieve sector selection functionality. By designing transmission lines with specific characteristic impedances and electrical lengths (quarter-wavelength at operating frequency), the system can selectively activate different antenna sectors through a single switching element, dramatically simplifying the feed network architecture.
Solution Approach 2:
The transmission lines in the patent serve multiple functions simultaneously: they act as impedance transformers, phase shifters, and sector selection switches. This multi-functionality eliminates the need for separate power dividers and multiple switching elements, reducing overall device complexity while maintaining full sector selection capability.
3Adaptability or versatility
If conventional power divider networks are used to distribute RF energy, then RF energy distribution to multiple sectors is achieved, but RF losses increase
Solution Approach 1:
The patent employs transmission lines with carefully selected impedance parameters to distribute RF energy to multiple sectors. By using impedance transformation ratios (such as 2:1 or 4:1) achieved through quarter-wavelength transmission lines with specific characteristic impedances, the system can efficiently power multiple antenna sectors without the RF losses inherent in conventional power divider networks.
4Loss of energy
If impedance-matching paths with different impedances are used, then RF losses are reduced and circuitry is simplified, but the need for precise impedance control increases
Solution Approach 1:
The patent uses standard transmission line impedance values (50 ohms, 25 ohms, 17.7 ohms) that can be precisely manufactured using conventional PCB fabrication techniques. The quarter-wavelength electrical length at the center operating frequency provides a well-defined impedance transformation ratio, making the design robust and manufacturable with standard precision tolerances.
Solution Approach 2:
The patent applies different impedance values to specific segments of the feed network tailored to local requirements. Each transmission line segment has an impedance optimized for its specific function (impedance transformation, phase shifting, or matching), allowing precise control where needed while maintaining overall system simplicity and manufacturability.
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 reduces RF losses and simplifies feed network operations by using a smaller number of switching elements, enabling efficient and controlled RF energy distribution to all or selected sectors of a multi-sector base station antenna.
Implementation Method 1
each RF transmission line may have an electrical length of one-quarter of a wavelength corresponding to a center frequency of an operating frequency band of the arrays
Implementation Method 2
The impedance-matching paths may be coupled to a plurality of RF transmission lines, respectively, that are switchably coupled to ground by a plurality of switching elements
Data Source
AI summary
Radio frequency (RF) feed networks are provided. An RF feed network includes a plurality of impedance-matching paths that have different impedances. respectively. The impedance-matching paths are coupled between arrays of a base station antenna and an input of the RF feed network. Related methods of operating a base station antenna are also provided.