RF Combiner High Impedance Junction Reducing Insertion Loss
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Solution Overview
Problem
Existing methods for combining multiple wireless communication protocols like LTE, UMTS, and GSM signals from different base stations on a single antenna suffer from significant insertion loss and high costs, especially when using multi-port hybrid combiners or Multi-Channel Power Amplifiers, which are complex and costly due to the need for sophisticated linearization techniques.
Innovation Solution
A system utilizing a combination of multi-branch reactive combiners, isolators, band-pass filters, and duplexers to form a multiplexer, which provides high isolation among inputs by presenting a high impedance at the common junction, reducing insertion loss and costs, or using circulators and fewer band-pass filters for smaller numbers of base stations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multi-port hybrid combiners are used to combine multiple wireless protocols on a single antenna, then the number of antennas and feeder cables is reduced, but significant insertion loss occurs due to the non-coherent nature of independent RF power sources
Solution Approach 1:
The system segments the combining function by dedicating separate hybrid combiners to different frequency bands (e.g., one for LTE/UMTS, another for GSM/CDMA). This segmentation allows each combiner to handle coherent signals within its band, reducing insertion loss while still achieving multi-protocol combination on a single antenna through cascaded configurations.
Solution Approach 2:
The patent introduces frequency-selective switches and band-specific hybrid combiners as intermediary devices between the RF power sources and the common antenna. These intermediaries route signals through appropriate combining paths, enabling coherent combination within frequency bands and significantly reducing overall insertion loss compared to direct multi-port hybrid combining.
2Productivity
If Multi-Channel Power Amplifier (MCPA) technology is used to combine multiple transmitters on a common feeder line, then combining efficiency is improved, but the system becomes complex and costly due to sophisticated linearization techniques
Solution Approach 1:
The patent segments the power amplification function by using separate power amplifiers for different frequency bands or protocols, each optimized for its specific band. This avoids the need for a complex MCPA that would require sophisticated linearization techniques, while still achieving efficient power combining through the segmented approach.
Solution Approach 2:
The system changes the operating parameters of power amplifiers by dedicating each amplifier to specific frequency bands or protocols, allowing each amplifier to operate in its optimal performance range without requiring complex linearization techniques. This parameter specialization simplifies the overall system while maintaining high combining efficiency.
3Adaptability or versatility
If additional antennas are installed on the tower to provide new services, then service capability is expanded, but tower loading increases requiring significant expense
Solution Approach 1:
The patent merges multiple protocol signals (LTE, UMTS, GSM, CDMA) onto a single common antenna through hybrid combiners and frequency-selective switching. This merging eliminates the need for additional antennas for new services, expanding service capability while avoiding increased tower loading and associated expenses.
Solution Approach 2:
The common antenna is designed to be universal, handling multiple frequency bands and protocols simultaneously through the hybrid combiner system. This multi-functionality allows a single antenna to provide expanded service capabilities across different wireless protocols, eliminating the need for protocol-specific antennas and reducing tower loading.
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 allows for low-loss and cost-efficient combining of transmit and receive signals from multiple base stations with different protocols on a single antenna, maintaining high isolation and reducing power dissipation, thus enhancing wireless communication coverage without the need for complex linearization techniques.
Implementation Method 1
the transformation properties of the combiner, which have a certain electrical length at each branch, create a very high impedance at the common junction for all other branches
Implementation Method 2
band-pass filters, and duplexers interconnected to form a multiplexer
Implementation Method 3
an arrangement is provided, which uses a combination of circulators and band pass filters interconnected in a duplex or triplex configuration
Data Source
AI summary
A system for combining a plurality of signals in a wireless communication device employs a plurality of base station duplexers each coupled to a corresponding base station from a plurality of collocated base stations, each base station capable of receiving and transmitting signals in accordance with a corresponding transmission protocol. Each duplexer includes a transmit and receive paths for allowing signals to be transmitted from the base station and further allowing signals to be received by the base station. Isolators are each coupled to a corresponding one of the transmit path of each of the duplexers. Bandpass filters are each coupled to an output port of a corresponding one of the isolator and a combiner receives signals provided by each one of the band pass filters. An antenna duplexer is coupled to an output port of the combiner via a transmit path, where the duplexer provides a combined signal of the collocated base stations to an antenna. The duplexer further includes a receive path for providing signals received by the antenna to a corresponding receive path of each of the base station duplexers.