Multi-Band RF Circuit Impedance Matching Without Attenuation Poles
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Solution Overview
Problem
Existing radio-frequency circuits face increased transmission loss when simultaneously transmitting signals in multiple bands due to the formation of attenuation poles in certain frequency bands.
Innovation Solution
A radio-frequency circuit design incorporating specific filter and switch configurations, including series capacitors and inductors, to manage impedance matching across multiple bands, preventing attenuation poles and ensuring low-loss signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an impedance matching circuit including a capacitor element arranged in series is arranged between the filter for band B1/B3 and the switch to optimize the impedance in the range of band B1/B3, then the impedance matching for band B1/B3 is improved, but an optional attenuation pole is formed in the passband of band B32, resulting in an increase in the transmission loss of the signal in band B32
Solution Approach 1:
The patent divides the impedance matching function into separate circuits for different bands. The first impedance matching circuit (with capacitor C1 and inductor L1) is dedicated to bands B1/B3, while the second impedance matching circuit (with capacitor C2 and inductor L2) is dedicated to band B32. This segmentation allows each circuit to be optimized for its specific band without creating attenuation poles in other bands.
Solution Approach 2:
The patent introduces a dual impedance matching circuit configuration that acts as an intermediary between the filter and the switch. The first impedance matching circuit interfaces with bands B1/B3 while the second impedance matching circuit interfaces with band B32, mediating the impedance transformation in a way that prevents attenuation pole formation in the B32 passband.
2Device complexity
If a simple filter and switch configuration is used, then the device complexity is reduced, but the ability to simultaneously transmit signals in multiple bands with low loss is compromised
Solution Approach 1:
The patent creates a multi-functional impedance matching system where the first impedance matching circuit serves bands B1/B3 and the second impedance matching circuit serves band B32. This universal configuration enables the circuit to simultaneously handle multiple bands with low loss while maintaining a relatively compact structure.
Solution Approach 2:
The patent employs switches that can dynamically connect different signal paths for different bands. The first switch connects the common terminal to either the first terminal (for bands B1/B3) or the third terminal (for band B32), enabling dynamic adaptation to different operating conditions while maintaining low transmission loss.
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 simultaneous transmission of signals across multiple bands with reduced loss by effectively managing impedance and avoiding attenuation poles, thereby enhancing signal quality and efficiency.
Implementation Method 1
a first capacitor arranged in series in the second signal path between the second terminal and the second filter; a first inductor connected between the second signal path between the first capacitor and the second filter and ground
Data Source
AI summary
A radio-frequency circuit includes: a switch circuit having a common terminal and terminals; a signal path P1 connected to the terminal and transmitting a signal in band A; a signal path P2 connected to the terminal and transmitting a signal in band B; a filter arranged in the signal path P2; a signal path P3 connected to the terminal and transmitting a signal in band D, which can be transmitted simultaneously with band A and can be transmitted simultaneously with band B; a capacitor arranged in series in the signal path P2 between the terminal and the filter; an inductor connected between the signal path P2 between the capacitor and the filter and ground; and a switch circuit 300 having terminals, the terminal connected to the signal path P2 between the capacitor and the filter, and the terminal connected to the signal path P3.