Programmable Duplexer with Active Temperature Compensation
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Solution Overview
Problem
Current duplexers for 3G cellular handsets, particularly those using SAW technology, struggle to meet the stringent frequency separation requirements of 3GPP bands 2, 3, and 8 due to narrow transition bands and temperature-related frequency shifts.
Innovation Solution
A programmable duplexer with temperature compensation, featuring adjustable receiver and transmitter filters that adjust their pass bands based on temperature indications and channel pair selections to maintain optimal transition bands, reducing sensitivity to manufacturing tolerances and temperature variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If SAW technology is used for duplexer filters, then manufacturing is simplified and device structure is reduced, but frequency separation precision deteriorates and transition band performance becomes insufficient for 3GPP bands 2, 3, and 8
Solution Approach 1:
The patent applies dynamics by making the filter pass bands adjustable rather than fixed. The receiver and transmitter filters incorporate tuning mechanisms that allow their frequency characteristics to be dynamically adjusted after manufacturing, enabling precise frequency separation for different 3GPP bands without requiring complex manufacturing processes.
Solution Approach 2:
The patent changes the parameters of the filter pass bands to optimize performance. By allowing the pass band frequencies to be adjusted independently, the system can achieve the required frequency separation for bands 2, 3, and 8 while maintaining manufacturing simplicity. This is achieved through programmable filter tuning that modifies operational parameters rather than physical structure.
2Device complexity
If standard SAW filter Q values of 300-500 are used, then device complexity is reduced, but transition band steepness becomes insufficient to meet rigorous 3GPP band requirements
Solution Approach 1:
The patent makes the filter characteristics dynamic by implementing adjustable pass bands that can be tuned to achieve the required transition band steepness. Rather than relying on high fixed Q values, the system dynamically adjusts the filter response to meet the specific requirements of different 3GPP bands, maintaining lower device complexity.
3Device complexity
If fixed pass band frequencies are used in duplexers, then device complexity is minimized, but temperature variations cause undesirable frequency shifts that degrade performance
Solution Approach 1:
The patent implements feedback mechanisms through temperature sensor circuitry that monitors the operating temperature and provides signals to adjust the filter pass band frequencies. This closed-loop system compensates for temperature-induced frequency shifts, maintaining stable frequency characteristics across varying thermal conditions without significantly increasing device complexity.
Solution Approach 2:
The patent changes the operational parameters of the filters based on temperature conditions. By programmatically adjusting the pass band frequencies in response to temperature variations, the system maintains frequency stability while keeping the physical device structure relatively simple.
4Reliability
If margin is added for manufacturing and temperature variations in SAW duplexers, then reliability is improved, but the transition band becomes excessively narrow and performance requirements cannot be met
Solution Approach 1:
The patent resolves this contradiction by making the filter pass bands dynamically adjustable, which allows the system to achieve the required transition band width for bands 2, 3, and 8 without needing excessive design margins. The programmable tuning capability provides the necessary flexibility to meet performance requirements while maintaining reliability across manufacturing variations.
Data Source
AI summary
Embodiments disclosed herein relate to programmable duplexers. The frequency pass band of the programmable duplexer is changed according to a selection of a channel-pair to control or maximize the transition band between the receiver path and the transmitter path. The programmable duplexer permits selections of desired pass bands without the need for multiple duplexer filters.Embodiments disclosed herein also relate to temperature compensating a programmable duplexer based upon one or more temperature indications. The one or more temperature indications may be based upon a temperature of a semiconductor circuit, a temperature of a substrate of a one-port resonator of the programmable duplexer, and/or a temperature of the one-port resonator. The resulting programmable duplexer has an added additional advantage of lessening the temperature variations of the programmable duplexer.