Antenna Diplexer Feed Network for Dual Band GSM
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Solution Overview
Problem
Dual band antennas for GSM900 and GSM1800 frequencies face inefficiencies due to coupling between radiating elements and increased area and cost from multiple elements, especially when frequency bands are close.
Innovation Solution
An antenna design featuring a passive feed network for one band and an active radio network for an adjacent band, utilizing diplexers with band pass filters and a phase shifter, allowing shared radiating elements across distinct frequency bands with reduced interference and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple radiating elements are used for dual band operation, then frequency band coverage is improved, but area occupied and cost increase
Solution Approach 1:
The patent makes single radiating elements serve dual functions by equipping them with diplexers that route signals for both GSM900 and GSM1800 bands. Each radiating element becomes universal, handling multiple frequency bands without requiring separate dedicated elements for each band, thereby reducing the total number of elements and occupied area.
Solution Approach 2:
The patent merges the functionality of separate radiating elements for different bands into a shared array. By combining GSM900 and GSM1800 radiating elements into a single interspersed array with common feed networks, the system achieves dual band operation with fewer physical elements, reducing area while maintaining frequency coverage.
2Adaptability or versatility
If multiple radiating elements are used for dual band operation, then frequency band coverage is improved, but cost increases
Solution Approach 1:
The patent makes single radiating elements serve dual functions by equipping them with diplexers that route signals for both GSM900 and GSM1800 bands. Each radiating element becomes universal, handling multiple frequency bands without requiring separate dedicated elements for each band, thereby reducing the total number of elements and occupied area.
Solution Approach 2:
The patent merges the functionality of separate radiating elements for different bands into a shared array. By combining GSM900 and GSM1800 radiating elements into a single interspersed array with common feed networks, the system achieves dual band operation with fewer physical elements, reducing area while maintaining frequency coverage.
3Area of stationary object
If radiating elements for adjacent frequency bands are placed close together, then area is reduced, but coupling occurs between elements
Solution Approach 1:
The patent introduces diplexers as intermediary components between radiating elements and feed networks. These diplexers with band-pass filters act as mediators that selectively route frequency bands, preventing harmful coupling between adjacent band elements while allowing close placement. The filters in diplexers isolate frequency bands, eliminating interference despite physical proximity.
Solution Approach 2:
The patent applies different filtering characteristics to different ports of diplexers connected to adjacent radiating elements. Each diplexer is locally optimized with band-pass filters tuned to specific bands, creating local frequency isolation that prevents coupling interference while maintaining overall system compactness.
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
Enables efficient transmission and reception across adjacent frequency bands with reduced area and cost, minimizing coupling issues and optimizing radiating element usage.
Implementation Method 1
The diplexer has a first filter coupling the first port to the second port and a second filter coupling the first port to the third port. In one example, involving the GSM900 band, the first filter is a band pass filter having a pass band of 790-862 MHz and the second filter is a band pass filter having a pass band of 880-960 MHz.
Implementation Method 2
A passive feed network includes a phase shifter, which is coupled to an input transmission line and an plurality of output transmission lines. Each of the output transmission lines may be coupled to one of the second ports of one of the diplexers.
Data Source
AI summary
An antenna having a passive feed network in one band, and an active radio network in an adjacent band, is provided. The antenna includes radiating elements arranged in an array dimensioned to transmit and receive RF signals. The antenna includes diplexers having a first port, a second port and a third port. The first port of each diplexer coupled to at least one radiating element. The diplexer has a first filter coupling the first port to the second port and a second filter coupling the first port to the third port. A passive feed network includes a phase shifter, which is coupled to an input transmission line and a plurality of output transmission lines. Each of the output transmission lines may be coupled to one of the second ports of one of the diplexers. An active radio is coupled to each of the third ports of the plurality of diplexers.