Multi-band dipole antenna with LC filtering for base station
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Solution Overview
Problem
Existing multi-band base station antennas face challenges in reducing signal scattering between different frequency bands, leading to undesirable effects on antenna beam shape and performance, and there is a need for compact designs that can support multiple frequency bands without increasing the number of antennas, which is constrained by structural and cost considerations.
Innovation Solution
The development of multi-band dipole-type radiating elements with front and rear facing arms, utilizing a multi-layer printed circuit board with patterned metallization and resonant LC circuits for capacitive coupling, which provides low-pass filtering and improved isolation across multiple bands and polarizations, allowing for reduced scattering and compact antenna designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple linear arrays of radiating elements are deployed to support multiple frequency bands, then service coverage in different frequency bands is improved, but the number of base station antennas increases, leading to increased weight, wind loading, and tower leasing costs
Solution Approach 1:
The patent combines multiple frequency band operations into a single radiating element structure. The element integrates a first dipole arm for a first frequency band and a second dipole arm for a second frequency band, allowing one antenna to replace what would traditionally require multiple separate antennas, thereby reducing overall weight and tower loading while maintaining multi-band service coverage
Solution Approach 2:
The radiating element is designed with universal functionality to operate across multiple frequency bands simultaneously. By incorporating multiple dipole arms with different electrical lengths and impedance characteristics, a single antenna element can serve multiple frequency bands (e.g., 700 MHz, 2.1 GHz, 3.5 GHz), making the antenna system more versatile without increasing the number of deployed antennas
2Adaptability or versatility
If multiple linear arrays of radiating elements are deployed to support multiple frequency bands, then service coverage in different frequency bands is improved, but wind loading on the antenna tower increases
Solution Approach 1:
The patent merges multiple frequency band functions into a single radiating element, reducing the total number of antenna components. This consolidation decreases the overall surface area and structural mass exposed to wind, thereby reducing wind loading forces on the tower while maintaining the ability to provide service across multiple frequency bands
3Adaptability or versatility
If different linear arrays of radiating elements are used for different frequency bands, then frequency band service is improved, but the number of base station antennas increases, increasing deployment cost
Solution Approach 1:
The patent merges support for multiple frequency bands into a single radiating element by integrating multiple dipole arms with different electrical characteristics. This design allows one antenna to replace multiple separate antennas, simplifying the overall system architecture and reducing deployment complexity while maintaining comprehensive frequency band service
Solution Approach 2:
The radiating element achieves universal operation across multiple frequency bands through its multi-arm dipole structure. Each arm is designed with specific electrical length and impedance to resonate at different frequencies, enabling a single antenna to perform the function of what would traditionally require multiple specialized antennas, thereby reducing device complexity
4Ease of manufacture
If conventional dipole radiating elements are used, then manufacturing simplicity is maintained, but signal scattering between frequency bands occurs, degrading antenna beam shape
Solution Approach 1:
The patent segments the dipole structure into multiple independent arms, each optimized for specific frequency bands. The first dipole arm and second dipole arm are electrically isolated through impedance transformation networks, preventing signal scattering between bands while maintaining manufacturing simplicity through standardized PCB fabrication processes
Solution Approach 2:
The patent introduces impedance transformation networks as intermediary components between different dipole arms. These networks act as mediators that isolate signal paths for different frequency bands, preventing harmful signal scattering while allowing each arm to operate independently. The intermediary structures are integrated into the PCB design, maintaining ease of manufacture
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 solution achieves reduced signal scattering, improved column-to-column isolation, and increased operational efficiency across multiple frequency bands, enabling a compact and efficient multi-band antenna design that supports multiple air-interface standards without the need for additional antennas, thereby reducing tower leasing costs and increasing capacity.
Implementation Method 1
The front and rear facing layers can be configured as patterned metallization (e.g., copper) layers that partially overlap to provide capacitive coupling therebetween, which advantageously supports low-pass filtering operations associated with the resonant circuit.
Implementation Method 2
the rear facing arm may be configured to include a resonant LC (or CLC) circuit
Implementation Method 3
Compact multi-band and dual-polarized radiating elements for base station antennas
Data Source
AI summary
Multi-band antennas utilize compact multi-band dipole-type radiating elements having multiple arms, including a front facing arm and a rear facing arm that respectively target higher and lower frequency bands. These higher and lower frequency bands may include, but are not limited to, a relatively wide band (e.g., 1695-2690 MHz) associated with the front facing arm and somewhat narrower and nonoverlapping band (e.g., 1427-1518 MHz) associated with the rear facing arm. The front facing arm may extend on a “front” layer of a multi-layer printed circuit board and the rear facing arm may extend at least partially on a “rear” layer of the printed circuit board. A resonant LC (or CLC) network is provided, which is integrated into the rear facing arm and at least capacitively coupled to the front facing arm. This resonant network advantageously supports low-pass filtering from the front facing arm to the rear facing arm, to thereby support the multiple and nonoverlapping bands.